Impedance matching in wireless power systems

• US 9,843,228 B2
• Filed: 07/27/2016
• Issued: 12/12/2017
• Est. Priority Date: 09/27/2008
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Kurs, Andre B., Karalis, Aristeidis, Kesler, Morris P.
• Primary Examiner(s): AMAYA, CARLOS DAVID
• Application Number:
  US15/220,635
• Publication Number:
  US 20160336812A1
• Time in Patent Office: 503 Days
• Field of Search: 307104
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• 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 53/124 Detection or removal of foreign bodies
• 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 53/38 specially adapted for charging by inductive energy transfer
• CPC Class Codes: G06F 1/16 Constructional details or arrangements
• CPC Class Codes: H01F 2003/005 Magnetic cores for receiving several windings with perpendicular axes, e.g. for antennae or inductive power transfer
• 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 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• 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: H04L 9/3278 using physically unclonable functions [PUF]
• CPC Class Codes: H04N 21/42222 Additional components integrated in the remote control device, e.g. timer, speaker, sensors for detecting position, direction or movement of the remote control, microphone or battery charging device
• CPC Class Codes: H04N 5/64 Constructional details of receivers, e.g. cabinets or dust covers furniture aspects of television cabinets A47B81/06
• 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 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

A wireless power system for powering a television includes a source resonator, configured to generate an oscillating magnetic field, and at least one television component attached to at least one device resonator, wherein the at least one device resonator is configured to wirelessly receive power from the source resonator via the oscillating magnetic field when the distance between the source resonator and the at least one device resonator is more than 5 cm, and wherein at least one television component draws at least 10 Watts of power.

Claims

1. A module for use in a wireless power transfer system, the module comprising:

a first inductive element formed by at least one loop of electrically conductive material; and

additional circuitry connected to the first inductive element and comprising terminals for connection to a power supply or electrical load,

wherein the first inductive element forms a high-Q resonator with at least a portion of the additional circuitry, the resonator having an intrinsic Q value greater than 100 for at least one resonant frequency between 10 kHz and 100 MHz; and

wherein the additional circuitry comprises;

a first capacitor connected in series with the first inductive element to form a first circuit pathway;

a second capacitor connected in parallel to the first circuit pathway and forming a second circuit pathway; and

a second inductive element connected in series with the first and second circuit pathways.

2. The module of claim 1, wherein the second inductive element is an adjustable inductive element.

3. The module of claim 2, wherein the second inductive element comprises an adjustable inductor.

4. The module of claim 2, wherein the second inductive element comprises an inductor and an adjustable capacitor connected in series.

5. The module of claim 1, wherein the additional circuitry comprises a third capacitor connected in series with the first capacitor and the first inductive element, and on an opposite side of the first inductive element from the first capacitor, along the first circuit pathway.

6. The module of claim 5, wherein capacitance values of the first and third capacitors are the same.

7. The module of claim 1, wherein the module forms a component of a wireless power transfer system, and wherein during use of the system:

a power source of the wireless power transfer system transfers power wirelessly to a power receiving device comprising an electrical load; and

the module is configured to perform impedance matching in the wireless power transfer system, the impedance matching comprising matching a reflected impedance from the power receiving device to a target impedance for a driving circuit of the power source.

8. The module of claim 7, wherein the module is configured to perform impedance matching when voltages of the same magnitude but opposite sign are applied to the terminals.

9. The module of claim 1, wherein the module forms a component of a wireless power receiving device, and wherein during use of the device:

the power receiving device receives power wirelessly from a power source; and

the module is configured to perform impedance matching in the wireless power receiving device, the impedance matching comprising matching an impedance of the load to a target impedance for a resonator of the power receiving device.

10. The module of claim 9, wherein the module is configured to perform impedance matching when voltages of the same magnitude but opposite sign are applied to the terminals.

11. The module of claim 1, wherein the second capacitor is an adjustable capacitor.

12. The module of claim 11, wherein the first capacitor is an adjustable capacitor.

13. The module of claim 12, wherein:

the module forms a component of a wireless power transfer system that transfers power to a power receiving device comprising an electrical load; and

during operation of the wireless power transfer system, a capacitance value of the first capacitor is adjusted to compensate for a change in the electrical load.

14. The module of claim 12, wherein:

the module forms a component of a wireless power transfer system that transfers power to a power receiving device comprising an electrical load; and

during operation of the wireless power transfer system, a capacitance value of the second capacitor is adjusted to compensate for a change in the electrical load.

15. The module of claim 2, wherein:

the module forms a component of a wireless power transfer system that transfers power to a power receiving device comprising an electrical load; and

during operation of the wireless power transfer system, an inductance value of the second inductive element is adjusted to compensate for a change in the electrical load.

16. The module of claim 1, wherein:

a capacitance value of the first capacitor is C₃ if the module comprises only two capacitors;

the module comprises a third capacitor connected in series with the first capacitor and the first inductive element along the first circuit pathway; and

the capacitance values of the first and third capacitors are each 2C₃.

17. The module of claim 16, wherein:

the module forms a component of a wireless power transfer system that transfers power to a power receiving device comprising an electrical load;

the first and third capacitors are each adjustable capacitors; and

during operation of the wireless power transfer system, the capacitance values of the first and third capacitors are adjusted to compensate for a change in the electrical load.

18. The module of claim 2, wherein:

an inductance value of the second inductive element is L₂ if the module comprises only two inductive elements;

the module comprises a third inductive element connected in series with the first and second conductive pathways; and

inductance values of the second and third inductive elements are each ½

L₂.

19. The module of claim 18, wherein:

the module forms a component of a wireless power transfer system that transfers power to a power receiving device comprising an electrical load;

the third inductive element is an adjustable inductive element; and

during operation of the wireless power transfer system, the inductance values of the second and third inductive elements are adjusted to compensate for a change in the electrical load.

20. A method, comprising:

adjusting an impedance matching network coupled to a power source in a wireless power transfer system to compensate for a change in an electrical load coupled to a power receiving device of the wireless power transfer system, the impedance matching network comprising;

a first inductive element formed by at least one loop of electrically conductive material;

a first adjustable capacitor connected in series with the first inductive element to form a first circuit pathway;

a second adjustable capacitor connected in parallel to the first circuit pathway and forming a second circuit pathway; and

a second adjustable inductive element connected in series with the first and second circuit pathways,

wherein the first inductive element forms a portion of a high-Q resonator having an intrinsic Q value greater than 100 for at least one resonant frequency between 10 kHz and 100 MHz; and

wherein adjusting the impedance matching network comprises adjusting at least one of a capacitance value of the first adjustable capacitor, a capacitance value of the second adjustable capacitor, and an inductance value of the second adjustable inductive element.