Zero-Voltage Switching PWM Strategy Based Capacitor Current-Balancing Control for Half-Bridge Three-Level DC/DC Converter

The current imbalance among the two input capacitors is one of the important issues of the half-bridge threelevel (HBTL) DC/DC converter, which would affect system performance and reliability. In this paper, a zero-voltage switching (ZVS) pulse-wide modulation (PWM) strategy including two operation modes is proposed. Based on the proposed ZVS PWM strategy, a capacitor current-balancing control is proposed for the HBTL DC/DC converter, where the currents on the two input capacitors can be kept balanced by alternating the two operation modes of the proposed ZVS PWM strategy. Therefore, the proposed control strategy can improve the performance and reliability of the converter in the aspect of balancing the thermal stresses and lifetimes among the two input capacitors. Finally, simulation and experimental studies are conducted and results verify the proposed control strategy.