Wireless power transmission system

1. A wireless power transmission device, comprising:

a power charger configured to receive power from a power supply device;

a transmitter comprising a source resonator;

a controller configured to control an electrical connection between the power charger and the transmitter to charge the source resonator with power by applying current to an inductor of the source resonator and to transmit the charged power to a target resonator through a mutual resonance;

a measuring unit configured to measure a voltage applied to a capacitor of the source resonator; and

a detector configured to detect an envelope of the voltage based on the measured voltage,

wherein the controller is further configured to:

open an electrical connection between the power supply device and the source resonator to prevent current from being provided to the source resonator from the power supply device upon the source resonator being charged with a value of power while the source resonator is transmitting power to the target resonator through mutual resonance,

turn on a switch that electrically connects the power charger and the transmitter to charge the source resonator with power, and

turn off the switch that electrically connects the power charger and the transmitter to transmit power the source resonator is charged with.

2. The wireless power transmission device of claim 1 , wherein the power charger is configured to control an amount of current provided to the transmitter.

3. The wireless power transmission device of claim 1 , wherein the power charger comprises a variable resistor that is connected, in series, to the power supply device.

4. The wireless power transmission device of claim 1 , wherein the controller is configured to control the electrical connection between the power charger and the transmitter based on an amount of power that the source resonator is charged with.

5. The wireless power transmission device of claim 1 , wherein the power charger comprises a plurality of resistors connected, in parallel, to the power supply device.

6. The wireless power transmission device of claim 1 , further comprising a calculator configured to calculate energy stored in the source resonator based on the measured voltage and the measured current.

7. A wireless power reception device, comprising:

a charger comprising a target resonator;

a power output unit configured to transfer power to a load;

a controller configured to open an electrical connection between the charger and the power output unit to charge the target resonator with power through mutual resonance with a source resonator, and to deliver the charged power to the load;

a measuring unit configured to measure a voltage applied to a capacitor of the target resonator; and

a detector configured to detect an envelope of the voltage based on the measured voltage,

wherein the controller is further configured to:

control an electrical connection between the target resonator and the load to prevent power from being delivered to the load from the target resonator upon the target resonator being charged with a value of power while charging the target resonator through mutual resonance with the source resonator,

turn off a switch that electrically connects the charger and the power output unit while charging the target resonator with power, and

turn on the switch that electrically connects the charger and the power output unit to deliver, to the load, power that the target resonator is charged with.

8. The wireless power reception device of claim 7 , wherein the target resonator comprises at least one inductor.

9. The wireless power reception device of claim 8 , wherein the power output unit is further configured to deliver power that the capacitor and the at least one inductor are charged with, to the load.

10. The wireless power reception device of claim 7 , wherein the controller is configured to control the electrical connection between the charger and the power output unit based on an amount of power that the target resonator is charged with.

11. The wireless power reception device of claim 7 , wherein the capacitor is configured to change a resonant frequency of the target resonator, in response to being electrically connected to the target resonator.

12. The wireless power reception device of claim 7 , further comprising a calculator configured to calculate energy stored in the target resonator based on the measured voltage and the measured current.

13. The wireless power reception device of claim 7 , wherein the load comprises a battery.

14. A method of transmitting wireless power, the method comprising:

charging a source resonator with power provided from a power supply device by applying current to an inductor of the source resonator;

controlling an electrical connection between the power supply device and the source resonator;

transmitting, to a target resonator, the charged power through mutual resonance;

measuring a voltage applied to a capacitor of the source resonator; and

detecting an envelope of the voltage based on the measured voltage,

wherein the controlling comprises:

opening an electrical connection between the power supply device and the source resonator to prevent current from being provided to the source resonator from the power supply device upon the source resonator being charged with a value of power while the source resonator is transmitting power to the target resonator through mutual resonance;

turning on a switch that electrically connects the power charger and the transmitter to charge the source resonator with power, and

turning off the switch that electrically connects the power charger and the transmitter to transmit power the source resonator is charged with.

15. The method of claim 14 , wherein the charging comprises adjusting an amount of current provided to the source resonator.

16. The method of claim 14 , wherein the controlling comprises controlling an electrical connection between the power supply device and the source resonator based on an amount of power the source resonator is charged with.

17. A method of receiving wireless power, the method comprising:

charging a target resonator with power that a source resonator is charged with, through mutual resonance between a source resonator and the target resonator;

delivering, to a load, the power that the target resonator is charged with;

measuring a voltage applied to a capacitor of the target resonator; and

detecting an envelope of the voltage based on the measured voltage,

wherein the charging comprises:

opening an electrical connection between the target resonator and the load to prevent power from being delivered to the load from the target resonator upon the target resonator being charged with a value of power while charging the target resonator through mutual resonance with the source resonator,

turning off a switch that electrically connects the charger and the power output unit while charging the target resonator with power, and

turning on the switch that electrically connects the charger and the power output unit to deliver, to the load, power that the target resonator is charged with.

18. The method of claim 17 , wherein the target resonator comprises an inductor.

19. The method of claim 18 , wherein the delivering comprises delivering, to the load, power that the capacitor and the inductor are charged with.

20. The method of claim 17 , further comprising:

controlling an electrical connection between the target resonator and the load based on an amount of power that the target resonator is charged with.

21. The method of claim 17 , further comprising:

changing a resonant frequency of the target resonator using the capacitor.

22. A wireless power transmission device, comprising:

a power charger configured to receive power from a power supply device;

a transmitter comprising a source resonator; and

a controller configured to control an electrical connection between the power charger and the transmitter to charge the source resonator with power by applying current to an inductor of the source resonator and to transmit the charged power to a target resonator through a mutual resonance;

a measuring unit configured to measure a voltage applied to a capacitor of the source resonator; and

a detector configured to detect an envelope of the voltage based on the measured voltage,

wherein the controller is configured to:

open the electrical connection between the power charger and the transmitter based on an amount of power with which the source resonator is charged,

turn on a switch that electrically connects the power charger and the transmitter to charge the source resonator with power, and

turn off the switch that electrically connects the power charger and the transmitter to transmit power the source resonator is charged with.

23. The wireless power transmission device of claim 1 , wherein the value of power corresponds to a peak value of energy to be charged in the source resonator.