A Diagnosis Strategy for High-Frequency Link Bidirectional AC-DC Matrix Converter

In order to enhance the stability of high-frequency link bidirectional AC-DC matrix converter (HFLMC) during system execution, a fault diagnosis strategy is proposed to identify open-circuit fault of power devices in this paper. Firstly, detailed electrical waveform analysis to summarize the output voltage fault characteristics of the converter under normal and failure situations are shown. Based on this analysis, a fault diagnosis strategy is proposed which can identify the fault location either in an IGBT or in a diode in the H-bridge converter (HBC). In addition, the faulty bidirectional switch of three-phase to single-phase matrix converter (3-1MC) is detected by the switch group error voltage in different switching states. The proposed method has the advantages of accurate diagnosis and simple implementation. Finally, the simulation results testify the accuracy of the theoretical analysis and the feasibility of the proposed fault diagnosis strategy.