DC-link voltage balance control method considering the wide regulation range in SOR for single-phase cascaded H-bridge rectifier

In this paper, a DC-link voltage balance control method that considers the wide regulation range in the steady-state operating region is proposed for a single-phase cascaded H-bridge rectifier. A mathematical model of the DC-link voltage is also established while considering the imbalance caused by the inconsistency of the active power absorbed and consumed by the cell. On the basis of the steady-state operating region of the cascaded H-bridge rectifier, the operating loci of different balance methods are analyzed and a novel balance method is proposed. The DC-link voltage regulation range of the proposed method is then compared with that of two other commonly used methods based on the operating locus in the steady-state operating region. The comparison results show that the proposed method has the widest regulation range in the steady-state operating region wherever the cascaded H-bridge rectifier is operated. The experimental results also verify the effectiveness and superiority of the proposed method.