Simulation of modular multilevel converter and DC grids on FPGA with sub-microsecond time-step

Abstract

Real-time simulation is an important tool of validating the performance of the modular multilevel converter (MMC). By using the field programmable gates array (FPGA), MMC valves with hundreds of sub-modules and the large number of inputs and outputs can be simulated in real-time. In the traditional FPGA based real-time simulation, only the MMC valves are implemented on FPGA, while the rest parts including AC or DC grids and inductors are implemented on CPU. However, the subsystem simulated on CPU has slower dynamics than the subsystem simulated on FPGA. There is a delay of CPU time-step between these two subsystems, which may affect the accuracy of the results especially under fault condition. This paper presents a real-time simulation of modular multilevel converters, and DC grids fully based FPGA with sub-microseconds time-step. Benefitting from using the electric hardware solver (eHS), all the components including the MMC valves and DC grid system can be easily implemented on FPGA. Thus, the high-fidelity of the simulation is guaranteed. The results of the proposed FPGA based real-time simulation are provided.