Wireless power transmitter with a plurality of magnetic oscillators

Patent metadata

Field	Value
Publication number	US-9601267-B2
Application number	US-201314077102-A
Country	US
Kind code	B2
Filing date	Nov 11, 2013
Priority date	Jul 3, 2013
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A power transmitter is configured to wirelessly transfer power to at least one power receiver. The power transmitter includes at least one excitation circuit configured to generate a time-varying first magnetic field in response to a time-varying electric current flowing through the at least one excitation circuit. The time-varying first magnetic field has an excitation frequency. The power transmitter further includes a plurality of magnetic oscillators. Each magnetic oscillator of the plurality of magnetic oscillators has a mechanical resonant frequency substantially equal to the excitation frequency. The plurality of magnetic oscillators is configured to generate a time-varying second magnetic field in response to the first magnetic field.

First claim

What is claimed is:

1. A power transmitter configured to wirelessly transfer power to at least one power receiver, the power transmitter comprising:
at least one excitation circuit configured to generate a time-varying first magnetic field in response to a time-varying electric current flowing through the at least one excitation circuit, the time-varying first magnetic field having an excitation frequency; and
a plurality of magnetic oscillators, each magnetic oscillator of the plurality of magnetic oscillators having a mechanical resonant frequency substantially equal to the excitation frequency, the plurality of magnetic oscillators configured to generate a time-varying second magnetic field in response to the first magnetic field.

2. The power transmitter of claim 1 , wherein the at least one excitation circuit comprises at least one coil surrounding at least a portion of the plurality of magnetic oscillators.

3. The power transmitter of claim 1 , wherein an impedance of the at least one excitation circuit has an imaginary component that is equal to zero at a frequency substantially equal to the mechanical resonant frequency.

4. The power transmitter of claim 1 , further comprising at least one substrate mechanically coupled to the plurality of magnetic oscillators.

5. The power transmitter of claim 1 , wherein the plurality of magnetic oscillators is a micro-electro-mechanical system (MEMS) structure.

6. The power transmitter of claim 1 , wherein each magnetic oscillator of the plurality of magnetic oscillators comprises a movable magnetic element configured to rotate about an axis in response to a torque applied to the movable magnetic element by the first magnetic field.

7. The power transmitter of claim 6 , wherein the movable magnetic element comprises at least one spring configured to apply a restoring force to the movable magnetic element upon rotation of the movable magnetic element.

8. The power transmitter of claim 1 , wherein the plurality of magnetic oscillators is arranged in a three-dimensional array.

9. The power transmitter of claim 8 , wherein the three-dimensional array comprises:
at least one first plane comprising a first set of magnetic oscillators of the plurality of magnetic oscillators, each magnetic oscillator of the first set of magnetic oscillators having a magnetic moment pointing in a first direction, the first set of magnetic oscillators having a first summed magnetic moment comprising a time-varying component and a time-invariant component; and
at least one second plane comprising a second set of magnetic oscillators of the plurality of magnetic oscillators, each magnetic oscillator of the second set of magnetic oscillators having a magnetic moment pointing in a second direction, the second set of magnetic oscillators having a second summed magnetic moment comprising a time-varying component and a time-invariant component, wherein the time-invariant component of the first summed magnetic moment and the time-invariant component of the second summed magnetic moment have substantially equal magnitudes and point in substantially opposite directions.

10. The power transmitter of claim 8 , wherein the three-dimensional array comprises:
a first plane comprising a first set of magnetic oscillators of the plurality of magnetic oscillators arranged to have a first polarity; and
a second plane adjacent to the first plane, the second plane comprising a second set of magnetic oscillators of the plurality of magnetic oscillators arranged to have a second polarity different than the first polarity to at least partially reduce a quasi-static portion of a summed magnetic moment generated by the first set of magnetic oscillators and the second set of magnetic oscillators.

11. A method of transmitting power wirelessly, the method comprising:
generating a time-varying first magnetic field having an excitation frequency; and
generating a time-varying second magnetic field by applying the first magnetic field to a plurality of magnetic oscillators, each magnetic oscillator of the plurality of magnetic oscillators having a mechanical resonant frequency substantially equal to the excitation frequency.

12. The method of claim 11 , wherein generating the time-varying first magnetic field comprises flowing an electrical current through at least one excitation circuit comprising at least one coil surrounding at least a portion of the plurality of magnetic oscillators.

13. The method of claim 12 , wherein an impedance of the at least one excitation circuit has an imaginary component that is equal to zero at a frequency substantially equal to the mechanical resonant frequency.

14. The method of claim 11 , wherein the plurality of magnetic oscillators is a micro-electro-mechanical system (MEMS) structure.

15. The method of claim 11 , wherein generating the time-varying second magnetic field comprises rotating a movable magnetic element of each magnetic oscillator of the plurality of magnetic oscillators about an axis in response to a torque applied to the movable magnetic element by the first magnetic field.

16. The method of claim 15 , further comprising applying a restoring force to the movable magnetic element upon rotation of the movable magnetic element.

17. The method of claim 11 , wherein the plurality of magnetic oscillators is arranged in a three-dimensional array.

18. The method of claim 17 , wherein the three-dimensional array comprises:
at least one first plane comprising a first set of magnetic oscillators of the plurality of magnetic oscillators, each magnetic oscillator of the first set of magnetic oscillators having a magnetic moment pointing in a first direction, the first set of magnetic oscillators having a first summed magnetic moment comprising a time-varying component and a time-invariant component; and
at least one second plane comprising a second set of magnetic oscillators of the plurality of magnetic oscillators, each magnetic oscillator of the second set of magnetic oscillators having a magnetic moment pointing in a second direction, the second set of magnetic oscillators having a second summed magnetic moment comprising a time-varying component and a time-invariant component, wherein the time-invariant component of the first summed magnetic moment and the time-invariant component of the second summed magnetic moment have substantially equal magnitudes and point in substantially opposite directions.

19. A power transmitter configured to wirelessly transfer power to at least one power receiver, the power transmitter comprising:
means for generating a time-varying first magnetic field having an excitation frequency; and
means for generating a time-varying second magnetic field in response to the time-varying first magnetic field.

20. The power transmitter of claim 19 , wherein the means for generating the time-varying first magnetic field comprises at least one excitation circuit configured to have a time-varying electric current flowing through the at least one excitation circuit.

21. The power transmitter of claim 19 , wherein the means for generating the time-varying second magnetic field comprises a plurality of magnetic oscillators, each magnetic oscillator of the plurality of magnetic oscillators having a mechanical resonant frequency substantially equal to the excitation frequency.

Assignees

• Qualcomm Inc

Inventors

• Widmer Hanspeter
• Cook Nigel P
• Bittner Markus

Classifications

• H02J7/32

  for charging batteries from a charging set comprising a non-electric prime mover {rotating at constant speed} · CPC title

• H02J50/10

  using inductive coupling · CPC title

• H01F38/14 Primary

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• H03B15/006

  using spin transfer effects or giant magnetoresistance · CPC title

• H02J7/025

  Electricity · mapped topic