A Repetitive Control System For Suppressing Torque Ripple Of IPMSM

In recent years, with advances of the power electronics, permanent magnet synchronous motor(PMSM) has been widely used in industrial production and household appliances with its simple structure, high efficiency and good maintainability. In motor control, people usually install position and speed sensors at the edge of the motor to obtain information on the pole position, thereby the torque of the motor is controlled. However, such kinds of sensors require additional space in the axial direction of the motor and increase the costs. Sensorless driven approach has been developed and applied on the air conditioners and refrigerator compressors to overcome this problem. The sudden load disturbance will cause the speed and torque ripple of the system and the performance of this control system will be poor.For the above, a repetitive control system of position sensorless is proposed for interior permanent magnet synchronous motors(IPMSM) to suppress the torque ripple. The speed loop is composed with a composite control structure that using the series-parallel connection of the repetitive controllers and PI controller for improving the tracking performance of the speed and reducing its fluctuations caused by the load or other disturbances. A motor disturbances observer and a repetitive controller are added in the extended back-EMF observer to reducing the influences by the load disturbances and the error of the angle estimations, therefore the torque ripple is suppressed. The simulation experiment is carried out in the Matlab/Simulink simulation environment and the effectiveness of this method is proved.Finally, the hardware and software systems of permanent magnet synchronous motor sensorless control system are designed by TMS320F2812 DSP control chip.