I. Introduction
Permanent magnet synchronous motor (PMSM) has strong nonlinearity, strong coupling, multivariable and time-varying characteristics. Need to choose the appropriate control strategy to improve the stability, speed and robustness of the system. The vector control of the permanent magnet synchronous motor is to decompose the stator current into the excitation current component and the torque current component to realize decoupling control. Permanent magnet synchronous motor (PMSM) is widely used in defense, aerospace, household appliances and other fields due to its simple structure, reliable operation, high power factor, speed regulation and mechanical characteristics [1]–[2]. The vector control of permanent magnet synchronous motor is to decompose the stator current into excitation current component and torque current component to realize decoupling control. Because of its dynamic response speed, high reliability, wide speed range and accurate torque control, It has become one of the most widely used motor control strategies. Vector control in the control process, the control structure of the double-loop of speed and current must be realized by rotor speed and position detection [3]. Since the PMSM is operated in a self-controlled manner, there is no need to add a start winding when the heavy load is started, and there is no problem such as oscillation and loss of synchronization when the load is abrupt. The ideal permanent magnet synchronous motor has a 120° flat-topped trapezoidal wave, and a constant torque can be generated after inputting a square wave current. The actual permanent magnet synchronous motor back EMF waveform is not a regular trapezoidal wave, nor is it a sine wave. Its torque coefficient changes with the change of the rotor position angle. When the square wave current is passed, low frequency torque ripple is generated. In addition, PMSM Generally, the two-phase conduction mode is used for control. There is a commutation torque ripple due to the current rising rate and the falling rate during commutation [4]. Meanwhile, the SVPWM modulation method used in this paper generates higher harmonics and causes voltage. The current is distorted, which in turn affects the overall performance of the motor speed regulation.