Tunable wireless power architectures

• US 9,787,141 B2
• Filed: 05/31/2016
• Issued: 10/10/2017
• Est. Priority Date: 08/04/2011
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: Karalis, Aristeidis, Kesler, Morris P., Hall, Katherine L., Pallo, Nathan Andrew
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): BUKHARI, AQEEL H
• Application Number:
  US15/168,853
• Publication Number:
  US 20160352152A1
• Time in Patent Office: 497 Days
• Field of Search: None
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• 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: 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: 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

Described herein are improved configurations for a wireless power transfer. The parameters of components of the wireless energy transfer system are adjusted to control the power delivered to the load at the device. The power output of the source amplifier is controlled to maintain a substantially 50% duty cycle at the rectifier of the device.

Claims

1. A wireless energy source, comprising:

a source resonator;

a power supply;

an amplifier connected to the power supply and to the source resonator and comprising a plurality of switching elements; and

a controller connected to the amplifier,

wherein during operation of the source;

the power supply drives the source resonator through the amplifier with an oscillating voltage signal;

the controller is configured to adjust a duty cycle of the switching elements so that zero voltage switching is substantially maintained; and

the controller is configured to adjust an output power level of the oscillating voltage signal driving the source resonator in response to a change in a power demand by a load receiving power wirelessly from the source resonator by adjusting a bus voltage of the amplifier.

2. The source of claim 1, further comprising an impedance matching network connected to the amplifier and to the source resonator and comprising at least one tunable element, wherein the controller is configured to adjust the impedance matching network by adjusting the at least one tunable element.

3. The source of claim 2, further comprising an impedance matching control connected to the controller, wherein during operation of the source:

the impedance matching control is configured to measure at least one of an output voltage and an output current of the amplifier; and

the controller is configured to adjust the impedance matching network based on the at least one measured output voltage and output current.

4. The source of claim 3, wherein during operation of the source, the controller is configured to adjust the impedance matching network to substantially maintain zero current switching in the amplifier.

5. The source of claim 2, wherein during operation of the source, the controller is configured to adjust both the bus voltage of the amplifier and the impedance matching network in response to the change in the power demand by the load.

6. The source of claim 1, wherein the controller is configured to adjust at least one of the duty cycle and the bus voltage when the power demand by the load is reduced.

7. The source of claim 1, further comprising a sensor connected to the controller and configured to measure information about the power demand by the load during operation of the source.

8. The source of claim 7, wherein the information comprises an impedance of a device comprising the load.

9. The source of claim 6, wherein the information comprises at least one of an output voltage and an output current of the amplifier.

10. The source of claim 1, further comprising a communication interface configured to communicate with the load through at least one communication channel to receive information about the power demand of the load.

11. The source of claim 1, wherein the power supply generates a direct current electrical signal that does not pass through a DC-to-DC converter to drive the source resonator.

12. The source of claim 1, wherein at least some of the switching elements comprise MOSFETs, and wherein each of the MOSFETs is connected to at least one of a capacitive element and a diode.

13. The source of claim 12, wherein the diode comprises a Schottky diode.

14. The source of claim 1, wherein the controller is configured to adjust phases of the plurality of switching elements.

15. The source of claim 1, wherein the controller is configured to adjust the switching elements of the amplifier according to a switching frequency that defines a switching period for the amplifier.

16. The source of claim 15, wherein the controller is configured to adjust the switching elements of the amplifier according to a switching sequence that is symmetric between two halves of the switching period.

17. The source of claim 14, wherein the controller is configured to adjust the switching elements of the amplifier according to a switching sequence that is asymmetric between two halves of the switching period.

18. The source of claim 1, further comprising a sensor connected to the controller and configured to measure an AC output impedance of the amplifier, wherein the controller is configured to determine the duty cycle based on the measured AC output impedance.

21. The source of claim 18, wherein during operation of the source, the controller is configured to adjust both the bus voltage of the amplifier and the impedance matching network in response to the change in a power demand by a load receiving power wirelessly from the source resonator.

19. A wireless energy source, comprising:

a source resonator;

a power supply;

an amplifier connected to the power supply;

an adjustable impedance matching network connected to the amplifier and to the source resonator; and

a controller connected to the amplifier and to the impedance matching network,

wherein during operation of the source;

the power supply drives the source resonator through the amplifier with an oscillating voltage signal;

the controller is configured to adjust the impedance matching network to substantially maintain zero voltage switching in the amplifier; and

the controller is configured to adjust an output power level of the oscillating voltage signal driving the source resonator by adjusting a bus voltage of the amplifier.

20. The source of claim 19, further comprising an impedance matching control connected to the controller, wherein during operation of the source:

the impedance matching control is configured to measure at least one of an output voltage and an output current of the amplifier; and

the controller is configured to adjust the impedance matching network based on the at least one measured output voltage and output current.