Lossless clamping circuit of power converter having relatively higher efficiency

• US 20050024803A1
• Filed: 07/27/2004
• Published: 02/03/2005
• Est. Priority Date: 07/30/2003
• Status: Active Grant

• Current Assignee: Delta Electronics Incorporated
• Original Assignee: Delta Electronics Incorporated
• Inventors: Liu, Teng, Ying, Jianping, Zeng, Jianhong, Fu, Yue, Guo, Xingkuan
• Granted Patent: US 7,184,287 B2
• Time in Patent Office: Days
• US Class Current: 361/82
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/342 Active non-dissipative snubbers
• CPC Class Codes: H02M 3/33576 having at least one active switching element at the secondary side of an isolation transformer
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

An energy-feedback clamping circuit of a power converter is proposed. The converter includes a transformer coupled to a full-wave rectifier circuit. The clamping circuit includes: two clamping diodes having two anodes coupled to each other at a common-anode terminal and two cathodes coupled to two terminals of a secondary winding of the transformer, a first clamping capacitor having a first terminal coupled to a cathode of a first rectifying diode of the rectifier circuit and a second terminal coupled to the common-anode terminal, a second clamping capacitor having a first terminal coupled to a connecting node of the output filtering inductor and capacitor of the rectifier circuit and a second terminal coupled to the common-anode terminal, and a converter circuit having an input terminal coupled to the second clamping capacitor and an output terminal for offering a power source.

Claims

1. A lossless clamping circuit for clamping a reverse voltage over two terminals of a power element of a power converter, wherein said power converter comprises a transformer having a secondary winding electrically connected to a full-wave rectifier circuit, and said full-wave rectifier circuit comprises a first rectifying diode, a second rectifying diode, an output filtering inductor, and an output filtering capacitor, comprising:

two clamping diodes having two anodes electrically connected to each other to form a common-anode terminal and two cathodes electrically connected to two terminals of said secondary winding of said transformer;

a first clamping capacitor having a first terminal electrically connected to a cathode of said first rectifying diode and a second terminal electrically connected to said common-anode terminal;

a second clamping capacitor having a first terminal electrically connected to a connecting node of said output filtering inductor and said output filtering capacitor, and a second terminal electrically connected to said common-anode terminal; and

a converter circuit having an input terminal electrically connected to said second clamping capacitor and an output terminal for offering a power source.

2. The circuit according to claim 1, wherein said power source is employed to feedback an electrical energy to one of a primary winding and said secondary winding of said transformer.

3. The circuit according to claim 1, wherein said power source is employed as an auxiliary power source.

4. The circuit according to claim 1, wherein said converter circuit is a boost circuit.

5. The circuit according to claim 4, wherein said boost circuit comprises:

an inductor having a first terminal electrically connected to said connecting node;

a switch having a first terminal electrically connected to a second terminal of said inductor and a second terminal electrically connected to said common-anode terminal; and

a diode having an anode electrically connected to said second terminal of said inductor and a cathode electrically connected to a cathode of said first rectifying diode.

6. The circuit according to claim 5, wherein said inductor is an energy feedback inductor, said diode is an energy feedback diode, and said switch is an energy feedback switch.

7. A lossless clamping circuit for clamping a reverse voltage over two terminals of a power element of a power converter, wherein said power converter comprises a transformer having a secondary winding electrically connected to a full-wave rectifier circuit, and said full-wave rectifier circuit comprises a first rectifying diode, a second rectifying diode, an output filtering inductor, and an output filtering capacitor, comprising:

two clamping diodes having two anodes electrically connected to each other to form a common-anode terminal and two cathodes electrically connected to two terminals of said secondary winding of said transformer;

a clamping capacitor having a first terminal electrically connected to a cathode of said first rectifying diode and a second terminal electrically connected to said common-anode terminal; and

a converter circuit having an input terminal electrically connected to said clamping capacitor and an output terminal for offering a power source.

8. The circuit according to claim 7, wherein said power source is employed to feedback an electrical energy to one of a primary winding and said secondary winding of said transformer.

9. The circuit according to claim 7, wherein said power source is employed as an auxiliary power source.

10. A lossless clamping circuit for clamping a reverse voltage over a full-bridge rectifier circuit of a power converter, wherein said power converter comprises a transformer having a secondary winding electrically connected to said full-bridge rectifier circuit, comprising:

a clamping capacitor electrically connected to an output terminal of said full-bridge rectifier circuit; and

a converter circuit having an input terminal electrically connected to said clamping capacitor and an output terminal for offering a power source.

11. The circuit according to claim 10, wherein said power source is employed to feedback an electrical energy to one of a primary winding and said secondary winding of said transformer.

12. The circuit according to claim 10, wherein said power source is employed as an auxiliary power source.

13. A lossless clamping circuit for clamping a reverse voltage over two terminals of a power element of a double current circuit of a power converter, wherein said power converter comprises a transformer having a secondary winding electrically connected to a full-wave rectifier circuit, and said double current circuit comprises a first double current diode and a second double current diode, comprising:

two clamping diodes having two anodes electrically connected to each other to form a common-anode terminal and two cathodes electrically connected to two terminals of said secondary winding of said transformer;

a clamping capacitor having a first terminal electrically connected to a connecting node of said first double current diode and said second double current diode, and a second terminal electrically connected to said common-anode terminal; and

a converter circuit having an input terminal electrically connected to said clamping capacitor and an output terminal for offering a power source.

14. The circuit according to claim 13, wherein said power source is employed to feedback an electrical energy to one of a primary winding and said secondary winding of said transformer.

15. The circuit according to claim 13, wherein said power source is employed as an auxiliary power source.

16. A lossless clamping circuit for clamping a reverse voltage over two terminals of a power element of a double current circuit of a power converter, wherein said power converter comprises a transformer having a secondary winding electrically connected to a full-wave rectifier circuit, and said double current circuit comprises a first double current diode and a second double current diode, comprising:

two clamping diodes having two cathodes electrically connected to each other to form a common-cathode terminal and two anodes electrically connected to two terminals of said secondary winding of said transformer;

a clamping capacitor having a first terminal electrically connected to a connecting node of said first double current diode and said second double current diode, and a second terminal electrically connected to said common-cathode terminal; and

a converter circuit having an input terminal electrically connected to said clamping capacitor and an output terminal for offering a power source.