A Topology-Reconfigurable Fault-Tolerant Two-and-Single Stage AC–DC Converter for High Reliability Applications

Abstract

A novel topology-reconfigurable two-and- single stage ac–dc converter with fault-tolerant capability for high reliability applications is proposed in this article. In the proposed converter, two bidirectional switches are used to connect the midpoints of the bridge branches between the rectifier stage and the dc–dc stage, and the proposed converter can be configured from the two-stage structure into the single-stage structure by turning on the bidirectional switches for the postfault conditions, therefore, the reliability of the power supply is reinforced. The two-stage structure for the normal condition works with an interleaved bridgeless power factor correction (PFC) rectifier and resonant dc–dc converter. The single-stage structure working under the postfault condition is made up of a PFC half-stage and resonant dc–dc half-stage, and the single-stage structure still has the same working performance as the two-stage structure. Operational principles, control scheme, and characteristics analysis of the topology-reconfigurable converter are analyzed. Finally, experimental results for both normal condition and postfault condition based on 1 kW prototype are provided to verify the effectiveness of the proposed converter.