Systems and methods for calibration of a wireless power transmitter
Systems and methods for alignment and calibration of a wireless power transmitter and a wireless power receiver are disclosed. According to one aspect, a wireless power transmit coil is first aligned with a wireless power receive coil. An alignment signal is received indicated that the transmit coil and the receive coil are aligned is received by the wireless power transmitter. A signal indicative of a characteristic of an electrical signal received by the wireless power receiver is generated and communicated to the wireless power transmitter. A calibration feedback signal is generated to adjust a driving signal of the wireless power transmitter based on the received signal.
1. A wireless power receiver for receiving wireless power via a wireless field, the wireless power receiver comprising:
a wireless power receive coil configured to receive the wireless power; and
a controller configured to receive an alignment signal indicative of an alignment of the receive coil with a transmit coil of a wireless power transmitter, and when the alignment signal indicates that the transmit coil is substantially aligned with the receive coil, the controller is further configured to:
determine a characteristic of an electrical signal received by the wireless power receive coil; and
generate a feedback signal to adjust a driving signal based on the determined characteristic of the electrical signal.
2. The wireless power receiver of claim 1 , wherein the characteristic includes a voltage of the electrical signal received by the wireless power receiver.
3. The wireless power receiver of claim 1 , wherein the characteristic includes a current of the electrical signal received by the wireless power receiver.
4. The wireless power receiver of claim 1 , further comprising a sensor configured to generate the alignment signal.
5. The wireless power receiver of claim 4 , wherein the sensor includes a plurality of sensing coils positioned about the receive coil.
6. The wireless power receiver of claim 4 , wherein the sensor includes a first sensing coil, a second sensing coil, and a third sensing coil positioned within a plane about the receive coil.
7. The wireless power receiver of claim 6 , wherein the first sensing coil, the second sensing coil, and the third sensing coil are displaced by about 120 degrees from one another along the plane.
8. The wireless power receiver of claim 6 , wherein the sensor is configured to generate the alignment signal when a voltage measured at each of first sensing coil, the second sensing coil, and the third sensing coil is greater than a first threshold, and a difference of the voltage measured at each of the first sensing coil, the second sensing coil, and the third sensing coil is less than a second threshold.
9. The wireless power receiver of claim 1 , further comprising a regulator configured to generate a signal at a voltage level for charging a load.
10. A wireless power transmitter for transferring wireless energy via a wireless field, the wireless power transmitter comprising:
a wireless power transmit coil configured to generate the wireless field; and
a controller operationally coupled to the wireless power transmit coil and configured to receive an alignment signal indicative of an alignment of the transmit coil with a receive coil of a wireless power receiver, and when the alignment signal indicates that the transmit coil is substantially aligned with the receive coil, the controller is further configured to:
receive a signal indicative of a characteristic of an electrical signal received by the wireless power receiver; and
generate a feedback signal to adjust the a driving signal based on the received signal.
11. The wireless power transmitter of claim 10 , wherein the characteristic includes a voltage of the electrical signal received by the wireless power receiver.
12. The wireless power transmitter of claim 10 , wherein the characteristic includes a current of the electrical signal received by the wireless power receiver.
13. The wireless power transmitter of claim 10 , further comprising a sensor configured to generate the alignment signal.
14. The wireless power transmitter of claim 10 , further comprising an impedance adjustment circuit, and wherein the impedance adjustment circuit is configured to adjust an impedance of the wireless power transmitter based on the feedback signal.
15. The wireless power transmitter of claim 10 , wherein the feedback signal is configured to adjust at least one of a voltage level and frequency of the driving signal.
16. The wireless power transmitter of claim 10 , further comprising a memory coupled to the controller, and wherein the controller is configured to store parameters regarding the driving signal in the memory.
17. The wireless power transmitter of claim 16 , wherein the controller is configured to receive identification information corresponding to the wireless power receiver, and wherein the controller is configured to store the identification information along with the parameters regarding the driving signal in the memory.
18. A method of calibrating a wireless field comprising:
receiving power via the wireless field with a receive coil, the wireless field generated by a transmit coil of a wireless power transmitter based on a driving signal;
receiving an alignment signal indicative of an alignment of the receive coil with the transmit coil, and when the alignment signal indicates that the transmit coil is substantially aligned with the receive coil, the method further comprising:
determining a characteristic of an electrical signal received by the receive coil; and
generating a feedback signal to adjust the driving signal based on the determined characteristic of the electrical signal.
19. The method of claim 18 , wherein the characteristic includes a voltage received by the wireless power receiver.
20. The method of claim 18 , wherein the characteristic includes a current received by the wireless power receiver.
21. The method of claim 18 , further comprising measuring a plurality of sensing signals indicative of an electrical signal characteristic received by a plurality of alignment sensing coils; determining a plurality of difference values equal to the difference in magnitude of each of the plurality of sensing signals; and determining that the transmit coil is in alignment with the receive coil when each of the difference values is less than a first threshold value.
22. The method of claim 21 , further comprising comparing each of the plurality of sensing signals with a second threshold value prior to calculating the difference values.
23. A method for calibrating a wireless field comprising:
generating the wireless field using a transmit coil based on a driving signal to transmit power to a wireless power receive coil of a wireless power receiver;
receiving an alignment signal indicative of an alignment between the transmit coil and the receive coil, and when the alignment signal indicates that the transmit coil is substantially aligned with the receive coil, the method further comprising:
receiving a signal indicative of a characteristic of an electrical signal received by the wireless power receiver; and
generating a feedback signal to adjust the driving signal based on the received signal.
24. The method of claim 23 , wherein the characteristic includes a voltage received by the wireless power receiver.
25. The method of claim 23 , wherein the characteristic includes a current received by the wireless power receiver.
26. The method of claim 23 , further comprising adjusting an impedance of the wireless power transmitter based on the feedback signal.
27. The method of claim 23 , further comprising adjusting at least one of a voltage level and frequency of the driving signal.
28. The method of claim 23 , further comprising storing parameters regarding the driving signal in a memory.
29. The method of claim 28 , further comprising receiving identification information corresponding to the wireless power receiver; and storing the identification information along with the parameters regarding the driving signal in the memory.
30. An apparatus for receiving wireless power via a wireless field, the apparatus comprising:
means for receiving the wireless power via the wireless field;
means for receiving an alignment signal indicative of an alignment of the means for receiving power with a transmit coil, and when the alignment signal indicates that the transmit coil is substantially aligned with the means for receiving power, the apparatus further comprising:
means for determining a characteristic of an electrical signal received by the means for receiving the wireless power; and
means for generating a feedback signal to adjust a driving signal based on the determined characteristic of the electrical signal.
31. The apparatus of claim 30 , wherein the means for receiving power comprises a receive coil, and wherein the means for receiving an alignment signal, the means for determining a characteristic of an electrical signal, and the means for generating a feedback signal comprise a controller.
32. An apparatus for transferring wireless power via a wireless field, the apparatus comprising:
means for generating the wireless field based on a driving signal to transmit the wireless power to a wireless power receive coil of a wireless power receiver;
means for receiving an alignment signal indicative of an alignment between the means for generating the wireless field and the receive coil, and when the alignment signal indicates that the means for generating the wireless field is substantially aligned with the receive coil, the means for receiving the alignment signal further configured to:
receive a signal indicative of a characteristic of an electrical signal received by the wireless power receiver; and
generate a feedback signal to adjust the driving signal based on the received signal.
33. The apparatus of claim 32 , wherein the means for generating the wireless field comprises a transmit coil, and wherein the means for receiving an alignment signal, the means for determining a characteristic of an electrical signal, and the means for generating a feedback signal comprise a controller.