Torque Ripple Suppression With Compensation Control Method for Permanent Magnet Synchronous Motor With Asymmetric Magnetomotive Force

Due to manufacturing imperfections and assembly tolerances (MIAT), the actual motor inevitably deviates from the desired motor, which may significantly degrade its performance. To ease the influence of MIAT, researchers have studied both motor design and compensation control methods. Compared with the motor design method, compensation control is more cost-effective and flexible but has not been well investigated, especially for motors experiencing asymmetric magnetomotive force (AMMF) due to MIAT. The main purpose of this paper is to suppress the torque ripple for permanent magnet synchronous motor under AMMF caused by MIAT using the compensation control method. This paper firstly analyzes the influence of AMMF on electromagnetic torque performance, then derives the compensation currents for torque ripple suppression. Subsequently, a modified field-oriented-control is established. Moreover, it is found that MIAT can cause neutral voltage oscillation, which significantly affects the current tracking performance. Therefore, a novel space-vector-pulse-width-modulation is proposed to ease the influence of neutral voltage oscillation. The experiments confirmed that the proposed method can reduce the torque ripple by 87.8% and 80.8% during speed acceleration and steady state, respectively. Furthermore, this method has the advantages of better dynamic performance, improved frequency spectrum performance, and higher motor efficiency at high speeds.