The Repetitive Controller Design for Inhibiting the Torque Ripple of PMSM

The permanent magnet synchronous motor will produce the periodic pulsation due to the cogging torque, flux harmonic and current measurement error, which will produce torque oscillation and speed fluctuation and will at last prevent the motor from running smoothly. Based on the advantage that the repetitive control is not affected by model uncertainty during operation, the dynamic programming theory and the iterative strategy have been combined to design the optimal controller, by which the real-time tracking performance of permanent magnet synchronous motor has been optimized to reduce the periodic torque ripple. At the same time, the repeated control is combined with the existing proportional integral (PI) current controller, and the compensation reference current is generated iteratively between each cycle to minimize the mean square torque error, which meets the requirements of steady-state speed and regulating system dynamic performance. The feasibility of the proposed method is verified by the specific motor tests.