RECEIVED WIRELESS POWER REGULATION

• US 20170338695A1
• Filed: 11/04/2015
• Published: 11/23/2017
• Est. Priority Date: 11/05/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: PowerbyProxi Limited (Apple Inc.)
• Inventors: PORT, Brendon Raymond
• Granted Patent: US 10,923,953 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An inductive power receiver 3 for an inductive power transfer system 1 comprising: a power pick up stage 8 including a receiving coil for receiving power transmitted by a transmitter; a load stage connected to the power pick up stage; a power regulation stage 9 configured to provide an equivalent voltage in series with the power pick up stage 8 wherein the equivalent voltage switches between at least a first amplitude and a second amplitude that is different from the first amplitude; and a controller configured to control the power regulation stage 9 to regulate the power delivered to the load stage.

Claims

1. An inductive power receiver for an inductive power transfer system comprising:

a power pick up stage including a receiving coil for receiving power transmitted by a transmitter;

a load stage connected to the power pick up stage;

a power regulation stage configured to provide an equivalent voltage in series with the power pick up stage wherein the equivalent voltage switches between at least a first amplitude and a second amplitude that is different from the first amplitude; and

a controller configured to control the power regulation stage to regulate the power delivered to the load stage.

2. The receiver claim 1 wherein the load stage comprises a power conversion stage configured to convert the voltage from the combination of the power regulation stage and the power pick up stage to a DC voltage for a load.

3. The receiver in claim 2 wherein the power conversion stage is a half bridge rectifier, a full bridge rectifier, or a half bridge converter in parallel with a capacitor.

5. The receiver in claim 3, wherein the controller is configured to dynamically control the conduction timing of switching devices of the power conversion stage.

6. The receiver in claim 2 wherein the amplitude of the DC voltage is different to both the first amplitude and the second amplitude, the difference is at least 2V between the amplitude of the DC voltage and the first amplitude and at least 2V between the amplitude of the DC voltage and the second amplitude, and/or at least one of the first amplitude and the second amplitude is less than 2V in magnitude.

11. The receiver in claim 3 wherein the half bridge converter is switched substantially in synchronism with an AC power signal induced in the receiving coil.

12. The receiver in claim 3 wherein the equivalent voltage is controlled based on a voltage or current from the power pick up stage.

13. The receiver in claim 3 wherein the power pick up stage further includes a resonant tuned capacitor and the equivalent voltage is controlled based on the resonant tuned capacitor voltage.

16. The receiver in claim 1 wherein the controller is configured to regulate the power delivered based on a phase reference signal.

17. The receiver in claim 16 wherein a time delay between the phase reference signal and a control signal is selected by the controller.

19. The receiver in claim 16 wherein the phase reference is configured to measure the phase of a voltage that appears across the load stage.

20. The receiver in claim 17 wherein an increase in the time delay results in a decrease in the power delivered to the load stage.

21. The receiver in claim 1 wherein the power pick up stage further comprises a capacitor and a switch wherein a resonant frequency of the power pick up stage depends on the state of the switch.

22. The receiver in claim 21 wherein:

the power transmitted by the transmitter is transmitted at a first frequency;

when the switch is off the power pick up stage resonates at a second frequency; and

the first frequency is different from the second frequency.

23. The receiver in claim 22 wherein the second frequency is lower than the first frequency, at least about 7 percent lower than the first frequency, or at least about 25 percent lower than the first frequency.

26. The receiver in claim 1 wherein the equivalent voltage varies periodically, with a fundamental frequency that is substantially similar to the transmitter operating frequency.

27. The receiver in claim 1 configured for integration into a cellular phone for charging from a charging mat using inductive power transfer.

4. (canceled)

7. (canceled)

8. (canceled)

14. The receiver in claim 8 wherein controller is configured to compare the resonant tuned capacitor voltage against two or more thresholds and determine the conduction timing of the switching devices based on the comparison.

15. The receiver in claim 14 wherein the thresholds are adjusted to vary the equivalent voltage, and thereby vary the power delivered to the load.

9. (canceled)

10. (canceled)

18. (canceled)

24. (canceled)

25. (canceled)

28. A method of controlling an inductive power receiver for an inductive power transfer system comprising:

generating an voltage in series with a pick-up coil of the receiver; and

controlling the voltage phase to substantially match AC power received in the pick-up coil from a transmitter.