Research On Permanent Magnet Synchronous Motor Control System Of Electric Vehicle Based On SiC Inverter

In recent years,as people pay more and more attention to environmental issues,electric vehicles will gradually replace fuel-powered vehicles and become the most common means of transportation for people.As one of the three cores of electric vehicles,motor drives are gradually developing in the direction of high energy efficiency,high power density,and high reliability.Traditional silicon-based power devices have become increasingly difficult to meet the needs of new electric vehicle motor drivers due to their own material characteristics.Silicon carbide(SiC)power devices can effectively replace silicon-based power devices because of their high withstand voltage,high temperature resistance,and low loss characteristics.Applying it to the motor driver of electric vehicles can significantly increase the power density of the controller and reduce it.The volume meets the requirements of miniaturization and light weight.However,SiC MOSFET high-frequency applications will also cause unavoidable problems in the motor control system,such as bridge arm crosstalk and common mode interference,which affect the reliable operation of the control system.Therefore,analyzing and studying the key issues of SiC devices in permanent magnet synchronous motors is particularly important for the development of motor drives.This article first studies the driving characteristics of SiC MOSFETs.The static and dynamic operating characteristics of the SiC MOSFET power devices used are studied and analyzed.The crosstalk phenomenon of the bridge arms in the bridge circuit is theoretically analyzed,the extreme value formula of the crosstalk voltage is deduced,and several common crosstalk suppression are analyzed.Circuit,a new type of crosstalk suppression circuit is proposed,and the effectiveness of the new type of suppression circuit is verified by establishing a simulation model.This paper studies the control system of Permanent Magnet Synchronous Motor(PMSM).The structure of permanent magnet synchronous motor is theoretically analyzed,and its mathematical model is analyzed.According to the mathematical model of the permanent magnet synchronous motor,several different control strategies are studied,and the algorithm simulation model is built on Matlab/Simulink based on theoretical derivation,and the simulation verifies the feasibility of the control algorithm.n this paper,the vector modulation strategy of the inverter is improved.The reason of the common mode voltage that causes the common mode interference of the inverter is analyzed,and a voltage reconstruction type overmodulation strategy is proposed based on the vector modulation strategy that suppresses the common mode voltage.In addition,the negative effects caused by the dead zone in the low-speed region of the common-mode voltage suppression strategy are analyzed,and the dead zone compensation is carried out.A simulation model is built on the simulation platform for the improved inverter modulation strategy,and the simulation experiment verifies its superiority.Based on the theoretical research,this paper designs the hardware and software of the permanent magnet synchronous motor control system based on SiC inverter.The hardware circuit mainly includes the main control system circuit,the drive circuit of the SiC power device,the inverter main circuit and the sampling and conditioning circuit.The software control program is designed on the basis of the hardware circuit design.It mainly introduces the main program flow diagram,the main interrupt control block diagram and the inverter vector modulation strategy flow diagram.Finally,an experimental platform was built,the circuit was debugged,and the above theoretical research was experimentally verified.The results proved the feasibility of the new drive circuit and the improved inverter modulation strategy.