Abstract：The resonant cavity parameters design of CLLC DC-DC converter is the guarantee of its stable operation, but the existing design method based on first harmonic approximation (FHA) can not achieve accuracy and efficiency. From the point of view of design, this paper firstly analyzed the limitation of FHA. Then, based on the results of time domain analysis of CLLC DC-DC converter, a simplified time domain model of CLLC DC-DC converter was established by reasonably simplifying the waveforms. The gain formula and boundary conditions were derived and the design basis under different load conditions was discussed. The design formulas obtained by this method were simple and accurate, which greatly simplify the design process. On this basis, this paper presented a complete design process and a 5kW CLLC DC-DC converter prototype was made. The simulation and experimental results proved the correctness of the theory.
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2022, Vol. 37 
