US 6,051,961 A · Soft-switching cell for reducing switching losses in pulse-width-modulated converters

Abstract

A circuit technique substantially reduces the switching losses of a pulse-width-modulated (PWM) converter caused by the turning-on (closing) and turning-off (opening) characteristic of the switch and the reverse-recovery characteristic of the rectifier. The losses are reduced by using a new switch cell which includes a snubber inductor, a clamp diode, a clamp capacitor, a main switch, and an auxiliary switch. The reverse-recovery-related losses are reduced by the snubber inductor connected in series with the main switch and the rectifier to control the rate of change of rectifier current during its turn-off. In addition, the main switch operates with zero-current and zero-voltage switching, while the auxiliary switch operates with zero-voltage switching. A proper operation of the proposed circuit requires overlapping gate drives of the main and the auxiliary switches. The circuit technique can be applied to any member of the PWM converter family.

Claims23

Dependent claims

A power converter including a zero-current, zero-voltage switching (ZC-ZVS) cell, said ZC-ZVS cell having a first terminal, a second terminal and a third terminal, said ZC-ZVS cell comprising:

a diode;
a first switch coupled between said second terminal and an anode of said diode;
a second switch coupled between said second terminal and a cathode of said diode;
a capacitor coupled between said third terminal and said cathode of said diode;
and
an inductor coupled between said anode of said diode and said third terminal.

3 more elements

Dependencies are inferred from the claim text.

Soft-switching cell for reducing switching losses in pulse-width-modulated converters

Life of this patent

Soft-switching cell for reducing switching losses in pulse-width-modulated converters

Life of this patent

Abstract

Claims23