AC-DC power conversion system with zero voltage switching
AssigneeDelta Electronics, Inc.
InventorsTomas Sadilek, Yungtaek Jang, Peter Barbosa
Life of this patent
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Abstract
A circuit technique substantially reduces the switching losses in an AC-DC power conversion system caused by turn-on characteristics of a main switch and the reverse-recovery characteristic of a rectifier. The losses are reduced by using an active soft-switching cell having a series inductor, a series capacitor, a main switch, a rectifier switch, and an auxiliary switch. The reverse-recovery related losses are reduced by the series inductor connected between the main and rectifier switches to control the rate of current change in the body diode of the rectifier switch during its turn-off. The main switch, the rectifier switch, and the auxiliary switch operate under zero-voltage switching (ZVS) conditions.
Claims18
A power converter configured for coupling to (i) an AC circuit having first and second terminals and (ii) a DC circuit, comprising:
- a first inductor, having first and second terminals, the first terminal of the first inductor being coupled to the first terminal of the AC circuit;
- first and second rectifiers connected at a common node, wherein the first and second rectifiers form a series circuit coupled in parallel to the DC circuit, and wherein the common node is coupled to the second terminal of the AC circuit;
- an active soft-switching cell, comprising:
- a second inductor having first and second terminals;
- first and second switches, wherein the first switch, the second inductor and the second switch form a series circuit coupled in parallel to the series circuit of the first and the second rectifiers;
- a third switch;
- and a first capacitor, wherein the third switch and the first capacitor form a series circuit that is coupled in parallel to the second inductor;
- and wherein the second terminal of the first inductor is coupled to the first terminal or the second terminal of the second inductor, wherein one of the first and second switch serves as a rectifier switch that opens and closes simultaneously with the third switch, and wherein the second inductor has an inductance that reduces the rate of current change when the rectifier switch opens.
A multi-phase power converter configured for coupling to (i) an AC circuit having a plurality of terminals (“phase terminals”), each coupled to a phase of a multi-phase AC power source, and (ii) a DC circuit, the multi-phase power converter having a plurality of component circuits (“phase legs”), each phase leg comprising:
- a first inductor, having first and second terminals, the first terminal of the first inductor being coupled to one of the phase terminals of the AC circuit;
- and an active soft-switching cell, comprising:
- a second inductor having first and second terminals;
- first and second switches, wherein the first switch, the second inductor and the second switch form a series circuit that is coupled in parallel to the DC circuit;
- a third switch;
- and a first capacitor, wherein the third switch and the first capacitor form a series circuit that is coupled in parallel to the second inductor;
- and wherein the second terminal of the first inductor is coupled to the first terminal or the second terminal of the second inductor, wherein, in each phase leg, one of the first and second switch serves as a rectifier switch that opens and closes simultaneously with the third switch, and wherein the second inductor has an inductance that reduces the rate of current change when the rectifier switch opens.
Dependencies are inferred from the claim text.