An Open-Circuit Fault-Tolerant Asymmetric Half-Bridge Dual-Output Converter With Topology Reconstruction

To improve the reliability of the asymmetric half-bridge (AHB) dual-output converter, a simple fault-tolerant strategy is proposed in this article. By reconstructing the topology with two redundant switches, the normal output voltages can still be retained after an open-circuit fault (OCF) occurs on any original switch. Depending on the different faulty switches, two reconstructed topologies will be obtained in the postfault modes, and they can operate similarly with the modified modulation scheme. Therefore, the fault-tolerant strategy is cost efficient and easy to be implemented. In addition, a simple fault detection scheme is also proposed for the fault-tolerant AHB dual-output converter. Only a voltage sensor is added between the midpoints of the bridges in two AHB converters, with which the OCF of all switches can be quickly diagnosed. Consequently, the fault-tolerant operation can be implemented immediately after an OCF happens, contributing to a smooth mode transition. In this article, the operational principle of the proposed fault-tolerant converter and fault detection scheme are explained in detail, and the experimental results are also provided to verify the effectiveness.