Torque Ripple Reduction of PMSM With Small Capacitor Drive Systems Based on Combined Control Method

Small capacitor motor drive systems have received increased attention due to higher reliability and longer lifespan. However, small capacitor motor drive systems suffer from poor dynamic performance and larger torque ripple. In this paper, a combined control method is presents to improve the performance of small capacitor motor drive systems. On the one hand, this combined control strategy adopts injected harmonic current to reduce the fluctuation voltage on the DC-link, which provide better conditions for high-performance operation of permanent magnet synchronous motor. To satisfy the harmonic standard of IEC61000-3-2, the guideline of injected harmonic current is deduced according to motor power and the input power factor. On the other hand, an improved repetitive control in parallel with PI control is applied into motor control to effectively suppress motor torque ripple under the condition of the periodic pulsation voltage on the DC-link. In addition, this control method has good dynamic motor performance. Experiments are conducted, and the results verify the feasibility and effectiveness of the combined control strategy.