RESONANT POWER CONVERTER

• US 20100328967A1
• Filed: 07/02/2008
• Published: 12/30/2010
• Est. Priority Date: 07/02/2008
• Status: Abandoned Application

• Current Assignee: Setec Pty., Ltd.
• Original Assignee: Stetec Pty Limited
• Inventors: Langford, Peter Alan, Haksoz, Yalcin, Cody, Denis John
• Application Number:
  US12/448,541
• Publication Number:
  US 20100328967A1
• Time in Patent Office: Days
• US Class Current: 363/21.02
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• 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

A resonant power converter including synchronous rectifiers adapted to operate with an overlapping conduction phase and a fixed frequency.

Claims

1. A resonant power converter operating at a fixed frequency, including:

a resonant circuit, with a resonant voltage at the fixed frequency, on a primary side of an isolating unit; and

an output circuit on a secondary side of the isolating unit, coupled by the isolating unit to the resonant circuit, including switches for conducting during respective overlapping conduction phases, and for generating a DC voltage at an output of the converter.

2. A resonant power converter as claimed in claim 1, wherein switching of the switches is synchronised with the resonant voltage and switch when a voltage over the switches is substantially zero.

3. A resonant power converter as claimed in claim 1, including a control unit for controlling the switches.

4. A resonant power converter as claimed in claim 3, wherein the control unit is on the secondary side of the isolating unit and coupled to the primary side by a control isolating device.

5. A resonant power converter as claimed in claim 3, wherein the control unit is on the primary side of the isolating unit and coupled to the secondary side by a control isolating device.

6. A resonant power converter as claimed in claim 4, wherein the control isolating device is a control transformer.

7. A resonant power converter as claimed in claim 3, wherein the control unit receives an output voltage signal, representative of an output voltage of the converter, for adjusting overlap of the conduction phases.

8. A resonant power converter as claimed in claim 3, wherein the control unit receives an resonant voltage signal, representative of the resonant voltage, for controlling the switches in synchronicity with the resonant voltage.

9. A resonant power converter as claimed in claim 8, wherein the control unit receives the resonant voltage signal by sensing electrical current in the resonant circuit.

10. A resonant power converter as claimed in claim 9, including a current transformer in series in the resonant circuit for sensing the electrical current.

11. A resonant power converter as claimed in claim 8, including a voltage sensor for sending the resonant voltage signal to the control unit by sensing voltages over the switches.

12. A resonant power converter as claimed in claim 11, wherein the voltage sensor includes a voltage sensing circuit and an amplifier/filter for each switch.

13. A resonant power converter as claimed in claim 3, wherein the control unit includes a digital signal processor for controlling the converter.

14. A resonant power converter as claimed in claim 1, wherein the output circuit is in parallel with the resonant circuit.

15. A resonant power converter as claimed in claim 1, wherein the output circuit is in series with the resonant circuit.

16. A resonant power converter as claimed in claim 1, wherein the switches are arranged in a centre-tapped configuration.

17. A resonant power converter as claimed in claim 1, wherein the switches are arranged in a full bridge configuration.

18. A resonant power converter as claimed in claim 1, wherein the resonant circuit includes a resonant inductor and a resonant capacitor.

19. A resonant power converter as claimed in claim 18, wherein the resonant inductor and resonant capacitor are in parallel.

20. A resonant power converter as claimed in claim 18, wherein the resonant inductor and resonant capacitor are in series.

21. A resonant power converter as claimed in claim 18, wherein the resonant inductor is provided by leakage inductance of the isolating unit.

22. A resonant power converter as claimed in claim 1, wherein the resonant circuit includes a blocking capacitor.

23. A resonant power converter as claimed in claim 1, including a clamping circuit for discharging stored energy in a stray inductance of the secondary side of the isolating unit to the output of the converter.

24. A resonant power converter as claimed in claim 23, wherein the clamping circuit is an active clamp including clamping diodes, each connected to one terminal of each switch and the output via a clamping switch.

25. A resonant power converter as claimed in claim 23, wherein the clamping circuit is a passive clamp including a clamping capacitor across each switch.

26. A resonant power converter as claimed in claim 1, wherein the switches include switchable transistors in parallel with diodes.

27. A resonant power converter as claimed in claim 1, wherein the isolating unit is a transformer, with a primary winding on the primary side and a secondary winding on the secondary side.

28. A resonant power converter as claimed in claim 1, wherein the conduction phases overlap by between zero and forty percent of each period of the resonant frequency.

29. A resonant power converter as claimed in claim 1, wherein the DC output is variable.

30. A resonant power converter including synchronous rectifiers adapted to operate with an overlapping conduction phase and a fixed frequency.

31. A control unit for a resonant power converter with synchronous rectifiers operating at a fixed frequency, including:

a sensor circuit for sensing electrical power in the resonant power converter; and

control circuits for controlling the synchronous rectifiers, based on the sensed electrical power, wherein the synchronous rectifiers are controlled to have an overlapping conduction phase.

32. A method of operating a fixed frequency resonant power converter having output synchronous rectifiers, including controlling the rectifiers to operate with overlapping conduction phases.