Research And Application Of MMC Converter Based On SIC

VSC-HVDC is an important means to solve the problem of long-distance transmission or high-voltage transmission technology.MMC is the converter topology with the widest application,highest efficiency and best output power quality in VSCHVDC.With the more mature fabrication technology of silicon carbide materials,silicon carbide power devices provide experimental basis for the improvement of power systems in technologies such as greatly reducing switching losses.The research and application of the SiC-MMC is to combine SiC power device with the MMC-HVDC,which is an important technical means to improve the efficiency and life of the MMC-HVDC system.Based on the accurate modeling and simulation of SiC power devices,this paper applies Ethernet-based hardware co-simulation technology to large-scale power system simulation,and uses shared memory to optimize the allocation of simulation system resources as a technological innovation,designs the MMC converter simulation system and its hardware circuit based on the SiC.According to this,this paper designs the real-time communication system and control platform design of SiC-MMC converter based on AURORA.The main research contents are as follows:1.This paper studies the module library of simscape and its basic modeling method,puts forward a parametric modeling idea to realize data fitting by means of lookup table method,realizes the accurate modeling and simulation of silicon carbide power devices.Through the in-depth study of the working principle and conduction characteristics of silicon carbide power devices,this paper introduces the specific modeling methods of nonlinear variable resistors and nonlinear variable capacitance elements,verifies the usability and accuracy of the models through comparative analysis.2.Aiming at the technical problem that the simulation time of large power electronic system or complex model is too long,this paper uses the self-designed SiC power device simulation model to build the SiC-MMC simulation system.Using FPGA Hardware Collaborative simulation technology based on Ethernet and System Generator components,this paper realizes the real-time simulation of SiC-MMC,realizes the optimization of resource allocation of simulation system based on shared memory.3.Based on the selection of silicon carbide power switch devices and sub-module controllers and the main hardware circuits such as the main circuit of the system,power device drive circuit,AD acquisition circuit,power supply circuit and peripheral interface circuit,this paper designs the hardware circuit of the SiC-MMC and the comparison of SiC-MMC characteristics.Based on SiC-MMC system,this paper improves the simulation technology level to the physical level,which provides an experimental platform for the subsequent research and application.4.Based on XILINX FPGA's GTP high-speed serial transceiver,AXI4 data flow protocol and AURORA communication protocol design SiC-MMC Real-time communication system,this paper realizes the 1.25 G optical fiber communication system between module controllers.Based on AURORA's SiC-MMC real-time communication system,this paper designs a SiC-MMC control platform based on AURORA and its control strategy.