INDUCTIVE POWER TRANSFER SYSTEM AND METHOD

• US 20150028849A1
• Filed: 12/18/2012
• Published: 01/29/2015
• Est. Priority Date: 12/16/2011
• Status: Active Application

• Current Assignee: Auckland UniServices Limited (Auckland University)
• Original Assignee: Auckland UniServices Limited (Auckland University)
• Inventors: Boys, John Talbot, Covic, Grant Anthony
• Application Number:
  US14/365,873
• Publication Number:
  US 20150028849A1
• Time in Patent Office: Days
• US Class Current: 324/76.11
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/20 characterised by converters located in the vehicle
• CPC Class Codes: G01R 21/006 Measuring power factor
• CPC Class Codes: G01V 3/10 using induction coils
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

Foreign object detection apparatus for an IPT system, includes a control means adapted to detect the presence of a foreign object on or adjacent to an IPT primary pad of the system.

Claims

1. A foreign object detection apparatus for an IPT system, the apparatus comprising a control means adapted to detect the presence of a foreign object on or adjacent to an IPT primary pad of the system.

2. The apparatus as claimed in claim 1 wherein the control means uses the IPT primary pad and/or an IPT secondary pad to detect the foreign object.

3. The apparatus as claimed in claim 1 wherein the control means is adapted to detect when an IPT secondary pad is in a charging position with respect to the IPT primary pad.

4. The apparatus as claimed in claim 1 wherein the control means is adapted to selectively reduce power transferred by the system on detection of a foreign object.

5. The apparatus as claimed in claim 1 in which the control means detects a foreign object by at least:

determining an expected rate of power transfer;

determining the actual rate of power transfer; and

comparing the expected rate of power transfer with the actual rate of power transfer.

6. The apparatus as in claimed in claim 5 further comprising determining if the actual rate of power transfer is less than the expected rate of power transfer by more than a predetermined amount.

7. The apparatus as claimed in claim 1 including means to measure relative position between an IPT primary pad of the system and an IPT secondary pad of the system.

8. The apparatus as claimed in claim 7 wherein the means to measure relative position are adapted to measure electrical characteristics of the IPT primary and secondary pads.

9. The apparatus as claimed in claim 7 wherein the means to measure relative position are adapted to measure the lateral offset of the primary and secondary pads by the phase and magnitude of short circuit currents.

10. The apparatus as claimed in claim 7 wherein the means to measure relative position are adapted to measure the lateral offset by the voltage(s) induced in the IPT secondary pad.

11. The apparatus as claimed in claim 7 further including means to measure distance between the primary and secondary pads by comparing magnitudes of currents in the IPT primary and IPT secondary pads.

12. The apparatus as claimed in claim 1 including a communication means for communicating information about one or both of the IPT primary pad and the IPT secondary pad to the control means.

80. The apparatus as claimed in claim 1 wherein the control means is operable to detect the presence of a foreign object by detecting a reduction in magnitude of the short circuit current in a secondary pad which receives power inductively from the primary pad.

13. A method of operating an IPT system to detect the presence of a foreign object, the method including:

determining an expected rate of power transfer;

determining the actual rate of power transfer; and

comparing the expected rate of power transfer with the actual rate of power transfer.

14. The method as in claimed in claim 13 further comprising determining if the actual rate of power transfer is less than the expected rate of power transfer by more than a predetermined amount.

15. The method as claimed in claim 13 including measuring relative position between an IPT primary pad of the system and an IPT secondary pad of the system.

16. The method as claimed in claim 15 wherein measuring relative position includes measuring electrical characteristics of the IPT primary and secondary pads.

17. The method as claimed in claim 15 wherein measuring relative position includes measuring the lateral offset of the primary and secondary pads by the phase and magnitude of short circuit currents.

18. The method as claimed in claim 15 wherein measuring relative position includes measuring the lateral offset by the voltage(s) induced in the IPT secondary pad.

19. The method as claimed in claim 15 further including measuring distance between the primary and secondary pads by comparing magnitudes of currents in the IPT primary and IPT secondary pads.

20. The method as claimed in claim 13 including communicating information about one or both of the IPT primary pad and the IPT secondary pad to a control means.

21. A foreign object detection apparatus for an IPT system, the apparatus comprising a control means adapted to determine VAR currents due to relative position between an IPT primary pad and an IPT secondary pad, and measure the actual VAR currents in the IPT primary pad to determine whether a foreign object is present on or adjacent to the IPT primary pad.

22. The apparatus as claimed in claim 21 wherein the control means includes position detection means to detect the relative position of the IPT primary and IPT secondary pad.

23. The apparatus as claimed in claim 22 wherein the position detection means measure electrical characteristics of the IPT primary and IPT secondary pads to detect the position of one pad relative to the other.

24. The apparatus as claimed in claim 22 wherein the position detection means measure the lateral offset of the primary and secondary pads by the phase and magnitude of short circuit currents.

25. The apparatus as claimed in claim 22 wherein the position detection means measure the lateral offset by the voltage(s) induced in the IPT secondary pad.

26. The apparatus as claimed in claim 22 wherein the position detection means measure distance between IPT primary and secondary pads by comparing magnitudes of currents in the IPT primary and IPT secondary pads.

27. The apparatus as claimed in claim 21 including communicating information about one or both of the IPT primary pad and the IPT secondary pad to the control means.

28. A method of operating an IPT system to detect the presence of a foreign object, the method including:

determining VAR currents due to relative position of an IPT primary pad and an IPT secondary pad; and

measuring the actual VAR currents in the IPT primary pad to determine whether a foreign object is present on or adjacent to the IPT primary pad.

29. The method as claimed in claim 28 including measuring relative position of the IPT primary pad and the IPT secondary pad of the system.

30. The method as claimed in claim 29 wherein measuring relative position includes measuring electrical characteristics of the IPT primary and IPT secondary pads to detect the position of one pad relative to the other.

31. The method as claimed in claim 28 wherein measuring relative position includes measuring the lateral offset of the primary and secondary pads by the phase and magnitude of short circuit currents.

32. The method as claimed in claim 28 wherein measuring relative position includes measuring the lateral offset by the voltage(s) induced in the IPT secondary pad.

33. The method as claimed in claim 29 further including measuring distance between the IPT primary pad and the IPT secondary pad by comparing magnitudes of currents in the IPT primary and IPT secondary pads.

34. The method as claimed in claim 28 including communicating information about one or both of the IPT primary pad and the IPT secondary pad to a control means.

35-79. -79. (canceled)