Design And Implementation Of Modular Multi-level Convertor Electromagnetic Transient Process Real-time Simulator Based On FPGA

Modular multilevel converter(MMC)has many advantages,such as low harmonics,low switching frequency,high modularity and good scalability.It is widely used in high voltage applications of power grid.The electromagnetic transient simulation of MMC system is the research hot topic of electromagnetic transient simulation at the present stage.More and more electromagnetic transient real-time simulation system adopt Field Programmable Gate Array(FPGA).However,the research on MMC electromagnetic transient real-time simulation based on FPGA is not sufficient.Because of the weakness of the MMC electromagnetic transient real-time simulation system,such as the simulation step growth,the low accuracy and the small simulation scale,this paper proposes and implements a FPGA based MMC electromagnetic transient real-time simulation system.In order to ensure high precision of electromagnetic transient simulation data,the system uses IEEE-754 single precision floating-point standard.The multiple periodic mixed accumulation of data in the system of floating point numbers in the system will lead to the problem of data conflict.In order to solve this problem,this paper proposes a packet cycle hybrid accumulative circuit.The circuit architecture realizes the mixed accumulation of multiple data sets,and requires only a small amount of logical resources to achieve a significant increase in computational efficiency.In addition,the system can greatly improve the data throughput through the parallel bridge arm model,the packet parallel in the bridge arm and the deep pipeline technology.Compared with other similar systems,the maximum number of bridge arms in this system simulation increases from 3 to 12 in single board FPGA,sub-module maximum amount in each bridge arm increases from 512 to 640,and resources consuming per sub-module simulation are significantly reduced.The implementation of the system shows that the system designed in this paper can correctly carry out the system electromagnetic transient simulation of the MMC circuit,and the computation scale can reach 12 bridge arms,and 640 sub modules of each bridge arm in a single board.The calculated results are exactly the same with the standard data.The system can work correctly at the clock frequency of 150 MHz and reach a time step of 2?s,which meets the real-time requirement of the system electromagnetic transient simulation.In addition,the hardware resource consumption of the system is kept in a reasonable range after optimization,and it takes up 70.28% logical resources of the FPGA development board.Compared with the similar systems at present,the design of electromagnetic transient real-time simulation system for MMC circuits can support larger simulation scale and achieve higher computation speed and accuracy.