Fixed-frequency modified gating signals controlled high-frequency isolated LCL-T DC-DC resonant power converter

Abstract

In this paper, a fixed-frequency modified gating signals controlled LCL-T type of resonant power converter is proposed. The converter is designed to operate in lagging power factor (pf) mode to ensure zero-voltage switching (ZVS) of the inverter switches. Steady-state analysis of the converter is carried out using the Fourier series approach by considering the effect of n-harmonics. A 300 W converter is designed, and its performance is studied using PSIM simulations. It is shown that all inverter switches turn-on with ZVS for entire loading conditions with the minimum input voltage, while only one switch loses ZVS when the input voltage is maximum. Also, a small change in pulse width is enough to regulate the output voltage for wide variations in the input voltage and the load. Power loss breakdown analysis is performed. The experimental prototype of the LCL-T resonant converter is built and tested to validate the theoretical and simulation results. The results have been compared and discussed. © 2024 Informa UK Limited, trading as Taylor & Francis Group.