A new, partial series resonant converter for efficient DC to DC conversion

A variation of the series resonant power converter is proposed which clamps the capacitor voltage, and effectively inhibits the resonance for a part of the cycle. The resonant capacitors are charged to the supply voltage during each half cycle and discharged into the load. Output power is controlled by adjusting the rate of pulsed energy transfer to the load. This circuit behaves differently compared to the conventional series resonant converter, and advantages include operation below rather than above resonance making it possible to attain a high frequency power product using slower semiconductor switches. The circuit can be operated as either a zero current switching or a zero voltage switching power converter. Zero voltage switching is the preferred mode of operation and includes the addition of a parallel inductor. Experimental results are presented on a 6 kW battery charger, using IGBTs and switching at 50 kHz.<>