Research of capacitor voltage balance control method for H-bridge inverter of hybrid 9-level inverter

This paper proposes a capacitor voltage balance control method for low-voltage H-bridge inverter of hybrid 9-level inverter based on capacitor voltage imbalance predictive estimation and the injection of zero-sequence voltage. To investigate the proposed method, the charging model of capacitor voltage of H-bridge inverter is established and the inherent mechanism of capacitor voltage imbalance is analyzed in detail. The principle of the proposed method is simple to implement without additional hardware equipment. The simulation and experimental results demonstrate the validity of the proposed method.