Double voltage rectification modulation for bidirectional CLLLC resonant converter for wide voltage range operation

It is difficult to achieve wide voltage range for full-bridge-based bidirectional CLLLC resonant DC/DC converter due to the large resonant current caused by the small magnetizing inductance. This paper proposes a double voltage rectification (DVR) modulation on the rectification side to achieve twice of the voltage gain for the backward direction to effectively widen the operation voltage range, which matches the ratio of the two DC port voltages where the conventional half-bridge modulation is used in the forward direction. The switches on the input side still turn on with zero voltage switching (ZVS), and the body diodes on the rectification side still turn off with zero current switching (ZCS). Moreover, the turning-on and -off of the MOSFETs on the rectification side are also ZVS, which causes no additional losses and guarantees high frequency operation. Finally, a 3kW bidirectional CLLLC resonant converter prototype with 100-kHz resonant frequency is built to validate the proposed modulation.