Life-Cycle-Oriented-Based Design and Optimization of LLC Resonant Converters for Light-EV Charging

This paper presents a sustainability-oriented multi-objective design and optimization framework for a 4 kW LLC resonant converter intended for on-board charger applications. The proposed approach combines conventional electrical and thermal design procedures with life-cycle-based environmental modeling to achieve an optimal balance between efficiency, cost, volume, and carbon footprint. The methodology determines resonant parameters (Lr , Lm, and Cr ) across a frequency range of 100-250 kHz and evaluates each configuration analytically, including magnetic component design, semiconductor loss estimation, and heatsink sizing. Environmental impacts are incorporated through cradleto- gate and use-phase Global Warming Potential (GWPman and GWPuse) metrics for semiconductor, magnetic, and passive components. The optimization results reveal that SiC-based MOSFETs provide higher efficiency and lower operational emissions but at the expense of increased manufacturing footprint and cost, whereas Si-based diodes offer a more balanced trade-off between environmental and economic performance. A 4 kW prototype designed using the GWPuse-weighted optimal parameters achieved a peak efficiency of 98.1% within an input range of 325-375 V and an output range of 250-450 V, experimentally validating the proposed framework. Overall, the study demonstrates that integrating sustainability metrics into LLC converter design enables the development of high-performance, environmentally responsible, and cost-effective power conversion systems.