@booklet {RID:1019161452410-70, title = {Series Resonant Converter Applied to Contactless Energy Transmission}, year = {Submitted}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev and Beatriz V. Borges and JB Klaassens} } @conference {8faff8b4f58643439b886ee1131cf1c7, title = {Development of a Control Algorithm for Three-Phase Inverter in Two-Phase Electric Drives Reducing the Number of Commutations}, booktitle = {Proceedings - 2019 1st International Conference on Control Systems, Mathematical Modelling, Automation and Energy Efficiency, SUMMA 2019}, series = {Proceedings - 2019 1st International Conference on Control Systems, Mathematical Modelling, Automation and Energy Efficiency, SUMMA 2019}, year = {2019}, note = {

The paper was powered by research grant RFBR 19-48-480001

}, month = {11}, pages = {444{\textendash}449}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Important requirements for the modern electric drives are the high overload capacity and a wide range of speed control. A two-phase adjustable low-power drive has these properties, but its implementation in small-scale mechanics is hindered by the need a frequency converter that provides a three-phase power grid into a two-phase network, which is important when the power of the mechanisms increases. Previous studies have already shown the possibility of using a typical frequency converter based on a three-phase full-bridge voltage inverter applying space-vector PWM method. The switching frequency of the inverter remains, unfortunately, relatively high. It is not possible to reduce this frequency without degrading the harmonic composition. The goal of this work is to develop an algorithm for controlling the two-phase electric drive system, while reducing the numberof commutations of the switching devices of the three-phase inverter, and at the same time keeping the deviations of the instantaneous values of the phase currents close enough to the reference.

}, keywords = {control system, relay current regulator, switching devices, three-phase bridge inverter, two-phase motor}, doi = {10.1109/SUMMA48161.2019.8947487}, author = {Belousov, {Aleksey Sergeevich} and Meshcheryakov, {Viktor Nikolayevich} and Stanimir Valtchev and Kryukov, {Oleg Viktorovich}} } @article {Valtchev2019, title = {Comparison of Spiral and Square Coil Configurations in Wireless Power Transfer System for Contactless Battery Charging}, journal = {2019 Electric Vehicles International Conference, EV 2019}, year = {2019}, note = {n/a}, abstract = {n/a}, author = {Al-Saadi, M. and S Valtchev and Romba, L. and Gon?alves, J. and Cr?ciunescu, A.} } @inbook {cefb501e407941708df06e2b152c6510, title = {Control for the Contactless Series Resonant Energy Converter}, booktitle = {Emerging Capabilities and Applications of Wireless Power Transfer}, year = {2019}, note = {n/a}, pages = {102{\textendash}140}, publisher = {IGI Global}, organization = {IGI Global}, abstract = {

This chapter presents control methods applied in the operation of the series loaded series resonant (SLSR) power converters in a most efficient operation zone. The choice of the control method is affected by the objective to guarantee suitably the efficiency, being this method in the same time, relatively easy to apply. The first part of the chapter compares three basic principles of regulation: frequency mode (FM), pulse width mode (PWM), and their combination (PWM/FM). Finally, a new method for instantaneous regulation is developed. The proposed technique consists of a simplified observation of a state variable value to limit each portion of supplied energy, depending on the requirement for power in each half period. The result of this regulation is comparable to the current mode (CM) control applied to the hard-switching power converters. The viability of this new regulation method is demonstrated by simulations of its analogue circuit implementations and experimentally proved. The circuit is also prepared for the changes in the magnetic coupling (contactless energy transfer).

}, doi = {10.4018/978-1-5225-5870-5.ch005}, author = {Stan Valtchev and Svilen Valtchev} } @inbook {51791118e689422d9c7b809e47e261c6, title = {Efficiency Improvement in Wireless Power System}, booktitle = {Emerging Capabilities and Applications of Wireless Power Transfer}, year = {2019}, note = {n/a}, pages = {23{\textendash}48}, publisher = {IGI Global}, organization = {IGI Global}, abstract = {

This chapter focuses on mid-range wireless power transfer (WPT) systems applied to electric vehicle (EV) battery chargers. The WPT is recently considered as an efficient electric energy transfer process between two or more points in space, without wiring. The technology associated with each specific process of WPT differs from case to case depending on the distance between those points and the power to be transferred between them. The widely adopted distance categories are named short-range, mid-range, and long-range. The short-range is normally defined as up to a few millimeters range. The mid-range is between a few millimeters and a few meters. The long-range distance is defined as a longer than that of the previous category, stretching up to a few kilometers.

}, doi = {10.4018/978-1-5225-5870-5.ch002}, author = {Luis Romba and Stan Valtchev} } @inbook {db8671845ba045d7908c80a86ee6a352, title = {Electromagnetic Influence of WPT on Human{\textquoteright}s Health: Modelling, Simulation, and Measurement}, booktitle = {Emerging Capabilities and Applications of Wireless Power Transfer}, year = {2019}, note = {n/a}, pages = {141{\textendash}161}, publisher = {IGI Global}, organization = {IGI Global}, abstract = {

The focus of this chapter is the electromagnetic interference (EMI) and the electromagnetic compatibility (EMC) that the wireless power transfer (WPT) systems reveal as problems. The wireless power transfer (WPT) was introduced by Nikola Tesla more than one hundred years ago, and only recently it attracted the attention of specialists, due to the improved technical means. The WPT technology now has many applications, especially for charging of various electronic devices (i.e., mobile phones, laptops, implants, and home appliances), informatics, and electronics equipment. The high-power equipment and installations (e.g., intelligent machining systems, robots, forklift trucks, and electric cars) are also getting wireless. Moreover, much attention has been focused on the electric transportation system for improving the safe and convenient charging of electric vehicle (EV) batteries.

}, doi = {10.4018/978-1-5225-5870-5.ch006}, author = {Baikova, {Elena N.} and Luis Romba and Stan Valtchev} } @article {Valtchev2019, title = {Energy saving system of cascade variable frequency induction electric drive}, journal = {E3S Web of Conferences}, volume = {124}, year = {2019}, note = {n/a}, abstract = {n/a}, author = {Meshcheryakov, V.N. and Lastochkin, D.V. and Shakurova, Z.M. and S Valtchev} } @article {Valtchev2019, title = {Minimization of the stator current in induction motor with defined load on the shaft by maintaining optimum absolute slip}, journal = {E3S Web of Conferences}, volume = {124}, year = {2019}, note = {n/a}, abstract = {n/a}, author = {Meshcheryakov, V.N. and Danilov, V.V. and Khasanov, Sh.R. and S Valtchev} } @article {Valtchev2019, title = {Three-Phase Unidirectional Transformerless Hybrid Rectifier with Boost Converter}, journal = {Proceedings - 2019 IEEE 1st Global Power, Energy and Communication Conference, GPECOM 2019}, year = {2019}, note = {n/a}, pages = {158-163}, abstract = {n/a}, author = {Goncalves, J.T. and S Valtchev and Melicio, R. and Al-Saadi, M.} } @conference {f80f432e12d445a383e469c5819af41e, title = {Asynchronous electric drive power-hardware-in-the-loop system}, booktitle = {Proceedings - 2018 17th International Ural Conference on AC Electric Drives, ACED 2018}, volume = {2018-April}, year = {2018}, note = {

Sem PDF conforme despacho.

}, month = {4}, pages = {1{\textendash}5}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Power Hardware-in-the-Loop (PHiL) system for asynchronous electric drives application based on power inverter with Field Programmable Gate Array (FPGA)-based control system is discussed. Proposed PHiL structure and scheme for asynchronous electric drives are under discussion as well. Described PHiL can be used for power inverters multi-stage testing.

}, keywords = {FPGA, HiL, induction motor, PHiL, power inverter, real-time, simulator}, doi = {10.1109/ACED.2018.8341722}, author = {Mikhail Mudrov and Anatoliy Ziuzev and Konstantin Nesterov and Stanimir Valtchev} } @conference {e748d2edd5ab459097291212c3d7fbdd, title = {Design and analysis of wireless sensor network powered through neutral to earth voltage}, booktitle = {Proceedings - 2018 17th International Ural Conference on AC Electric Drives, ACED 2018}, volume = {2018-April}, year = {2018}, note = {n/a}, month = {4}, pages = {1{\textendash}6}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

A low power wireless sensor network utilizing the neutral to earth voltage as a power source is developed and analyzed. It consists of a batteryless energy harvesting powered wireless sensor nodes, a gateway (if needed) and a local or remote server (if used). An invasive energy harvesting method to use the voltage between the neutral conductor and the ground conductor is used for the sensor module. A test network is built in a household. Statistics of the household{\textquoteright}s electric current and the corresponding neutral conductor{\textquoteright}s voltage is obtained during a two months period. The statistics is further processed to verify the working principle of the proposed network and to enlighten its strengths and weaknesses. The sensor nodes are developed using widely existing electronic components and don{\textquoteright}t require specialized devices.

}, keywords = {decentralized management, Energy Efficiency, energy harvesting, load management, Neutral to Earth Voltage, Wireless Sensor Network}, doi = {10.1109/ACED.2018.8341718}, author = {Kaloyan Mihaylov and Rumen Arnaudov and Stanimir Valtchev} } @conference {f7d13f988afd4f7ca5be287d8cce448e, title = {On reliability and energy efficiency increasing of the vehicles electric drives}, booktitle = {Proceedings - 2018 17th International Ural Conference on AC Electric Drives, ACED 2018}, volume = {2018-April}, year = {2018}, note = {n/a}, month = {4}, pages = {1{\textendash}6}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Problem of the reliability increasing of the vehicles electric drives is discussed in context of the reduction of the electric motor heating during variable character of movement. Opportunities of the induction motor stator winding heating reduction by means of the control of the vehicles electric drives in transient and steady state modes of movement are shown. Analytical expressions for dynamic torque, optimal on minimal of the winding temperature rise during acceleration, as well as expressions for dynamic torque and value of the motor torque limitation, optimal on energy consumption during acceleration are presented. It is shown that desire to reduce the stator winding temperature rise by means of dynamic torque optimal value selection or motor torque limitation can lead to the rise of energy consumption. Results of the modeling are presented.

}, keywords = {electromechanical systems, energy consumption, induction motors, insulation aging rate, land vehicles, stator winding, temperature measurement, thermodynamic model}, doi = {10.1109/ACED.2018.8341714}, author = {Braslavsky, {Isaak Ya} and Metelkov, {Vladimir P.} and Kostylev, {Alex V.} and Stanimir Valtchev} } @article {b3b33893e31041a4833839a473dedd11, title = {Electromagnetic field generated by a wireless energy transfer system: comparison of simulation to measurement}, journal = {Journal of Electromagnetic Waves and Applications}, volume = {32}, number = {5}, year = {2018}, note = {

info:eu-repo/grantAgreement/FCT/5876/147353/PT$\#$ This work is funded by Portuguese Funds through the Foundation for Science and Technology-FCT under the project LAETA 2015-2020, reference UID/EMS/50022/2013.

}, month = {3}, pages = {554{\textendash}571}, publisher = {Taylor \& Francis}, abstract = {

This paper presents a wireless energy transfer system operating at the frequency values of kHz order: modeling, simulation, and comparison with prototype measurement results. Wireless energy transfer system model using finite element method was carried out to simulate the electric field and the magnetic flux density for different air gap sizes between the transmitter and the receiver coils. Results are presented and compared with the electromagnetic emission measurements radiated by the wireless energy transfer system prototype. The electric field comparison between the simulated and the prototype measurement values shows an error of roughly 8.7{\%}. In the recent years, the interest in the wireless energy transfer technology, especially for electric vehicles batteries charging, is rapidly increasing. As a result of the increasing application of this technology in the industrial and consumer electronic products, more concerns are raised about the electromagnetic compatibility, since the wireless energy transfer systems produce electromagnetic emissions in the surrounding environment.

}, keywords = {electric field, magnetic flux density, modeling, prototype, Simulation, Wireless energy transfer}, issn = {0920-5071}, doi = {10.1080/09205071.2017.1399832}, author = {Baikova, {E. N.} and Romba, L. and Valtchev, {S. S.} and Melicio, R. and {Fern{\~a}o Pires}, V. and A. Krusteva and G. Gigov} } @conference {c8c1dc070bac4ef3a19efb92ceeb8194, title = {Power electrical drive Power-Hardware-in-the-Loop system: 2018 X International Conference on Electrical Power Drive Systems (ICEPDS)}, booktitle = {2018 10th International Conference on Electrical Power Drive Systems, ICEPDS 2018 - Conference Proceedings}, year = {2018}, note = {n/a}, month = {12}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Power Hardware-in-the-Loop (PHiL) system for electric drives application based on power converter with Field Programmable Gate Array (FPGA) -based control system which realizes in real time model of converter, motor and mechanism is discussed. Two PHiL structures are under consideration. Difference between both of them is shown. Test results obtained in the PHiLs with Converter Under Test (CUT) control system are presented in the paper. Proposed PHIL is intended for converters testing and for their operating modes studying. The PHIL repeats electric drive instantaneous current and angular velocity.

}, keywords = {FPGA, HiL, induction motor, PHiL, power inverter, real-time, simulator, vector control system, VFD}, doi = {10.1109/ICEPDS.2018.8571801}, author = {Mikhail Mudrov and Anatoliy Ziuzev and Konstantin Nesterov and Stanimir Valtchev} } @conference {a409be6dc6a34fa0bfd8ff1b7f16efdb, title = {Identification of the Common Mode Impedance of a Microgrid DC-DC Buck Converter in Normal Service and under Insulation Fault}, booktitle = {Proceedings - 2018 IEEE 18th International Conference on Power Electronics and Motion Control, PEMC 2018}, year = {2018}, note = {

Sem PDF.

}, month = {11}, pages = {1079{\textendash}1084}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

In this paper, we identify the common mode impedance of a parallel converter cell and the impact of each converter on the entire system. The study is done in two cases, favorable when all the sane converters, and degraded when at least one converter in insulation fault. We also put the distinction load type to see their effect on the propagation path. The equivalent method of the Thevenin and impedance circuit is used for the prediction electromagnetic interference generated by these converters. The good knowledge of these electromagnetic interferences allows a proper optimization of the filters (volume/efficiency), and the optimum choice of exploitation of the whole of the cell. The model is tested by PSpice simulation with a wide frequency range up to 30 MHz.

}, keywords = {common mode, component, EM disturbances, microgrid earthing system, modeling, switching}, doi = {10.1109/EPEPEMC.2018.8521856}, author = {Djelloul Bensaad and A. Hadjadj and Achour Ales and Stanimir Valtchev} } @conference {dc9361538e24425eb5ab2d0452999530, title = {An Improved Voltage Ripple Control Algorithm for Modular Multilevel Converter Based Variable Speed Drive}, booktitle = {Proceedings - 2018 IEEE 18th International Conference on Power Electronics and Motion Control, PEMC 2018}, year = {2018}, note = {n/a}, month = {11}, pages = {968{\textendash}973}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Modular Multilevel Converter (MMC) is one of the most promising topologies for high power-medium voltage application. However, the use of MMC in variable speed drive applications is still limited. This is due to the fact that the fluctuation of the submodules capacitor voltage is large at low speed constant torque operation. This paper proposes an improved balancing approach based on Space Vector Pulse Width Modulation (SVPWM). The proposed method uses only one SVPWM, which not only simplifies the calculation but also reduces the submodules capacitor fluctuation and the circulating current in the MMC, thereby allowing the operation of MMC-based variable speed drive over the entire operating speed range and improve the converter efficiency. The closed loop operation of the MMC-based variable speed drive is verified through extensive simulations.

}, doi = {10.1109/EPEPEMC.2018.8522009}, author = {Bashir, {Safia Babikir} and Zidan, {Hasan A.} and Stanimir Valtchev} } @conference {26526a4c369343d085ff988088c96d50, title = {Electric Drives Power-Hardware-in-the-Loop System Structures}, booktitle = {2018 20th European Conference on Power Electronics and Applications, EPE 2018 ECCE Europe}, year = {2018}, note = {

Sem PDF

}, month = {10}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Power-Hardware-in-the-Loop (PHiL) system for electric drives application based on power converter with Field Programmable Gate Array (FPGA)-based control system is discussed. PHiL structures are under discussion as well. During the PHiL mathematical model analysis instantaneous current repeating quality is increased. Variable frequency drive (VFD) was selected for testing.

}, keywords = {Field Programmable Gate Array (FPGA, Industrial application, Real time simulation, Simulation, Variable speed drive}, author = {Mikhail Mudrov and Anatoliy Ziuzev and Konstantin Nesterov and Stanimir Valtchev} } @conference {d75c3b9e7f1f42f2a8f74027a78059da, title = {Simulation and experiment on electric field emissions generated by wireless energy transfer}, booktitle = {Technological Innovation for Resilient Systems - 9th IFIP WG 5.5/SOCOLNET Advanced Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2018, Proceedings}, series = {IFIP Advances in Information and Communication Technology}, year = {2018}, note = {

info:eu-repo/grantAgreement/FCT/5876/147324/PT$\#$ This work was funded in part by the Center of Technology and Systems of Uninova and the Portuguese FCT-PEST program UID/EEA/00066/2013.

}, month = {1}, pages = {243{\textendash}251}, publisher = {Springer New York LLC}, organization = {Springer New York LLC}, abstract = {

This paper presents a wireless energy transfer (WET) system operating at the frequency of tens of kHz. It treats the modeling and simulation of WET prototype and its comparison with experimental measuring results. The wireless energy transfer system model was created to simulate the electric field between the emitting and the receiving coils, applying the finite element method. The results from the simulation are compared to the measured values of the electric field emission from the wireless energy transfer equipment. In the recent years the interest in the WET technology, especially for the electric vehicles (EV) batteries charging, is rapidly growing. The WET systems pollute the environment by electromagnetic emissions. Due to the expanding use of this technology in industrial and consumer electronics products, the problems associated with the electromagnetic compatibility (EMC), and the adverse impact on the human health becomes highly important.

}, keywords = {electric field, modeling, prototype, Simulation, Wireless energy transfer}, isbn = {9783319785738}, doi = {10.1007/978-3-319-78574-5_23}, author = {Baikova, {E. N.} and Romba, L. and Melicio, R. and Valtchev, {S. S.}}, editor = {Camarinha-Matos, {L. M.} and Adu-Kankam, {K. O.} and M. Julashokri} } @conference {3ba0f79f2eaf4b878d419b785a6801e4, title = {Wireless battery charger for EV with circular or planar coils: comparison}, booktitle = {Technological Innovation for Resilient Systems - 9th IFIP WG 5.5/SOCOLNET Advanced Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2018, Proceedings}, series = {IFIP Advances in Information and Communication Technology}, year = {2018}, note = {n/a}, month = {1}, pages = {214{\textendash}223}, publisher = {Springer New York LLC}, organization = {Springer New York LLC}, abstract = {

This paper presents the experimental results obtained in the wireless energy transfer (WET) system prototype based on coils: circular or planar. With these experimental results we can choose the tuning settings to improve the efficiency of power transmission of the WET systems. In WET for electric vehicle batteries charging, the coil shape and the range between the coils are the most important issues of those systems.

}, keywords = {Circular coil, Magnetic coupling, Planar coil, V2B, V2G, V2H, Wireless energy transfer}, isbn = {9783319785738}, doi = {10.1007/978-3-319-78574-5_20}, author = {Romba, L. and Baikova, {E. N.} and Borges, C. and Melicio, R. and Valtchev, {S. S.}}, editor = {Camarinha-Matos, {L. M.} and Adu-Kankam, {K. O.} and M. Julashokri} } @conference {d36b7e74c8694e1ab9c7362a255403bc, title = {Perspectives and Trends of Electric Vehicle Development with Wireless Charging System}, booktitle = {1st International Conference on Infocommunications and Intelligent Transport Technologies (IITT{\textasciiacute}2018). Proceedings}, year = {2018}, note = {n/a}, pages = {235{\textendash}241}, publisher = {Lipetsk State Technical University}, organization = {Lipetsk State Technical University}, abstract = {n/a}, author = {O. Mescheryakova and Mescheryakov, {Viktor Nikolaevich} and Stan Valtchev} } @article {Cavalheiro_2018, title = {Prospects of Tunnel {FETs} in the Design of Power Management Circuits for Weak Energy Harvesting {DC} Sources}, journal = {{IEEE} Journal of the Electron Devices Society}, volume = {6}, year = {2018}, note = {n/a}, pages = {382{\textendash}391}, publisher = {Institute of Electrical and Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/jeds.2018.2808950}, url = {https://doi.org/10.1109\%2Fjeds.2018.2808950}, author = {David Nunes Cavalheiro and Francesc Moll and Stanimir Valtchev} } @article {Valtchev2018, title = {Ultra-Low input power conversion circuits based on TFETs}, journal = {Ultra-Low Input Power Conversion Circuits based on TFETs}, year = {2018}, note = {n/a}, pages = {1-171}, abstract = {n/a}, author = {Cavalheiro, D. and Moll, F. and S Valtchev} } @book {201f498759214a42b710e8bff00c570c, title = {Ultra-Low Input Power Conversion Circuits based on Tunnel-FETs}, year = {2018}, note = {n/a}, publisher = {River Publishers}, organization = {River Publishers}, abstract = {n/a}, isbn = {9788793609761}, author = {David Cavalheiro and Francesc Moll and Stan Valtchev} } @conference {fe37cd52ff5942108718e4676b899963, title = {Wireless Energy and Low-Voltage DC Grids, Two Faces of Same Coin}, booktitle = {2018 IEEE 2nd International Electrical and Energy Conference (CIEEC)}, year = {2018}, note = {n/a}, publisher = {IEEE}, organization = {IEEE}, abstract = {n/a}, author = {Stan Valtchev} } @conference {a9c192b7fbec4ee99f1bf8a5ac118c65, title = {FPGA-based Hardware-in-the-Loop system bits capacity evaluation based on induction motor model}, booktitle = {Conference Proceedings - 2017 17th IEEE International Conference on Environment and Electrical Engineering and 2017 1st IEEE Industrial and Commercial Power Systems Europe, EEEIC / I and CPS Europe 2017}, year = {2017}, note = {

sem pdf conforme despacho.

}, month = {7}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

The Hardware-in-the-Loop (HiL) systems become nowadays popular. In the same time, the Field Programmable Gate Arrays (FPGAs) allow for creating the HiL with time step 1 μs or less. The FPGA usually executes the numerical operations on Fixed Point variables. That is why during the FPGA-based HiL creation process it is important to select a proper number of bits for the modeled variables. A mathematical model based on the induction motor is selected as a basis for comparative tests between the floating point model and the fixed point model. In consequence, recommendations for the Bit Capacity (the length of the digital word) selection are given, based on the obtained results.

}, keywords = {FPGA, HiL, HiL accuracy, induction motor, Real-time simulating}, doi = {10.1109/EEEIC.2017.7977827}, author = {Mikhail Mudrov and Anatoliy Zyuzev and Konstantin Nesterov and Stanimir Valtchev} } @conference {77a5fb0146684cf2901f30cfbdbdd846, title = {Hardware-in-The-loop system numerical methods evaluation based on brush DC-motor model}, booktitle = {Proceedings - 2017 International Conference on Optimization of Electrical and Electronic Equipment, OPTIM 2017 and 2017 Intl Aegean Conference on Electrical Machines and Power Electronics, ACEMP 2017}, year = {2017}, note = {

sem pdf conforme despacho.

}, month = {7}, pages = {428{\textendash}433}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Hardware-in-The-loop (HiL) systems nowadays become popular. During the HiL creation process it is important to select a proper numerical method because the accuracy of the process simulation, in case of the HiL, depends on the correct numerical approach selection. That is why it is important to evaluate the most popular numerical approaches. The {"}Sequential{"} Euler (solves equations step-by-step), the Forward Euler (the most popular method for HiL creators), and the Second-order Adams-Bashforth approach are under consideration. A mathematical model based on the DC-motor with independent excitation is selected as a basis for the experimental numerical calculation. In consequence, recommendations for the numerical method selection are given, based on the obtained results.

}, keywords = {DC-motor, Hardware-in-The-loop, Numerical approach, Real-Time simulation}, doi = {10.1109/OPTIM.2017.7975007}, author = {Mikhail Mudrov and Anatoliy Zyuzev and Nesterov Konstantin and Stanimir Valtchev and Svilen Valtchev} } @conference {451fb3d8a1e1410a874872859df80b4b, title = {Mechanical vibration using piezoelectric material}, booktitle = {Proceedings - 2017 International Conference on Optimization of Electrical and Electronic Equipment, OPTIM 2017 and 2017 Intl Aegean Conference on Electrical Machines and Power Electronics, ACEMP 2017}, year = {2017}, note = {

sem pdf conforme despacho.

}, month = {7}, pages = {681{\textendash}686}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

Piezoelectric energy harvesting has received great attention over the last 20 years. The main goal of this work is to discuss the potential advantages of introducing non-linearities in the dynamics of a beam type piezoelectric vibration energy harvester. The described device is essentially a cantilever beam partially covered by piezoelectric material with a force electromagnetically applied to the beam. Through experimental tests it has been confirmed the benefits of introducing non-linearities in these types of systems.

}, doi = {10.1109/OPTIM.2017.7975047}, author = {Sofia Ferreira and Stanimir Valtchev and Coito, Fernando and Mikhail Mudrov} } @conference {42cc475c70b34d5a98abc3a1efa98049, title = {Solar thermoelectric system with biomass back-up}, booktitle = {Technological Innovation for Smart Systems - 8th IFIP WG 5.5/SOCOLNET Advanced Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2017, Proceedings}, series = {IFIP Advances in Information and Communication Technology}, year = {2017}, note = {

sem pdf.

}, month = {1}, pages = {358{\textendash}369}, publisher = {Springer New York LLC}, organization = {Springer New York LLC}, abstract = {

With the objective of having a solar thermoelectric system, running for 24 h a day along the different seasons of the year it is necessary to dimension the adequate storage and back-up systems. The choice of the back-up source of energy depends on how sustainable the power plant should be. In this study, the choice was the use of biomass in order to have a 100{\%} renewable power plant. The selected site was the Alentejo region (Portugal). The local Direct Normal Irradiation (DNI) data was used to simulate with the System Advisor Model program (SAM) considering a solar system with north field and molten salt storage. The system needs no back-up during three months in a year. The use of biomass pellets is a viable alternative because it makes the power plant 100{\%} renewable and dispatchable without loss of energy due to over-dimension of the expensive solar field and molten storage system.

}, keywords = {Backup, Biomass, Pellets, Solar, Thermoelectric}, isbn = {978-3-319-56077-9}, doi = {10.1007/978-3-319-56077-9_35}, author = {Gon{\c c}alves, {Jos{\'e} Teixeira} and Camus, {Cristina In{\^e}s} and Valtchev, {Stanimir Stoyanov}} } @article {9e5d14fb82c4487d9100a66282db7c25, title = {TFET-Based Power Management Circuit for RF Energy Harvesting}, journal = {IEEE Journal of the Electron Devices Society}, volume = {5}, number = {1}, year = {2017}, note = {

sem pdf conforme despacho. ERDF TEC2013-45638-C3-2-R

}, month = {1}, pages = {7{\textendash}17}, publisher = {Institute of Electrical and Electronics Engineers}, abstract = {

This paper proposes a Tunnel FET (TFET)-based power management circuit (PMC) for ultra-low power RF energy harvesting applications. In contrast with conventional thermionic devices, the band-to-band tunneling mechanism of TFETs allows a better switching performance at sub-0.2 V operation. As a result, improved efficiencies in RF-powered circuits are achieved, thanks to increased rectification performance at low power levels and to the reduced energy required for a proper PMC operation. It is shown by simulations that heterojunction TFET devices designed with III-V materials can improve the rectification process at received power levels below-20 dBm (915 MHz) when compared to the application of homojunction III-V TFETs and Si FinFETs. For an available power of-25 dBm, the proposed converter is able to deliver 1.1 $μ }\text{W}$ of average power (with 0.5 V) to the output load with a boost efficiency of 86{\%}.

}, keywords = {energy harvesting, power management, radio-frequency, tunnel FET, UHF, ultra-low power}, issn = {2168-6734}, doi = {10.1109/JEDS.2016.2619908}, author = {David Cavalheiro and Francesc Moll and Stanimir Valtchev} } @conference {14984870e5774f6fbe0a2d3da9758f26, title = {Designing the control system with relay current regulator principle for general purpose industrial AC motor drive control}, booktitle = {12th International Scientific and Practical Conference {\textquotedblleft}Modern Complex Control Systems 2017{\textquotedblright}, Proceedings}, volume = {2}, year = {2017}, note = {n/a}, pages = {97{\textendash}102}, publisher = {Russian Academy of Sciences}, organization = {Russian Academy of Sciences}, abstract = {n/a}, isbn = {978-588247-826-0}, author = {Stan Valtchev and Vladimir Ivashkin} } @conference {4e1bed4aaea64f939b70da0966dc32b8, title = {Designing the universal vector control system with relay current regulator principle for general purpose industrial AC motor drive control}, booktitle = {12th International Scientific and Practical Conference {\textquotedblleft}Modern Complex Control Systems 2017{\textquotedblright}, Proceedings}, volume = {2}, year = {2017}, note = {n/a}, pages = {320{\textendash}330}, publisher = {Russian Academy of Sciences}, organization = {Russian Academy of Sciences}, abstract = {n/a}, author = {Victor Mesherayakov and Vladimir Voekov and Vladimir Ivashkin and Stan Valtchev} } @conference {1532d047ee774e23a295a59d1d7807ff, title = {Electric vehicle battery charger controlled by magnetic core reactor to Wireless Power Transfer system}, booktitle = {Conference Proceedings - 2017 17th IEEE International Conference on Environment and Electrical Engineering and 2017 1st IEEE Industrial and Commercial Power Systems Europe, EEEIC / I and CPS Europe 2017}, year = {2017}, note = {

Sem PDF.

}, publisher = {Institute of Electrical and Electronics Engineers Inc.}, organization = {Institute of Electrical and Electronics Engineers Inc.}, address = {United States}, abstract = {

This paper presents a control process and frequency adjustment based on the Magnetic Core Reactor prototype. For the past decades, there has been significant development in the technologies used in Wireless Power Transfer systems. In the Wireless Power Transfer systems it is essential that the operating frequency of the primary circuit be equal to the resonant frequency of the secondary circuit so there is the maximum energy transfer. The Magnetic Core Reactor allows controlling of the frequencies on both sides of the transmission and reception circuits. In addition, the assembly diagrams and test results are presented.

}, keywords = {Electric vehicles, Magnetic core reactor, Strongly coupled magnetic resonance, Wireless power transfer}, doi = {10.1109/EEEIC.2017.7977782}, author = {Romba, {L. F.} and Valtchev, {S. S.} and Melicio, R. and Mudrov, {M. V.} and Ziuzev, {A. M.}} } @article {Valtchev2017, title = {Insights into Tunnel FET-Based Charge Pumps and Rectifiers for Energy Harvesting Applications}, journal = {IEEE Transactions on Very Large Scale Integration (VLSI) Systems}, volume = {25}, number = {3}, year = {2017}, note = {n/a}, pages = {988-997}, abstract = {n/a}, author = {Cavalheiro, D. and Moll, F. and S Valtchev} } @conference {bc9346ce8de34843b9f67bf57b37ec04, title = {Single-phase wireless power transfer system controlled by magnetic core reactors at transmitter and receiver}, booktitle = {Technological Innovation for Smart Systems - 8th IFIP WG 5.5/SOCOLNET Advanced Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2017, Proceedings}, series = {IFIP Advances in Information and Communication Technology}, year = {2017}, note = {

Sem PDF.

}, pages = {419{\textendash}428}, publisher = {Springer New York LLC}, organization = {Springer New York LLC}, abstract = {

The applications of wireless power transmission have become widely increasing over the last decade, mainly in the battery charging systems for electric vehicles. This paper focuses on the single-phase wireless power transfer prototype controlled by magnetic core reactors in either side of the system: that of the transmitter, and that of the receiver. The described wireless power transfer system prototype employs a strong magnetic coupling technology to improve the power transmission efficiency. In the same time, a magnetic core reactor is used to control the {\textquotedblleft}tuning{\textquotedblright} between the transmitter and the receiver frequencies, allowing for that increase of the system efficiency. Finally, practical results of the implemented prototype are presented.

}, keywords = {Magnetic core reactor, Strongly magnetic coupling, Wireless power transfer}, isbn = {9783319560762}, doi = {10.1007/978-3-319-56077-9_41}, author = {Luis Romba and Valtchev, {Stanimir S.} and Rui Mel{\'\i}cio} } @article {a13a3abe7ece4089864a93e712734759, title = {Three-phase magnetic field tested in wireless power transfer system}, journal = {International Review of Electrical Engineering}, volume = {11}, number = {6}, year = {2016}, note = {

sem pdf.

}, month = {1}, pages = {586{\textendash}597}, publisher = {Praise Worthy Prize}, abstract = {

This paper presents a magnetic field three dimensional mapping produced by a threephase prototype for wireless power transfer. The presented magnetic field mapping is a contribution to improve the design of electric vehicles battery chargers using the wireless power transfer. To collect the magnetic field data, a prototype was built, in order to support the tests. The prototype primary is an electrical three-phase system that allows to be connected electrically and geometrically in star or delta. The losses due to the magnetic field dispersion and the generated interferences in the surrounding equipment or in human body are discussed. The different standards organizations related to electric vehicles battery chargers are presented. Finally the magnetic field influence on the human body is addressed.

}, keywords = {Battery chargers, Electromagnetic compatibility, Magnetic field, Wireless power transfer}, issn = {1827-6660}, doi = {10.15866/iree.v11i6.9889}, author = {Luis Romba and Valtchev, {Stanimir S.} and Rui Mel{\'\i}cio} } @article {Valtchev2016, title = {A battery-less, self-sustaining RF energy harvesting circuit with TFETs for ?w power applications}, journal = {14th IEEE International NEWCAS Conference, NEWCAS 2016}, year = {2016}, note = {n/a}, abstract = {n/a}, author = {Cavalheiro, D. and Moll, F. and S Valtchev} } @article {Valtchev2016, title = {A comparison of TFET rectifiers for RF energy harvesting applications}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {14-19}, abstract = {n/a}, author = {Cavalheiro, D. and Moll, F. and S Valtchev} } @article {Valtchev2016, title = {Designing the universal vector control system with relay current regulator principle for general purpose industrial AC motor drive control}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {680-685}, abstract = {n/a}, author = {Mesherayakov, V. and Voekov, V. and Ivashkin, V. and S Valtchev} } @conference {949de8ceef3346c4a8b9f64365a15137, title = {Electric Vehicle Battery Charger: Wireless Power Transfer System Controlled by Magnetic Core Reactor}, booktitle = {CETC2016 - Conference on Electronics, Telecommunications and Computers, Proceedings}, year = {2016}, note = {n/a}, publisher = {ISEL - Instituto Superior de Engenharia de Lisboa}, organization = {ISEL - Instituto Superior de Engenharia de Lisboa}, abstract = {n/a}, author = {Luis Romba and Stan Valtchev and Melicio, R.} } @conference {d4668e54da4745299d289f6b314052e6, title = {Electromagnetic Emissions from Wireless Power Transfer System}, booktitle = {CETC2016 - Conference on Electronics, Telecommunications and Computers, Proceedings}, year = {2016}, note = {n/a}, publisher = {ISEL - Instituto Superior de Engenharia de Lisboa}, organization = {ISEL - Instituto Superior de Engenharia de Lisboa}, abstract = {n/a}, author = {Baikova, {E. N.} and Romba, {L. F.} and Stan Valtchev and Rui Mel{\'\i}cio and {Fern{\~a}o Pires}, V.} } @conference {9ae4dc3c60cc45f1b02a445e85ad85a7, title = {Electromagnetic Interference from a Wireless Power Transfer System: Experimental Results}, year = {2016}, note = {

Sem PDF.; International Conference on Renewable Energies and Power Quality , ICREPQ{\textquoteright}16 ; Conference date: 04-05-2016 Through 06-05-2016

}, abstract = {n/a}, author = {Stan Valtchev} } @conference {99b74044d94d40fd89ccd72251ee95ac, title = {Electromagnetic Interference from a Wireless Power Transfer System: Experimental Results}, year = {2016}, note = {

International Conference on Renewable Energies and Power Quality , ICREPQ{\textquoteright}16 ; Conference date: 04-05-2016 Through 06-05-2016

}, abstract = {n/a}, author = {Baikova, {E. N.} and Stan Valtchev and Rui Mel{\'\i}cio} } @conference {99b74044d94d40fd89ccd72251ee95ac, title = {Electromagnetic Interference from a Wireless Power Transfer System: Experimental Results}, year = {2016}, note = {

International Conference on Renewable Energies and Power Quality , ICREPQ{\textquoteright}16 ; Conference date: 04-05-2016 Through 06-05-2016

}, abstract = {n/a}, author = {Baikova, {E. N.} and Stan Valtchev and Rui Mel{\'\i}cio} } @inbook {Baikova_2016, title = {Electromagnetic Interference Impact of Wireless Power Transfer System on Data Wireless Channel}, booktitle = {Technological Innovation for Cyber-Physical Systems}, year = {2016}, note = {n/a}, pages = {293{\textendash}301}, publisher = {Springer Science $\mathplus$ Business Media}, organization = {Springer Science $\mathplus$ Business Media}, abstract = {n/a}, doi = {10.1007/978-3-319-31165-4_29}, url = {http://dx.doi.org/10.1007/978-3-319-31165-4_29}, author = {Elena N. Baikova and Stanimir S. Valtchev and Rui Mel{\'{\i}}cio and V{\'{\i}}tor M. Pires} } @article {Valtchev2016, title = {Electronic differential for electric vehicle with evenly split torque}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {1204-1209}, abstract = {n/a}, author = {Folgado, J. and SS Valtchev and Coito, F.} } @conference {a17b1f9c7f1b4455b97e22d0b59709f0, title = {Energy harvesting: an interesting topic for education programs in engineering specialities}, booktitle = {Proceedings of the tenth international scientific-practical conference {\guillemotleft}Internet-Education-Science{\guillemotright} (IES-2016)}, year = {2016}, note = {n/a}, pages = {149{\textendash}156}, publisher = {ВНТУ}, organization = {ВНТУ}, abstract = {

Nowadays some possible alternative methods to replace the batteries as power source, or to achieve better maintenance of existing (or smaller) batteries, are the so called Energy Harvesting (EH) methods, i.e. to obtain energy from the environment or recover and store energy generated by the human body in its usual activities. However, this requires specific technology and materials and usually a multidisciplinary team. For this reason, inclusion a topic on energy harvesting in educational programs of several engineering specialties at technical universities is of great importance.In this paper we present some results from interdisciplinary collaboration at Faculty of Science and Technology at Nova University of Lisbon on the energy harvesting. Experiments were performed in order to calculate the power that could be generated from the chest movements during breathing and from the feet during walking, etc. For the experiments, mostly piezoelectric effect was explored.

}, isbn = {978-966-641-646-2}, author = {Vassilenko, Valentina and Stan Valtchev and Pamies-Teixeira, {Jorge Joaquim} and Serhii Pavlov} } @article {Valtchev2016, title = {Experimental study of wireless inductive system for electric vehicles batteries charging}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {286-290}, abstract = {n/a}, author = {G. Gigov and A. Krusteva and S Valtchev} } @article {Valtchev2016, title = {Improving magnetic coupling for battery charging through 3D magnetic flux}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {291-297}, abstract = {n/a}, author = {Jorge, L.F.R. and SS Valtchev and Melicio, R.} } @article {Valtchev2016, title = {The mathematical modeling of alternating current electric drive with DC-DC converter and ultracapacitors}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {511-515}, abstract = {n/a}, author = {Braslavsky, I. and Plotnikov, I. and S Valtchev} } @article {Valtchev2016, title = {Modeling and supervisory control of a virtual X8-VB quadcopter}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {686-693}, abstract = {n/a}, author = {Brito, V. and Palma, L. B. and Coito, F. V. and S Valtchev} } @article {Valtchev2016, title = {Some aspects of the reliability increasing of the transport electric drives}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {706-710}, abstract = {n/a}, author = {Braslavsky, I.Y. and Metelkov, V.P. and S Valtchev and Esaulkova, D.V. and Kostylev, A.V. and Kirillov, A.V.} } @article {Valtchev2016, title = {Study of the electromagnetic interference generated by wireless power transfer systems}, journal = {International Review of Electrical Engineering}, volume = {11}, number = {5}, year = {2016}, note = {n/a}, pages = {526-534}, abstract = {n/a}, author = {Baikova, E.N. and SS Valtchev and Melicio, R. and A. Krusteva and Fern{\~a}o Pires, V.} } @article {Valtchev2016, title = {Study on electromagnetic emissions from wireless energy transfer}, journal = {Proceedings - 2016 IEEE International Power Electronics and Motion Control Conference, PEMC 2016}, year = {2016}, note = {n/a}, pages = {492-497}, abstract = {n/a}, author = {Baikova, E.N. and SS Valtchev and Melicio, R. and V. F. Pires and A. Krusteva and G. Gigov} } @article {Valtchev2016, title = {Three-phase magnetic field system for wireless energy transfer}, journal = {2016 International Symposium on Power Electronics, Electrical Drives, Automation and Motion, SPEEDAM 2016}, year = {2016}, note = {n/a}, pages = {73-78}, abstract = {n/a}, author = {Romba, L.F. and SS Valtchev and Melicio, R.} } @conference {55f43cd9a1884aac85b2bdb6edd30b56, title = {Wireless Energy Transfer with Three-Phase Magnetic Field System: Experimental Results}, year = {2016}, note = {

Sem PDF.; International Conference on Renewable Energies and Power Quality , ICREPQ{\textquoteright}16 ; Conference date: 04-05-2016 Through 06-05-2016

}, abstract = {n/a}, author = {Luis Romba and Stan Valtchev and Rui Mel{\'\i}cio} } @conference {55f43cd9a1884aac85b2bdb6edd30b56, title = {Wireless Energy Transfer with Three-Phase Magnetic Field System: Experimental Results}, year = {2016}, note = {

Sem PDF.; International Conference on Renewable Energies and Power Quality , ICREPQ{\textquoteright}16 ; Conference date: 04-05-2016 Through 06-05-2016

}, abstract = {n/a}, author = {Luis Romba and Stan Valtchev and Rui Mel{\'\i}cio} } @article {Valtchev2016, title = {Wireless power transfer impact on data channel}, journal = {2016 International Symposium on Power Electronics, Electrical Drives, Automation and Motion, SPEEDAM 2016}, year = {2016}, note = {n/a}, pages = {582-587}, abstract = {n/a}, author = {Baikova, E.N. and SS Valtchev and Melicio, R. and V. F. Pires} } @conference {Mihaylov_2015, title = {Smart microgrid sensorless load monitoring and management in {TN}-S and {TN}-C-S electrical networks}, booktitle = {2015 International Conference on Electrical Drives and Power Electronics ({EDPE})}, year = {2015}, note = {n/a}, month = {sep}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/edpe.2015.7325288}, url = {http://dx.doi.org/10.1109/edpe.2015.7325288}, author = {Kaloyan Mihaylov and Stanimir Valtchev and Rumen Arnaudov} } @conference {Mihaylov_2015, title = {Sensorless load monitoring and management in electric power grid through energy harvesting}, booktitle = {2015 International Conference on Renewable Energy Research and Applications ({ICRERA})}, year = {2015}, note = {n/a}, month = {nov}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/icrera.2015.7418667}, url = {http://dx.doi.org/10.1109/icrera.2015.7418667}, author = {Kaloyan Mihaylov and Stanimir Valtchev and Rumen Arnaudov} } @conference {Cavalheiro_2015, title = {Pespectives of {TFET} devices in ultra-low power charge pumps for thermo-electric energy sources}, booktitle = {2015 {IEEE} International Symposium on Circuits and Systems ({ISCAS})}, year = {2015}, note = {n/a}, month = {may}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/iscas.2015.7168825}, url = {http://dx.doi.org/10.1109/iscas.2015.7168825}, author = {David Cavalheiro and Francesc Moll and Stanimir Valtchev} } @conference {Cavalheiro_2015, title = {Tunnel {FET} device characteristics for {RF} energy harvesting passive rectifiers}, booktitle = {2015 {IEEE} 13th International New Circuits and Systems Conference ({NEWCAS})}, year = {2015}, note = {n/a}, month = {jun}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/newcas.2015.7182102}, url = {http://dx.doi.org/10.1109/newcas.2015.7182102}, author = {David Cavalheiro and Francesc Moll and Stanimir Valtchev} } @conference {Cavalheiro_2015, title = {Novel {UHF} Passive Rectifier with Tunnel {FET} Devices}, booktitle = {2015 {IEEE} Computer Society Annual Symposium on {VLSI}}, year = {2015}, note = {n/a}, month = {jul}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/isvlsi.2015.57}, url = {http://dx.doi.org/10.1109/isvlsi.2015.57}, author = {David Cavalheiro and Francesc Moll and Stanimir Valtchev} } @conference {Stanimir_Valtchev23904136, title = {400V DC Supply Discussed Once Again, and Unavoidable (more efficient, more reliable, safer)}, booktitle = {Symposium INTELEC95, Presentation and publication of article, available to authorized industry and academy participants, Zaltbommel}, year = {2015}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23904179, title = {Investigation of the Tesla Transformer as a Device for One-Wire Power and Signaling and as a Device for Power and Signaling through the Ground}, booktitle = {Advanced Doctoral Conference DOCEIS, Caparica}, year = {2015}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @inbook {Mihaylov_2015, title = {Investigation of the Tesla Transformer as a Device for One-Wire Power and Signaling and as a Device for Power and Signaling Through the Ground}, booktitle = {{IFIP} Advances in Information and Communication Technology}, year = {2015}, note = {n/a}, pages = {459{\textendash}466}, publisher = {Springer Science $\mathplus$ Business Media}, organization = {Springer Science $\mathplus$ Business Media}, abstract = {n/a}, doi = {10.1007/978-3-319-16766-4_49}, url = {http://dx.doi.org/10.1007/978-3-319-16766-4_49}, author = {Kaloyan Mihaylov and Rui Neves-Medeiros and Rumen Arnaudov and Stanimir Valtchev} } @conference {Stanimir_Valtchev23887748, title = {Novel Charge Pump Converter with Tunnel FET Devices for Ultra-Low Power Energy Harvesting Sources}, booktitle = {MWSCAS, Fort Collins, Colorado}, year = {2015}, note = {n/a}, abstract = {n/a}, doi = {10.1109/MWSCAS.2015.7282034}, url = {http://doi.org/10.1109/MWSCAS.2015.7282034}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23903999, title = {Resonant Power Converters in Contactless Energy Transfer: Electric Vehicle and Renewable Energy Processing, Invited Speech}, booktitle = {XVIth International Scientific Technical Conference Alternating Current Electric Drives (ACED), pp. 195-200}, year = {2015}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23904047, title = {Resonant Power Converters in Electromagnetic Energy Transfer, Invited Speech}, booktitle = {12th International Conference on Applied Electromagnetics \cyrchar\CYRP\cyrchar\CYRE\cyrchar\CYRS 2015, proceedings pp. 103-108}, year = {2015}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Habibullin_2014, title = {Active power filter with common {DC} link for compensation of harmonic distortion in power grids}, booktitle = {2014 16th International Power Electronics and Motion Control Conference and Exposition}, year = {2014}, note = {n/a}, month = {sep}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/epepemc.2014.6980700}, url = {http://dx.doi.org/10.1109/epepemc.2014.6980700}, author = {Maksim Habibullin and Vladimir Pikalov and Viktor Mescheryakov and Stanimir Valtchev} } @conference {Valtchev_2014, title = {Conversion of wind-induced vibrations into electricity}, booktitle = {2014 {IEEE} 36th International Telecommunications Energy Conference ({INTELEC})}, year = {2014}, note = {n/a}, month = {sep}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/intlec.2014.6972170}, url = {http://dx.doi.org/10.1109/intlec.2014.6972170}, author = {Stanimir Valtchev and Joana Almeida and Jorge P. Teixeira and J. Ben Klaassens} } @conference {Mihaylov_2014, title = {Energy harvesting from the voltage drop in {TN}-S, {TN}-C-S and other consumer electric networks}, booktitle = {2014 16th International Power Electronics and Motion Control Conference and Exposition}, year = {2014}, note = {n/a}, month = {sep}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/epepemc.2014.6980699}, url = {http://dx.doi.org/10.1109/epepemc.2014.6980699}, author = {Kaloyan Mihaylov and Rumen Arnaudov and Stanimir Valtchev} } @conference {Valtchev_2014, title = {A wireless energy transceiver based on induction heating equipment}, booktitle = {2014 16th International Power Electronics and Motion Control Conference and Exposition}, year = {2014}, note = {n/a}, month = {sep}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/epepemc.2014.6980642}, url = {http://dx.doi.org/10.1109/epepemc.2014.6980642}, author = {Stanimir Valtchev and Rui Neves-Medeiros and Anastassia Krusteva and George Gigov and Plamen Avramov} } @conference {814faa3b3dc54a37b13ec749e6ff8a7d, title = {Perspectives of Tunnel FET (TFET) in Ultra-Low- Power Analog-Circuit design}, booktitle = {Proceedings of the XVIII Conference on the Design of Circuits and Integrated Systems Donostia - San Sebasti{\'a}n, Nov. 2013}, year = {2014}, note = {n/a}, month = {1}, pages = {152{\textendash}157}, abstract = {

The improved characteristics of Tunnel FETs (TFETs) like steep sub-threshold swing and low off-currents make them an attractive choice for low power operations compared to MOSFETs and Multi-gate FETs like FINFETs. Such characteristics are favorable to digital design, but the drain current saturation in their output characteristics can also benefit the analog design. In this paper, it is shown by simulations that analog characteristics as voltage gain, power consumption and bandwidth are improved using TFETs compared to their counterparts, at a sub-22 nm technology node and 0.8 V supply voltage.

}, keywords = {Analog design, Common source amplifier, FINFET, Output resistance, Tunnel FET (TFET), ultra-low power}, isbn = {978-84-8081-401-0}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {Stanimir_Valtchev23898745, title = {The Active Power Filter with Relay Current Regulator and a Common DC Link for Compensation of Harmonic Distortion in Power Networks}, booktitle = {DOCEIS{{\textquoteright}}14 Conference}, year = {2014}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @inbook {Habibullin_2014, title = {Active Power Filter with Relay Current Regulator and Common {DC} Link for Compensation of Harmonic Distortion in Power Grids}, booktitle = {Technological Innovation for Collective Awareness Systems}, year = {2014}, note = {n/a}, pages = {427{\textendash}434}, publisher = {Springer Science $\mathplus$ Business Media}, organization = {Springer Science $\mathplus$ Business Media}, abstract = {n/a}, doi = {10.1007/978-3-642-54734-8_47}, url = {http://dx.doi.org/10.1007/978-3-642-54734-8_47}, author = {Maksim Maratovich Habibullin and Igor Sergeevich Pavlov and Viktor Nikolaevich Mescheryakov and Stanimir Valtchev} } @conference {Stanimir_Valtchev23921330, title = {Experimental study on induction heating equipment applied in wireless energy transfer for smart grids}, booktitle = {DOCEIS{{\textquoteright}}14 Conference, Caparica,}, year = {2014}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @book {Stanimir_Valtchev23877834, title = {Experimental study on induction heating equipment applied in wireless energy transfer for smart grids}, series = {IFIP Advances in Information and Communication Technology}, year = {2014}, note = {n/a}, abstract = {n/a}, doi = {10.1007/978-3-642-54734-8\_54}, url = {http://doi.org/10.1007/978-3-642-54734-8\_54}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23904447, title = {Regulation and Command Systems in Power Converters, Especially The Resonant (and Wireless Energy) Converters, Key-note Speech}, booktitle = {12th International Conference on Development and Application Systems (DAS), Suceava}, year = {2014}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921324, title = {Renewable Energy + Telecommunications = Smart Grid}, booktitle = {Symposium INTELEC95, Presentation and on-line publication of article, available to authorized industry and academy participants}, year = {2014}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23904450, title = {Renewable Energy and Telecommunications in Smart Grid}, booktitle = {EU Joint Research Centre (JRC) Workshop on Costs, Benefits and Impact Assessment of Smart Grids for Europe and Beyond, Antalya}, year = {2014}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921334, title = {Resonant Power Conversion through a Saturable Reactor}, booktitle = {DOCEIS{{\textquoteright}}14 Conference, Caparica}, year = {2014}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @inbook {Jorge_2014, title = {Resonant Power Conversion through a Saturable Reactor}, booktitle = {Technological Innovation for Collective Awareness Systems}, year = {2014}, note = {n/a}, pages = {461{\textendash}469}, publisher = {Springer Science $\mathplus$ Business Media}, organization = {Springer Science $\mathplus$ Business Media}, abstract = {n/a}, doi = {10.1007/978-3-642-54734-8_51}, url = {http://dx.doi.org/10.1007/978-3-642-54734-8_51}, author = {Luis Jorge and Stanimir Valtchev and Coito, Fernando} } @conference {Stanimir_Valtchev23921328, title = {Tracking a mobile robot position using vision and inertial sensor}, booktitle = {DOCEIS{{\textquoteright}}14 Conference, Caparica}, year = {2014}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @inbook {Coito_2014, title = {Tracking a Mobile Robot Position Using Vision and Inertial Sensor}, booktitle = {Technological Innovation for Collective Awareness Systems}, year = {2014}, note = {n/a}, pages = {201{\textendash}208}, publisher = {Springer Science $\mathplus$ Business Media}, organization = {Springer Science $\mathplus$ Business Media}, abstract = {n/a}, doi = {10.1007/978-3-642-54734-8_23}, url = {http://dx.doi.org/10.1007/978-3-642-54734-8_23}, author = {Francisco Coito and Ant{\'o}nio Eleut{\'e}rio and Stanimir Valtchev and Coito, Fernando} } @conference {Stanimir_Valtchev23886152, title = {HV DC as the Next Generation Telecom Power Supply}, booktitle = {Symposium INTELEC{{\textquoteright}}95}, year = {2013}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23887706, title = {Perspectives of Tunnel FET (TFET) in the Ultra-Low-Power Analog-Circuit design}, booktitle = {Proceedings 28th Conference DCIS}, year = {2013}, note = {n/a}, abstract = {n/a}, isbn = {978-84-8081-401-0}, author = {Stanimir Valtchev} } @article {Stanimir_Valtchev23877766, title = {Study of a single-phase series active power filter with hysteresis control}, journal = {Journal of Energy and Power Engineering}, year = {2013}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @article {966ca6a524854fb98ad8a29fc7d93070, title = {Culture of the European Student with an Insight to the Future Needs of the Global (European) Labour Market}, journal = {Proceedings of the European Politechnical University}, volume = {1}, number = {NA}, year = {2012}, note = {

{"}Sem PDF conforme despacho{"}

}, month = {1}, pages = {78{\textendash}82}, abstract = {

Recent issues of global heating and energy shortages are imposing a need to change our paradigm around transportation. Somehow, electric vehicles are progressively standing as a strong and necessary alternative for the society. Technically and technologically the acceptance of the EV is easier now than ever but the psychology of the consumers and the running business of internal combustion vehicles, the whole existing infrastructure are too much conservative to be changed easily. The changes in technology require changes in the engineering society and its human resources. The objective of this paper is to give a contribution to the discussion and reflection of potential future scenarios where EV/HEV{\textquoteleft}s are spread across the society. It gives an overview of the range of knowledge and competences necessary for a sustainable and streamlined development of those. In fact, it is expected that a new kind of professional profiles need to be created or developed to supply the work market with the right human resources. The paper provides some discussion on the creation of new profiles or adaption of existing ones. Among different possible scenarios the creation of post-graduation courses for students holding undergraduate profiles in the fields referred to earlier would be an interesting and viable solution for fast response. The post graduation would be focused in specific key areas of the EV/HEV. Several factors are pointed out to endorse this scenario

}, keywords = {Educational System, Electric vehicles, Hybrid Electric Vehicles, New professional profiles}, issn = {1314-5711}, author = {Valtchev, {Stanimir Stoyanov} and Pamies-Teixeira, {Jorge Joaquim}} } @conference {c6daf07aa5c64dfa9e887b435befaf1b, title = {Energy Harvesting and the Human Health}, booktitle = {Education Science Inovations}, volume = {1}, year = {2012}, note = {n/a}, month = {1}, pages = {451{\textendash}460}, abstract = {

Currently, the energy supply for the portable and autonomous equipment comes almost exclusively from the battery. Unfortunately the maintenance of those sources of energy brings disadvantages due to the need for frequent recharging or replacement. In many cases the battery brings extra weight and volume to the electronic equipment, limiting its autonomy. Some possible alternative methods to replace the batteries as power source, or to achieve better maintenance of existing (or smaller) batteries, are the so called Energy Harvesting (EH) methods, i.e. to obtain energy from the environment. For the medical equipment, there is also a possibility to recover and store energy generated by the human body in its usual activities. To harvest energy from the human body or from the environment requires specific technology and materials. The electronic circuits must have extremely high efficiency both in energy conversion and energy consumption. Experiments were performed in order to calculate the power that could be generated from the chest during breathing, from the feet, during walking, etc. For the experiments, mostly piezoelectric effect was explored.

}, keywords = {Chest Energy, energy harvesting, Feet Force, Human Health, Piezoelectric Power Converter, Step Force}, author = {Vassilenko, Valentina and Valtchev, {Stanimir Stoyanov} and Pamies-Teixeira, {Jorge Joaquim}} } @conference {5a1adf8c3449419d952d8a02f81fd2b8, title = {High frequency wireless energy for improving the EV autonomy}, booktitle = {International Symposium on Electric Vehicle and 4-th Annual Conference of Polish Society for Environment Friendly Vehicles}, year = {2012}, note = {

Conference EV Warsaw

}, month = {1}, pages = {6}, abstract = {

There have been many and very significant advances in the Wireless Power Transfer, resulting up to now in flexible and safe battery charging eliminating the necessity of power cables. The relatively low frequencies (tens of kilohertz) applied for those {"}classical{"} chargers are already well developed. A {"}new{"} technology appeared now that makes possible to apply a strong magnetic resonant coupling. Similar experiments were applied by N. Tesla more than a hundred years ago but now the researchers are capable to reach much higher frequencies. To achieve the necessary high level of magnetic field coupling it is essential to allow high levels of electric current intensity inside the resonant loops. In this article the achievement of highest magnetic field is analysed and experimented. Some results are discussed based on the choice of the resonant loop type and construction. The applications in the on-line energy supply for the EV are one of the aimed goals. The other goal may be the future more efficient induction machine.

}, keywords = {Battery charging, Electric Vehicle, High Frequency, Wireless Energy}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {1594ef67bfc4411bb95a5d211cb62cf3, title = {New Methodology for Structural Health Monitoring of GLARE in Ships}, booktitle = {Proceedings ICEM15}, year = {2012}, note = {

Conferencia mecanica aplicada, Porto 2012

}, month = {1}, pages = {1{\textendash}8}, abstract = {n/a}, isbn = {978-972-8826-26-0}, author = {Valtchev, {Stanimir Stoyanov} and Pamies-Teixeira, {Jorge Joaquim} and Miranda, {Rosa Maria Mendes} and Santos, {Telmo Jorge Gomes dos} and {DEE Group Author}} } @conference {2c94556f6fa04cac973cb06900a1479c, title = {R\&D of an thermoelectric system - An innovative Linear Fresnel Reflector}, booktitle = {MATCHMAKING RESEARCH Conference}, year = {2012}, note = {n/a}, month = {1}, pages = {1{\textendash}5}, abstract = {

The research on the solar concentrating equipment is intensified in the recent years in many scientific and industry groups and institutions. This growing interest is based mainly on the higher efficiency and lower investment in material that is typical for this solar technology. This work started not to answer a market problem but with the idea of development a new application for an domestic size collector of line-focussing Fresnel collector. Which is will be a important step for the renewable energy. If successful, in a few years a common person will be ready to produce solar thermoelectricity at home with the double benefit of producing electricity and hot steam. The paper presents a design methodology and heat transfer calculation for an concentrating system based on the Linear Fresnel Reflector (LFR) concept. The basic absorber design is an trapezoidal inverted air cavity without glass cover. The absorber is covered with a selective surface and is oriented north- south. This arrangement has shown good optical and thermal performance results validated by measurements during outdoor tests.

}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {ea0c31b76be040cea8dfa19208d16a51, title = {Survey on EV electrical drive train with induction motor}, booktitle = {International Symposium on Electric Vehicles}, year = {2012}, note = {

Conferencia de EV em Varsovia

}, month = {1}, pages = {1{\textendash}5}, abstract = {

In the last time many research works were devoted to the electrical drive train with induction motors due to its robust construction and low cost in comparison with its competitor, PM synchronous motor. The construction of the induction motor is simple but its efficient control needs more sophisticated algorithms and appropriate inverters in order to obtain the highest technical and economical performance. In this paper we present a review of the last research results on the induction motor topologies dedicated to EV, on the architecture of inverters and of the efficient control strategies. There will be presented many promising solutions which are analysed and compared in order to offer to the EV electrical drive train designers the necessary information for a selection to be done.

}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @article {Stanimir_Valtchev23877799, title = {Actions for Broadening the Engineering Culture of the European Student with an Insight to the Future Needs of the Global (European) Labour Market}, journal = {Proceedings of the International conference of the European Polytechnical University}, year = {2012}, note = {n/a}, abstract = {n/a}, issn = {1314-5711}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921390, title = {The Efficient and Stable Charging of Electric Vehicle Batteries: Simplified Instantaneous Regulation}, booktitle = {DoCEIS 2012, Caparica}, year = {2012}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @article {Valtchev2012, title = {The efficient and stable charging of electric vehicle batteries: Simplified instantaneous regulation}, journal = {IFIP Advances in Information and Communication Technology}, volume = {372 AICT}, year = {2012}, note = {n/a}, pages = {363-374}, abstract = {n/a}, author = {Medeiros, R. and S Valtchev and S Valtchev} } @article {Valtchev_Baikova_Jorge_2012, title = {Electromagnetic field as the wireless transporter of energy}, journal = {Facta universitatis - series: Electronics and Energetics}, volume = {25}, number = {3}, year = {2012}, note = {n/a}, pages = {171-181}, publisher = {National Library of Serbia}, abstract = {n/a}, doi = {10.2298/FUEE1203171V}, url = {http://dx.doi.org/10.2298/FUEE1203171V}, author = {Stanimir Valtchev and Baikova, Elena and Luis Jorge} } @article { valtchev2012, title = {Energy harvested from respiratory effort}, journal = {BIODEVICES 2012 - Proceedings of the International Conference on Biomedical Electronics and Devices}, year = {2012}, note = {n/a}, pages = {388-392}, abstract = {n/a}, author = {Cavalheiro, D. and Silva, A.C. and S Valtchev and Teixeira, JP and Vassilenko, V.} } @article {RID:1019161453990-39, title = {Energy harvested from respiratory effort}, journal = {BIODEVICES 2012 - Proceedings of the International Conference on Biomedical Electronics and Devices}, year = {2012}, note = {n/a}, pages = {388-392}, abstract = {n/a}, author = {Cavalheiro, D. and Silva, A.C. and S Valtchev and Teixeira, JP and Vassilenko, V.} } @article {Stanimir_Valtchev23877800, title = {Energy Harvesting and the Human Health}, journal = {Proceedings of the International conference of the European Polytechnical University}, year = {2012}, note = {n/a}, abstract = {n/a}, issn = {1314-5711}, author = {Stanimir Valtchev} } @article {Valtchev2012, title = {Experimental study of the energy portions control in Series Resonant Converters}, journal = {Proceedings of the International Conference on Optimisation of Electrical and Electronic Equipment, OPTIM}, year = {2012}, note = {n/a}, pages = {827-832}, abstract = {n/a}, author = {S Valtchev and S Valtchev} } @conference {Stanimir_Valtchev23921353, title = {High frequency wireless energy for improving the EV autonomy}, booktitle = {International Symposium on Electric Vehicle and 4-th Annual Conference of Polish Society for Environment Friendly Vehicles}, year = {2012}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @article { valtchev2012, title = {New method employing the electrical impedance for monitoring mechanical damage evolution in glass-reinforced: Applications to riveted joints}, journal = {Materials and Design}, volume = {42}, year = {2012}, note = {n/a}, pages = {25-31}, abstract = {n/a}, author = {Matos Filipe, L. and Santos, T.G. and S Valtchev and Pamies Teixeira, J. and Miranda, R. M.} } @conference {Stanimir_Valtchev23921423, title = {New Methodology for Structural Health Monitoring of GLARE in Ships}, booktitle = {15th International Conference on Experimental Mechanics (ICEM15), Porto}, year = {2012}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921348, title = {R\&D of an thermoelectric system - An innovative Linear Fresnel Reflector}, booktitle = {MATCHMAKING RESEARCH Conference}, year = {2012}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921351, title = {Survey on EV electrical drive train with induction motor}, booktitle = {International Symposium on Electric Vehicle and 4-th Annual Conference of Polish Society for Environment Friendly Vehicles}, year = {2012}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Antchev_2011, title = {Study of a single-phase series active power filter with hysteresis control}, booktitle = {11th International Conference on Electrical Power Quality and Utilisation}, year = {2011}, note = {n/a}, month = {oct}, publisher = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, organization = {Institute of Electrical {\&} Electronics Engineers ({IEEE})}, abstract = {n/a}, doi = {10.1109/epqu.2011.6128921}, url = {http://dx.doi.org/10.1109/epqu.2011.6128921}, author = {Mihail Hr. Antchev and Mariya P. Petkova and Hristo M. Antchev and Vanjo T. Gourgoulitsov and Stanimir S. Valtchev} } @conference {ebb74f2ed7364bab8ab4ccd6c80e79d8, title = {Actions for Broadening the Engineering Culture of the European Student with an Insight to the Future Needs of the Global (European) Labour Market}, booktitle = {Proceedings of the First International Conference of the European Polytechnical University}, year = {2011}, note = {n/a}, month = {1}, pages = {78{\textendash}82}, abstract = {n/a}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {b056b7cefb3e4aedbe7b532b129600f7, title = {Electromagnetic Field as Wireless Transporter of Energy}, booktitle = {PES 2011: Proceedings of extended abstracts}, volume = {NA}, year = {2011}, note = {n/a}, month = {1}, pages = {143{\textendash}144}, abstract = {n/a}, isbn = {ISBN 978-86-6125-035-4}, author = {Valtchev, {Stanimir Stoyanov}} } @conference {9aa42342143340b99247568c52662560, title = {Energy Harvesting and the Human Health}, booktitle = {Proceedings of the First International Conference of the European Polytechnical University}, year = {2011}, note = {n/a}, month = {1}, pages = {451{\textendash}460}, abstract = {n/a}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {076b416bae184a8abfb151302a0c578f, title = {The Energy That{\textquoteright}s Around}, booktitle = {Conference {\textquotedblleft}Millennium Development Goals{\textquotedblright}, IEEE Student Branch, 21st March 2011}, year = {2011}, note = {n/a}, month = {1}, pages = {{\textendash}}, abstract = {n/a}, author = {Valtchev, {Stanimir Stoyanov}} } @booklet {aa01c515af2049caa98209a4a5a96b6a, title = {High Level Education Through Research Training Networks: A Potential StrategyTo Build Knowledge In EV/HEV}, volume = {NA}, year = {2011}, note = {n/a}, month = {1}, type = {Other}, abstract = {n/a}, author = {Valtchev, {Stanimir Stoyanov} and Pamies-Teixeira, {Jorge Joaquim} and {DEE Group Author}} } @booklet {7a8cfa8bf99b470e80ce9f0f38b8e5aa, title = {Study on Contactless Power Transmission Methods}, volume = {NA}, year = {2011}, note = {n/a}, month = {1}, type = {Other}, abstract = {n/a}, author = {Valtchev, {Stanimir Stoyanov}} } @conference {26ed288cf350419185168cc055fc1cf7, title = {An UHF Wireless Power Harvesting System - Analysis and Design}, booktitle = {PES 2011: Proceedings of extended abstracts}, year = {2011}, note = {n/a}, month = {1}, pages = {141{\textendash}142}, abstract = {

This paper presents a system to harvest electromagnetic energy from the environment. The proposed solution differs from others already existent in the literature because it makes possible to harvest energy from a large frequency spectrum. Typically the existing energy harvesting systems only gather energy from one specific source, thus not taking advantage of the several RF sources existing in one place. The full system and its componentsare simulated and implemented, and the results obtained are shown. The system harvest energy from UHF sources, and converts the harvested energy to a DC voltage, in order to feed electronic devices. This conversion is made through the utilization of a voltage multiplier, followed by a voltage regulator.

}, isbn = {978-86-6125-035-4}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {Stanimir_Valtchev23898498, title = {Actions for Broadening the Engineering Culture of the European Student with an Insight to the Future Needs of the Global (European) Labour Market}, booktitle = {First Conference with International Participation {"}Education, Science, Innovations{"}, Pernik, Proceedings of ESI'2011, pp. 78-82}, year = {2011}, note = {n/a}, abstract = {n/a}, issn = {131451-1}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23898455, title = {The Efficient and Stable Charging of Electric Vehicle Batteries: Simplified Instantaneous Regulation}, booktitle = {International Symposium on Electric Vehicles ISEV2011, presentation 03084, Beijing}, year = {2011}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {0ee3582e234c486f93ca595ca4ab5294, title = {The Efficient and Stable Charging of Electric Vehicle Batteries: Simplified Instantaneous Regulation}, year = {2011}, note = {

3rd International Symposium on Electrical Vehicles (ISEV 2011) ; Conference date: 24-09-2011 Through 25-09-2011

}, abstract = {n/a}, author = {Valtchev, {Stanimir Stoyanov} and Rui Neves-Medeiros} } @conference {Stanimir_Valtchev23898494, title = {Electromagnetic Field as Wireless Transporter of Energy}, booktitle = {10th International Conference on Applied Electromagnetics (\cyrchar\CYRP\cyrchar\CYRE\cyrchar\CYRS Conference)}, year = {2011}, note = {n/a}, abstract = {n/a}, isbn = {978-86-6125-035-4}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23898552, title = {Energy Harvesting and the Human Health}, booktitle = {First Conference with International Participation {"}Education, Science, Innovations{"} Proceedings of ESI'2011, pp. 451-460}, year = {2011}, note = {n/a}, abstract = {n/a}, issn = {131451-1}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23898446, title = {The Energy That{\textquoteright}s Around}, booktitle = {{Conference {\textquotedblleft}Millennium Development Goals{\textquotedblright}}, year = {2011}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23898466, title = {High Level Education Through Research Training Networks: A Potential Strategy To Build Knowledge In EV/HEV}, booktitle = {International Symposium on Electric Vehicles ISEV2011, keynote speech, Beijing}, year = {2011}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @article {Valtchev2011, title = {An instantaneous regulation for the wired and wireless super-resonant converters}, journal = {INTELEC, International Telecommunications Energy Conference (Proceedings)}, year = {2011}, note = {n/a}, abstract = {n/a}, author = {S Valtchev and Medeiros, R. and S Valtchev and Klaassens, B.} } @conference {Stanimir_Valtchev23886101, title = {Medium concentration system HSUN: demonstration results and application of diverse silicon cells}, booktitle = {26th European Photovoltaic Solar Energy Conference and Exhibition (PVSEC)}, year = {2011}, note = {n/a}, abstract = {n/a}, doi = {10.4229/26thEUPVSEC2011-1DV.4.30}, url = {http://doi.org/10.4229/26thEUPVSEC2011-1DV.4.30}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23886088, title = {Pre-Certification of HSUN\textregistered Module According To IEC 62108}, booktitle = {26th European Photovoltaic Solar Energy Conference and Exhibition (PVSEC)}, year = {2011}, note = {n/a}, abstract = {n/a}, doi = {10.4229/26thEUPVSEC2011-1DV.4.42}, url = {http://doi.org/10.4229/26thEUPVSEC2011-1DV.4.42}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23898443, title = {Study on Contactless Power Transmission Methods}, booktitle = {DoCEIS Conference}, year = {2011}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @article {Valtchev2011, title = {Tuning techniques for kinetic MEMS energy harvesters}, journal = {INTELEC, International Telecommunications Energy Conference (Proceedings)}, year = {2011}, note = {n/a}, abstract = {n/a}, author = {Todorov, G. and Todorov, T. and Ivanov, I. and S Valtchev and Klaassens, B.} } @article {Stanimir_Valtchev11271347, title = {An UHF Wireless Power Harvesting System {\textendash} Analysis and Design}, journal = {International Journal of Emerging Sciences (IJES)}, year = {2011}, note = {n/a}, abstract = {n/a}, issn = {2222-4254}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23898489, title = {An UHF Wireless Power Harvesting System {\textendash} Analysis and Design}, booktitle = {10th International Conference on Applied Electromagnetics (\cyrchar\CYRP\cyrchar\CYRE\cyrchar\CYRS Conference)}, year = {2011}, note = {n/a}, abstract = {n/a}, isbn = {978-86-6125-035-4}, author = {Stanimir Valtchev} } @conference {OA2407, title = {The Charging of Hybrid and Electrical Vehicles? Batteries: Contactless Energy Transfer as the key to the future}, booktitle = {2010 International Symposium on Electric Vehicle and 2-nd Annual Conference of Polish Society for Environment Friendly Vehicles}, year = {2010}, month = {July}, abstract = {Would it be necessary to charge rapidly the electric vehicle (EV) and hybrid electric vehicle (HEV)? It is not easy to answer without a thorough look at the capability of the modern propulsion battery and the power necessities of the EV and HEV. The different possible solutions are compared and maximum speed of charging is analysed. The wired connection for charging is compared to the wireless energy transfer and because of the limitations imposed by the modern and future batteries, the contactless energy transfer is chosen as the future charging method.}, keywords = {Battery, Charging, Contactless Energy Transfer, Electric?Hybrid Vehicle}, url = {http://oa.uninova.pt/2407/}, author = {Stanimir Valtchev and Jorge Pamies Teixeira} } @conference {OA2339, title = {Improved strategy for an instantaneous super-resonant converter regulation}, booktitle = {12th International Conference on Optimization of Electrical and Electronic Equipment (OPTIM)}, year = {2010}, month = {July}, pages = {631{\textendash}638}, abstract = {The proposed regulation strategy consists in obtaining at the right time the correct information about the energy contained in the resonant tank. This information allows a stable operation of the switches and a higher efficiency of any Series Loaded Series Resonant (SLSR) power converter, especially when contactless energy transfer is concerned. The strategy is based on guaranteeing the correct portion of energy transported by the resonant tank to the load. The portion has to vary corresponding to the error signal taken from the output voltage and remains unchanged if the error signal is at its minimum. In a certain way this method is similar to the Current Mode Control of the classical power converters. The viability of the idea is demonstrated by simulation of a realistic analogue circuit (on preparation for a digital implementation in the near future).}, url = {http://oa.uninova.pt/2339/}, author = {Stanimir Valtchev and Svilen Valtchev} } @conference {OA2408, title = {An Insight to Potential Actions Facing Future Needs of Electric and Hybrid Electric Vehicles}, booktitle = {2010 International Symposium on Electric Vehicle and 2-nd Annual Conference of Polish Society for Environment Friendly Vehicles}, year = {2010}, month = {July}, abstract = {Recent issues of global heating and energy shortages are imposing a need to change our paradigm around transportation. Somehow, electric vehicles are progressively standing as a strong and necessary alternative for the society. Technically and technologically the acceptance of the EV is easier now than ever but the psychology of the consumers and the running business of internal combustion vehicles, the whole existing infrastructure are too much conservative to be changed easily. The changes in technology require changes in the engineering society and its human resources. The objective of this paper is to give a contribution to the discussion and reflection of potential future scenarios where EV?HEV?s are spread across the society. It gives an overview of the range of knowledge and competences necessary for a sustainable and streamlined development of those. In fact, it is expected that a new kind of professional profiles need to be created or developed to supply the work market with the right human resources. The paper provides some discussion on the creation of new profiles or adaption of existing ones. Among different possible scenarios the creation of post-graduation courses for students holding undergraduate profiles in the fields referred to earlier would be an interesting and viable solution for fast response. The post graduation would be focused in specific key areas of the EV?HEV. Several factors are pointed out to endorse this scenario}, keywords = {Educational System, Electric vehicles, Hybrid Electric Vehicles, New professional profiles}, url = {http://oa.uninova.pt/2408/}, author = {Jorge Pamies Teixeira and Stanimir Valtchev} } @conference {OA2406, title = {Resonant power conversion in contactless battery charging for Electric Vehicle ? Hybrid Electric Vehicle}, booktitle = {2010 International Symposium on Electric Vehicle and 2-nd Annual Conference of Polish Society for Environment Friendly Vehicles}, year = {2010}, month = {July}, abstract = {The electromagnetic resonance became irreplaceable tool for wirelessly transfer energy and information. Since long this effect is widely used in communications but recently it is deeply studied and applied at the contactless transfer of energy. The electric?hybrid car battery charging is an urgent need and the knowledge about the resonant contactless transfer became very important. The study of the Series Loaded Series Resonant converter shows it as well suitable for the contactless energy transfer. The idealized Series Resonant Power Converter is used as a base for defining the best (most efficient) modes of operation. Based on the magnetic parameters of the loosely coupled transformer (magnetic link), the characteristics of the contactless power converter are described in approximated form, thus permitting an easier and faster calculation of the converter variables. This is used for instantaneous control of the converter, free from previously known defects.}, keywords = {Battery, Charging, Contactless Energy Transfer, Electric?Hybrid Car, Resonant Converters}, url = {http://oa.uninova.pt/2406/}, author = {Stanimir Valtchev} } @unpublished {OA2348, title = {Seguidor fotovoltaico: uma varia{\c c}{\~a}o do P\&O - Simula{\c c}{\~a}o e Prototipagem}, year = {2010}, month = {July}, publisher = {FCT-UNL}, abstract = {This dissertation tries to track the route of power production from photovoltaic sources. A worldwide look into the photovoltaic solar power production is given. The theory behind the PV cell and its application in PV power modules is presented. The DC ? DC power converters usually associated with solar PV panels are showed. The main maximum power point tracking (MPPT) algorithms are also showed. A solar PV system was dimensioned using the theoretical models and the solar PV modules (BS ? 40) available at the Departamento de Engenharia Electrot{\'e}cnica (DEE). This system was used as a reference for designing a simulator implemented in MatLab?Simulink. This simulator includes all the components needed to test the different MPP tracking algorithms. Those components are: A PV solar module, which can be associated with others to form a solar panel; A Flyback DC ? DC power converter and a classic perturb and observe (P\&O) tracking algorithm. A solar power meter that gives values in W?m2 was built in order to validate simulation values of the solar PV modules. Measuring the solar module characteristics (tension ? current) and knowing the solar irradiation at that given time it is possible to check if the simulated values and the measured ones agree. With the data collected in the simulation a new MPP tracking algorithm was presented. This is based in the classic P\&O algorithm, but using modules that try to overcome the local maxima problem. It also tries to minimize the control oscillations in the converter?inverter, this is done in order to minimize losses and to maximize power production.}, url = {http://oa.uninova.pt/2348/}, author = {Paulo Bonif{\'a}cio}, editor = {Stanimir Valtchev} } @unpublished {OA2412, title = {Resonant Effects Applied in Power Conversion for Contactless Energy Transfer}, journal = {Seminar on Resonant Processes and Contactless Energy}, year = {2010}, month = {August}, url = {http://oa.uninova.pt/2412/}, author = {Stanimir Valtchev} } @conference {OA2367, title = {Resonant Effects Applied in Power Conversion for Contactless Energy Transfer and Energy Harvesting}, booktitle = {Invited Seminar (Lecture) of S. Valtchev}, year = {2010}, month = {August}, url = {http://oa.uninova.pt/2367/}, author = {Stanimir Valtchev} } @conference {eb0c6540d1f741cb9694ee18e7b6b4d1, title = {The Charging of Hybrid and Electrical Vehicles{\textquoteright} Batteries: Contactless Energy Transfer as the key to the future}, booktitle = {-}, year = {2010}, note = {

A keynote speech at an international symposium

}, month = {1}, pages = {{\textendash}}, abstract = {

Would it be necessary to charge rapidly the electric vehicle (EV) and hybrid electric vehicle (HEV)? It is not easy to answer without a thorough look at the capability of the modern propulsion battery and the power necessities of the EV and HEV. The different possible solutions are compared and maximum speed of charging is analysed. The wired connection for charging is compared to the wireless energy transfer and because of the limitations imposed by the modern and future batteries, the contactless energy transfer is chosen as the future charging method.

}, keywords = {Battery, Charging, Contactless Energy Transfer, Electric/Hybrid Vehicle}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {b35b45437f9e4ab4bbbad59de1041d40, title = {An Insight to Potential Actions Facing Future Needs of Electric and Hybrid Electric Vehicles}, booktitle = {-}, year = {2010}, note = {

A keynote speech at the international symposium in Warsaw

}, month = {1}, pages = {{\textendash}}, abstract = {

Recent issues of global heating and energy shortages are imposing a need to change our paradigm around transportation. Somehow, electric vehicles are progressively standing as a strong and necessary alternative for the society. Technically and technologically the acceptance of the EV is easier now than ever but the psychology of the consumers and the running business of internal combustion vehicles, the whole existing infrastructure are too much conservative to be changed easily. The changes in technology require changes in the engineering society and its human resources. The objective of this paper is to give a contribution to the discussion and reflection of potential future scenarios where EV/HEV{\textquoteleft}s are spread across the society. It gives an overview of the range of knowledge and competences necessary for a sustainable and streamlined development of those. In fact, it is expected that a new kind of professional profiles need to be created or developed to supply the work market with the right human resources. The paper provides some discussion on the creation of new profiles or adaption of existing ones. Among different possible scenarios the creation of post-graduation courses for students holding undergraduate profiles in the fields referred to earlier would be an interesting and viable solution for fast response. The post graduation would be focused in specific key areas of the EV/HEV. Several factors are pointed out to endorse this scenario

}, keywords = {Educational System, Electric vehicles, Hybrid Electric Vehicles, New professional profiles}, author = {Valtchev, {Stanimir Stoyanov} and Pamies-Teixeira, {Jorge Joaquim} and {DEE Group Author}} } @conference {10caf5c27c404af6b94f19c4615fc301, title = {Resonant Effects Applied in Power Conversion for Contactless Energy Transfer and Energy Harvesting}, booktitle = {-}, year = {2010}, note = {

Invited seminar in City University of Tokyo, Japan

}, month = {1}, pages = {{\textendash}}, abstract = {n/a}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {277f25b3086e486c94acee35399968e9, title = {Resonant power conversion in contactless battery charging for Electric Vehicle / Hybrid Electric Vehicle}, booktitle = {-}, year = {2010}, note = {

A technical paper at the international symposium, planned to be published in book but still waiting

}, month = {1}, pages = {{\textendash}}, abstract = {

The electromagnetic resonance became irreplaceable tool for wirelessly transfer energy and information. Since long this effect is widely used in communications but recently it is deeply studied and applied at the contactless transfer of energy. The electric/hybrid car battery charging is an urgent need and the knowledge about the resonant contactless transfer became very important. The study of the Series Loaded Series Resonant converter shows it as well suitable for the contactless energy transfer. The idealized Series Resonant Power Converter is used as a base for defining the best (most efficient) modes of operation. Based on the magnetic parameters of the loosely coupled transformer (magnetic link), the characteristics of the contactless power converter are described in approximated form, thus permitting an easier and faster calculation of the converter variables. This is used for instantaneous control of the converter, free from previously known defects.

}, keywords = {Battery, Charging, Contactless Energy Transfer, Electric/Hybrid Car, Resonant Converters}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @article {Valtchev2010, title = {Improved strategy for an instantaneous super-resonant converter regulation}, journal = {Proceedings of the International Conference on Optimisation of Electrical and Electronic Equipment, OPTIM}, year = {2010}, note = {n/a}, pages = {631-638}, abstract = {n/a}, author = {S Valtchev and S Valtchev} } @proceedings {OA2373, title = {Battery chargers and battery management for the future electric vehicles}, journal = {Cooperation work between S. Valtchev and TU Delft}, year = {2009}, month = {September}, abstract = {

This was a cooperation with Electric Power Processing laboratory of TU Delft. During this stay organized and financed by TU Delft, S.Valtchev supported by teaching some students, PhD students and post-doc associates (in workshops?seminars).

}, url = {http://oa.uninova.pt/2373/}, author = {Stanimir Valtchev} } @conference {OA2021, title = {Control strategy for efficient operation of super-resonant SLSR (contactless) converters}, booktitle = {XLIV INTERNATIONAL SCIENTIFIC CONFERENCE ON INFORMATION, COMMUNICATION AND ENERGY SYSTEMS AND TECHNOLOGIES (before 1990 was: "Day of the Radio Conference")}, year = {2009}, month = {June}, pages = {527{\textendash}530}, url = {http://oa.uninova.pt/2021/}, author = {Stanimir Valtchev and Rosen Miletiev and Rumen Arnaoudov and Svilen Valtchev} } @unpublished {OA2126, title = {Accionamento de um Motor Passo a Passo com Velocidade e Direc{\c c}{\~a}o Controladas e com Bin{\'a}rio de Arranque Aumentado}, year = {2009}, month = {February}, publisher = {FCT-UNL}, abstract = {Os motores passo a passo podem ser vistos como motores el{\'e}ctricos sem comuta{\c c}{\~a}o electromec{\^a}nica (escovas e an{\'e}is). Tipicamente, todos os enrolamentos no motor s{\~a}o parte do estator, e o rotor ou {\'e} um magneto permanente ou, no caso dos motores de relut{\^a}ncia vari{\'a}vel, um bloco dentado de algum material ferro-magn{\'e}tico macio. Toda a comuta{\c c}{\~a}o deve ser lidada externamente pelo controlador do motor, e normalmente, os motores e os controladores s{\~a}o dimensionados de modo que o motor possa ser posicionado numa posi{\c c}{\~a}o fixa, assim como rodar em ambos os sentidos. Os motores passo a passo podem ser usados em sistemas de controlo em malha aberta; estes s{\~a}o geralmente adequados para sistemas que operam em baixas acelera{\c c}{\~o}es com cargas fixas, mas o controlo em malha fechada pode ser essencial para acelera{\c c}{\~o}es elevadas, particularmente se envolverem cargas vari{\'a}veis. Se um motor de passo num sistema de controlo em malha aberta sofre um bin{\'a}rio demasiado grande, todo o conhecimento da posi{\c c}{\~a}o do rotor ser{\'a} perdido e o sistema dever{\'a} ser reiniciado. Nesta disserta{\c c}{\~a}o, {\'e} proposto um novo conversor el{\'e}trico em malha aberta, especialmente dimensionado para motores de pequenas dimens{\~o}es e de alto bin{\'a}rio, alimentados com correntes unidirecionais. Este conversor {\'e} baseado na mudan{\c c}a do declive de subida da corrente em cada enrolamento, atrav{\'e}s da descarga de um condensador adicional carregado.}, url = {http://oa.uninova.pt/2126/}, author = {Pedro Sousa}, editor = {Stanimir Valtchev and M{\'a}rio Neves} } @conference {a8392b587ca04862aa059141a0870a11, title = {Control strategy for efficient operation of super-resonant SLSR (contactless) converters}, booktitle = {-}, year = {2009}, note = {

An international conference in Veliko Turnovo, 25-27 June 2009, mostly on telecommunication problems

}, month = {1}, pages = {527{\textendash}530}, abstract = {

A new faster control method is presented, inattempt to achieve stable operation and higher efficiency of anySeries Loaded Series Resonant (SLSR) power converter, andespecially when the application requires contactless energytransfer. This instantaneously reacting control method is basedon calculated individual energy portions delivered to theresonant circuit. Its viability is demonstrated by simulation of ananalogue circuit implementation.

}, keywords = {Contactless Energy Transfer, Energy Portions Control, Series Loaded Series Resonant Converter}, author = {Valtchev, {Stanimir Stoyanov} and {DEE Group Author}} } @conference {Stanimir_Valtchev23921427, title = {Control strategy for efficient operation of super-resonant SLSR (contactless) converters}, booktitle = {Proceedings of ICEST{{\textquoteright}}09, V. Turnovo, pp. 527-530}, year = {2009}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {OA1789, title = {Conventional and HTS Disc motor with pole variation control}, booktitle = {2nd International Conference on Power Engineering, Energy and Electrical Drives (POWERENG{\textquoteright}2009)}, year = {2009}, pages = {513{\textendash}518}, abstract = {In this paper, a poly-phase disc motor innovative feeding and control strategy, based on a variable poles approach, and its application to a high temperature superconductor (HTS) disc motor, are presented. The stator windings may be electronically commutated to implement a 2, 4, 6 or 8 poles winding, thus changing the motor{\textquoteright}s torque?speed characteristics. The motor may be a conventional induction motor with a conductive disc rotor, or a new HTS disc motor, with conventional copper windings at its two iron semi-stators and a HTS disc as a rotor. The conventional induction motor{\textquoteright}s operation principle is related with the induced electromotive forces in the conductive rotor. Its behaviour, characteristics and modelling through Steinmetz and others theories are well known. The operation principle of the motor with HTS rotor, however, is rather different and is related with vortices{\textquoteright} dynamics and pinning characteristics; this is a much more complex process than induction, and its modelling is quite complicated. In this paper, the operation was simulated through finite-elements commercial software (FLUX2D), whereas superconductivity was simulated by the E-J power law. The electromechanical performance of both motor{\textquoteright}s computed are compared. Considerations about the systems overall efficiency, including cryogenics, are also discussed.}, url = {http://oa.uninova.pt/1789/}, author = {D In{\'a}cio and J. A. In{\'a}cio and J. Pina and S Valtchev and M. Neves and J. Martins and A. Rodrigues} } @article {Valtchev2009, title = {Conventional and HTS disc motor with pole variation control}, journal = {POWERENG 2009 - 2nd International Conference on Power Engineering, Energy and Electrical Drives Proceedings}, year = {2009}, note = {n/a}, pages = {513-518}, abstract = {n/a}, author = {D In{\'a}cio and S In{\'a}cio and J. Pina and S Valtchev and M V Neves and Martins, J.F.A. and A L Rodrigues} } @conference {OA1784, title = {A New Open-Loop Control Method for Stepping Motor Driving}, booktitle = {2nd International Conference on Power Engineering, Energy and Electrical Drives (POWERENG{\textquoteright}2009)}, year = {2009}, pages = {605{\textendash}610}, url = {http://oa.uninova.pt/1784/}, author = {P. Sousa and Stanimir Valtchev and M{\'a}rio Neves and A. Rodrigues} } @article {Valtchev2009, title = {A new open-loop control method for stepping motor driving}, journal = {POWERENG 2009 - 2nd International Conference on Power Engineering, Energy and Electrical Drives Proceedings}, year = {2009}, note = {n/a}, pages = {605-610}, abstract = {n/a}, author = {P. Sousa and S Valtchev and M V Neves and A L Rodrigues} } @article {OA1818, title = {Resonant Contactless Energy Transfer With Improved Efficiency}, journal = {IEEE Transactions on Power Electronics}, volume = {24}, number = {3}, year = {2009}, pages = {685{\textendash}699}, publisher = {IEEE}, abstract = {This paper describes the theoretical and experimental results achieved in optimizing the application of the series loaded series resonant converter for contactless energy transfer. The main goal of this work is to define the power stage operation mode that guarantees the highest possible efficiency. The results suggest a method to select the physical parameters (operation frequency, characteristic impedance, transformer ratio, etc.) to achieve that efficiency improvement. The research clarifies also the effects of the physical separation between both halves of the ferromagnetic core on the characteristics of the transformer. It is shown that for practical values of the separation distance, the leakage inductance, being part of the resonant inductor, remains almost unchanged. Nevertheless, the current distribution between the primary and the secondary windings changes significantly due to the large variation of the magnetizing inductance. An approximation in the circuit analysis permits to obtain more rapidly the changing values of the converter parameters. The analysis results in a set of equations which solutions are presented graphically. The graphics show a shift of the best efficiency operation zone, compared to the converter with an ideally coupled transformer. Experimental results are presented confirming that expected tendency.}, url = {http://oa.uninova.pt/1818/}, author = {Stanimir Valtchev and Beatriz Borges and Kostadin Brandisky and J. Ben Klaassens} } @article { valtchev2009, title = {Resonant contactless energy transfer with improved efficiency}, journal = {IEEE Transactions on Power Electronics}, volume = {24}, number = {3}, year = {2009}, note = {n/a}, pages = {685-699}, abstract = {n/a}, author = {S Valtchev and Borges, B. and Brandisky, K. and JB Klaassens} } @unpublished {OA1223, title = {Projecto de uma caixa de velocidades el{\'e}ctrica por meio da varia{\c c}{\~a}o do n{\'u}mero de p{\'o}los para motores em disco de rotor em alum{\'\i}nio e em materiais supercondutores de alta temperatura (SAT)}, year = {2008}, month = {May}, publisher = {FCT-UNL}, abstract = {Nesta disserta{\c c}{\~a}o apresenta-se um motor em disco polif{\'a}sico inovador bem como uma estrat{\'e}gia de controlo com base no m{\'e}todo de varia{\c c}{\~a}o de velocidade por comuta{\c c}{\~a}o do n{\'u}mero de pares de p{\'o}los. A configura{\c c}{\~a}o das bobinas aliada {\`a} escolha das correntes e tens{\~o}es que se injectam nas bobinas dos estatores, permite comutar electronicamente o n{\'u}mero de p{\'o}los do motor entre 2, 4 6 e 8 p{\'o}los, conseguindo-se controlar a caracter{\'\i}stica bin{\'a}rio?velocidade do motor. O motor em disco possui a bobinagem feita em cobre com dois semi-estatores, em que quando utiliza o rotor em alum{\'\i}nio (com condutividade diferente de zero) comporta-se como um motor de indu{\c c}{\~a}o convencional. Quando se substitui o rotor em alum{\'\i}nio por um constitu{\'\i}do por um supercondutor de alta temperatura (SAT), o dispositivo comporta-se como um motor de histerese. O princ{\'\i}pio de funcionamento do motor em disco convencional {\'e} baseado na indu{\c c}{\~a}o de for{\c c}a electromotrizes no rotor e, consequentemente, uma vez que o alum{\'\i}nio {\'e} bom condutor el{\'e}ctrico, correntes el{\'e}ctricas induzidas, originadas por haver um campo magn{\'e}tico vari{\'a}vel que {\'e} criado pelos semi-estatores. O comportamento deste tipo de motores, no que diz respeito a principais caracter{\'\i}sticas (como o bin{\'a}rio?velocidade para os diferentes n{\'u}meros de pares de p{\'o}los), circuito equivalente de Steinmetz, entre outras teorias associadas {\'e} j{\'a} conhecido h{\'a} bastante tempo. O princ{\'\i}pio de funcionamento do motor SAT {\'e} diferente do apresentado anteriormente, funciona com base na din{\^a}mica de v{\'o}rtices e devido ao facto de aparecer o fen{\'o}meno de ancoragem de fluxo (flux pinning) nos supercondutores de alta temperatura. Como o campo magn{\'e}tico varia, ent{\~a}o o disco roda. Este motor tem um princ{\'\i}pio de funcionamento muito mais complexo que o motor de indu{\c c}{\~a}o sendo a obten{\c c}{\~a}o do modelo do motor SAT complicada. A obten{\c c}{\~a}o do modelo do motor SAT n{\~a}o {\'e} abordado nesta disserta{\c c}{\~a}o. Os comportamentos e modos de opera{\c c}{\~a}o do motor com disco de alum{\'\i}nio e em materiais SAT s{\~a}o simulados atrav{\'e}s de um programa comercial de elementos finitos, nesta disserta{\c c}{\~a}o, sendo a supercondutividade simulada com base na rela{\c c}{\~a}o entre o campo el{\'e}ctrico e a densidade de corrente pela lei da potencia{\c c}{\~a}o (E-J power law). Com as simula{\c c}{\~o}es pretende-se comparar o rendimento electromec{\^a}nico de ambos os motores.}, url = {http://oa.uninova.pt/1223/}, author = {Steve In{\'a}cio}, editor = {M{\'a}rio Neves and Jo{\~a}o Pina and Stanimir Valtchev} } @unpublished {OA2372, title = {Contactless Power Transfer}, journal = {Seminar of S.Valtchev on Contactless Power Transfer}, year = {2008}, month = {July}, abstract = {This seminar was a presentation of S.Valtchev on the methods of wireless energy transfer. The seminar was invited by the colleagues of the Power Processing Laboratory of TU Delft, the Netherlands.}, url = {http://oa.uninova.pt/2372/}, author = {Stanimir Valtchev} } @mastersthesis {OA2207, title = {Series Resonant Power Converter for Contactless Energy Transfer with Improved Efficiency}, year = {2008}, month = {April}, school = {UTL-IST (Portugal), TU Delft (the Netherlands)}, type = {phd}, abstract = {The development of more efficient power converters is the most important and challenging task for Power Electronics specialists. In the same time, many currently existing or yet to appear future applications require full mechanical independence between the transmitter and receiver of the electrical energy. This contactless form of energy transfer is the concern of the presented work. The work is based on the study of the Series Loaded Series Resonant converter which prove to be the best suitable for the contactless energy transfer. The work investigates the idealized Series Resonant Power Converter with the objective to find the best efficiency zones of operation. Generalized expressions obtained are original and useful. Based on the magnetic parameters of the loosely coupled transformer (magnetic link), the characteristics of the contactless power converter are described in approximated form. The approximation permits easier and faster calculation of the converter variables, thus predicting a shift of the maximum efficiency zone compared to the ideal converter case. The approximated form of the equations permitted to present a new instantaneous form of regulation which combines the frequency and pulse width modes which is free from the previously known defects. The method is based on calculating the energy portions supplied to the load during each half period. Measurements performed on industrial converters and on the laboratory experimental converter, confirm the predicted theoretically behaviour of the converter.}, keywords = {contactless energy (Power) transfer ? series resonant converter ? efficiency ? loosely (non-ideally) coupled transformer ? Inductive Coupled Power Transfer (ICPT) ? super-resonant operation ? resonant converter regulation in FM and PWM}, url = {http://oa.uninova.pt/2207/}, author = {Stanimir Valtchev}, editor = {Beatriz Borges and J. Ben Klaassens} } @article {OA1764, title = {An electrical gearbox by means of pole variation for induction and superconducting disc motor}, journal = {Journal of Physics: Conference Series}, volume = {97}, year = {2008}, pages = {012221}, abstract = {In this paper, a poly-phase disc motor innovative feeding and control strategy, based on a variable poles approach, and its application to a HTS disc motor, are presented. The stator windings may be electronically commutated to implement a 2, 4, 6 or 8 poles winding, thus changing the motor{\textquoteright}s torque?speed characteristics. The motor may be a conventional induction motor with a conductive disc rotor, or a new HTS disc motor, with conventional copper windings at its two iron semi-stators, and a HTS disc as a rotor. The conventional induction motor{\textquoteright}s operation principle is related with the induced electromotive forces in the conductive rotor. Its behaviour, characteristics (namely their torque?speed characteristics for different number of pole pairs) and modelling through Steinmetz and others theories are well known. The operation principle of the motor with HTS rotor, however, is rather different and is related with vortices{\textquoteright} dynamics and pinning characteristics; this is a much more complex process than induction, and its modelling is quite complicated. In this paper, the operation was simulated through finite-elements commercial software, whereas superconductivity was simulated by the E-J power law. The Electromechanical performances of both motors where computed and are presented and compared. Considerations about the systems overall efficiency, including cryogenics, are also discussed.}, url = {http://oa.uninova.pt/1764/}, author = {S In{\'a}cio and D In{\'a}cio and J M Pina and Stanimir Valtchev and M V Neves and A L Rodrigues} } @article {Valtchev2008, title = {An electrical gearbox by means of pole variation for induction and superconducting disc motor}, journal = {Journal of Physics: Conference Series}, volume = {97}, number = {1}, year = {2008}, note = {n/a}, abstract = {n/a}, author = {S In{\'a}cio and D In{\'a}cio and J M Pina and S Valtchev and M V Neves and A L Rodrigues} } @article {OA1816, title = {Power electronics performance in cryogenic environment: evaluation for use in HTS power devices}, journal = {Journal of Physics: Conference Series}, volume = {97}, year = {2008}, pages = {012219}, publisher = {iopscience}, abstract = {Power electronics (PE) plays a major role in electrical devices and systems, namely in electromechanical drives, in motor and generator controllers, and in power grids, including high-voltage DC (HVDC) power transmission. PE is also used in devices for the protection against grid disturbances, like voltage sags or power breakdowns. To cope with these disturbances, back-up energy storage devices are used, like uninterruptible power supplies (UPS) and flywheels. Some of these devices may use superconductivity. Commercial PE semiconductor devices (power diodes, power MOSFETs, IGBTs, power Darlington transistors and others) are rarely (or never) experimented for cryogenic temperatures, even when designed for military applications. This means that its integration with HTS power devices is usually done in the hot environment, raising several implementation restrictions. These reasons led to the natural desire of characterising PE under extreme conditions, e. g. at liquid nitrogen temperatures, for use in HTS devices. Some researchers expect that cryogenic temperatures may increase power electronics{\textquoteright} performance when compared with room-temperature operation, namely reducing conduction losses and switching time. Also the overall system efficiency may increase due to improved properties of semiconductor materials at low temperatures, reduced losses, and removal of dissipation elements. In this work, steady state operation of commercial PE semiconductors and devices were investigated at liquid nitrogen and room temperatures. Performances in cryogenic and room temperatures are compared. Results help to decide which environment is to be used for different power HTS applications.}, url = {http://oa.uninova.pt/1816/}, author = {P Pereira and S Valtchev and J. Pina and A Gon{\c c}alves and M Ventim Neves and A L Rodrigues} } @article {Valtchev2008, title = {Power electronics performance in cryogenic environment: Evaluation for use in HTS power devices}, journal = {Journal of Physics: Conference Series}, volume = {97}, number = {1}, year = {2008}, note = {n/a}, abstract = {n/a}, author = {P Pereira and S Valtchev and J. Pina and Gon?alves, A. and M V Neves and A L Rodrigues} } @article {OA1817, title = {A test rig for thrust force measurements of an all HTS linear synchronous motor}, journal = {Journal of Physics: Conference Series}, volume = {97}, year = {2008}, pages = {012220}, publisher = {IOPScience}, abstract = {This paper presents the design of a test rig for an all HTS linear synchronous motor. Although this motor showed to have several unattractive characteristics, its design raised a number of problems which must be considered in future HTS machines design. HTS electromagnetic properties led to the development of new paradigms in electrical machines and power systems, as e. g. in some cases iron removal and consequent assembly of lighter devices. This is due to superconductor{\textquoteright}s ability to carry high currents with minimum losses and consequent generation in the surrounding air of flux densities much higher than the allowed by ferromagnetic saturation. However, severe restrictions in HTS power devices design that goes further beyond cryogenic considerations must be accounted in. This is usually the case when BSCCO tapes are used as conductors. Its bending limitations and the presence of flux components perpendicular to tape surface, due to the absence of iron, have to be considered for it may turn some possible applications not so attractive or even practically unfeasible. An all HTS linear synchronous motor built by BSCCO tapes as armature conductors and two trapped-flux YBCO bulks in the mover was constructed and thrust force measurements are starting to be performed. Although the device presents severe restrictions due to the exposed and other reasons, it allowed systematising its design. A pulsed-field magnetiser to generate opposite fluxes for both YBCO bulks is also detailed. Thrust force numerical predictions were already derived and presented.}, url = {http://oa.uninova.pt/1817/}, author = {J. Pina and P Pereira and S Valtchev and A Gon{\c c}alves and M Ventim Neves and A Alvarez and L Rodrigues} } @article {Valtchev2008, title = {A test rig for thrust force measurements of an all HTS linear synchronous motor}, journal = {Journal of Physics: Conference Series}, volume = {97}, number = {1}, year = {2008}, note = {n/a}, abstract = {n/a}, author = {J. Pina and P Pereira and S Valtchev and Gon?alves, A. and M V Neves and A Alvarez and L Rodrigues} } @conference {OA1044, title = {Power Electronics Performance in Cryogenic Environment: Evaluation for Use in HTS Power Devices}, booktitle = {8th European Conference on Applied Superconductivity (EUCAS)}, year = {2007}, month = {September}, abstract = {Power electronics (PE) plays a major role in electrical devices and systems, namely in electromechanical drives, in motor and generator controllers, and in power grids, including high-voltage DC (HVDC) power transmission. PE is also used in devices for the protection against grid disturbances, like voltage sags or power breakdowns. To cope with these disturbances, back-up energy storage devices are used, like uninterruptible power supplies (UPS) and flywheels. Some of these devices may use superconductivity. Commercial PE semiconductor devices (power diodes, power MOSFETs, IGBTs, power Darlington transistors and others) are rarely (or never) experimented for cryogenic temperatures, even when designed for military applications. This means that its integration with HTS power devices is usually done in the hot environment, raising several implementation restrictions. These reasons led to the natural desire of characterising PE under extreme conditions, e. g. at liquid nitrogen temperatures, for use in HTS devices. Some researchers expect that cryogenic temperatures may increase power electronics{\textquoteright} performance when compared with room-temperature operation, namely reducing conduction losses and switching time. Also the overall system efficiency may increase due to improved properties of semiconductor materials at low temperatures, reduced losses, and removal of dissipation elements. In this work, steady state operation of commercial PE semiconductors and devices were investigated at liquid nitrogen and room temperatures. Performances in cryogenic and room temperatures are compared. Results help to decide which environment is to be used for different power HTS applications}, url = {http://oa.uninova.pt/1044/}, author = {Pedro Pereira and S Valtchev and Jo{\~a}o Pina and Anabela Gon{\c c}alves and M{\'a}rio Neves and Amadeu Rodrigues} } @conference {OA1792, title = {An Electrical Gearbox by means of pole variation for induction and superconducting disc motor}, booktitle = {8th European Conference on Applied Superconductivity (EUCAS)}, year = {2007}, abstract = {In this paper, a poly-phase disc motor innovative feeding and control strategy, based on a variable poles approach, and its application to a HTS disc motor, are presented. The stator windings may be electronically commutated to implement a 2, 4, 6 or 8 poles winding, thus changing the motor{\textquoteright}s torque?speed characteristics. The motor may be a conventional induction motor with a conductive disc rotor, or a new HTS disc motor, with conventional copper windings at its two iron semi-stators, and a HTS disc as a rotor. The conventional induction motor{\textquoteright}s operation principle is related with the induced electromotive forces in the conductive rotor. Its behaviour, characteristics (namely their torque?speed characteristics for different number of pole pairs) and modelling through Steinmetz and others theories are well known. The operation principle of the motor with HTS rotor, however, is rather different and is related with vortices{\textquoteright} dynamics and pinning characteristics; this is a much more complex process than induction, and its modelling is quite complicated. In this paper, the operation was simulated through finite-elements commercial software, whereas superconductivity was simulated by the E-J power law. The Electromechanical performances of both motors where computed and are presented and compared. Considerations about the systems overall efficiency, including cryogenics, are also discussed.}, url = {http://oa.uninova.pt/1792/}, author = {S In{\'a}cio and D In{\'a}cio and J. Pina and S Valtchev and M Ventim Neves and A. Rodrigues} } @conference {OA1773, title = {High Performance, Environment Friendly, Modular and Fault Tolerant Renewable Energy Microgrid}, booktitle = {12th International Energy Conference \& Exhibition (ENERGEX2007)}, year = {2007}, url = {http://oa.uninova.pt/1773/}, author = {Jo{\~a}o Pina and C. Caracaleanu and A Gon{\c c}alves and Pedro Pereira and S Valtchev and M{\'a}rio Neves and A. Rodrigues} } @conference {OA1813, title = {A test rig for thrust force measurements f an all HTS linear synchronous motor}, booktitle = {8th European Conference on Applied Superconductivity (EUCAS)}, year = {2007}, abstract = {This paper presents the design of a test rig for an all HTS linear synchronous motor. Although this motor showed to have several unattractive characteristics, its design raised a number of problems which must be considered in future HTS machines design. HTS electromagnetic properties led to the development of new paradigms in electrical machines and power systems, as e. g. in some cases iron removal and consequent assembly of lighter devices. This is due to superconductor{\textquoteright}s ability to carry high currents with minimum losses and consequent generation in the surrounding air of flux densities much higher than the allowed by ferromagnetic saturation. However, severe restrictions in HTS power devices design that goes further beyond cryogenic considerations must be accounted in. This is usually the case when BSCCO tapes are used as conductors. Its bending limitations and the presence of flux components perpendicular to tape surface, due to the absence of iron, have to be considered for it may turn some possible applications not so attractive or even practically unfeasible. An all HTS linear synchronous motor built by BSCCO tapes as armature conductors and two trapped-flux YBCO bulks in the mover was constructed and thrust force measurements are starting to be performed. Although the device presents severe restrictions due to the exposed and other reasons, it allowed systematising its design. A pulsed-field magnetiser to generate opposite fluxes for both YBCO bulks is also detailed. Thrust force numerical predictions were already derived and presented.}, url = {http://oa.uninova.pt/1813/}, author = {Jo{\~a}o Pina and Pedro Pereira and S Valtchev and A Gon{\c c}alves and M{\'a}rio Neves and A. Rodrigues} } @conference {OA791, title = {Topology of an Electrical Gearbox with Variable Poles for Induction and Superconducting Disc Motors}, booktitle = {X Portuguese-Spanish Congress in Electrical Engineering}, year = {2007}, url = {http://oa.uninova.pt/791/}, author = {In{\'a}cio Steve and Jo{\~a}o Pina and Stanimir Valtchev and M{\'a}rio Neves and Amadeu Rodrigues} } @conference {OA2020, title = {Efficient Resonant Inductive Coupling Energy Transfer Using New Magnetic and Design Criteria}, booktitle = {IEEE 36th Power Electronics Specialists Conference, PESC {\textquoteright}05}, year = {2005}, month = {June}, pages = {1293{\textendash}1298}, abstract = {This paper describes some theoretical and experimental results obtained in an effort to optimize the Series Resonant Converter (SRC) when used with a loosely coupled transformer for Inductive Coupling Power Transfer (ICPT). The main goal of this work is to define precisely which mode of operation of the power stage is the most efficient. The results also suggest a way to choose the design criteria for the physical parameters (operation frequency, characteristic impedance, transformer ratio, etc.) to achieve that mode of operation. The analysis involves also the investigation of the separated in two halves pot core ferrite transformer, especially the way it changes its magnetizing and leakage fluxes and hence, inductances. It is shown that for the practical values of the separation distance, the leakage inductance remains almost unchanged. Nevertheless the current distribution between the primary and the secondary windings changes drastically due to the large variation of the magnetizing inductance. The analysis has lead to a set of equations with solutions that show graphically the way to an optimized operation of the converter, i.e. higher primary currents and higher transformer ratios to fit in the desired mode.}, url = {http://oa.uninova.pt/2020/}, author = {Stanimir Valtchev and Kostadin Brandisky and Beatriz Borges and J. Ben Klaassens} } @article {Valtchev2005, title = {Efficient resonant inductive coupling energy transfer using new magnetic and design criteria}, journal = {PESC Record - IEEE Annual Power Electronics Specialists Conference}, volume = {2005}, year = {2005}, note = {n/a}, pages = {1293-1298}, abstract = {n/a}, author = {S Valtchev and BV Borges and Brandisky, K. and JB Klaassens} } @conference {OA2019, title = {Magnetic and Design Criteria for Inductive Coupling Energy Transfer}, booktitle = {5th Conference on Telecommunications CONFTELE}, year = {2005}, url = {http://oa.uninova.pt/2019/}, author = {Stanimir Valtchev and Kostadin Brandisky and Beatriz Borges and J. Ben Klaassens} } @conference {Stanimir_Valtchev23921489, title = {Magnetic and Design Criteria for Inductive Coupling Energy Transfer}, booktitle = {Conference on Telecommunications CONFTELE, , Proceedings ISBN 972{\textendash}98115{\textendash}9{\textendash}8, paper Cr1107, Tomar}, year = {2005}, note = {n/a}, abstract = {n/a}, isbn = {972{\textendash}98115{\textendash}9{\textendash}8}, author = {Stanimir Valtchev} } @conference {OA2335, title = {Contactless Energy Transmission with Optimal Efficiency}, booktitle = {IEEE 28th Annual Conference of the Industrial Electronics Society IECON 02}, year = {2002}, month = {November}, pages = {1330{\textendash}1335}, url = {http://oa.uninova.pt/2335/}, author = {Stanimir Valtchev and Beatriz Borges and J. Ben Klaassens} } @article {Valtchev2002, title = {Contactless energy transmission with optimal efficiency}, journal = {IECON Proceedings (Industrial Electronics Conference)}, volume = {2}, year = {2002}, note = {n/a}, pages = {1330-1335}, abstract = {n/a}, author = {S Valtchev and BV Borges and JB Klaassens} } @conference {OA2409, title = {Series Resonant Converter Applied to Contactless Energy Transmission}, booktitle = {3rd Conference on Telecommunications CONFTELE}, year = {2001}, month = {April}, pages = {474{\textendash}478}, url = {http://oa.uninova.pt/2409/}, author = {Stanimir Valtchev and Beatriz Borges and J. Ben Klaassens} } @conference {OA2016, title = {A Basic Computer?Aided Course on Dynamic Processes in Mechatronic Systems for Aeronautical Engineers}, booktitle = {9th Annual Conference of the European Association for Education in Electrical and Information Engineering (EAEEIE)}, year = {1998}, month = {May}, pages = {293{\textendash}298}, url = {http://oa.uninova.pt/2016/}, author = {S. Volsky and Elena Lomonova and J. Ben Klaassens and Stanimir Valtchev} } @conference {Stanimir_Valtchev23921507, title = {A Basic Computer{\textendash}Aided Course on Dynamic Processes in Mechatronic Systems for Aeronautical Engineers}, booktitle = {European Association for Education in Electrical and Information Engineering (EAEEIE) 9th Annual Conference, Lisbon}, year = {1998}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @article {OA1994, title = {A multiple-switch high-voltage DC-DC converter}, journal = {IEEE Transactions on Industrial Electronics}, volume = {IE-44}, number = {6}, year = {1997}, month = {December}, pages = {780{\textendash}787}, publisher = {IEEE}, abstract = {Series connection of power devices has evolved into a mature technique and is widely applied in HV dc systems. Static and dynamic voltage balance is ensured by shunting individual devices with dissipative snubbers. The snubber losses become pronounced for increased operating frequencies and adversely affect power density. Capacitive snubbers do not exhibit these disadvantages, but they require a zero-voltage switching mode. Super-resonant power converters facilitate the principle of zero-voltage switching. A high-voltage dc-dc power converter with multiple series-connected devices is proposed. It allows the application of nondissipating snubbers to assist the voltage sharing between the multiple series-connected devices and lowers turn-off losses. Simulation results obtained with a circuit simulator are validated in an experimental converter operating with two series-connected devices. The behavior of the series connection is examined for MOSFET{\textquoteright}s and insulated gate bipolar transistors (IGBT{\textquoteright}s) by both experimental work with a 2-kW prototype and computer simulation. Applications can be found in traction and heavy industry, where the soft-switching converter is directly powered from a high-voltage source.}, url = {http://oa.uninova.pt/1994/}, author = {MPN vanWesenbeeck and JB Klaassens and U vonStockhausen and AMD Anciola and SS Valtchev} } @conference {OA2015, title = {An{\'a}lise Te{\'o}rica, Simula{\c c}{\~a}o, Optimiza{\c c}{\~a}o e Caracteriza{\c c}{\~a}o Experimental do Conversor CC?CC em Ponte Completa, com Modula{\c c}{\~a}o de Fase, Comuta{\c c}{\~a}o no Zero da Tens{\~a}o e Bobina de Coeficiente de Auto?indu{\c c}{\~a}o Vari{\'a}vel}, booktitle = {Ia Conferencia de Telecomunica{\c c}{\~o}es CONFTELE}, year = {1997}, month = {April}, pages = {471{\textendash}474}, url = {http://oa.uninova.pt/2015/}, author = {J. Beirante and Beatriz Borges and Stanimir Valtchev} } @conference {OA2013, title = {Design Improvement and Experimental Characterization of the Full Bridge, Faze Shift, Zero Voltage Switched DC?DC Converter with Secondary Clamped Inductor}, booktitle = {European Power Electronics Conference EPE?97}, year = {1997}, pages = {4.448{\textendash}4.453}, url = {http://oa.uninova.pt/2013/}, author = {J. Beirante and Beatriz Borges and Stanimir Valtchev} } @booklet {OA1996, title = {IEEE Meritorious Paper Award for 1996}, year = {1997}, url = {http://oa.uninova.pt/1996/}, author = {Stanimir Valtchev} } @article { valtchev1997, title = {A multiple-switch high-voltage dc-dc converter}, journal = {IEEE Transactions on Industrial Electronics}, volume = {44}, number = {6}, year = {1997}, note = {n/a}, pages = {780-787}, abstract = {n/a}, author = {MPN vanWesenbeeck and JB Klaassens and U vonStockhausen and Mu{\~n}oz De Morales Anciola, A. and SS Valtchev} } @conference {OA2011, title = {LkW?250 kHz full bridge zero voltage switched phase shift DC-DC converter with improved efficiency}, booktitle = {17th International Telecommunications Energy Conference, INTELEC {\textquoteright}95}, year = {1995}, month = {October}, pages = {803{\textendash}807}, url = {http://oa.uninova.pt/2011/}, author = {S Valtchev and BV Borges and V Anunciada} } @conference {OA2009, title = {A multiple-switch high-voltage DC-DC converter}, booktitle = {17th Telecommunications Energy Conference, INTELEC {\textquoteright}95}, year = {1995}, month = {October}, pages = {322{\textendash}329}, url = {http://oa.uninova.pt/2009/}, author = {MPN vanWesenbeeck and JB Klaassens and U vonStockhausen and AMD Anc{\'\i}ola and SS Valtchev} } @conference {OA2012, title = {Improved Full?Bridge Zero?Voltage?Switched Phase?Shift DC?DC Converter Using a Secondary?Clamped Inductor}, booktitle = {Proceedings of the 1995 IEEE Industrial Electronics, Control, and Instrumentation IECON 21st International Conference}, year = {1995}, month = {November}, pages = {258{\textendash}264}, url = {http://oa.uninova.pt/2012/}, author = {Stanimir Valtchev and Beatriz Borges} } @article {OA1993, title = {Super?Resonant Converter with Switched Resonant Inductor with PFM?PWM Control,}, journal = {IEEE Transactions on Power Electronics}, volume = {10}, number = {6}, year = {1995}, month = {November}, pages = {760{\textendash}765}, publisher = {IEEE}, url = {http://oa.uninova.pt/1993/}, author = {Stanimir Valtchev and J. Ben Klaassens and Marinus van Wesenbeeck} } @unpublished {OA2371, title = {Super-resonant power converter operation in soft-switching mode}, journal = {Seminar of S.Valtchev on the new PhD thesis chapter}, year = {1995}, month = {February}, abstract = {This new chapter of the PhD thesis was an addition to the presented already material at TU Sofia, Bulgaria. This was necessary to obtain the permission to prepare the thesis for its final version. Unfortunatelly this thesis was never presented but it served for the core to the presented in IST, Portugal, later on.}, url = {http://oa.uninova.pt/2371/}, author = {Stanimir Valtchev} } @article { valtchev1995, title = {1 kW/250 kHz full bridge zero voltage switched phase shift DC-DC converter with improved efficiency}, journal = {INTELEC, International Telecommunications Energy Conference (Proceedings)}, year = {1995}, note = {n/a}, pages = {803-807}, abstract = {n/a}, author = {Stanimir Valtchev and Beatriz V. Borges and Anunciada, Victor} } @article {Valtchev1995, title = {1 kW/250 kHz full bridge zero voltage switched phase shift DC-DC converter with improved efficiency}, journal = {INTELEC, International Telecommunications Energy Conference (Proceedings)}, year = {1995}, note = {n/a}, pages = {803-807}, abstract = {n/a}, author = {Stanimir Valtchev and Beatriz V. Borges and Anunciada, Victor} } @article { valtchev1995, title = {Improved full bridge zero voltage switched phase shift DC/DC converter using a secondary clamped inductor}, journal = {IECON Proceedings (Industrial Electronics Conference)}, volume = {1}, year = {1995}, note = {n/a}, pages = {258-264}, abstract = {n/a}, author = {Stanimir Valtchev and Beatriz V. Borges} } @article { valtchev1995, title = {Improved full bridge zero voltage switched phase shift DC/DC converter using a secondary clamped inductor}, journal = {IECON Proceedings (Industrial Electronics Conference)}, volume = {1}, year = {1995}, note = {n/a}, pages = {258-264}, abstract = {n/a}, author = {Stanimir Valtchev and Beatriz V. Borges} } @inbook {a61fcaf1530b4022be09f37907d1f043, title = {LkW/250 kHz full bridge zero voltage switched phase shift DC-DC converter with improved efficiency}, booktitle = {INTELEC 95 - SEVENTEENTH INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE}, year = {1995}, note = {n/a}, pages = {803{\textendash}807}, publisher = {IEEE}, organization = {IEEE}, abstract = {n/a}, isbn = {0-7803-2750-0}, author = {S Valtchev and Borges, {B. V.} and V Anunciada} } @article { valtchev1995, title = {Multiple switch high-voltage DC-DC converter}, journal = {INTELEC, International Telecommunications Energy Conference (Proceedings)}, year = {1995}, note = {n/a}, pages = {322-329}, abstract = {n/a}, author = {MPN vanWesenbeeck and JB Klaassens and U vonStockhausen and Munoz de Morales Anciola, A. and SS Valtchev} } @article {Valtchev1995, title = {Super-Resonant Converter with Switched Resonant Inductor with PFM-PWM Control}, journal = {IEEE Transactions on Power Electronics}, volume = {10}, number = {6}, year = {1995}, note = {n/a}, pages = {760-765}, abstract = {n/a}, author = {SS Valtchev and van Wesenbeeck, M.P.} } @mastersthesis {OA2075, title = {Modelvorming en simulatie van een super-resonante converter met een hoogspanningstransformator}, year = {1993}, month = {September}, school = {TU Delft}, type = {masters}, abstract = {VEEM93A13}, url = {http://oa.uninova.pt/2075/}, author = {Andre Wahjudi}, editor = {J. Ben Klaassens and Stanimir Valtchev and MPN vanWesenbeeck} } @conference {OA1997, title = {High Efficiency Resonant Power Conversion}, booktitle = {High Efficiency Resonant Power Conversion}, year = {1992}, month = {April}, abstract = {Mode of operation and area of rnhanced efficiency for series-resonant converters is presented. Frequency control on voltage source DC-DC converters is discussed and other principles of control are introduced. Optimum modes of operation for power transistor resonant converters are also considered. For even better efficiency a resonant current shaping is discussed.}, url = {http://oa.uninova.pt/1997/}, author = {Stanimir Valtchev} } @conference {OA2007, title = {Some Regulation Characteristics of Pulse?Width Modulated Series Resonant Power Conversion}, booktitle = {6th Conference on Power Electronics and Motion Control PEMC{\textquoteright}90}, year = {1990}, month = {October}, pages = {83{\textendash}87}, url = {http://oa.uninova.pt/2007/}, author = {Stanimir Valtchev} } @article {OA1992, title = {Efficient Resonant Power Conversion}, journal = {IEEE Transactions on Industrial Electronics}, volume = {37}, number = {6}, year = {1990}, pages = {490{\textendash}495}, publisher = {IEEE}, abstract = {The DC analysis of a series-resonant converter operating above resonant frequency is presented. The results are used to analyze the current form factor and its effect on the efficiency. The selection of the switching frequency to maximize the efficiency is considered. The derived expressions are generalized and can be applied to calculations in any of the switching modes for a series-resonant circuit. For switching frequencies higher than the resonant frequency, an area of more efficient operation is indicated which will aid in the design of this class of converters and power supplies. It is pointed out that (especially for power MOSFETs where ohmic losses dominate) it is more attractive to select switching frequencies that are higher than the resonant frequency because of the possibility of nondissipative snubbers. Slowing down the rise of the gate voltage and, hence, the slow decrease of ON resistance during turn-on is also not a drawback to high-frequency switching. Because of this safer operation, the standard intrinsic diode of the power MOSFET could be used at high frequencies instead of the more expensive FREDFET}, url = {http://oa.uninova.pt/1992/}, author = {Stanimir Valtchev and J. Ben Klaassens} } @article {Valtchev1990, title = {Efficient Resonant Power Conversion}, journal = {IEEE Transactions on Industrial Electronics}, volume = {37}, number = {6}, year = {1990}, note = {n/a}, pages = {490-495}, abstract = {n/a}, author = {SS Valtchev and JB Klaassens} } @conference {OA2008, title = {High Efficiency Resonant Power Conversion}, booktitle = {1st USSR Conference (with international participation) of Power Electronics Systems and Low?Power Converters Equipment (SES i UMPT)}, year = {1990}, url = {http://oa.uninova.pt/2008/}, author = {Stanimir Valtchev and J. Ben Klaassens} } @conference {Stanimir_Valtchev23921514, title = {High Efficiency Resonant Power Conversion}, booktitle = {1st USSR Conference (with international participation) of Power Electronics Systems and Low{\textendash}Power Converters Equipment (SES i UMPT), Alma{\textendash}Ata, USSR}, year = {1990}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921517, title = {Some Regulation Characteristics of Pulse{\textendash}Width Modulated Series Resonant Power Conversion}, booktitle = {6th Conference PEMC{{\textquoteright}}90, pp. 83{\textendash}87, Budapest}, year = {1990}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {OA2006, title = {Equipment for Measuring the Road?Tyre Cohesion}, booktitle = {6th National Congress of Mechanics}, year = {1989}, month = {September}, url = {http://oa.uninova.pt/2006/}, author = {Alexander Tatzov and D. Dimitrov and T. Borisov and R. Botchev and P. Pashov and P. Petrov and D. Petrov and Stanimir Valtchev} } @conference {OA2005, title = {Some Properties of the Transistor Series Resonant Power Convertors}, booktitle = {The Day of the Radio Conference}, year = {1989}, month = {May}, url = {http://oa.uninova.pt/2005/}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921526, title = {Equipment for Measuring the Road{\textendash}Tyre Cohesion}, booktitle = {6th National Congress of Mechanics, Varna}, year = {1989}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {Stanimir_Valtchev23921528, title = {Some Properties of the Transistor Series Resonant Power Convertors}, booktitle = {The Day of the Radio Conference, 5{\textendash}6 May 1989, Sofia}, year = {1989}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {OA2003, title = {Behavior of the Series Resonant Energy Converter at Frequencies Differing from the Resonant One}, booktitle = {The Day of the Radio Conference}, year = {1988}, month = {May}, url = {http://oa.uninova.pt/2003/}, author = {Stanimir Valtchev and Georgi Krustev} } @conference {OA2004, title = {Experimental Results of the MOS Transistor Series Resonant Energy Converter Exploration}, booktitle = {The Day of the Radio Conference}, year = {1988}, month = {May}, url = {http://oa.uninova.pt/2004/}, author = {Stanimir Valtchev and Georgi Krustev} } @conference {OA2002, title = {Power Transistor Pulse Generator for Technological Purposes}, booktitle = {Jubileum Scientific Session of VMEI?Gabrovo, Power Electronics Section}, year = {1986}, month = {October}, url = {http://oa.uninova.pt/2002/}, author = {Stanimir Valtchev and Georgi Krustev and Evgeni Popov} } @article {OA1991, title = {An Electronic System for Rowers{\textquoteright} Propulsion Motion Activities Studies}, journal = {Problems of the Physical Culture and Sport (now: "Sport and Science Magazine")}, number = {2}, year = {1986}, month = {February}, pages = {13{\textendash}17}, url = {http://oa.uninova.pt/1991/}, author = {Vasil Vasilev and Vihren Batchev and Mihail Milev and Stanimir Valtchev and Alexander Tatzov} } @article {Stanimir_Valtchev11271310, title = {An Electronic System for Rowers{{\textquoteright}} Propulsion Motion Activities Studies}, journal = {Problems of the Fitness}, year = {1986}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @conference {OA2001, title = {PWM Servosystem for DC Motors Control}, booktitle = {Scientific and Technological Conference "Industrial Robots?84"}, year = {1984}, url = {http://oa.uninova.pt/2001/}, author = {Vasil Vasilev and Stanimir Valtchev} } @conference {OA2000, title = {Control System for Power Converter of DC to Sinusoidal AC Voltage}, booktitle = {National Conference (with international participation) of Power Electronics SILEKTRON?83}, year = {1983}, url = {http://oa.uninova.pt/2000/}, author = {Branimir Natchev and Stanimir Valtchev} } @conference {OA1999, title = {Driver Circuit for Power Transistor Switches}, booktitle = {National Conference (with international participation) of Power Electronics SILEKTRON?83}, year = {1983}, url = {http://oa.uninova.pt/1999/}, author = {Branimir Natchev and Stanimir Valtchev} } @conference {OA1998, title = {Power Converter of DC to Sinusoidal AC Voltage for Robotic Purposes}, booktitle = {Scientific Session VMEI?83, Section Robotics}, year = {1983}, url = {http://oa.uninova.pt/1998/}, author = {Vasil Vasilev and Branimir Natchev and Stanimir Valtchev} } @unpublished {OA2370, title = {Power supply for 2 kW ? 25 kV CO2 gas laser}, year = {1980}, month = {September}, publisher = {Ministry of Science and Technology Bulgaria ? USSR (limited access)}, type = {Project Report}, abstract = {International project (1251?78 and 1252?78) in which the Technical University of Sofia (S.Valtchev, N.Stefanov) has sucessfully acomplished the task of constructing and implementing in production a high precision (0.01\% regulation) power supply for a cirurgical laser tool (1977-1980). The construction involved a vacuum tube cascaded with MOS-FET to obtain very high quality current source necessary for the stable characteristics of the gas discharge in the laser tube.}, keywords = {CO2, laser, medicine, precision}, url = {http://oa.uninova.pt/2370/}, author = {Stanimir Valtchev} } @article {OA1990, title = {Experimental Research of the Boron Nitride Diffusion}, journal = {Elektropromishlenost i Priborostroene (now: Elektrotechnica \& Elektronica)}, number = {1}, year = {1978}, month = {January}, pages = {31{\textendash}35}, url = {http://oa.uninova.pt/1990/}, author = {Alexander Atanasov and Ivan Valtchev and Dobrinka Kolevska and Stanimir Valtchev} } @article {Stanimir_Valtchev11271297, title = {Experimental Research of the Boron Nitride Diffusion}, journal = {Elektropromishlenost i Priborostroene}, year = {1978}, note = {n/a}, abstract = {n/a}, author = {Stanimir Valtchev} } @booklet {OA2179, title = {Eng. Stanimir Valtchev, Top MSc Graduate of the year 1974, Award and Engraved Wrist-Watch}, year = {1974}, month = {September}, publisher = {Rector of TU Sofia, Bulgaria}, abstract = {Eng. Stanimir Valtchev, Top MSc Graduate of the year 1974, Specialized in Technology of Electronic Equipment and Integrated Circuits}, url = {http://oa.uninova.pt/2179/}, author = {Stanimir Valtchev} }