A Five-Switch Bridge Based Reconfigurable LLC Converter for Deeply Depleted PEV Charging Applications

This letter presents a reconfigurable dual LLC converter based on a five-switch bridge to charge the deeply depleted plug-in electric vehicle onboard battery packs. Due to the reconfiguration of the primary-side switch network, two resonant tanks could operate in integrated half-bridge, half-bridge, hybrid-bridge, and full-bridge modes. Thus, four operation modes are derived, with their normalized voltage gains scaled to 1:2:3:4, respectively. Those four modes enable a squeezed switching frequency span, which is close to the resonant frequency. Therefore, the efficiency performance over an ultra-wide output voltage range can be optimized. Zero-voltage-switching can be realized in all power mosfets over the entire load range. The operating principles, voltage gains analysis are briefed. A 1.1-kW-rated prototype converting the 390-V input to 100-420 V output, is designed and tested to validate the proof of concept. A total of 97.64% of peak efficiency and good efficiency over the full charging range is reported.