Capacitor Voltage Balance Control of Active Neutral Point Clamped Five-Level Inverter

The prospects for the active neutral point clamped five-level inverter are broad in medium-voltage high-power applications. This paper has analyzed the relationship between dc-link capacitors voltage and neutral point current and then proposed a control strategy based on zero-sequence voltage injection to regulate the voltage across the dc-link capacitors. In view of an excessive fluctuation of the voltage across Flying capacitors, a more accurate control method is proposed by introducing the auxiliary modulation wave. The simulation results show that the proposed control methods are feasible and effective.