Capacitive-loaded push-pull parallel-resonant converter

The results of a theoretical and experimental investigation of a capacitive-loaded push-pull parallel-resonant DC-DC converter (CL-PPRC) are presented and discussed. The converter is driven by a lower than resonance frequency, and the secondary voltage is rectified and smoothed by a capacitive filter. The CL-PPRC is shown to operate in the zero voltage switching (ZVS) mode with a boostlike DC transfer ratio which is approximately linear with the period of the switching frequency. Experimental results of a 180 W, high output voltage (1.8 kV) prototype are in good agreement with the analysis, models, and simulation results presented. The basic characteristic of ZVS, the fact that the resonant current is passing through the switches only during a fraction of the period, the high voltage transfer ratio, and the inherent input/output isolation, make the newly proposed topology a viable design alternative in avionic and aerospace applications