Research On The Influence Of Electric Vehicle Drive Motor Control Algorithm On Efficiency And External Characteristic

With the development of automotive electrification,electric vehicles have become the research focus of the automotive industry.Drive motors are the power source for electric vehicles.Their operating efficiency and external characteristic directly determine the overall performance of electric vehicles.For the efficiency and external characteristic performance of the drive motor,the drive motor control algorithm studied in this paper is first selected: The Flux-weakening control algorithm and the overmodulation control algorithm.This paper analyzes the mathematical model and vector control principle of permanent magnet synchronous motor.Define the Flux-weakening field of the drive motor and the optimal field weakening trajectory.In addition,based on the SVPWM modulation principle,the basic principle of SVPWM overmodulation is introduced.Aiming at the Flux-weakening control of negative d-axis current compensation method,the disadvantages and mechanism of its existence are analyzed.A Flux-weakening control algorithm based on torque control is proposed.Based on the above research,the optimized Flux-weakening control algorithm model was built,and a targeted simulation experiment was carried out.The simulation results show that the Flux-weakening control algorithm proposed in this paper has deeper weakening magnetic field and better Flux-weakening trajectory than the Flux-weakening control of negative d-axis current compensation method,and it is suitable for electric vehicle application scenarios.Aiming at the problem of poor dynamic response performance of the motor under high-speed weak magnetic conditions,the overmodulation control algorithm is studied to improve the utilization of the DC bus voltage of the inverter and increase the maximum output power of the motor.The overmodulation algorithm is optimized based on the dual-region overmodulation algorithm and the superposition overmodulation control algorithm,which simplifies the algorithm complexity and facilitates the digital implementation of the algorithm.Based on the above research,an overmodulation algorithm model was built and a targeted simulation experiment was carried out.The simulation results show that the proposed modulation control algorithm improves the utilization of the DC bus voltage of the inverter,increases the maximum output power of the drive motor,and improves the dynamic response performance of the motor under high-speed Flux-weakening conditions.The experimental platform of the drive motor was built,and the experimental research on the Flux-weakening control algorithm and overmodulation control algorithm of the drive motor was carried out.The experimental results show that: 1)The Flux-weakening control algorithm effectively improves the speed range of the drive motor,but when the motor speed is high,the dynamic response of the motor becomes worse due to the limitation of the maximum output power of the motor;2)The overmodulation control algorithm effectively improves the maximum output power of the motor and improves the dynamic response performance of the motor under high-speed Flux-weakening conditions;3)The Flux-weakening control algorithm and the overmodulation control algorithm improve the efficiency and external characteristic of the drive motor.