Research On Sensorless Composite Control Of Permanent Magnet Synchronous Motor For Electric Vehicles

The interior permanent magnet synchronous motor(IPMSM)is widely used in electric vehicles and rail transportation due to its advantages of high torque density,low noise,and strong robustness.In traditional drive control,mechanical sensors are commonly used to detect the motor rotor’s speed and position information.However,mechanical sensors generate errors due to environmental interference,which affects the performance of the drive control system.If the sensor fails due to malfunction,it may even lead to safety accidents.In recent years,sensorless technology has gradually become a new trend in development.This not only reduces the size and cost of the vehicle but also improves the safety performance under all operating conditions,with good application prospects.In this context,this paper focuses on the sensorless control of IPMSM in the entire speed range and investigates the control strategies based on the mid-high speed range,zero-low speed range,and the entire speed range.The main research work is as follows:(1)In response to the high frequency oscillation and phase delay problems caused by the traditional Sliding Mode Observer(SMO)in practical applications,a new high-speed control strategy for the IPMSM sensorless system with improved SMO is proposed.By analyzing and deriving the SMO algorithm,a new segmented exponential function is adopted to replace the traditional sign function in the SMO algorithm,and a phase-locked loop module is introduced to estimate the rotor position and speed information of the IPMSM.The stability of the algorithm is proven by the Lyapunov stability criterion.The improved SMO control strategy is simulated and analyzed using Matlab/Simulink,and the simulation results show that the improved SMO algorithm effectively reduces the high frequency oscillation and phase delay problems and improves the accuracy of the estimated rotor speed and position information.(2)In response to the poor accuracy of the SMO algorithm in estimating the motor speed and position in the zero and low-speed range,a rotating high-frequency voltage signal injection method is proposed to achieve accurate estimation.The principle of the rotating high-frequency voltage signal injection method is first derived using a mathematical model,and a rotor position observer is designed based on this principle.A simulation model is then constructed to analyze the performance of the proposed method.The simulation results show that the rotating highfrequency voltage injection method has good control effect and estimation accuracy in the zero and low-speed range.(3)Based on the advantages of the rotating high-frequency voltage signal injection method and the improved sliding mode observer(SMO)algorithm,a composite control strategy applicable to the entire speed range is proposed by combining these two methods.In this strategy,the rotating high-frequency voltage signal injection method is used for estimation in the zero and low-speed range,and the improved SMO algorithm is used for estimation in the medium and high-speed range,and a weighted switching control method is adopted to switch between the two methods.Simulation analysis was carried out using Matlab/Simulink,and experimental verification was conducted on a physical platform.The simulation and experimental results both indicate that the proposed composite control strategy can make the motor run smoothly in the entire speed range and can switch smoothly in the transition zone,showing good control performance.