Analysis and design on the reduction of DC-link electrolytic capacitor for AC/DC/AC converter applied to AC motor drives

This paper presents the design of a three-phase quasi-direct AC/DC/AC converter with minimum energy storage in the DC-link capacitor. The proposed digital control scheme can achieve unity power factor, lower current distortion on the utility side, and fast response to DC-link voltage regulation. A power balancing control scheme is used to minimize the required DC-link capacitor. The design procedure of the proposed method, accompanied with given simulation results, has been described.