SYSTEM AND METHOD FOR REGULATING INDUCTIVE POWER TRANSMISSION

• US 20140292097A1
• Filed: 06/02/2014
• Published: 10/02/2014
• Est. Priority Date: 03/17/2008
• Status: Active Grant

• Current Assignee: Powermat Technologies, Ltd.
• Original Assignee: Powermat Technologies, Ltd.
• Inventors: MACH, Elieser, ROFE, Arik, GREENWALD, Oola, RAVEH, Guy
• Granted Patent: US 9,960,640 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• 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 50/12 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

Abstract

An inductive power transfer system is provided that includes at least one inductive power receiver having at least one secondary inductor for forming an inductive couple with a primary inductor and providing power to an electric load and at least one inductive power outlet having at least one primary inductor wired to a power supply via a driver configured to provide a driving voltage across the primary inductor. The driving voltage is oscillating at a transmission frequency significantly different from the natural frequency of the inductive couple. The system further includes at least one power monitor and at least one frequency modulator operable to adjust the natural frequency of the inductive couple thereby regulating power provided to the electric load.

Claims

1. An inductive power receiver for providing power to an electric load, said inductive power receiver comprising:

at least one secondary inductor for forming an inductive couple with a primary inductor associated with an inductive power outlet;

at least one power monitor operable to monitor output power of said secondary inductor; and

at least one receiver-side frequency modulator operable to adjust the natural frequency of the inductive couple thereby bringing monitored output power closer to the required operating voltage of said electric load such that induced power provided to the electric load is regulated during power transfer.

2. The inductive power receiver of claim 1 wherein said frequency modulator comprises at least one frequency modulation coil operable to modify magnetic permeability of at least one magnetic flux guide.

3. The inductive power receiver of claim 1 wherein said frequency modulator comprises at least one variable capacitor.

4. The inductive power receiver of claim 1 wherein said frequency modulator comprises at least one variable inductor.

5. The inductive power receiver of claim 1 wherein said frequency modulator comprises at least one dimension modifier configured to modify the dimensions of at least one inductor.

6. The inductive power receiver of claim 5 wherein said dimension modifier is configured to adjust distance between an inductive coil and a ferromagnetic core.

7. The inductive power receiver of claim 1 wherein said frequency modulator comprises at least one dimension modifier configured to modify the dimensions of at least one capacitor.

8. The inductive power receiver of claim 7 wherein said dimension modifier comprises at least one piezoelectric crystal wired to a variable direct current supply and coupled to at least one capacitive plate of the capacitor such that the distance between the capacitive plates is adjusted when the direct current supply is varied.

9. The inductive power receiver of claim 1 further comprising at least one magnetic flux guide for directing magnetic flux from the primary inductor to the secondary inductor wherein said frequency modulator comprises at least one modulation coil wired to a variable direct current supply and operable to modify magnetic permeability of the magnetic flux guide.

10. The inductive power receiver of claim 1 further comprising at least one magnetic flux guide for directing magnetic flux from the primary inductor to the secondary inductor wherein said frequency modulator comprises at least one dimension modifier configured to adjust the dimensions between the flux guide and the secondary inductor.

11. The inductive power receiver of claim 10 wherein said dimension modifier comprises at least one piezoelectric crystal coupled to the flux guide and the secondary inductor and wired to a variable direct current supply such that the distance between the flux guide and the secondary inductor is adjusted when the direct current supply is varied.

12. An inductive power outlet for providing power to at least one electric load via at least one inductive power receiver, said inductive power outlet comprising:

at least one primary inductor for forming an inductive couple with at least one secondary inductor of said at least one inductive power receiver;

a driver configured to provide a driving voltage across said primary inductor, said driving voltage oscillating at a transmission frequency significantly different from the natural frequency of said inductive couple;

a signal detector operable to receive instruction signals from a signal emitter associated with said inductive power receiver during power transfer;

at least one outlet-side frequency modulator operable to adjust the natural frequency of the inductive couple according to said instruction signals such that induced power provided to the electric load is regulated during power transfer.

13. The inductive power outlet of claim 12 wherein said signal detector comprises said primary inductor operable to detect signals emitted by said secondary inductor as a coil-to-coil signal transmission system.

14. The inductive power outlet of claim 12 wherein said frequency modulator comprises at least one dimension modifier.

15. The inductive power outlet of claim 14 wherein said dimension modifier comprises at least one piezoelectric crystal wired to a variable direct current supply.

16. The inductive power outlet of claim 12 wherein said dimension modifier is configured to adjust distance between said primary inductive coil and a ferromagnetic core.

17. The inductive power outlet of claim 12 wherein said dimension modifier is configured to modify the dimensions of at least one capacitor.

18. The inductive power outlet of claim 12 further comprising at least one magnetic flux guide for directing magnetic flux from the primary inductor to the secondary inductor wherein said frequency modulator comprises at least one modulation coil wired to a variable direct current supply and operable to modify magnetic permeability of the magnetic flux guide.

19. A method for regulating power transfer across an inductive couple between an inductive power outlet and an inductive power receiver, the method comprising:

providing an inductive power outlet comprising a primary coil and a driver;

providing an inductive power receiver comprising a secondary coil, a power monitor

providing at least one frequency modulator;

said driver providing a voltage to a primary coil oscillating at a transmission frequency significantly different from the natural frequency of said inductive couple;

inducing a secondary voltage across said secondary coil wired to an electric load;

determining a required power range for said electric load;

monitoring power received by the electric load during power transfer;

comparing said power received by the electric load to the required power during power transfer;

if the monitored power lies outside the required power range instructing said frequency modulator to adjust the natural frequency of said inductive couple during power transfer; and

said frequency modulator adjusting the natural frequency of said inductive couple during power transfer such that the monitored power is regulated during power transfer.

20. The method of claim 19 wherein the step of instructing said frequency modulator to adjust the natural frequency of said inductive couple during power transfer comprises:

a signal emitter associated with said inductive power receiver sending a signal; and

a signal detector associated with said inductive power transmitter receiving said signal.