A Novel Variable Inductance Ratio LCLC Converter for Electric Energy Router Applications

Extensive research has explored how LLC converters achieve a wide gain range, yet balancing this range with efficiency remains a significant challenge. To tackle this issue, this paper introduces a novel variable inductance ratio LCLC converter with three operating modes: Full-bridge (FB) for low gain range, Dual-half-bridge (DHB) for medium gain range, and Half-bridge (HB) for high gain range applications. The operational principles of the proposed converter are presented, and brief design considerations are discussed. The proposed converter achieves flexible switching between LCLC and LLC dual modes, significantly reducing unnecessary excitation current while maintaining zero-voltage switching (ZVS). This effectively resolves the trade-off between wide gain range and high average efficiency. Compared to conventional solutions, the design requires less additional cost and volume while delivering superior average efficiency across the entire gain range. To validate the proposed converter, a 2 kW LCLC prototype was developed, with 200-600 V input voltage and 48 V output voltage.