Post-fault operation of open-circuit fault in three-phase PWM converter

In this paper, a simple and low-cost post-fault operation of open-circuit fault for three-phase pulse-width modulated (PWM) converter is proposed. An open-circuit fault causes the current difference in the switches and increases the harmonics and output voltage ripples, which significantly degrades the system performances. It is because of a zero-vector affected by the open-circuit fault. Therefore, the proposed postfault operation method is based on changing the original PWM switching patterns into modified PWM switching patterns which is totally substituting faulted zero-vector to healthy zero-vector. With the proposed method, the current difference in the switches can be significantly reduced and the output voltage ripples can also be minimized. The simulation and experiment are conducted to show the usefulness of the proposed method for the three-phase PWM converter.