Research On Real-time Simulation Of Power System With MMC Based On FPGA

Real-time simulation has become an effective means to study transient characteristics,communication planning and feasibility verification of secondary equipment through hardware-in-the-loop testing.Compared with the real-time simulation of traditional power systems,modular multilevel converter(MMC)has increased the computing power requirements of real-time simulation due to the existence of a large number of power electronic devices,FPGA has gradually become the main underlying hardware of the MMC real-time simulation platform due to its customizable and highly parallel characteristics.Aiming at the challenges of complex calculation of MMC new topology,difficult fault simulation,as well as limited hardware resources and difficulty in commercialization of FPGA,based on the FPGA universal real-time simulation platform(FRTDS),this thesis makes an in-depth study on the real-time simulation of power system with MMC.Aiming at solving the problem of large amount of pre stored data calculated by state space node method(SSN)in double port sub module MMC,a group diversity equivalent model for optimizing storage is proposed.In the SSN group division,the sub module connection simplification process is derived by using the sub module cascade structure of MMC bridge arm,so as to dynamically separate the sub modules that do not affect each other when calculated by state variable method,so as to optimize the pre stored data requirements.In order to realize the global fault test of MMC simulation system while retaining a large simulation scale,a dynamic fault setting area scheme is proposed.The scheme is extended on the basis of SSN,delimits a small fault setting area in the simulation system,realizes fault simulation and controls the additional calculation.Using the non centralized feature of real-time simulation fault test,the fault setting area can be changed in the simulation process to realize global fault test.The method and principle of the scheme realization are proposed by analyzing the dynamic process of the fault setting area.In order to improve the performance of FRTDS,the optimal use of resources is taken as the guiding ideology.The structure of FRTDS execution unit is optimized by analyzing the characteristics of SSN algorithm;Unify the query logic of the pre stored data of the group diversity equivalent model to simplify the design of the decoding circuit;The structure of FRTDS memory area is analyzed and the ping-pong buffer circuit is improved to realize the dynamic fault setting area scheme.The solution performance of the improved FRTDS is 1.17 times higher than that of the original structure.The MMC real-time simulation composed of double port sub module is realized in the improved FRTDS,the system simulation results show that the diversity equivalent model and fault setting scheme proposed in this thesis are correct.At the same time,when applied in FRTDS,it can realize more large-scale MMC real-time simulation.