Torque Ripple Compensation With Anti-Overvoltage for Electrolytic Capacitorless PMSM Compressor Drives

As the dc-link capacitance decreases obviously, the dc-link voltage fluctuates severely in the electrolytic capacitorless permanent magnet synchronous motor (PMSM) drives for compressor applications. The control performance of the compressor deteriorates, and the dc-link may suffer from the fault of overvoltage. In this article, an acceleration extraction-based torque ripple compensation method considering safe operation with dc-link anti-overvoltage is proposed for electrolytic capacitorless PMSM compressor drives. The fluctuation characteristics of the compressor torque and the speed caused by the interaction of the dc-link voltage and the load are analyzed. The load torque is estimated online using the orthogonality theory to suppress the torque ripple. Based on the hybrid proportional-integral-resonant regulator, an anti-overvoltage control strategy is proposed for the safe operation of the regenerating state. Experimental results are performed in the air-conditioner compressor drive system to verify the effectiveness of the proposed method.