Harmonic Current Compensation of PMSM Based on Disturbance Observer and Robustness Analysis

Due to the influences of rotor flux harmonics and nonlinear characteristics of the inverter, high-order harmonic components are contained in the stator current, which results the torque ripples. This disadvantage limits the application of proportional integral controller in synchronous coordinate system in high performance drive system. To solve the problem, firstly, this paper models and analyzes the disturbance in PMSM. The results show that the performance of the motor is mainly affected by the periodic high-order harmonic current. Secondly, a disturbance observer based on band pass filter is designed to estimate the periodic disturbance in the system, and the harmonic current is compensated by internal feedback. Then, design principle of the observer parameter is given. Finally, the simulation model is built. The results verify the correctness, effectiveness and robustness of the proposed method.