INDUCTIVE POWER TRANSFER SYSTEM

• US 20120248892A1
• Filed: 08/06/2010
• Published: 10/04/2012
• Est. Priority Date: 08/07/2009
• Status: Active Grant

• Current Assignee: Auckland UniServices Limited (Auckland University)
• Original Assignee: Auckland UniServices Limited (Auckland University)
• Inventors: Covic, Grant Anthony, Kissin, Michael Le Gallais
• Granted Patent: US 10,566,838 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 5/005 without mechanical contact between the collector and the power supply line
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• 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 53/126 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: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A magnetic flux pad (BPP) is provided for generating or receiving magnetic flux. The pad may be used with an inductive power transfer system, and comprises a magnetically permeable core (4) and two substantially flat overlapping coils (2, 3) magnetically associated with the core (4). The coils (2, 3) are arranged so that there is essentially no mutual coupling between them.

Claims

1. A magnetic flux pad for generating or receiving magnetic flux, the magnetic flux pad comprising:

a magnetically permeable core; and

two substantially flat overlapping coils magnetically associated with the magnetically permeable core, whereby there is substantially no mutual coupling between the coils.

2. A magnetic flux pad as claimed in claim 1 wherein the coils are substantially completely magnetically decoupled.

3. A magnetic flux pad as claimed in claim 1, wherein the coils partially overlap.

4. A magnetic flux pad as claimed in claim 1 wherein the coils are substantially coplanar.

5. A magnetic flux pad as claimed in claim 1 wherein the coils are provided on one side of the magnetic permeable core, and a shielding means is provided on the other side of the magnetic permeable core.

6. A magnetic flux pad as claimed in claim 5 wherein the shielding means comprises a shielding plate made of a suitable material such as aluminium.

7. A magnetic flux pad as claimed in

claim 1 further comprising a dielectric cover provided on a side of the coils opposite the magnetically permeable core.

8. A magnetic flux pad as claimed in claim 1 wherein the flux pad is adapted to receive currents from a power supply which are out of phase with each other to produce a time varying magnetic field which also varies spatially.

9. A magnetic flux pad as claimed in claim 8 wherein the time varying magnetic field produced by the out-of-phase currents in the coils produces a time varying magnetic field which moves spatially and alternately between poles.

24. A magnetic flux pad as claimed in claim 2 wherein the coils partially overlap.

10. Power supply apparatus for an inductive power transfer system, the power supply apparatus comprising:

a magnetic flux pad for generating a magnetic flux, the magnetic flux pad comprising a magnetically permeable core, two substantially flat overlapping coils magnetically associated with the magnetically permeable core; and

a power supply adapted to provide a current in one coil which has a different phase to a current in the other coil.

11. Power supply apparatus as claimed in claim 10 wherein the power supply is adapted to adjust the phase to produce a field that varies with time and with spatial position on the magnetic flux pad.

12. Power supply apparatus as claimed in claim 10 further comprising means to detect where a field is or is not required in a vicinity of the magnetic flux pad and adjust relative phase and/or amplitude of the current in the coils in response to an output of a sensing means.

13. Power supply apparatus as claimed in claim 10 wherein the power supply includes an inverter for each coil.

14. Power supply apparatus as claimed in claim 10 wherein the power supply comprises two inverters which are synchronised with each other to produce a current in one coil which is 90°

out of phase with the current in the other coil.

15. Power supply apparatus as claimed in claim 10 wherein the magnetic flux pad produces a sliding time varying magnetic field.

16. Power supply apparatus as claimed in claim 10 wherein the power supply operates the coils 180°

out of phase with each other.

17. Power supply apparatus as claimed in claim 16 wherein the power supply includes one inverter for energising both coils.

25. Power supply apparatus as claimed in claim 11 further comprising means to detect where a field is or is not required in a vicinity of the magnetic flux pact and adjust relative phase and/or amplitude of the current in the coils in response to an output of a sensing means.

26. Power supply apparatus as claimed in claim 13 wherein the power supply comprises two inverters which are synchronised with each other to produce a current in one coil which is 90°

out of phase with the current in the other coil.

18. A method for providing an IPT magnetic flux pad having a plurality of coils in which there is no mutual magnetic coupling between the coils, the method comprising:

overlapping the coils, and

varying the overlap between the coils such that an overlap position is achieved whereby there is substantially no mutual coupling between the coils.

19. A method as claimed in claim 18 wherein the absence of mutual coupling is detected by detecting when an open circuit voltage induced in one of the coils by energisation of the other coil is minimised.

20. (canceled)

21. (canceled)

22. (canceled)