Closed-form expressions for the frequency-domain model of the series resonant converter

The steady-state analysis of the series resonant converter is presented using a novel frequency-domain model. Closed-form expressions are derived for the infinite Fourier series. The effects of load resistance, nonzero resistance of the inductor coil, and transistor and diode voltage drops are considered. The output current and voltage characteristics are plotted using the transistor conduction angle as the parameter. The operating point is easily obtained by superimposing on these characteristics a shifted load line that accounts for transistor and diode voltage drops. An example illustrating the solving procedures using the graphical and Newton-Raphson (N-R) methods is included