Black Start and Fault Tolerant Operation of Isolated Matrix Converter for dc Microgrids

This paper studies the transient behavior of a three-phase isolated bidirectional dc/ac converter operating as a rectifier. The purpose is to assess the viability of this converter for dc microgrid applications. A capacitor pre-charge method is developed to suppress inrush currents while charging the dc side capacitors during converter startup. The operation of the converter under grid fault transients is also studied, to assess the ability of the converter to maintain continuity of service to the dc microgrid in the case of grid undervoltage or loss of phase. A model of the converter was simulated on PSIM to validate the capacitor pre-charge method and grid fault responses.