Patent ID: 6239989
Filing Date: 2001-05-29
Classification: H02M

Abstract:
A buck reset forward converter comprising:a smooth choke connected in series with a smooth capacitor;a resistive load connected in parallel with said smooth capacitor;a transformer comprising a primary winding and a secondary winding, said primary winding being connected to an input DC voltage source, said secondary winding being connected to said smooth choke;a controller;a switch connected in series with said primary winding, and controlled via said controller for being periodically and alternately turned ON and turned OFF;a forward switch connected in series with said secondary winding, and controlled via forward voltage of said secondary winding such that (a) said forward switch is opened when forward voltage of said secondary winding is negative, and (b) said forward switch is closed when forward voltage of said secondary winding is positive;a fly-wheeling switch connected in parallel with said smooth choke, connected in series with said smooth capacitor, and controlled via forward voltage of said secondary winding such that (a) said fly-wheeling switch is closed when forward voltage of said secondary winding is negative, and (b) said fly-wheeling switch is opened when forward voltage of said secondary winding is positive;a clamp diode connected in series between an storage capacitor and said secondary winding, and controlled via reverse voltage of said secondary winding such that (a) said clamp diode is opened when reverse voltage of said secondary winding is less than the voltage of said storage capacitor, and (b) said clamp diode is closed when reverse voltage of said secondary winding is greater than the voltage of said storage capacitor;an auxiliary inductor connected in series with said smooth capacitor;an auxiliary switch connected between said storage capacitor and said auxiliary inductor, and controlled via forward voltage of said secondary winding such that (a) said auxiliary switch is closed when forward voltage of said secondary winding is negative, and (b) said auxiliary switch is opened when forward voltage of said secondary winding is positive;an auxiliary diode connected to said auxiliary inductor and said auxiliary switch such that (a) said auxiliary diode is opened when said auxiliary switch is closed, and (b) said auxiliary diode is closed when said auxiliary switch is opened.