Stanimir Valtchev

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.

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.

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.

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.

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.

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.