WIRELESS POWER TRANSMISSION SYSTEM

• US 20110025133A1
• Filed: 03/31/2009
• Published: 02/03/2011
• Est. Priority Date: 04/03/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Sauerlaender, Georg, Waffenschmidt, Eberhard
• Granted Patent: US 8,810,071 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• 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 50/10 using inductive coupling
• 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

Abstract

A Wireless power transmission system comprises a base unit (1) with multiple magnetic field generator circuits and a device (10), separable from said base unit (1) having a receiving inductor, adapted to receive power inductively when said device (10) is in proximity to one of said generator circuits, wherein said base unit (1) comprises a controller (3), configured to determine a transmission circuit (2′) from said generator circuits when said receiving inductor is in proximity to said transmission circuit (2′), whereupon said transmission circuit (2′) is operated to generate a first magnetic field (8), having a first phase, to induce a current in said receiving inductor and at least one of the remaining generator circuits is operated as a compensation circuit (2″, 52, 82) to generate a second magnetic field (21), having an opposite phase to said first phase.

Claims

1. Wireless power transmission system, comprising

a base unit (1) with multiple magnetic field generator circuits and

a device (10), separable from said base unit (1) having a receiving inductor, adapted to receive power inductively when said device (10) is in proximity to one of said generator circuits,

wherein said base unit (1) comprises a controller (3), configured to determine a transmission circuit (2′

) from said generator circuits when said receiving inductor is in proximity to said transmission circuit (2′

), whereupon said transmission circuit (2′

) is operated to generate a first magnetic field (8), having a first phase, to induce a current in said receiving inductor and at least one of the remaining generator circuits is operated as a compensation circuit (2″

, 52, 82) to generate a second magnetic field (21), having an opposite phase to said first phase.

2. System according to claim 1, wherein said transmission circuit (2′

) and said at least one compensation circuit (2″

, 52, 82) are operated so that the amplitude of magnetic flux of said first magnetic field (8) corresponds to the amplitude of magnetic flux of said second magnetic field (21).

3. System according to claim 1, wherein said generator circuits each comprise a coil (2) with multiple windings for generating said magnetic fields (8, 21).

4. System according to claim 3, wherein the number of windings of the transmission circuit (2′

) corresponds to the number of windings of the at least one compensation circuit (2″

, 52, 82).

5. System according to claim 1, wherein each generator circuit has an associated detector (4), connected to the controller (3), for detecting the proximity of the receiving inductor to the corresponding generator circuit.

6. System according to claim 5, wherein said detectors (4) are RFID detectors and said device comprises an RFID tag (17).

7. System according to claim 1, wherein said generator circuits are arranged in a plane, forming a transmission area.

8. System according to claim 7, wherein said compensation circuit (2″

, 52, 82) comprises at least one conductor winding, arranged on a periphery of said transmission area to generate said second magnetic field (21).

9. System according to claim 1, wherein the controller (3) is configured to determine said at least one compensation circuit (2″

, 52, 82) from said multiple generator circuits, so that said transmission circuit (2′

) and said compensation circuit (2″

, 52, 82) are adjacent to each other.

10. System according to claim 1, wherein said base unit (1) comprises a sensor, connected to the controller (3) for sensing the magnetic field, so that said compensation circuit (2″

, 52, 82) is operated to minimise the magnetic far-field of said transmission circuit (2′

).

11. Device (10) for use in a system according to claim 1.

12. Base unit (1) for use in a wireless power transmission system comprising multiple magnetic field generator circuits and a controller (3), configured to determine a transmission circuit (2′

) from said generator circuits when a receiving inductor is in proximity to said transmission circuit (2′

), whereupon said transmission circuit (2′

) is operated to generate a first magnetic field (8), having a first phase, to induce a current in said receiving inductor and at least one of the remaining generator circuits is operated as a compensation circuit (2″

, 52, 82) to generate a second magnetic field (21), having an opposite phase to said first phase.

13. Method for operating a wireless power transmission system, comprising a base unit (1), having multiple magnetic field generator circuits and a device (10), separable from said base unit (1) having a receiving inductor, adapted to receive power inductively when said device (10) is in proximity to one of said generator circuits, wherein

the proximity of the receiving inductor to a transmission circuit (2′

) of said generator circuits is determined,

said transmission circuit (2′

) is operated to generate a first magnetic field (8) to induce a current in said receiving inductor and

at least one of the remaining generator circuits is operated as a

compensation circuit (2″

, 52, 82) to generate a second magnetic field (21) in opposite phase to said first magnetic field (8).

14. Computer program enabling to carry out the method according to claim 13 when executed on a computer.

15. (canceled)