Hybrid modulation method combining variable frequency and double phase-shift for a 10kW LLC resonant converter

Features of the wide input voltage, high efficiency, and high power density are eagerly required in electric vehicle charging pile applications (EVCPA). To realise these features, this study devises a novel variable frequency and double phase-shift hybrid modulation method into the full-bridge three-level LLC resonant converter for EVCPA. Therein, this study deeply analyses the characteristics and conditions of soft switching in dual phase-shift operations, and wide voltage gain range realisations under technique of variable frequency. A 10kW/400V/25A prototype with 95.5% efficiency is built for verification, whose experimental results show that the proposed converter can well achieve the aforementioned features to further drive its wide applications.