INDUCTIVE CHARGER AND CHARGING METHOD

• US 20110163714A1
• Filed: 09/01/2009
• Published: 07/07/2011
• Est. Priority Date: 09/05/2008
• 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: Visser, Robert Paul, Ettes, Wilhelmus, Van Der Linden, Jacob Adrianus
• Granted Patent: US 8,810,196 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• 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 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence

Abstract

The present invention provides a charger for inductively charging one or more battery powered appliances simultaneously. The charger comprises an external unit adapted to inductively provide power to the battery powered appliances, the external unit comprising: two or more primary coil pairs that are arranged in a circular pattern; an AC power source for providing an alternating current (AC) to the primary coil pairs for generating a rotating magnetic field between respective primary coils of the primary coil pairs; and a processor for driving the AC power source, wherein the one or more battery powered appliances are adapted to be arranged inside the circular pattern of the external unit, each appliance comprising a secondary coil for enclosing part of the magnetic field and in response generating a current for charging the battery of the appliance.

Claims

1. Inductive charger (10) to inductively provide power to one or more battery powered appliances, each appliance comprising a secondary coil for enclosing part of a magnetic field and in response generating a current for charging a battery of the appliance, the charger comprising:

two or more primary coil pairs that are arranged in a circular pattern, wherein the circular pattern is adapted for enclosing the one or more secondary coils (20) of the appliances, and

an AC power source for providing an alternating voltage (104) to the primary coil pairs for generating a rotating magnetic field (22) between respective primary coils (L1, L2, . . . , L8) of the primary coil pairs.

2. The charger of claim 1, wherein each primary coil pair is provided with one or more switches (S1, S2, . . . , S8) for short circuiting the respective primary coil pair.

3. The charger of claim 2, comprising a processor (30) for driving the AC power source, wherein the processor is adapted to short circuit at least one of the primary coil pairs using the corresponding switches (S1, S2, . . . , S8), and to supply the alternating voltage (104) to the remaining primary coil pairs.

4. The charger of claim 1, comprising four primary coil pairs.

5. The charger of claim 1, wherein the alternating voltage (104) has a frequency of about 10 kHz or more.

6. The charger claim 1, the charger (10) being adapted to rotate the magnetic field (22) at a frequency that is more than 1000 times below the frequency of the alternating voltage (104).

7. The charger of claim 1, the charger (10) being adapted to provide the alternating voltage (104) at a frequency that substantially corresponds to a resonance frequency of a series connection of a capacitor (C2-C8) and a corresponding primary coil pair.

8. The charger of claim 1, the charger (10) being adapted to provide the alternating voltage (104) at a frequency that substantially corresponds to a resonance frequency of the one or more appliances.

9. The charger of claim 1, comprising a cover (70) of high magnetic permeability material that encloses the outside of the primary coils.

10. Method to inductively provide power to one or more battery powered appliances, each appliance comprising a secondary coil (20) for enclosing part of a magnetic field (22) and in response generating a current for charging a battery (40) of the appliance, the method comprising the steps of:

providing a charger (10) including two or more primary coil pairs that are arranged in a circular pattern, wherein the circular pattern is adapted for enclosing the one or more secondary coils (20) of the appliances, and

using an AC power source for providing an alternating voltage (104) to the primary coil pairs for generating a rotating magnetic field (22) between respective primary coils (L1, L2, . . . , L8) of the primary coil pairs.

11. The method of claim 10, comprising the step of:

short circuiting at least one of the primary coil pairs, and

supplying the alternating voltage (104) to the remaining primary coil pairs.

12. The method of claim 11, wherein each primary coil pair is provided with one or more switches (S1, S2, . . . , S8) for short circuiting the respective primary coil pair.