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Series Resonant Converter Applied to Contactless Energy Transmission, Valtchev, Stanimir, Borges Beatriz V., and Klaassens JB , (Submitted) Abstract
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2019
Development of a Control Algorithm for Three-Phase Inverter in Two-Phase Electric Drives Reducing the Number of Commutations, Belousov, {Aleksey Sergeevich}, Meshcheryakov {Viktor Nikolayevich}, Valtchev Stanimir, and Kryukov {Oleg Viktorovich} , Proceedings - 2019 1st International Conference on Control Systems, Mathematical Modelling, Automation and Energy Efficiency, SUMMA 2019, 11, United States, p.444–449, (2019) 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.

Comparison of Spiral and Square Coil Configurations in Wireless Power Transfer System for Contactless Battery Charging, Al-Saadi, M., Valtchev S., Romba L., Gon?alves J., and Cr?ciunescu A. , 2019 Electric Vehicles International Conference, EV 2019, (2019) Abstract
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Control for the Contactless Series Resonant Energy Converter, Valtchev, Stan, and Valtchev Svilen , Emerging Capabilities and Applications of Wireless Power Transfer, p.102–140, (2019) 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).

Efficiency Improvement in Wireless Power System, Romba, Luis, and Valtchev Stan , Emerging Capabilities and Applications of Wireless Power Transfer, p.23–48, (2019) 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.

Electromagnetic Influence of WPT on Human's Health: Modelling, Simulation, and Measurement, Baikova, {Elena N. }, Romba Luis, and Valtchev Stan , Emerging Capabilities and Applications of Wireless Power Transfer, p.141–161, (2019) 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.

Energy saving system of cascade variable frequency induction electric drive, Meshcheryakov, V. N., Lastochkin D. V., Shakurova Z. M., and Valtchev S. , E3S Web of Conferences, Volume 124, (2019) Abstract
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Minimization of the stator current in induction motor with defined load on the shaft by maintaining optimum absolute slip, Meshcheryakov, V. N., Danilov V. V., Khasanov Sh.R., and Valtchev S. , E3S Web of Conferences, Volume 124, (2019) Abstract
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Three-Phase Unidirectional Transformerless Hybrid Rectifier with Boost Converter, Goncalves, J. T., Valtchev S., Melicio R., and Al-Saadi M. , Proceedings - 2019 IEEE 1st Global Power, Energy and Communication Conference, GPECOM 2019, p.158-163, (2019) Abstract
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2018
Asynchronous electric drive power-hardware-in-the-loop system, Mudrov, Mikhail, Ziuzev Anatoliy, Nesterov Konstantin, and Valtchev Stanimir , Proceedings - 2018 17th International Ural Conference on AC Electric Drives, ACED 2018, 4, Volume 2018-April, United States, p.1–5, (2018) 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.

Design and analysis of wireless sensor network powered through neutral to earth voltage, Mihaylov, Kaloyan, Arnaudov Rumen, and Valtchev Stanimir , Proceedings - 2018 17th International Ural Conference on AC Electric Drives, ACED 2018, 4, Volume 2018-April, United States, p.1–6, (2018) 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's electric current and the corresponding neutral conductor'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't require specialized devices.

On reliability and energy efficiency increasing of the vehicles electric drives, Braslavsky, {Isaak Ya}, Metelkov {Vladimir P. }, Kostylev {Alex V. }, and Valtchev Stanimir , Proceedings - 2018 17th International Ural Conference on AC Electric Drives, ACED 2018, 4, Volume 2018-April, United States, p.1–6, (2018) 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.

Electromagnetic field generated by a wireless energy transfer system: comparison of simulation to measurement, Baikova, {E. N. }, Romba L., Valtchev {S. S. }, Melicio R., {Fernão Pires} V., Krusteva A., and Gigov G. , Journal of Electromagnetic Waves and Applications, 3, Volume 32, Number 5, p.554–571, (2018) 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.

Power electrical drive Power-Hardware-in-the-Loop system: 2018 X International Conference on Electrical Power Drive Systems (ICEPDS), Mudrov, Mikhail, Ziuzev Anatoliy, Nesterov Konstantin, and Valtchev Stanimir , 2018 10th International Conference on Electrical Power Drive Systems, ICEPDS 2018 - Conference Proceedings, 12, United States, (2018) 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.

Identification of the Common Mode Impedance of a Microgrid DC-DC Buck Converter in Normal Service and under Insulation Fault, Bensaad, Djelloul, Hadjadj A., Ales Achour, and Valtchev Stanimir , Proceedings - 2018 IEEE 18th International Conference on Power Electronics and Motion Control, PEMC 2018, 11, United States, p.1079–1084, (2018) 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.

An Improved Voltage Ripple Control Algorithm for Modular Multilevel Converter Based Variable Speed Drive, Bashir, {Safia Babikir}, Zidan {Hasan A. }, and Valtchev Stanimir , Proceedings - 2018 IEEE 18th International Conference on Power Electronics and Motion Control, PEMC 2018, 11, United States, p.968–973, (2018) 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.

Electric Drives Power-Hardware-in-the-Loop System Structures, Mudrov, Mikhail, Ziuzev Anatoliy, Nesterov Konstantin, and Valtchev Stanimir , 2018 20th European Conference on Power Electronics and Applications, EPE 2018 ECCE Europe, 10, United States, (2018) 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.

Simulation and experiment on electric field emissions generated by wireless energy transfer, Baikova, {E. N. }, Romba L., Melicio R., and Valtchev {S. S. } , Technological Innovation for Resilient Systems - 9th IFIP WG 5.5/SOCOLNET Advanced Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2018, Proceedings, 1, p.243–251, (2018) 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.

Wireless battery charger for EV with circular or planar coils: comparison, Romba, L., Baikova {E. N. }, Borges C., Melicio R., and Valtchev {S. S. } , Technological Innovation for Resilient Systems - 9th IFIP WG 5.5/SOCOLNET Advanced Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2018, Proceedings, 1, p.214–223, (2018) 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.

Perspectives and Trends of Electric Vehicle Development with Wireless Charging System, Mescheryakova, O., Mescheryakov {Viktor Nikolaevich}, and Valtchev Stan , 1st International Conference on Infocommunications and Intelligent Transport Technologies (IITT´2018). Proceedings, p.235–241, (2018) Abstract
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