Parallel-tuned pick-up system with multiple voltage outputs

• US 20070120421A1
• Filed: 05/26/2004
• Published: 05/31/2007
• Est. Priority Date: 05/26/2003
• Status: Active Grant

• Current Assignee: Auckland UniServices Limited (Auckland University)
• Original Assignee: Auckland UniServices Limited (Auckland University)
• Inventors: Boys, John
• Granted Patent: US 7,781,916 B2
• Time in Patent Office: Days
• US Class Current: 307/11
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 7/217 using semiconductor devices only
• 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 pick-up is provided for an Inductively Coupled Power Transfer (ICPT) system having a parallel tuned resonant pick-up circuit. The pick-up has a plurality of independently controllable power supply outputs. This allows a first output to supply a high voltage load (e.g. 300V-550V) and one or more additional outputs for supplying other loads such as control circuitry which may only require 24V. The one or more additional outputs may be supplied via a current transformer connected in series with the resonant pick-up circuit. Control for each output may be achieved by partially or completely decoupling the pick-up from a primary conductive path of the ICPT system.

Claims

1. An ICPT system pick-up comprising:

a pick-up coil capable of generating a voltage by magnetic induction from a primary conductive pathway, the pick-up coil being part of a pick-up resonant circuit having a pick-up resonant frequency and a tuning capacitor connected in parallel with the pick-up coil;

a first output associated with a first controller to substantially control a voltage provided by the first output;

a current transformer connected in series with the pick-up resonant circuit;

one or more additional outputs associated with the current transformer; and

one or more additional controllers associated with each of the one or more additional outputs to substantially control a voltage provided by the one or more additional outputs,

whereby the voltages of the first output and the one or more additional outputs are independently controllable.

2. A pick-up as claimed in claim 1, wherein the first controller comprises a first decoupling device and the one or more additional controllers comprises an additional decoupling device, each decoupling device operable to allow the pick-up coil to be at least partly decoupled from the primary conductive pathway to thereby control the power flow from the primary conductive pathway to the pick-up coil.

3. A pick-up as claimed in claim 2, wherein each decoupling device comprises a switch, and activation or deactivation of the switch causes the pick-up coil to be decoupled or coupled from or to the primary conductive path.

4. A pick-up as claimed in claim 3, wherein the switch is a controlled switch adapted to be activated and deactivated in a duty cycle at a predetermined frequency.

5. A pick-up as claimed in claim 2, wherein at least one of the first decoupling device or the one or more additional decoupling devices comprises a zener diode.

6. A pick-up as claimed in claim 1, wherein the current transformer has a first winding and a second winding, the first winding being connected in series with the pick-up resonant circuit and the second winding being connected to at least one of the one or more additional controllers.

7. A pick-up as claimed in claim 6 further comprising a snubber capacitance provided across the first winding.

8. A pick-up as claimed in claim 3, wherein the first controller and the one or more additional controllers each comprise:

a rectifier having first and second output terminals; and

a DC inductor having first and second terminals, the first terminal of the DC inductor being connected to the first output terminal of the rectifier, the second terminal of the DC inductor being connected to a first terminal of the switch, and a second terminal of the switch being connected to the second output terminal of the rectifier.

9. A pick-up as claimed in claim 8, wherein a diode is connected between the first terminal of the switch and a first terminal of a filter capacitor, a second terminal of the filter capacitor is connected to the second terminal of the switch, and a load may be connected between the first and second terminals of the filter capacitor.

36. An ICPT system comprising a pick-up as set forth in claim 1.

10. An ICPT system pick-up comprising:

a pick-up coil capable of generating a voltage by magnetic induction from a primary conductive pathway, the pick-up coil being part of a pick-up resonant circuit having a pick-up resonant frequency and a tuning capacitor connected in parallel with the pick-up coil;

a first output associated with a first controller to control power transfer from the primary conductive pathway to the pick-up coil to correspond to a power required by a first output load connectable to the first output;

a current transformer connected in series with the pick-up resonant circuit;

one or more additional outputs associated with the current transformer; and

one or more additional controllers associated with each of the one or more additional outputs to control power transfer from the primary conductive pathway to the pick-up coil to correspond to a power required by one or more additional output loads connectable to each of the one or more additional outputs.

11. A pick-up as claimed in claim 10, wherein the first controller comprises a first decoupling device and each of the one or more additional controllers comprises an additional decoupling device, each decoupling device operable to allow the pick-up coil to be at least partly decoupled from the primary conductive pathway to thereby control the power flow from the primary conductive pathway to the pick-up coil.

12. A pick-up as claimed in claim 10, wherein the first controller activates or deactivates the first decoupling device to regulate the voltage across the first output to a first required output voltage, and each of the one or more additional controllers activates or deactivates the one or more additional decoupling devices to regulate the voltage across the one or more additional outputs to one or more required output voltages.

13. A pick-up as claimed in claim 11, wherein the first decoupling device and each of the one or more additional decoupling devices comprises a switch having first and second terminals, and activation or deactivation of the switch causes the pick-up coil to be decoupled or coupled from or to the primary conductive path.

14. A pick-up as claimed in claim 13, wherein the switch is a controlled switch adapted to be activated and deactivated in a duty cycle at a predetermined frequency.

15. A pick-up as claimed in claim 11, wherein at least one of the first decoupling device or the one or more additional decoupling devices comprises a zener diode.

16. A pick-up as claimed in claim 10, wherein the current transformer has a first winding and a second winding, the first winding being connected in series with the pick-up resonant circuit and the second winding being connected to at least one of the one or more additional controllers.

17. A pick-up as claimed in claim 15, further comprising a snubber capacitance provided across the first winding.

18. A pick-up as claimed in claim 13, wherein the first controller and the one or more additional controllers each comprise:

a rectifier having first and second output terminals; and

a DC inductor having first and second terminals, the first terminal of the DC inductor being connected to the first output terminal of the rectifier, the second terminal of the DC inductor being connected to a first terminal of the switch, and a second terminal of the switch being connected to the second output terminal of the rectifier.

19. A pick-up as claimed in claim 18, wherein a diode is connected between the first terminal of the switch and a first terminal of a filter capacitor, a second terminal of the filter capacitor is connected to the second terminal of the switch, and the first output load or the one or more additional output loads may be connected between the first and second terminals of the filter capacitor.

20. An adaptor circuit for an ICPT system, the adaptor circuit comprising a current transformer connectable in series with a parallel-tuned pick-up of the ICPT system;

and

an output associated with a controller operable to match a power transfer from a primary conductive pathway of the ICPT system with a power required by an output load connectable to the output.

21. An adaptor circuit as claimed in claim 20, wherein the controller comprises:

a control circuit of the adaptor circuit, the control circuit comprising a decoupling device operable to match the power transfer from the primary conductive pathway with the power required by the load by at least partly decoupling the pick-up coil from the primary conductive pathway.

22. An adaptor circuit as claimed in claim 21, wherein the control circuit activates or deactivates the decoupling device to regulate a voltage across the output to a required output voltage.

23. An adaptor circuit as claimed in claim 22, wherein the current transformer comprises a first and second winding the decoupling device comprises a switch connected in parallel with the second winding of the current transformer, and activation or deactivation of the switch causes the pick-up coil to be decoupled or coupled from or to the primary conductive path.

24. An adaptor circuit as claimed in claim 23, wherein the switch is a controlled switch adapted to be activated and deactivated in a duty cycle at a predetermined frequency.

25. An adaptor circuit as claimed in claim 21, wherein the decoupling device comprises a zener diode.

26. An adaptor circuit as claimed in claim 21, wherein the current transformer comprises a first winding and a second winding, the first winding being connected in series with the pick-up resonant circuit and the second winding being connected to the control circuit.

27. An adaptor circuit as claimed in claim 26, further comprising a snubber capacitance provided across the first winding.

28. An adaptor circuit as claimed in claim 23, wherein the control circuit comprises:

a rectifier having first and second output terminals; and

a DC inductor having first and second terminals, the first terminal of the DC inductor being connected to the first output terminal of the rectifier, the second terminal of the DC inductor being connected to a first terminal of the switch, and a second terminal of the switch being connected to the second output terminal of the rectifier.

29. An adaptor circuit as claimed in claim 28, wherein a diode is connected between the first terminal of the switch and a first terminal of a filter capacitor, a second terminal of the filter capacitor is connected to the second terminal of the switch, and the output load may be connected between the first and second terminals of the filter capacitor.

35. An ICPT pick-up comprising an adapter circuit as set forth in claim 20.

30. A method for controlling at least one independently controllable output from a parallel tuned pick-up of an ICPT system, the method comprising the steps of:

interconnecting a first current transformer in series with the parallel tuned pick-up; and

providing a controller adapted to match a power transfer from a primary conductive pathway of the ICPT system with a power required by an output load connectable to a first independently controllable output.

31. A method as claimed in claim 30, further comprising the step of:

controlling the power transfer from the primary conductive pathway with the power required by the output load by at least partly decoupling the pick-up coil from the primary conductive pathway.

32. A method as claimed in claim 31, further comprising the steps of:

detecting a voltage of the independently controllable output;

comparing the detected voltage with a required voltage; and

controlling a coupling between the pick-up coil and the primary conductive pathway by coupling or decoupling the pick-up coil to or from the primary conductive path to alter the voltage of the independently controllable output toward the required voltage.

33. A method as claimed in claim 31, further comprising the step of:

connecting a second current transformer in series with the parallel tuned pick-up to supply a second independently controllable output.

34. A method as claimed in claim 31 further comprising the step of:

providing a snubber capacitance across a primary winding of the current transformer.

37. An ICPT pick-up having two or more outputs comprising:

a pick-up resonant circuit, the pick-up resonant circuit comprising

a pick-up coil; and

a tuning capacitor connected in parallel with the pick-up coil; and

a controller operable to independently control a respective voltage of each of the two or more outputs.

38. An ICPT pick-up having two or more outputs comprising:

a pick-up resonant circuit, the pick-up resonant circuit comprising;

a pick-up coil; and

a tuning capacitor connected in parallel with the pick-up coil; and

a controller operable to independently control a power transferred from a primary conductive pathway of the ICPT pick-up to the pick-up coil for each of the two or more outputs.

39-41. -41. (canceled)