Mode Analysis and Fault-Tolerant Method of Open-Circuit Fault for a Dual Active-Bridge DC–DC Converter

Abstract

A dual active-bridge (DAB) dc–dc converter is widely used in bidirectional high-power conversion, such as renewable energy system or train traction system. The open-circuit fault of DAB may threaten the system safety operation and should be eliminated in time. In this article, each fault mode of DAB is analyzed in detail. The transient operations and the load-carrying capacity are carefully analyzed. Based on the analysis, a DAB fault-tolerant method called “primary-side lower power secondary-side bypass arm” (PLP-SBA) is proposed. When the fault occurs in the primary side, the power of DAB is cut down, and when the fault occurs in the secondary side, the entire fault bridge arm is bypassed. The PLP-SBA method can ensure a certain load-carrying capacity after an open-circuit fault. A 5-kW DAB experimental platform is built to verify the correctness and effectiveness of the DAB mode analysis and PLP-SBA method.