Three-level LLC Resonant Converter with Structure-reconfigurable Control

In the conventional series resonant DC/DC converter, it is difficult to realize the wide output range only under the pulse frequency modulation (PFM) because of the high-power loss caused by the increased switching frequency. Therefore, this paper proposes a three-level (TL) series resonant DC/DC converter with the structure-reconfigurable control to realize the wide output range for the high voltage applications. The proposed converter has two operation configurations, which can not only satisfy the wide output range but also shrink the switching frequency range close to the resonant frequency. Accordingly, the efficiency over the wide output range can be improved. Finally, the simulation results are presented to verify the effectiveness of the proposed converter.