Wireless power transmission apparatus and method

1. A wireless power transmission method comprising:

operating a source resonator among a source resonators;

detecting a waveform while the source resonator resonates;

determining a source resonator for wireless power transmission based on an attenuation ratio of the detected waveform during discharging and a comparison of a shape of the detected waveform with other waveforms, wherein the attenuation ratio is a ratio of an amplitude of an envelope attenuation from an initial point in time to a predetermined point in time during a detection time, to an amplitude of the envelope at the initial point in time; and

wirelessly transmitting power to a target resonator using the determined source resonator.

2. The wireless power transmission method of claim 1 , wherein the operating comprises:

supplying power to the source resonator during a first supply time; and

disconnecting one end of the source resonator in response to the first supply time having elapsed.

3. The wireless power transmission method of claim 2 , wherein the supplying comprises electrically connecting the source resonator to a direct current (DC) source during the first supply time; and

the disconnecting comprises disconnecting an electrical connection between the source resonator and the DC source in response to the first supply time having elapsed.

4. The wireless power transmission method of claim 1 , wherein the detecting comprises:

detecting an envelope of an electric signal produced by resonance occurring in the source resonator during a detection time; and

connecting both ends of the source resonator to a ground in response to the detection time having elapsed.

5. The wireless power transmission method of claim 1 , wherein the wirelessly transmitting comprises:

supplying power to the determined source resonator during a second supply time;

disconnecting one end of the determined source resonator in response to the second supply time having elapsed; and

connecting both ends of the determined source resonator to a ground in response to a transmission time having elapsed after a point in time at which the one end of the determined source resonator is disconnected.

6. The wireless power transmission method of claim 1 , wherein the operating comprises:

selecting the source resonator from the source resonators according to a preset order; and

operating the selected source resonator; and

the detecting comprises detecting waveforms for the source resonators in the preset order.

7. The wireless power transmission method of claim 6 , wherein the source resonators are arranged in a lattice pattern; and

the selecting comprises selecting a source resonator corresponding to a single row or a single column in the lattice pattern.

8. The wireless power transmission method of claim 5 , wherein the source resonators are classified into groups; and

the selecting comprises selecting a source resonator corresponding to a single group among the groups.

9. A non-transitory computer-readable storage medium storing instructions to cause computing hardware to perform the method of claim 1 .

10. A wireless power transmission apparatus comprising:

source resonators;

a switch configured to operate a source resonator among the source resonators by connecting the source resonator to a power source;

a detector configured to detect a waveform while the source resonator resonates; and

a switch controller configured to:

determine a source resonator for wireless power transmission based on an attenuation ratio of the detected waveform during discharging and a comparison of a shape of the detected waveform with other waveforms, wherein the attenuation ratio is a ratio of an amplitude of an envelope attenuated from an initial point in time to a predetermined point in time during a detection time to an amplitude of the envelope at the initial point in time, and

control the switch to wirelessly transmit power to a target resonator using the determined source resonator.

11. The wireless power transmission apparatus of claim 10 , wherein the switch comprises:

a first switch configured to selectively connect one end of each of source resonators connected together at the one end among the source resonators to the power source under control of the switch controller; and

a second switch configured to selectively connect another end of each of source resonators connected together at the other end among the source resonators to a ground under control of the switch controller.

12. The wireless power transmission apparatus of claim 10 , wherein each of the source resonators comprises:

a capacitor;

an inductor; and

a diode configured to prevent power received by the source resonator from flowing to another one of the source resonators.

13. The wireless power transmission apparatus of claim 10 , wherein the source resonators are arranged at intersection points at which parallel first axes intersect parallel second axes; and

the switch comprises:

a first switch configured to connect one end of each of source resonators arranged along a single first axis among the first axes to the power source; and

a second switch configured to connect one end of each of source resonators arranged along a single second axis among the second axes to a ground.

14. The wireless power transmission apparatus of claim 10 , wherein source resonators having one end connected together among the source resonators are arranged in a zigzag pattern; and

source resonators having another end connected together among the source resonators are arranged in a line.

15. The wireless power transmission apparatus of claim 10 , wherein the switch controller is further configured to:

control the switch to connect one end of the source resonator to the power source during a first supply time, and

disconnect the one end of the source resonator from the power source in response to the first supply time having elapsed.

16. The wireless power transmission apparatus of claim 10 , wherein the detector is further configured to detect, at one end of the source resonator, an envelope of an electric signal produced by resonance occurring in the source resonator during a detection time; and

the switch controller is further configured to control the switch to connect both ends of the source resonator to a ground in response to the detection time having elapsed.

17. The wireless power transmission apparatus of claim 10 , wherein the switch controller is further configured to:

control the switch to connect one end of the determined source resonator to the power source during a second supply time,

disconnect the one end of the determined source resonator from the power source in response to the second supply time having elapsed, and

connect both ends of the determined source resonator to a ground in response to a transmission time having elapsed after a point in time at which the one end of the determined source resonator is disconnected from the power source.

18. The wireless power transmission apparatus of claim 10 , wherein the source resonators are classified into groups; and

the switch controller is further configured to:

sequentially select the groups,

control the switch to operate source resonators corresponding to a selected group, and

sequentially acquire waveforms for the source resonators.

19. A wireless power transmission apparatus comprising:

source resonators;

a switch configured to operate a source resonator among the source resonators by connecting the source resonator to a power source;

a detector configured to detect a waveform while the source resonator resonates; and

a switch controller configured to:

determine, based on the detected waveform, whether a target resonator forming resonance coupling with a source resonator is present based on an attenuation ratio of the detected waveform during discharging, wherein the attenuation ratio is a ratio of an amplitude of an envelope attenuated from an initial point in time to a predetermined point in time during a detection time to an amplitude of the envelope at the initial point in time, and

control the switch to wirelessly transmit power to the target resonator using the determined source resonator in response to the target resonator being preset, wherein the switch controller is further configured to determine whether the target resonator is present based on a comparison of a shape of the detected waveform with other waveforms, and to transmit power to a neighboring source resonator in response to the target resonator being determined not to be preset.