Novel operation and control modes for series-resonant converters

A series-resonant converter (SRC) able to generate an output voltage either lower or higher than the source voltage is described. Moreover, a novel control scheme is presented which renders two degrees of freedom for control and which guarantees symmetrical steady-state waveforms in all operation modes. Both the average resonant current as well as the peak voltage of the resonant capacitor can be controlled independently. Special attention is given to an operation mode which facilitates converter operation when the output voltages approximately equal the source voltage (q approx equal to 1). Test results are presented of both controller and converter.