Simple equivalent circuit for the series-loaded resonant converter with voltage boosting capacitor

A simple, fundamental frequency equivalent circuit is derived for the series-loaded resonant converter with voltage boosting capacitor. The equivalent circuit permits direct and straightforward calculation of the steady-state resonant current and voltage conversion ratio; previous analyses have used time-domain techniques requiring complex calculation and numerical solution. Comparison with results from an idealised time-domain simulation is used to quantify the errors introduced by the fundamental frequency approximation. Practical results from a 1 MHz prototype demonstrate the accuracy of the technique for converter design