Real-time Simulation Model of Modular Multilevel Converter With Sorting Network Integrated

In order to achieve real-time simulation of modular multilevel converter (MMC), an efficient MMC real-time simulation model was proposed based on real time digital simulation (RTDS) platform and implemented with field programmable gate array (FPGA). Pipeline technology was utilized to implement equivalent calculation of MMC arms. Fast capacitor voltage balancing control were implemented in FPGA by integrating the bitonic sorting network to avoid massive amount of real-time data throughput, such as sub-module (SM) capacitor voltages and trigger signals. A single-terminal 201-level test system was built based on this model and compared with PSCAD/EMTDC results. Moreover, the FPGA resource utilization and timing performance under different number of pipelines and levels were discussed. Analysis results show that the model has high integration level and simulation accuracy, and can be used to simulate up to 501-level MMC with a single ML605 evaluation board. The model is suitable for building real-time simulation platform of large-scale DC grid including MMC. © 2020, Power System Technology Press. All right reserved.