A method to reduce DC-link voltage fluctuation of PMSM drive system with reduced DC-link capacitor

Abstract

Abstract. The reduction of the dc-link capacitance in the motor drive makes it possible to improve the system power density and lower the system cost. However, this can lead to relatively high dc-link voltage fluctuation, especially the sixth harmonic component. To serve the purpose of enhancing the dc-link voltage quality, a parameter-insensitive control method was proposed in this paper. The proposed method shapes the sixth harmonic component of the dc-link current in phase with that of the inductor current by the HF power injection technology. Since this practice can reduce the difference between these two sixth harmonic components, the sixth harmonic component of the dc-link voltage can be reduced as well. The simulation results show that the proposed method not only improves the ripple characteristic of dc-link voltage, but also achieves the aim of PMSM speed regulation.