Research On Zero-low-speed Characteristics Of Electric Vehicle Without Position Sensor

In the sensorless control system of built-in permanent magnet synchronous motor at zero low speed,high-precision rotor position and speed information must be estimated to ensure the stable operation of IPMSM and electric vehicles.However,the rotor position and speed estimated by IPMSM sensorless high-frequency voltage injection control strategy usually have low accuracy due to the use of BPF,SFF and other filters in signal demodulation.To solve this problem,a new signal demodulation method is adopted.The high-frequency response current containing IPMSM rotor position information is demodulated and optimized by the second-order generalized integrator(SOGI)instead of BPF and SFF,and the estimated rotor position angle is compensated appropriately to improve the estimation accuracy of rotor position and speed.At the same time,this topic is combined with the S61 R&D project of Chery New Energy Pure Electric Vehicle Industrialization.Aiming at the problem of sudden failure of position sensor of electric vehicle when it is running normally,a control strategy without position sensor is constructed as a redundant system of middle and high-grade SUV electric vehicle in case of position sensor failure,so as to ensure that the electric vehicle can still run smoothly and safely at zero and low speed under the condition of position sensor failure.Therefore,aiming at IPMSM sensorless high-frequency voltage injection control strategy,a new signal demodulation method and phase compensation are adopted to optimize the estimation accuracy of rotor position and speed.Aiming at the position sensor failure,a position sensor failure judgment method and redundant switching strategy are constructed.When the position sensor is judged to be faulty,The position sensor control strategy of the electric vehicle will be switched to the IPMSM sensorless control strategy injected by the optimized rotating high-frequency voltage signal in time to estimate the rotor position and speed information,so as to continue to ensure its safe and stable operation at zero low speed.Then,Matlab/Simulink is used to simulate and verify the high accuracy of rotor position and speed estimated by the optimized IPMSM sensorless high-frequency voltage injection control strategy,and the feasibility of the constructed position sensor fault judgment method and redundant switching control strategy.At last,after analyzing the structure of electric vehicle control system,the experimental platform of IPMSM drive control system with DSPTMS320F28379 D as the main control chip and the hardwa re platform of dynamometer system that provides load for IPMSM are built,and the control strategy of this paper is driven,controlled, analyzed and verified by the upper computer.