Capacitor Voltage Balancing control for 3LNPC LLC Resonant Converter

This paper concentrates on the capacitor voltage balancing in three-level neutral-point clamped (3LNPC) LLC resonant converter. Considering that the voltage stress applied to the power switch may exceed the rated voltage when a capacitor voltage imbalance occurs, a new control strategy is proposed to solve this problem. Detailed analysis on the commutation loops and operating states of the DC capacitors is provided. Finally, experimental results are shown to verify the effectiveness and validity of the proposed control strategy.