Design and Implementation of Three-Level Half-Bridge Bidirectional CL3C Resonant DC Converter

A three-level half bridge bidirectional resonant converter for the energy transferring between the DC bus and the battery of the electric vehicle is designed and implemented in this thesis. The three-level half-bridge CLLLC has the symmetrical characteristics and can achieve soft switching for reducing the switching losses. In addition, the voltage stress of power switches can be reduced with the three-level topology for improving the system efficiency. The operating principles of three-level half bridge bidirectional resonant converter are discussed in detail. Then, the steady-state equivalent models and the transfer functions of the resonant tank are also derived. Finally, a laboratory prototype with rated power 2 kW, DC bus voltage 400 V and battery voltage 250~400 V is implemented to validate the theoretical analysis. The highest efficiency in the charging and discharging stages are 94.8% at 800 W and 95.1% at 1 kW, respectively.