Power transmitting unit with adjustable field and methods for use therewith

1. A power transmitting device comprising:

a wireless power generator configured to generate a wireless power signal;

a transmit resonator configured to transmit the wireless power signal via a transmit magnetic field to a power receiving unit, the transmit resonator including:

a transmit coil configured to generate that transmit magnetic field in response to the wireless power signal; and

at least one variable magnetic element configured to adjust at least one property of the transmit coil by varying a reluctance of the at least one variable magnetic element in response to at least one control signal; and

a processing device configured to generate the at least one control signal to select the reluctance corresponding to the at least one property of the transmit coil.

2. The power transmitting device of claim 1 wherein the at least one property of the transmit coil includes an impedance of the transmit coil or a magnetic beam pattern of the transmit coil.

3. The power transmitting device of claim 2 further comprising a sensor that generates a signal that indicates an amount of impedance mismatch and wherein the processing device generates the at least one control signal based on the amount of impedance mismatch.

4. The power transmitting device of claim 1 wherein the processing device generates the at least one control signal based on an amount of wireless power received by the power receiving unit.

5. The power transmitting device of claim 4 further comprising a wireless radio unit configured to receive control data from the power receiving unit that indicates the amount of wireless power received by the power receiving unit.

6. The power transmitting device of claim 1 wherein the at least one variable magnetic element includes a plurality of ferrite elements arranged adjacent to the transmit coil.

7. The power transmitting device of claim 6 wherein the transmit coil includes a planar coil in a first plane and wherein the plurality of ferrite elements are arranged in a second plane that is non-coplanar with the first plane.

8. The power transmitting device of claim 6 wherein the at least one variable magnetic element further include a coil and a drive circuit that drives the coil in response to the at least one control signal to control the reluctance of the ferrite element.

9. The power transmitting device of claim 1 wherein the at least one variable magnetic element includes a high permeability layer and at least one adjustable control impedance that controls the reluctance of the high permeability layer.

10. The power transmitting device of claim 9 wherein the transmit coil includes a planar coil in a first plane and wherein the high permeability layer is arranged in a second plane that is non-coplanar with the first plane.

11. A power transmitting device comprising:

a wireless power generator configured to generate a wireless power signal;

a transmit resonator configured to transmit the wireless power signal via a transmit magnetic field to a power receiving unit, the transmit resonator including:

a transmit coil configured to generate that transmit magnetic field in response to the wireless power signal; and

at least one variable magnetic element configured to adjust the transmit magnetic field in response to at least one control signal, wherein the at least one variable magnetic element includes a ferrite element having magnetic reluctance that is controlled in response to the at least one control signal; and

a processing device configured to generate the at least one control signal.

12. The power transmitting device of claim 11 wherein the processing device generates the at least one control signal based on an amount of wireless power received by the power receiving unit.

13. The power transmitting device of claim 12 further comprising a wireless radio unit configured to receive control data from the power receiving unit that indicates the amount of wireless power received by the power receiving unit.

14. The power transmitting device of claim 12 further comprising a matching network that couples the wireless power generator to the transmit coil, wherein the matching network includes a sensor that generates a reflected signal that indicates a reflected impedance of the power receiving unit and wherein the processing device determines the amount of wireless power received by the power receiving unit based on the reflected impedance.

15. The power transmitting device of claim 11 wherein the at least one variable magnetic element includes a plurality of variable magnetic elements arranged adjacent to the transmit coil.

16. The power transmitting device of claim 15 wherein the transmit coil includes a planar coil in a first plane and wherein the plurality of variable magnetic elements are arranged in a second plane that is non-coplanar with the first plane.

17. The power transmitting device of claim 11 wherein the at least one variable magnetic element further include a coil and a drive circuit that drives the coil in response to the at least one control signal to control the magnetic reluctance of the ferrite element.

18. The power transmitting device of claim 11 wherein the at least one variable magnetic element includes a high permeability layer and at least one adjustable control impedance that controls a magnetic reluctance of the high permeability layer.

19. A method comprising:

generating a wireless power signal;

transmitting the wireless power signal via a transmit magnetic field generated by a transmit coil to a power receiving unit, by:

generating at least one control signal to select one of a plurality of magnetic beam patterns; and

adjusting, via a controllable ferrite, the transmit magnetic field to the one of a plurality of magnetic beam patterns in response to at least one control signal.

20. The method of claim 19 , wherein the controllable ferrite has a controllable magnetic reluctance.