Analysis and Implementation of a Fixed-Frequency LCLC Resonant Converter With Capacitive Output Filter

This paper presents the steady-state analysis of a fixed-frequency phase-shift LCLC resonant converter with a capacitive output filter which is a very attractive topology for high-voltage applications. A conventional modeling procedure cannot thoroughly describe the converter behavior particularly at the load side. A comprehensive converter analysis is presented, and the obtained analytical expressions precisely describe the converter behavior. This paper shows that the range of zero-voltage-switching operation would extend significantly since the variations of the phase shift can be reduced by this topology. Therefore, high efficiency is achievable for a wide range of operation. This paper also provides some converter practical description for high-voltage implementation. The experimental results obtained from a 1.8-kW prototype verify the theoretical analysis and demonstrate the validity and accuracy of the employed model.