An open-circuit fault diagnosis strategy for input series output parallel dual active bridge DC/DC converter based on the mean of AC voltages and currents

Abstract

A two-step fault diagnosis (FD) strategy is proposed for a single-switch open-circuit fault (OCF) of an input-series-output-parallel dual active bridge (DAB) converter in this paper. The strategy localizes the faulty switch through the primary AC voltage and current of each DAB module. The primary fault diagnosis can locate the secondary faulty switch and limit the primary faulty switch in the range of diagonal switches based on OCF characteristics. By actively controlling the relevant switches, the secondary fault diagnosis is carried out to locate the primary faulty switch. Finally, an experimental prototype is built to verify the proposed fault diagnosis strategy.