Due to the wide switching frequency range and low overall efficiency,traditional LLC resonant converters are not suitable for wide voltage gain applications such as photovoltaic energy storage system,this paper proposes a three-channel three-level wide voltage range LLC resonant converter.The proposed converter operates in dual-channel or three-channel modes,achieving a wide voltage range by combining the gains in different modes.It enables soft switching over the full voltage range,operates at a constant switching frequency,and offers advantages such as simple parameter and magnetic component design.The article details the working principles,gain characteristics,and the conditions for achieving zero voltage switching(ZVS).Finally,A GaN-based 200 W prototype with 200 V input and 5-20 V output is designed and built to verify the feasibility of the proposed converter and the correctness of the theoretical analysis.
DC-DC convertersresonant circuitszero voltage switchingthree-channelwide voltage range
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