Fixed frequency series-parallel dc/dc resonant converters

This thesis presents generalized modeling and analysis of constant frequency dc/dc resonant converters taking into account the effect of transformer leakage reactance. Frequency-domain analysis is used to obtain generalized evaluations to describe the steady-state characteristics of the series-parallel resonant converters with primary and tertiary resonance. Transient analysis using state-space method is also presented for the primary-side resonant converter. Simulation results showing the effect of the leakage reactance of the high frequency transformer on the performance of these converters are presented. Experimental results to verify the model and simulation results are also provided. A model is developed for a series-parallel resonant converter with integrated magnetics which is suggested for further size reduction in the converter. A design example is provided to illustrate the use of the generalized equations and performance curves.;It is shown that the transformer leakage inductance has a significant effect on the operation of the converter and hence cannot be neglected in the design of the converter. It is also shown that a series-parallel resonant converter with tertiary resonance is more suitable for operation at higher frequencies.