Open-Switch Fault Detection for Hybrid ANPC Inverter Based on Current Distortion

In this paper, an open-switch fault detection method is proposed for a hybrid active neutral-point clamped (ANPC) inverter. The hybrid ANPC topology used 4 silicon switches and 2 silicon carbide switches to generate the three-level output voltage. The open-switch fault in the hybrid ANPC inverter leads to a distortion of the output current. The current distortion decreases efficiency and eventually breaks down the system. Therefore, an open-switch fault detection method is required to improve the reliability of the hybrid ANPC inverter. Radius and angle in the dq-axis determine the location of the faulty switch. This method identifies the faulty switch without using additional sensors. Simulation results verified the validity of the proposed method.