Systems and methods for controlling wireless power transfer

• US 9,899,879 B2
• Filed: 02/15/2016
• Issued: 02/20/2018
• Est. Priority Date: 02/15/2016
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Faraone, Antonio, Bit-Babik, Giorgi G., Tran, Chi T.
• Primary Examiner(s): Hicks, Austin
• Application Number:
  US15/043,786
• Publication Number:
  US 20170237293A1
• Time in Patent Office: 736 Days
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• 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

Abstract

A system and method for wireless power transfer. The system includes a transmit coil having a first magnetic field having a first magnitude. The system also includes a receive coil, magnetically coupled to the transmit coil, having a second magnetic field having a second magnitude. The system also includes an electronic processor electrically coupled to the transmit coil and communicatively coupled to the receive coil. The electronic processor is configured to determine the first magnitude of the first magnetic field. The electronic processor is further configured to receive the second magnitude of the second magnetic field. The electronic processor is further configured to determine an efficiency based on the first magnitude and the second magnitude, and determine a power level for the transmit coil based on the efficiency.

Claims

1. A method for controlling a wireless power transfer system, the method comprising:

generating, with a transmit coil, a first magnetic field having a first magnitude;

magnetically coupling a receive coil to the transmit coil to generate a second magnetic field having a second magnitude;

determining, by an electronic processor electrically coupled to the transmit coil and communicatively coupled to the receiving coil, at least one selected from the group consisting of the first magnitude of the first magnetic field and a first current magnitude of a current in the transmit coil;

receiving, by the electronic processor, at least one selected from the group consisting of the second magnitude of the second magnetic field and a second current magnitude of a current in the receive coil;

determining, by the electronic processor, an efficiency based on at least one of the group consisting of the first magnitude, the second magnitude, the first current magnitude, and the second current magnitude;

determining, in response to the efficiency exceeding an efficiency threshold;

a first phase of the first magnetic field;

a second phase of the second magnetic field;

a phase difference based on the first and second phases;

a coil alignment based on the phase difference; and

a power level for the transmit coil based on the efficiency and the coil alignment.

2. The method of claim 1, wherein determining an efficiency includes determining a ratio based on the first magnitude and the second magnitude.

3. The method of claim 1, wherein determining an efficiency includes determining a ratio based on the first current magnitude and the second current magnitude.

4. The method of claim 1, further comprising:

generating, with a radiofrequency amplifier, a plurality of diagnostic current bursts.

5. The method of claim 1, further comprising:

adjusting, by the electronic processor, based on the efficiency, at least one of a group consisting of a first impedance for a first impedance matching network coupled to the transmit coil and a second impedance for a second impedance matching network coupled to the receive coil.

6. The method of claim 1, further comprising:

determining, by the electronic processor, a power level for the transmit coil based on the coil alignment.

7. The method of claim 1, further comprising:

adjusting, by the electronic processor, at least one of a group consisting of a first impedance for a first impedance matching network coupled to the transmit coil and a second impedance for a second impedance matching network coupled to the receive coil, based on the efficiency and the coil alignment.

8. A wireless power transfer system, the system comprising:

a transmit coil having a first magnetic field having a first magnitude;

a receive coil, magnetically coupled to the transmit coil, having a second magnetic field having a second magnitude; and

an electronic processor electrically coupled to the transmit coil and communicatively coupled to the receive coil, and configured to

determine at least one selected from the group consisting of the first magnitude of the first magnetic field and a first current magnitude of a current in the transmit coil;

receive at least one selected from the group consisting of the second magnitude of the second magnetic field and a second current magnitude of a current in the receive coil;

determine an efficiency based on at least one of the group consisting of the first magnitude, the second magnitude, the first current magnitude, and the second current magnitude;

determine, in response to the efficiency exceeding an efficiency threshold;

a first phase of the first magnetic field;

a second phase of the second magnetic field;

a phase difference based on the first and second phases;

a coil alignment based on the phase difference; and

a power level for the transmit coil based on the efficiency and the coil alignment.

9. The system of claim 8, wherein the electronic processor is further configured to determine a ratio based on the first magnitude and the second magnitude.

10. The system of claim 8, wherein the electronic processor is further configured to determine a ratio based on the first current magnitude and the second current magnitude.

11. The system of claim 8, further comprising:

a radiofrequency amplifier electrically coupled to the electronic processor, wherein the electronic processor is further configured to

generate, with the radiofrequency amplifier, a plurality of diagnostic current bursts.

12. The system of claim 8, further comprising:

a first impedance matching network electrically coupled to the electronic processor; and

a second impedance matching network communicatively coupled to the electronic processor,

wherein the electronic processor is further configured to adjust, based on the efficiency, at least one of a group consisting of a first impedance for the first impedance matching network and a second impedance for the second impedance matching network.

13. The system of claim 8, wherein the electronic processor is further configured to determine a power level for the transmit coil based on the coil alignment.

14. The system of claim 8, further comprising:

a first impedance matching network electrically coupled to the electronic processor; and

a second impedance matching network communicatively coupled to the electronic processor,

wherein the electronic processor is further configured to adjust, based on the efficiency and the coil alignment, at least one of a group consisting of a first impedance for first impedance matching network and a second impedance for the second impedance matching network.