New symmetrical bidirectional L3C resonant DC-DC converter with wide voltage range

This paper proposes a new symmetrical bidirectional L3C resonant converter with wide voltage range. Due to the proposed symmetrical resonant tank with notch resonant characteristic, the proposed converter is capable of not only achieving soft switching of all switches in forward and backward modes but also operating in a narrow switching frequency range even under wide voltage range. Also, due to zero gain at the notch resonant frequency, the proposed converter does not suffer from increased current and voltage stresses of components during start-up. The current rating of the resonant capacitor does not increases as the load increases and can further be reduced by adjusting the tertiary turn ratio of the transformer, making the proposed converter more realizable in high power application. Experimental results from a 3kW prototype are provided to validate the proposed concept.