Dead-time Compensation and Realization Method for 3-Level NPC Inverter

3-Level Neutral Point Clamped (NPC) Inverter has 4 switches in each leg. 2 pairs of switches of the inverter operate complimentarily, Si and S3 is a pair, the other is S2 and S4. But short circuit fault can be occurred due to a time distinction of turning on/off the switch. Thus, short circuit fault can be prevented by giving dead-time when turning on the switches which complementarily operate mutually. But these dead-time occur error between reference voltage and output voltage of each leg, and distort 3-phase output voltage and current. In this paper, a compensation method and its simple realizing method are proposed to minimize effect from these dead-time. The proposed method is implemented on software and does not require an additional hardware. The proposed method is applied to 3-Level NPC inverter and verified its validity through simulation.