Modular Multilevel Converter model implemented in FPGA for HIL test of industrial controllers

Since Modular Multilevel Converters (MMC) have a sophisticated control, the real time simulation platform becomes critical for hardware-in-the-loop (HIL) test of the actual controllers in various scenarios before commissioning. This paper presents a multi-rate real time simulator that is able to simulate electromagnetic transients of MMC systems and connect to industrial controllers through fiber optics and copper wires for HIL tests. The MMC is implemented in field-programmable gate array (FPGA) with a sub-μs time step and the rest of the power system is simulated in the central processing unit (CPU) with a time step of 10~50 μs. Input and output (I/O) drivers are implemented in the same FPGA for a fast-rate and low-latency communication. Each FPGA accommodates up to 1530 sub-modules (SM), and multiple FPGA connected to one simulator can simulate MMC with more SM and multi-MMC systems. The performance is demonstrated in a 1500-SM MMC study case.