Research On Disturbance Rejection Control Method Of Permanent Magnet Synchronous Motor System

Permanent magnet synchronous motor(PMSM)has the advantages of simple structure,high power density and high reliability,and has been widely used in the airborne actuation system of multi-electric aircraft.However,the complex and changeable working environment of the airborne actuator and the inherent defects of the PMSM system will cause many disturbances during the operation of the motor,then will cause the fluctuation of the motor speed and torque,reducing its control precision.Disturbances of PMSM system are divided into periodic disturbances and aperiodic disturbances,but the traditional PI control algorithm has no rejection effect on the both kinds of disturbances.Therefore,the disturbances rejection methods of PMSM system are studied in this paper.The periodic disturbances of PMSM system are mainly caused by the non-ideal structural design of the motor and the non-linear factors of the inverter,and they will cause the output torque ripple of the motor,affecting the steady state performance of the system.The non-ideal structural design of the motor will cause magnetic flux harmonics in the air gap of the motor,and the non-linear factors of the inverter will cause the output voltage harmonics of the inverter.The magnetic flux harmonics and the voltage harmonics will cause the current harmonics of the motor,then causes the torque ripple.The mathematical model of PMSM is built,and the resonance control algorithm is adopt to suppress the torque ripple by suppressing the specific current harmonics with large harmonic content.The aperiodic disturbances of PMSM system are mainly caused by the load mutation,and the disturbances will cause the dynamic fluctuation of motor speed and torque,affecting the tracking performance of the system.With the inherent disturbance rejection characteristic of sliding mode control algorithm,a sliding mode current controller,a sliding mode speed controller and a sliding mode load torque observer are designed.In order to reduce the chattering problem of the traditional sliding mode control algorithm,a new approach law method is proposed which can reduce the chattering by optimizing the path of system state in the phase of sliding mode approaching motion.The new approach law is applied in the sliding mode current controller and sliding mode speed controller,the improved sliding mode control algorithm has more advantages in disturbance immunity and response speed compared with the PI control algorithm,and the chattering problem of traditional sliding mode control algorithm is solved,and good dynamic performance of the PMSM system can be obtained.Finally,a hardware control platform of PMSM system with d SPACE controller as the core is built and experimental verification is carried out.The results validate the superior periodic disturbances rejection capability of the resonant control algorithm and the superior aperiodic disturbances rejection capability of the improved sliding mode control algorithm.