A high efficiency, high power density converter, operating at constant frequency and switching at zero voltage is presented. Zero voltage switching conditions are achieved over a broad input voltage and output current range. Continuous power transfer from the input to the output minimizes the output filter requirements and by using integrated magnetic technique, high power density can be achieved. By employing the same configuration to classical PWM topologies, a new family of ZVS-PWM converters can be derived. An experimental 5V, 100A converter was designed and built. The converter operates from an input voltage of 200Vdc to 400Vdc, at 400 KHz switching frequency.
A single ended forward converter, operating at constant frequency and switching at zero voltage is presented. By using a secondary switch, the main transformer’s core is symmetrically reset and a part of magnetizing energy is used to discharge the parasitic capacitance of the primary switch to zero. Zero voltage switching conditions are achieved over a broad input voltage and output current range. An experimental 500 KHz converter, which delivers an output power of 200W at 5V, is presented. Operating from an input voltage of 180 to 400 Vdc, the converter exhibits efficiency greater than 88% at full load.