APPARATUSES, SYSTEMS, AND METHODS FOR A MONOTONIC TRANSFER FUNCTION IN WIRELESS POWER TRANSFER SYSTEMS

• US 20130221756A1
• Filed: 02/23/2012
• Published: 08/29/2013
• Est. Priority Date: 02/23/2012
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: Singh, Manjit
• Granted Patent: US 9,148,024 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type

Abstract

A wireless power-transfer system includes a power-transmitting device and a power-receiving device. A frequency generator generates a power-transmit frequency to stimulate transmit coil and transmit resonance adjuster, which generate a near-field electromagnetic radiation at an adjustable coupling frequency. The power-receiving device includes a receive coil and a receive resonance adjuster for receiving the near-field electromagnetic radiation when the receive coil is within a coupling region of the transmit coil. The receive resonance frequency may be modified by the receive resonance adjuster. In the wireless power-transfer system, one or both of the transmit resonance adjuster and the receive resonance adjuster is configured to adjust its corresponding frequency to be sufficiently less than the power-transmit frequency such that a monotonic transfer function is developed between the power-transmit frequency and the receive resonance frequency.

Claims

1. A power-transmitting device, comprising:

a frequency generator configured to generate a power-transmit frequency; and

a transmit resonance circuit operably coupled to the power-transmit frequency and comprising;

a transmit coil configured to generate a near-field electromagnetic radiation at a coupling frequency for coupling to a receive coil within a coupling region of the transmit coil; and

a transmit resonance adjuster operably coupled to the transmit coil and configured to adjust the coupling frequency to be sufficiently less than the power-transmit frequency such that a monotonic transfer function is developed between the power-transmit frequency and a power-receiving device bearing the receive coil positioned in the coupling region.

2. The power-transmitting device of claim 1, wherein the power-transmit frequency is equal to or greater than about 110 kHz and the coupling frequency is equal to or less than about 80 kHz.

3. The power-transmitting device of claim 1, wherein the transmit resonance adjuster comprises a capacitor such that the coupling frequency is responsive to an inductance of the transmit coil and a capacitance of the capacitor.

4. The power-transmitting device of claim 3, wherein the capacitor is a variable capacitor and a variation in a capacitance of the variable capacitor modifies the coupling frequency.

5. The power-transmitting device of claim 1, wherein the transmit resonance adjuster includes a network comprising components to generate at least some of a capacitive portion of the transmit resonance circuit.

6. The power-transmitting device of claim 5, wherein the components of the network comprise at least one active component configured to operably and switchably couple at least one corresponding capacitor to the transmit coil.

7. The power-transmitting device of claim 1, further comprising a transmit controller configured to control the transmit resonance adjuster responsive to an analysis to determine the coupling frequency that will develop the monotonic transfer function.

8. A method of transmitting power, comprising:

generating a power-transmit frequency;

stimulating a transmit coil and a transmit resonance adjuster with the power-transmit frequency to generate a near-field electromagnetic radiation at a coupling frequency for coupling to a receive coil within a coupling region of the transmit coil; and

developing a monotonic transfer function between the power-transmit frequency and a power-receiving device bearing the receive coil positioned in the coupling region by adjusting the coupling frequency to be sufficiently less than the power-transmit frequency with the transmit resonance adjuster.

9. The method of claim 8, wherein the power-transmit frequency is equal to or greater than about 110 kHz and the coupling frequency is equal to or less than about 80 kHz.

10. The method of claim 8, further comprising adjusting at least a capacitive portion of the transmit resonance adjuster to adjust the coupling frequency.

11. The method of claim 10, wherein adjusting at least the capacitive portion comprises selectively and operably coupling one or more capacitors to the transmit coil.

12. The method of claim 8, further comprising:

performing an analysis to determine the coupling frequency that will develop the monotonic transfer function; and

controlling the transmit resonance adjuster to develop the coupling frequency.

13. A power-receiving device, comprising:

a receive resonance circuit configured to generate a receive resonance frequency, comprising;

a receive coil for receiving near-field electromagnetic radiation at a coupling frequency when within a coupling region of a transmit coil; and

a receive resonance adjuster operably coupled to the receive coil and configured to adjust the receive resonance frequency to be sufficiently less than a power-transmit frequency of a power-transmitting device bearing the transmit coil to develop a monotonic transfer function between the power-transmit frequency and the receive resonance frequency.

14. The power-receiving device of claim 13, wherein the power-transmit frequency is equal to or greater than about 110 kHz and the receive resonance frequency is equal to or less than about 80 kHz.

15. The power-receiving device of claim 13, wherein the receive resonance adjuster comprises a capacitor such that the receive resonance frequency is responsive to an inductance of the receive coil and a capacitance of the capacitor.

16. The power-receiving device of claim 15, wherein the capacitor is a variable capacitor and a variation in a capacitance of the variable capacitor modifies the receive resonance frequency.

17. The power-receiving device of claim 13, wherein the receive resonance adjuster comprises a network comprising components to generate at least some of a capacitive portion of the receive resonance circuit.

18. The power-receiving device of claim 17, wherein the components of the network comprise at least one active component configured as a switch operably coupled to include at least one corresponding capacitor.

19. The power-receiving device of claim 13, further comprising a receive controller configured to control the receive resonance adjuster responsive to an analysis to determine the receive resonance frequency that will develop the monotonic transfer function.

20. A method of receiving power, comprising:

stimulating a receive coil and a receive resonance adjuster to generate a receive resonance frequency by positioning the receive coil in a coupling region of a transmit coil generating a near-field electromagnetic radiation at a coupling frequency, wherein the coupling frequency is generated from a power-transmit frequency equal to or greater than the coupling frequency; and

developing a monotonic transfer function between the power-transmit frequency and the receive resonance frequency by adjusting the receive resonance frequency to be sufficiently less than the power-transmit frequency with the receive resonance adjuster.

21. The method of claim 20, wherein the power-transmit frequency is equal to or greater than about 110 kHz and the receive resonance frequency is equal to or less than about 80 kHz.

22. The method of claim 20, further comprising adjusting at least a capacitive portion of the receive resonance adjuster to adjust the receive resonance frequency.

23. The method of claim 22, wherein adjusting at least the capacitive portion comprises selectively and operably coupling one or more capacitors to the receive coil.

24. The method of claim 20, further comprising:

performing an analysis to determine the receive resonance frequency that will develop the monotonic transfer function; and

controlling the receive resonance adjuster to develop the receive resonance frequency.

25. A wireless power-transfer system, comprising:

power-transmitting device, comprising;

a frequency generator for generating a power-transmit frequency;

a transmit coil for generating a near-field electromagnetic radiation at a transmit resonance frequency; and

a transmit resonance adjuster operably coupled to the transmit coil and configured for adjusting the transmit resonance frequency; and

a power-receiving device, comprising;

a receive coil for receiving the near-field electromagnetic radiation when within a coupling region of the transmit coil; and

a receive resonance adjuster operably coupled to the receive coil and configured for adjusting a receive resonance frequency of combination of the receive coil and the receive resonance adjuster;

wherein one or both of the transmit resonance adjuster and the receive resonance adjuster is configured to adjust its corresponding frequency to be sufficiently less than the power-transmit frequency such that a monotonic transfer function is developed between the power-transmit frequency and the receive resonance frequency.

26. The power-receiving device of claim 25, wherein the power-transmit frequency is equal to or greater than about 110 kHz and the receive resonance frequency is equal to or less than about 80 kHz.