Time-domain analysis of S/SP compensated contactless resonant converters

Soc. for Elec. Eng. The series/series-parallel (S/SP) compensated contactless resonant converter has a desirable feature of being insensitive to variation of parameters including the transformer's coupling coefficient. However, the error resulting from the use of fundamental harmonic approximation is significant, which affects the design procedure and the effectiveness of the control. In this paper, a time-domain analysis of the S/SP converter was presented. A generalized equivalent circuit of the S/SP resonant tank was derived, and the cause of the waveform distortion was revealed. Then, more accurate expressions for the key variables of the resonant tank and the output voltage gain were given. Finally, a 1.5 kW contactless resonant converter with S/SP compensation was constructed. Experimental results are in good agreement with the calculated results.