Resonant Inverter

• US 20080247210A1
• Filed: 08/03/2006
• Published: 10/09/2008
• Est. Priority Date: 08/03/2005
• Status: Active Grant

• Current Assignee: Auckland UniServices Limited (Auckland University)
• Original Assignee: Auckland UniServices Limited (Auckland University)
• Inventors: Hu, Aiguo
• Granted Patent: US 8,406,017 B2
• Time in Patent Office: Days
• US Class Current: 363/131
• CPC Class Codes: H02M 3/3384 of the parallel type
• CPC Class Codes: H02M 7/53846 Control circuits
• 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 inverter includes inductive elements (L1, L2) that allow the number of magnetic components in the inverter to be reduced. The elements (L1, L2) may be designed with a leakage inductance to eliminate the need for a large DC inductor. They may also perform the function of a current splitting transformer. The inverter switches may also be driven directly from the inverter circuit without a separate controller being required.

Claims

1. A resonant inverter comprising an input for supply of current from a DC power source, and two or more inductive elements that form part of a resonant circuit of the inverter, wherein leakage inductance of one or both of the inductive elements substantially decouples the inverter from the power source.

2. A resonant inverter as claimed in claim 1 wherein the inductive elements are arranged to split current received from the power source.

25. A resonant inverter as claimed in claim 1 wherein one or more of the inductive elements comprises at least a part of a primary conductive path or track coil of an ICPT system.

26. A resonant inverter as claimed in claim 1 wherein one or more of the inductive elements comprises at least a part of an induction heating device.

27. A resonant inverter as claimed in claim 1 wherein the inverter is operable in a frequency range of substantially 50 Hz-500 kHz.

3. A resonant inverter an input for supply of current from a DC power source, a resonant circuit including two or more inductive elements and a capacitive element, the inductive elements being arranged to split current from the power source, switching means to controllable switch current from the power source into the resonant circuit, and wherein leakage inductance of one or both of the inductive elements substantially decouples the inverter from the power source.

4. A resonant inverter as claimed in claim 3 wherein the switching means comprising two switching devices operable in substantially opposite phase to alternately switch current from the power source into the inductive elements.

5. A resonant inverter as claimed in claim 3 wherein the inductive elements are coupled.

6. A resonant inverter as claimed in claim 3 wherein the inductive elements are not coupled.

7. A resonant inverter as claimed in claim 3 wherein the inductive elements comprise a single winding.

8. A resonant inverter as claimed in claim 3 wherein the inductive elements comprise a single component.

9. A resonant inverter as claimed in claim 3 wherein the inductive elements are coreless.

36. A resonant inverter as claimed in claim 3 wherein one or more of the inductive elements comprises at least a part of a primary conductive path or track coil of an ICPT system.

40. A resonant inverter as claimed in claim 3 wherein one or more of the inductive elements comprises at least a part of an induction heating device.

44. A resonant inverter as claimed in claim 3 wherein the inverter is operable in a frequency range of substantially 50 Hz-500 kHz.

10. A resonant inverter comprising an input for supply of current from a DC power source, a resonant circuit including two or more inductive elements and a capacitive element, the inductive elements being arranged to split current from the power source, two switching devices operable to controllably switch current from the power source into the resonant circuit in substantially opposite phase to alternately switch current from the power source into the inductive elements, each switching device being driven by a signal derived from the resonant circuit.

11. A resonant inverter as claimed in claim 10 wherein each switching device is provided between an inductive element and the power source, and a driving signal connection point is provided between each switching device and the corresponding inductive element, the driving signal for each switching device is derived from the driving signal connection point of the other switching device.

12. A resonant inverter as claimed in claim 10 wherein leakage inductance of one or both of the inductive elements substantially decouples the inverter from the power source.

13. A resonant inverter as claimed in claim 10 wherein the inductive elements are coupled.

14. A resonant inverter as claimed in claim 10 wherein the inductive elements are not coupled.

15. A resonant inverter as claimed in claim 10 wherein the inductive elements comprise a single winding.

16. A resonant inverter as claimed in claim 10 wherein the inductive elements comprise a single component.

17. A resonant inverter as claimed in claim 10 wherein the inductive elements are coreless.

37. A resonant inverter as claimed in claim 10 wherein one or more of the inductive elements comprises at least a part of a primary conductive path or track coil of an ICPT system.

41. A resonant inverter as claimed in claim 10 wherein one or more of the inductive elements comprises at least a part of an induction heating device.

45. A resonant inverter as claimed in claim 10 wherein the inverter is operable in a frequency range of substantially 50 Hz-500 kHz.

18. A resonant inverter comprising:

a first and a second input terminal for connection to a power source of substantially direct current electrical power;

two inductive elements each having first and second terminals, the first terminals of each of the inductors being connected to the first input terminal;

a capacitive element connected between the other terminals of the inductors, and;

a first switching means connected between the second terminal of one inductor and the second input terminal, and a second switching means connected between the second terminal of the other inductor and the second input terminal, and;

wherein leakage inductance of one or both of the inductive elements substantially decouples the inverter from the power source.

20. A resonant inverter as claimed in claim 18 wherein the inductive elements are coupled.

21. A resonant inverter as claimed in claim 18 wherein the inductive elements are not coupled.

22. A resonant inverter as claimed in claim 18 wherein the inductive elements comprise a single winding.

23. A resonant inverter as claimed in claim 18 wherein the inductive elements comprise a single component.

24. A resonant inverter as claimed in claim 18 wherein the inductive elements are coreless.

38. A resonant inverter as claimed in claim 18 wherein on or more of the inductive elements comprises at least a part of a primary conductive path or track coil of an ICPT system.

42. A resonant inverter as claimed in claim 18 wherein one or more of the inductive elements comprises at least a part of an induction heating device.

46. A resonant inverter as claimed in claim 18 wherein the inverter is operable in a frequency range of substantially 50 Hz-500 kHz.

19. A resonant inverter comprising:

a first and a second input terminal for connection to a power source of substantially direct current electrical power;

two inductive elements each having first and second terminals, the first terminals of each of the inductors being connected to the first input terminal;

a capacitive element connected between the other terminals of the inductor, and;

a first switching means connected between the second terminal of one inductor and the second input terminal, and a second switching means connected between the second terminal of the other inductor and the second input terminal, and;

each switching means is driven by a signal derived from the second inductor terminal to which that switch is not connected.

32. A resonant inverter as claimed in claim 19 wherein the inductive elements are coupled.

33. A resonant inverter as claimed in claim 19 wherein the inductive elements are not coupled.

34. A resonant inverter as claimed in claim 19 wherein the inductive elements comprise a single winding.

35. A resonant inverter as claimed in claim 19 wherein the inductive elements comprise a single component.

39. A resonant inverter as claimed in claim 19 wherein one or more of the inductive elements comprises at least a part of a primary conductive path or track coil of an ICPT system.

43. A resonant inverter as claimed in claim 19 wherein one or more of the inductive elements comprises at least a part of an induction heating device.

47. A resonant inverter as claimed in claim 19 wherein the inverter is operable in a frequency range of substantially 50 Hz-500 kHz.

28. A resonant inverter an input for supply of current from a DC power source, and two or more inductive elements that form part of a resonant circuit of the inverter, wherein leakage inductance of one or both of the inductive elements substantially provides a current source.

29. A method of designing a resonant inverter, the method the steps of selecting a magnetic component for a resonant circuit of the inverter which has sufficient leakage flux to substantially decouple the inverter from a DC power source.

30. (canceled)

31. A method of designing a resonant inverter substantially as herein described with reference to FIG. 8 of the accompanying drawings.