ENERGY RECOVERY AUXILIARY CIRCUIT FOR DC/DC RESONANT POWER CONVERTER TOPOLOGIES

A power converter apparatus employs an energy recovery auxiliary circuit to suppress overvoltage oscillations and achieve high efficiency in a resonant LLC power converter system having high power density. The power converter apparatus includes an inverter configured to receive a DC input power and produce an AC voltage, a resonant tank including a resonant inductor and a resonant capacitor coupled between the AC voltage and a primary winding of a transformer, a rectifier configured to produce a DC output power coupled to a secondary winding of the transformer. The power converter suppresses overvoltage oscillations on rectifier switches by employing an energy recovery auxiliary circuit to transfer, during a transition period, current from the secondary side to a clamping capacitor conductively coupled to the primary side of the converter. The energy is then recovered during a subsequent power transfer cycle, thereby improving overall efficiency of the power converter.