A Cascaded Three-Level Scheme for Dual-Output Resonant Converter

This paper proposes a cascading three-level scheme for dual-output resonant converter to achieve wide gain range and high power density. Specifically, a double output is achieved through two windings of the transformer to achieve a higher power density. The three-level boost converter is cascaded with the half-bridge resonant converter by the shared capacitor, and the charge and discharge time of the inductor is changed by adjusting the duty cycle of the front switches to adjust the voltage of the resonant capacitor. Thus, the resonant state of the resonator can be adjusted to obtain a wide range of gain adjustment. The system reduces the design difficulty of magnetic components through fixed-frequency control and weakens the influence of excitation inductance on voltage gain. In addition, the switches at the rear stage and the diodes on the secondary side can achieve soft switching, which helps to improve the converter efficiency. Based on detailed theoretical analysis, experimental results confirm the effectiveness of the proposed strategy.