TUNING CIRCUIT AND METHOD FOR WIRELESS POWER TRANSFER SYSTEMS

• US 20140015327A1
• Filed: 12/21/2012
• Published: 01/16/2014
• Est. Priority Date: 07/16/2012
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: Qualcomm, Inc.
• Inventors: Keeling, Nicholas A., Beaver, Jonathan, Kissin, Michael
• Granted Patent: US 9,679,695 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: B60L 2200/12 Bikes
• CPC Class Codes: B60L 2200/22 Microcars, e.g. golf cars
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 2270/32 of electricity
• CPC Class Codes: B60L 2270/34 of parts
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: B60L 53/38 specially adapted for charging by inductive energy transfer
• CPC Class Codes: B60L 53/63 in response to network capacity
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: B60L 55/00 : Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
• CPC Class Codes: B60L 58/12 : responding to state of charge [SoC]
• 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 50/10 : using inductive coupling
• CPC Class Codes: H02J 50/12 : of the resonant type
• CPC Class Codes: H02J 50/40 : using two or more transmitting or receiving devices H02J50/50 takes precedence
• 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: Y02E 60/00 : Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 10/126 : the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]
• CPC Class Codes: Y04S 30/12 : Remote or cooperative charging
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

This disclosure provides systems, methods and apparatus for wireless power transfer and particularly wireless power transfer to remote systems such as electric vehicles. In one aspect, a wireless power transfer system includes a transmitter and a receiver. The transmitter includes a first inductive element and a current generator. The current generator supplies a current to the first inductive element to generate an electromagnetic field. The receiver includes a second inductive element, a tuning circuit, and a controller. The second inductive element receives wireless power from the electromagnetic field. The tuning circuit has a reactance and includes a plurality of capacitive elements connected to the second inductive element. The plurality of capacitive elements supply an output current to a load. The controller selectively connects the plurality of capacitive elements in a plurality of configurations. The tuning circuit has substantially the same reactance in each of the plurality of configurations.

Claims

1. A wireless power receiver comprising:

an inductive element configured to receive wireless power from an electromagnetic field associated with a wireless power transmitter;

a tuning circuit having a reactance and comprising a plurality of capacitive elements connected to the inductive element, the plurality of capacitive elements configured to supply an output current to a load; and

a controller configured to selectively connect the plurality of capacitive elements in a plurality of configurations, the tuning circuit having substantially the same reactance in each of the plurality of configurations.

2. The wireless power receiver of claim 1, wherein the controller is further configured to selectively connect the plurality of capacitive elements in the plurality of configurations in order to vary the output current to the load.

3. The wireless power receiver of claim 1, wherein the tuning circuit comprises one or more sub-circuits, each sub-circuit comprising a subset of the plurality of capacitive elements selectively connectable in at least two configurations, the sub-circuits connected to each other in parallel.

4. The wireless power receiver of claim 3, wherein each sub-circuit comprises:

first, second, and third capacitive elements; and

first and second switching elements,

wherein the first and third capacitive elements are connected in parallel with each other and in series with the second capacitive element in a first switching configuration, and the second and third capacitive elements are connected in parallel with each other and in series with the first capacitive element in a second switching configuration.

5. The wireless power receiver of claim 4, wherein the capacitance of the first and second capacitive elements are substantially the same.

6. The wireless power receiver of claim 4, wherein the capacitance of the first capacitive element is greater than the capacitance of the second capacitive element.

7. The wireless power receiver of claim 1, further comprising a parameter measurer configured to measure a wireless power transfer parameter, wherein the controller is further configured to determine a first configuration of the plurality of capacitive elements based on the measured wireless power transfer parameter and to connect the plurality of capacitive elements in the first configuration.

8. The wireless power receiver of claim 7, wherein the parameter measurer is configured to measure a level of coupling between the inductive element and a second inductive element, the second inductive element configured to generate the electromagnetic field.

9. The wireless power receiver of claim 7, wherein the parameter measurer is configured to measure a short circuit current across the inductive element.

10. A method for receiving wireless power comprising:

receiving with an inductive element wireless power from an electromagnetic field associated with a wireless power transmitter; and

selectively connecting a plurality of capacitive elements of a tuning circuit in one of a plurality of configurations, the tuning circuit having a reactance and comprising the plurality of capacitive elements connected to the inductive element, the tuning circuit having substantially the same reactance in each of the plurality of configurations, the plurality of capacitive elements configured to supply an output current to a load.

11. The method of claim 10, wherein the output current is configured to be different in each of the plurality of configurations.

12. The method of claim 10, wherein the plurality of capacitive elements comprise one or more sub-circuits, each sub-circuit comprising a subset of the plurality of capacitive elements connectable in at least two configurations, the sub-circuits connected to each other in parallel.

13. The method of claim 12, wherein each sub-circuit comprises:

first, second, and third capacitive elements; and

first and second switching elements,

wherein the first and third capacitive elements are connected in parallel with each other and in series with the second capacitive element in a first switching configuration, and the second and third capacitive elements are connected in parallel with each other and in series with the first capacitive element in a second switching configuration.

14. The method of claim 13, wherein the capacitance of the first and second capacitive elements are substantially the same.

15. The method of claim 13, wherein the capacitance of the first capacitive element is greater than the capacitance of the second capacitive element.

16. The method of claim 10, further comprising:

measuring a wireless power transfer parameter;

determining a first configuration of the plurality of capacitive elements based on the measured wireless power transfer parameter; and

connecting the plurality of capacitive elements in the first configuration.

17. The method of claim 16, wherein said measuring the wireless power transfer parameters comprises measuring a level of coupling between the inductive element and a second inductive element, the second inductive element configured to generate the electromagnetic field.

18. The method of claim 16, wherein said measuring the wireless power transfer parameters comprises measuring a short circuit current across the inductive element.

19. A wireless power receiver comprising:

means for receiving wireless power from an electromagnetic field associated with a wireless power transmitter; and

means for selectively connecting a plurality of capacitive elements of a tuning circuit in one of a plurality of configurations, the tuning circuit having a reactance and comprising the plurality of capacitive elements connected to the means for receiving wireless power, the tuning circuit having substantially the same reactance in each of the plurality of configurations, the plurality of capacitive elements configured to supply an output current to a load.

20. The wireless power receiver of claim 19, wherein the tuning circuit comprises one or more sub-circuits, each sub-circuit comprising a subset of the plurality of capacitive elements selectively connectable in at least two configurations, the sub-circuits connected to each other in parallel.

21. The wireless power receiver of claim 20, wherein each sub-circuit comprises:

first, second, and third capacitive elements; and

first and second switching elements,

wherein the first and third capacitive elements are connected in parallel with each other and in series with the second capacitive element in a first switching configuration, and the second and third capacitive elements are connected in parallel with each other and in series with the first capacitive element in a second switching configuration.

22. The wireless power receiver of claim 19, further comprising:

means for measuring a wireless power transfer parameter, and

means for determining a first configuration of the plurality of capacitive elements based on the measured wireless power transfer parameter.

23. A non-transitory, computer-readable medium comprising instructions that when executed cause a processor to perform a method of:

receiving with an inductive element wireless power from an electromagnetic field associated with a wireless power transmitter; and

selectively connecting a plurality of capacitive elements of a tuning circuit in one of a plurality of configurations, the tuning circuit having a reactance and comprising the plurality of capacitive elements connected to the inductive element, the tuning circuit having substantially the same reactance in each of the plurality of configurations, the plurality of capacitive elements configured to supply an output current to a load.

24. A wireless power transfer system comprising:

a transmitter comprising

a first inductive element, and

a current generator configured to supply a current to the first inductive element to generate an electromagnetic field for transferring wireless power; and

a receiver comprising

a second inductive element configured to receive wireless power from the electromagnetic field,

a tuning circuit having a reactance and comprising a plurality of capacitive elements connected to the second inductive element, the plurality of capacitive elements configured to supply an output current to a load, and

a controller configured to selectively connect the plurality of capacitive elements in a plurality of configurations, the tuning circuit having substantially the same reactance in each of the plurality of configurations.