High-speed analysis of resonant power converters

A methodology for determining the steady-state operation of resonant power-switching converters is described. The technique, based on cyclic averaging, employs a reduced-order harmonic analysis to obtain the switching transition times which separate different modes during each cycle in the steady state. The internal state variables of the system, in the steady state, are then immediately determined. In comparison with previously published techniques, the methodology has the advantage of allowing any piecewise-linear state-space model of a power converter to be used to predict the steady-state performance without the prerequisite of a transient-based simulation. The simulated and experimental results for a prototype third-order CLC current-output converter are compared to demonstrate that the prediction accuracy is comparable with that of state-variable-simulation models, and that the execution speed is of the same order as that for FHA (first-harmonic analysis).