Research On Safety Control Strategy Of Permanent Magnet Synchronous Motor For Electric Vehicle

Electric vehicles have received widespread attention at home and abroad due to their energy saving and environmental protection advantages,and their safety and stability has gradually become a research focus in the field of electric vehicles.The motor drive system is the core of the vehicle's power system.Its safety and reliability are the foundation and prerequisite for the stable operation of electric vehicles.Therefore,it is an effective way to improve the performance of electric vehicle by accurately and quickly realizing fault detection and safety control of the motor drive system.In this paper,the motor drive system of permanent magnet synchronous motor is taken as the research object,and the problems of current sensor and position sensor fault diagnosis and safety control are analyzed.For current sensor faults,the working principle and fault of current sensor are analyzed.A method based on coordinate transformation is adopted to diagnose the fault of the current sensor and to locate and detect the fault.In order to cope with the current sensor failure,a model-based current reconstruction method is studied to solve the safety control problem after the current sensor failure.For position sensor faults,a model of lossless Kalman filter is proposed to diagnose the fault.The position sensor failsafe control strategy is divided into two cases: high speed area and low speed area.The fault handling method based on PLL is adopted for safety control in high speed region.In the low speed region,the high frequency current injection method is used for safety control.Based on the traditional coordinate system,a new coordinate system is established to optimize the two security control strategies.Finally,a new approach law sliding mode control is added to the control process of the driving system to improve the robustness of the system and ensure the smooth implementation of the security control strategy.With STM32 microcontroller as the main control chip,the hardware is designed in modules,and the software is designed in the basic architecture.The software simulation experiment and the dynamometer test verify that the control strategy can realize the reliable operation of motor after sensor failure and guarantee the safety of electric vehicle.