System and method for power output control in wireless power transfer systems

• US 9,859,955 B2
• Filed: 01/14/2013
• Issued: 01/02/2018
• Est. Priority Date: 08/24/2012
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: Qualcomm, Inc.
• Inventors: Keeling, Nicholas A., Beaver, Jonathan, Kissin, Michael, Van Boheemen, Edward
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Bukhari, Aqeel
• Application Number:
  US13/740,679
• Publication Number:
  US 20140054970A1
• Time in Patent Office: 1,814 Days
• Field of Search: None
• CPC Class Codes: B60L 2200/12 Bikes
• CPC Class Codes: B60L 2200/22 Microcars, e.g. golf cars
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• 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 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• 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: H02J 50/12 of the resonant type
• 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 5/79 for data transfer in combination with power transfer
• 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 system such as electric vehicles. In one aspect a circuit for wireless power transfer is provided. The circuit comprises an inductive element for receiving wireless power from a magnetic field associated with a wireless power transfer transmitter device. The circuit further comprises an output configured to be connected to a load. The circuit further comprises a voltage detector configured to detect the voltage across the load. The circuit further comprises at least one switching element between the inductive element and the output. The circuit further comprises a controller configured to maintain a current in the inductive element substantially constant as the voltage detected across the load varies.

Claims

1. A circuit for a wireless power receiver device, the circuit comprising:

an inductive element configured to receive wireless power from a magnetic field associated with a wireless power transmitter device, the received wireless power inducing an alternating current in the inductive element;

an output interface electrically coupled to the inductive element and configured to provide current to a load; and

a controller configured to maintain a magnitude of the alternating current in the inductive element constant such that changes in a voltage across the load do not cause corresponding changes in the magnitude of the alternating current.

2. The circuit of claim 1, further comprising a voltage detector configured to detect the voltage across the load, wherein the controller is configured to isolate the load from the output interface circuit based on the detected voltage, to decouple variations in the voltage across the load from the inductive element.

3. The circuit of claim 2, further comprising at least one switching element electrically coupled between the inductive element and the output interface.

4. The circuit of claim 3, wherein the controller is configured to maintain a voltage across the inductive element constant based on the voltage across the load.

5. The circuit of claim 4, further comprising:

a rectifier configured to convert the alternating current induced in the inductive element into a direct current; and

a boost converter configured to receive the direct current from the rectifier and control power output to the load.

6. The circuit of claim 5, wherein the controller maintains the direct current from the rectifier constant based on the voltage across the load.

7. The circuit of claim 5, wherein the controller is configured to control a duty cycle of the switching element based on the voltage across the load.

8. The circuit of claim 7, wherein the duty cycle of the switching element is proportional to the voltage across the load.

9. The circuit of claim 5, the controller configured to maintain the direct current output from the rectifier constant based on the voltage across the load.

10. The circuit of claim 5, wherein the circuit comprises a decoupling controller comprising the switching element.

11. A method of wireless power transfer, the method comprising:

receiving wireless power from a magnetic field, the received wireless power inducing an alternating current in an inductive element;

providing current to a load based on the alternating current in the inductive element; and

maintaining a magnitude of the alternating current in the inductive element constant such that changes in a voltage across the load do not cause corresponding changes in the magnitude of the alternating current.

12. The method of claim 11, further comprising:

detecting the voltage across the load; and

isolating the load from the output interface circuit based on the detected voltage, to decouple variations in the voltage across the load from the inductive element.

13. The method of claim 12, further comprising maintaining a voltage across the inductive element constant based on the voltage across the load.

14. The method of claim 13, further comprising:

converting the alternating current induced in the inductive element into a direct current;

receiving the direct current; and

controlling power output to the load.

15. The method of claim 14, further comprising maintaining the direct current constant based on the voltage across the load.

16. The method of claim 14, further comprising controlling a duty cycle of a switching element based on the voltage across the load.

17. The method of claim 16, wherein the duty cycle of the switching element is proportional to the voltage across the load.

18. The method of claim 14, further comprising maintaining the direct current constant based on the voltage across the load.

19. An apparatus for wireless power transfer, the apparatus comprising:

means for receiving wireless power from a magnetic field associated with a wireless power transfer transmitter device, the received wireless power inducing an alternating current in an inductive element;

means for providing current to a load; and

means for maintaining a magnitude of the alternating current in the inductive element constant such that changes in a voltage across the load do not cause corresponding changes in the magnitude of the alternating current.

20. The apparatus of claim 19, further comprising means for detecting the voltage across the load, wherein the means for maintaining is further for isolating the load from the output interface circuit based on the detected voltage, to decouple variations in the voltage across the load from the inductive element.

21. The apparatus of claim 20, further comprising means for maintaining a voltage across the inductive element constant based on the voltage across the load.

22. The apparatus of claim 21, further comprising:

means for converting the alternating current induced in the inductive element into a direct current;

means for receiving the direct current; and

means for controlling power output to the load.

23. The apparatus of claim 22, further comprising means for maintaining the direct current constant based on the voltage across the load.

24. The apparatus of claim 22, further comprising means for controlling a duty cycle of a switching element based on the voltage across the load.

25. The apparatus of claim 24, wherein the duty cycle of the switching element is proportional to the voltage across the load.

26. The apparatus of claim 22, further comprising means for maintaining the direct current constant based on the voltage across the load.