Method and apparatus for adaptive tuning of wireless power transfer

• US 9,236,771 B2
• Filed: 11/06/2008
• Issued: 01/12/2016
• Est. Priority Date: 05/13/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Toncich, Stanley S., Ozaki, Ernest T., Mohammadian, Alireza H.
• Primary Examiner(s): HUANG, WEN WU
• Application Number:
  US12/266,522
• Publication Number:
  US 20090284220A1
• Time in Patent Office: 2,623 Days
• Field of Search: 4551931- 3, 4552722- 4, 455/120, 455/121, 455/123, 455/125, 455 411- 3
• US Class Current: 1/1
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10178 including auxiliary means for focusing, repeating or boosting the electromagnetic interrogation field comparable booster antennas integrated on the record carrier itself G06K19/07794
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/502 the energy repeater being integrated together with the emitter or the receiver
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• 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
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/72 : for local intradevice communication
• CPC Class Codes: H04B 5/79 : for data transfer in combination with power transfer

Abstract

Exemplary embodiments are directed to wireless power transfer. A transmit antenna generates an electromagnetic field at a resonant frequency of to create a coupling-mode region within a near field of the transmit antenna. A receive antenna receives the resonant frequency when it is within the coupling-mode region and resonates substantially near the resonant frequency. One, or both, of the transmit and receive antennas are tunable antennas that can be adaptively tuned. The adaptive tuning is accomplished by detecting a mismatch at the tunable antenna and generating a mismatch signal responsive to a voltage standing wave ratio at the tunable antenna. A resonance characteristic of the tunable antenna can be modified by adjusting a capacitance of a variable capacitor network connected to the tunable antenna.

Claims

1. A wireless power repeater, comprising:

a power transfer component configured to receive power wirelessly from a transmitter external to the repeater at a level sufficient for charging an electronic device, the power transfer component further configured to transmit power wirelessly to a receiver external to the repeater at the level sufficient for charging the electronic device;

a voltage standing wave ratio detector circuit operably coupled to the power transfer component and configured to generate a mismatch signal indicating a degree of mismatch at the power transfer component based on the received power;

a controller configured to analyze the mismatch signal and to generate control signals responsive thereto; and

a variable capacitor operably coupled between the power transfer component and the controller, the variable capacitor having a capacitance and configured to modify the capacitance based on the control signals.

2. The wireless power repeater of claim 1, wherein the variable capacitor comprises a network selected from the group consisting of a T-network, an L-network, and a Pi-network.

3. The wireless power repeater of claim 1, wherein the variable capacitor comprises a plurality of variable capacitors, each variable capacitor controlled by one of the control signals, wherein a capacitance of each capacitor is adjusted based on its corresponding control signal.

4. The wireless power repeater of claim 3, wherein each of the plurality of variable capacitors comprises a plurality of switched capacitors operably coupled in parallel, each switched capacitor comprising a switch and a capacitor operably coupled in series, wherein each switched capacitor is selectively included in the variable capacitor based on the control signal operatively coupled thereto.

5. The wireless power repeater of claim 3, wherein each of the plurality of variable capacitors comprises at least one varactor operatively coupled to a corresponding control signal acting as a bias control for the at least one varactor, the at least one varactor selected from the group consisting of a reverse bias varactor diode and a MEMS variable capacitor.

6. The wireless power repeater of claim 1, wherein the power transfer component and the transmit power transfer component each comprise a coil.

7. The wireless power repeater of claim 1, wherein the power transfer component and the transmit power transfer component each comprise an antenna.

8. The wireless power repeater of claim 1, wherein the variable capacitor is configured to modify the capacitance of the variable capacitor to modify a resonance of the power transfer component and the variable capacitor.

9. A method of repeating transmission of wireless power, comprising:

resonating a power transfer component of a receiver antenna of a repeater substantially near a resonant frequency of a transmitter external to the repeater;

receiving power wirelessly from the transmitter at a level sufficient for charging an electronic device;

resonating the power transfer component substantially near a resonant frequency of a receiver external to the repeater;

transmitting power wirelessly to the receiver at the level sufficient for charging the electronic device; and

adaptively tuning the power transfer component, the adaptively tuning comprising;

detecting a mismatch based on a voltage standing wave ratio at the power transfer component;

generating a mismatch signal based on the detected mismatch; and

modifying a capacitance of a variable capacitor based on the mismatch signal.

10. The method of claim 9, wherein the power transfer component comprises a tunable power transfer component.

11. The method of claim 10, wherein the tunable power transfer component and the power transfer component are coils.

12. The method of claim 10, wherein the tunable power transfer component and the power transfer component are antennas.

13. The method of claim 9, wherein modifying the capacitance of the variable capacitor comprises selectively enabling a plurality of switched capacitors responsive to the mismatch signal, wherein the plurality of switched capacitors are operably coupled to form the variable capacitor.

14. The method of claim 9, wherein modifying the capacitance of the variable capacitor comprises biasing a plurality of varactors based on the mismatch signal, wherein the plurality of varactors are operably coupled to form the variable capacitor network.

15. The method of claim 9, wherein the power transfer component resonates over a coupling-mode region.

16. The method of claim 9, wherein modifying the capacitance comprises modifying a resonance of the tunable power transfer component.

17. A wireless power transfer system, comprising:

means for receiving power wirelessly from a transmitter external to the wireless power transfer system, the transmitter resonating substantially near a first resonant frequency;

means for transmitting power wirelessly to a receiver external to the wireless power transfer system, the receiver resonating substantially near a second resonant frequency; and

means for adaptively tuning the receiving power wirelessly means, the adaptively tuning means comprising;

means for detecting a mismatch based on a voltage standing wave ratio at the receiving power wirelessly means;

means for generating a mismatch signal based on the detected mismatch; and

means for modifying a capacitance of a variable capacitor based on the mismatch signal.

18. The system of claim 17, wherein the receiving power wirelessly means comprises a power transfer component, wherein the transmitting power wirelessly means comprises a transmit power transfer component, wherein the adaptively tuning means comprises a controller, wherein the mismatch detecting means comprises a voltage standing wave ratio detector circuit, wherein the generating mismatch signal means comprises the voltage standing wave ratio detector circuit, and wherein the modifying capacitance means comprises a variable capacitor.

19. The system of claim 18, wherein

the power transfer component comprises a tunable power transfer component.

20. The system of claim 19, wherein the tunable power transfer component, power transfer component, and the transmit power transfer component each comprise a coil.

21. The system of claim 19, wherein the tunable power transfer component, power transfer component, and the transmit power transfer component each comprise an antenna.

22. The system of claim 19, wherein the means for modifying the capacitance comprises means for modifying a resonance of the tunable power transfer component.

23. The system of claim 18, wherein the modifying capacitance means comprises selectively enabling a plurality of switched capacitors based on the mismatch signal, wherein the plurality of switched capacitors are operably coupled to form the variable capacitor.

24. The system of claim 18, wherein the modifying capacitance means comprises biasing a plurality of varactors based on the mismatch signal, wherein the plurality of varactors are operably coupled to form the variable capacitor.