DC link voltage balancing control of a three-phase cascade power regulation system with star connection

DC link voltage balancing is very important for the reliable operation of H-bridge cascade power regulation system (PRS). This paper proposes a novel method to balance the three-phase DC link voltage for the star-connected cascade PRS, which is based on the negative sequence voltage injection. The algorithm is analyzed and the performance is compared with the method based on zero sequence voltage injection. The simulation results verify the theoretical analysis and the effectiveness of the proposed method.