Steady state frequency domain analysis of parallel-series resonant converter

The steady-state analysis of a DC/DC resonant converter using a parallel-series (LLC type) resonant circuit is described by means of a simple equivalent circuit in the frequency domain. Analytical design equations and curves for circuit variables are given. Effects of inductor resistances are considered. Analytical design equations are obtained by representing the rectifier load as a controlled voltage source (sink). It is shown that all design equations can be derived from a simple transformation when the rectifier load is represented by an AC resistance. Design equations for a conventional series resonant converter are obtained as a special case of the parallel-series resonant converter. Design examples are given to illustrate the usefulness of the design equations and curves in the selection of the component values and their ratings. Simulation results using PSpice are given to support the analytical results.<
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