A model-based power switch fault diagnosis strategy for cascaded H-Bridge converter

Abstract

Cascaded H-Bridge (CHB) converter is a promising solution in medium-voltage high-power application, such as railway traction, grid-connected photovoltaic (PV) system. However, the large number of power switches involved in the topology is a potential reliability risk since the power switch is the most vulnerable component in a power electronic system. To achieve a fast and accurate power switch fault diagnosis (FD) in CHB, this paper proposes a model-based hierarchical FD strategy, consisting of phase-level and cell-level fault detection. There is no need of extra sensors or high computational burden. The effectiveness of the method is verified by simulation and experiment.