WIRELESS CHARGING SYSTEM AND METHOD

• US 20180097394A1
• Filed: 10/01/2016
• Published: 04/05/2018
• Est. Priority Date: 10/01/2016
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Lahti, Saku, Komulainen, Mikko S., Nokkonen, Erkki
• Granted Patent: US 10,389,159 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries

Abstract

A wireless charging system and a method for tuning the wireless charging system is described. The system can include matching circuitry coupled to a transmission coil and a controller coupled to the matching circuitry. The transmission coil can have a load inductance. The controller can control the matching circuitry to adjust a voltage associated with the capacitance value based on the load inductance to cause the voltage associated with the capacitance value and a current associated with the capacitance value to be in phase.

Claims

1. A wireless charging system, comprising:

matching circuitry operatively coupled to a transmission coil having a load inductance, the matching circuitry having a capacitance value; and

a controller operatively coupled to the matching circuitry and configured to control the matching circuitry to adjust a voltage associated with the capacitance value based on the load inductance to cause the voltage associated with the capacitance value to be in phase with a current associated with the capacitance value.

2. The wireless charging system of claim 1, wherein the matching circuitry comprises a capacitor in parallel with a switch, the voltage associated with the capacitance value being a voltage over the capacitor, wherein the switch is configured to selectively short the capacitor based on a control signal generated by the controller to adjust the voltage across the capacitor.

3. The wireless charging system of claim 1, wherein the matching circuitry comprises a capacitor defining the capacitance value, wherein a voltage over the capacitor and the voltage associated with the capacitance value have equivalently operable values.

4. The wireless charging system of claim 2, wherein the control signal is generated based on the load inductance.

5. The wireless charging system of claim 2, wherein the controller is configured to adjust a duty cycle in which the switch shorts the capacitor based on the load inductance.

6. The wireless charging system of claim 5, wherein the controller is configured to control the switch to selectively short the capacitor such that the voltage across the capacitor returns to zero when an input voltage supplied to the matching circuitry reaches its maximum.

7. The wireless charging system of claim 2, wherein the capacitor is coupled in series between the transmission coil and a power source providing an input voltage to the matching circuitry.

8. The wireless charging system of claim 1, further comprising a filter coupled in series between the transmission coil and the matching circuitry.

9. The wireless charging system of claim 1, wherein the controller is configured to control the matching circuitry to adjust the voltage associated with the capacitance value to tune the wireless charging system into resonance.

10. The wireless charging system of claim 2, wherein the capacitor is a fixed capacitor.

11. A wireless charging system, comprising:

matching circuitry coupled to a transmission coil having a load inductance, the matching circuitry comprising;

a capacitor having a capacitance value; and

a switch coupled in parallel to the capacitor and configured to selectively short the capacitor to adjust a voltage across the capacitor; and

a controller coupled to the switch of the matching circuitry, the controller being configured to control the switch to selectively short the capacitor to adjust an impedance of the wireless charging system based load inductance.

12. The wireless charging system of claim 11, wherein the capacitor is a fixed capacitor and the capacitance value is a fixed capacitance value.

13. The wireless charging system of claim 11, wherein the controller is configured to control the switch to selectively short the capacitor based on the load inductance.

14. The wireless charging system of claim 11, wherein the controller is configured to control the switch to selectively short the capacitor to force the voltage across the capacitor and a current of the capacitor to be in phase.

15. The wireless charging system of claim 11, wherein the controller is configured to adjust a duty cycle in which the switch shorts the capacitor based on the load inductance.

16. The wireless charging system of claim 15, wherein the controller is configured to control the switch to selectively short the capacitor such that the voltage across the capacitor returns to zero when an input voltage supplied to the matching circuitry reaches its maximum.

17. The wireless charging system of claim 11, wherein the capacitor is coupled in series between the transmission coil and a power source providing an input voltage to the matching circuitry.

18. The wireless charging system of claim 11, further comprising a filter coupled in series between the transmission coil and the matching circuitry.

19. The wireless charging system of claim 11, wherein the controller is configured to control the switch to selectively short the capacitor to tune the wireless charging system into resonance.

20. A method to tune a wireless charging system, the method comprising:

calculating a load inductance of the wireless charging system; and

adjusting a voltage across a capacitor of the wireless charging system based on the load inductance to cause the voltage and a current associated with the capacitor to be in phase.

21. The method of claim 20, wherein adjusting the voltage comprises selectively shorting the capacitor based on the load inductance.

22. The method of claim 21, further comprising calculating a duty cycle in which the capacitor is shorted based on the load inductance.

23. The method of claim 21, wherein the capacitor is selectively shorted such that the voltage across the capacitor returns to zero when an input voltage driving the wireless charging system reaches its maximum.

24. The method of claim 20, wherein the voltage across the capacitor is adjusted to tune the wireless charging system into resonance.