Wireless power system with associated impedance matching network
A wireless power system for powering a device having an electronic display includes: a device resonator including a loop of conductive material, the device resonator being coupled with an electronic display component; a matching network coupled with the loop of conductive material and including capacitive elements; and power and control circuitry coupled with the matching network at two terminals and configured to connect with a load of the electronic display component; wherein the matching network is configured to provide voltages of equal magnitude and opposite sign at the terminals when coupling power from the device resonator to the power and control circuitry; and wherein the device resonator is configured to wirelessly receive power from a source resonator via an oscillating magnetic field generated by the source resonator.
1. A wireless power system for powering a device, the system comprising:
at least one device resonator comprising at least one loop of conductive material;
a matching network coupled with the at least one loop of conductive material, wherein the device resonator and the matching network comprise at least two capacitive elements; and
power and control circuitry coupled with the matching network at two terminals and configured to connect with a load of the device;
wherein the matching network is configured to provide voltages of equal magnitude and opposite sign at the terminals when coupling power from the at least one device resonator to the power and control circuitry;
wherein the at least one device resonator is configured to wirelessly receive power from a source resonator via an oscillating magnetic field generated by the source resonator.
2. The system of claim 1 , wherein the device is a digital picture frame.
3. The system of claim 1 , wherein the device comprises an electronic display in a mobile navigation or wireless communication device.
4. The system of claim 1 , wherein the device is a computer.
5. The system of claim 1 , wherein the at least one device resonator comprises a trace on a printed circuit board.
6. The system of claim 1 , wherein the at least two capacitive elements comprise a tunable capacitor.
7. The system of claim 6 , wherein the tunable capacitor is in parallel with the at least one loop of conductive material relative to the two terminals.
8. The system of claim 7 , wherein the power and control circuitry is adapted to tune a capacitance of the tunable capacitor to increase efficiency.
9. The system of claim 6 , wherein the at least two capacitive elements comprise the tunable capacitor and two additional capacitors, wherein the tunable capacitor is in parallel with the at least one loop of conductive material relative to the two terminals, and wherein each of the two additional capacitors are in series with the at least one loop of conductive material relative to the two terminals.
10. The system of claim 9 , wherein the at least two capacitive elements of the matching network further comprise a second capacitor in parallel with the at least one loop of conductive material relative to the two terminals.
11. The system of claim 9 , wherein the two additional capacitors are tunable capacitors, the at least two capacitive elements further comprise two fixed capacitors, and each of the two fixed capacitors are in series with the at least one loop of conductive material relative to the two terminals.
12. The system of claim 1 , wherein the at least two capacitive elements comprise:
at least one capacitor in series with the at least one loop of conductive material relative to the two terminals; and
at least one capacitor in parallel with the at least one loop of conductive material relative to the two terminals.
13. The system of claim 12 , wherein the at least one capacitor in series comprises two capacitors in series with the at least one loop of conductive material relative to the two terminals.
14. The system of claim 13 , wherein a first of the two capacitors in series is connected between the at least one loop of conductive material and a first of the two terminals, and a second of the two capacitors in series is connected between the at least one loop of conductive material and a second of the two terminals.
15. The system of claim 12 , wherein the at least one capacitor in series comprises four capacitors in series with the at least one loop of conductive material relative to the two terminals.
16. The system of claim 12 , wherein the at least one capacitor in parallel comprises two capacitors in parallel with the at least one loop of conductive material relative to the two terminals.
17. The system of claim 12 , wherein the at least one capacitor in parallel comprises:
a tunable capacitor in parallel with the at least one loop of conductive material relative to the two terminals; and
a fixed capacitor in parallel with the at least one loop of conductive material relative to the two terminals.
18. The system of claim 1 , wherein the load draws at least 5 Watts of power.
19. The system of claim 1 , wherein the at least one device resonator is configured to wirelessly receive power from the source resonator via the oscillating magnetic field generated by the source resonator when a distance between the source resonator and the at least one device resonator is more than 2 cm.
20. The system of claim 1 , wherein the load draws at least 10 Watts of power.
21. The system of claim 1 , wherein the at least one device resonator is configured to wirelessly receive power from the source resonator via the oscillating magnetic field generated by the source resonator when a distance between the source resonator and the at least one device resonator is more than 5 cm.
22. The system of claim 1 , wherein the load draws at least 20 Watts of power.
23. An apparatus comprising:
a device having a load;
at least one device resonator comprising at least one loop of conductive material;
a matching network coupled with the at least one loop of conductive material and wherein the resonator and the matching network comprise at least two capacitive elements; and
power and control circuitry coupled with the matching network at two terminals and configured to connect with the load of the device;
wherein the matching network is configured to provide voltages of equal magnitude and opposite sign at the terminals when coupling power from the at least one device resonator to the power and control circuitry;
wherein the at least one device resonator is configured to wirelessly receive power from a source resonator via an oscillating magnetic field generated by the source resonator.
24. The apparatus of claim 23 , wherein the at least two capacitive elements of the matching network comprise a tunable capacitor.
25. The apparatus of claim 23 , wherein the at least two capacitive elements of the matching network comprise:
at least one capacitor in series with the at least one loop of conductive material relative to the two terminals; and
at least one capacitor in parallel with the at least one loop of conductive material relative to the two terminals.
26. The apparatus of claim 23 , wherein the load draws at least 5 Watts of power.
27. The apparatus of claim 23 , wherein the at least one device resonator is configured to wirelessly receive power from the source resonator via the oscillating magnetic field generated by the source resonator when a distance between the source resonator and the at least one device resonator is more than 2 cm.
28. The apparatus of claim 23 , wherein the load draws at least 10 Watts of power.
29. The apparatus of claim 23 , wherein the at least one device resonator is configured to wirelessly receive power from the source resonator via the oscillating magnetic field generated by the source resonator when a distance between the source resonator and the at least one device resonator is more than 5 cm.
30. The apparatus of claim 23 , wherein the load draws at least 20 Watts of power.
31. The system of claim 1 , wherein a first capacitor of the at least two capacitors is electrically between one of the two terminals and the loop of conductive material and a second capacitor of the at least two capacitors is electrically between the other of the two terminals and the loops of conductive material.
32. The system of claim 1 , wherein the first and second capacitors each have the same capacitance.
33. The apparatus of claim 23 , wherein the device comprises an electronic display and the load provides power to the electronic display.
34. The apparatus of claim 23 , wherein the load is a battery.
35. The apparatus of claim 23 , wherein the device is a vehicle.
36. The apparatus of claim 23 , wherein a first capacitor of the at least two capacitors is electrically between one of the two terminals and the loop of conductive material and a second capacitor of the at least two capacitors is electrically between the other of the two terminals and the loops of conductive material.
37. The apparatus of claim 36 , wherein the first and second capacitors each have the same capacitance.