Stanimir Valtchev

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.

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.

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.

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.

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.

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.

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.