Wireless power transmitter and method of controlling the same

1. A method of controlling wireless transmission to a wireless power receiver in a wireless power transmitter, the method comprising:

transmitting charging power to the wireless power receiver by applying the charging power to a resonator of the wireless power transmitter;

receiving power information of the wireless power receiver from the wireless power receiver;

determining whether to adjust the charging power based on the power information of the wireless power receiver; and

adjusting, upon determining whether to adjust the charging power, a size of the charging power applied to the resonator.

2. The method of claim 1 , wherein adjusting the charging power comprises:

increasing the charging power to a first power;

decrementing the first power step by step until a voltage at the wireless power receiver meets a predetermined threshold; and

when the voltage at the wireless power receiver meets the predetermined threshold, fixing the charging power.

3. The method of claim 2 , wherein the voltage at the wireless power receiver includes a voltage at an input end or an output end of a Direct Current (DC) to DC converter of the wireless power receiver.

4. The method of claim 3 , wherein the predetermined threshold for the voltage at the input end of the DC to DC converter of the wireless power receiver ranges from 5.2V to 5.5V, and the predetermined threshold for the voltage at the output end of the DC to DC converter of the wireless power receiver is 5V.

5. The method of claim 3 , further comprising:

transmitting a command signal to instruct the wireless power receiver to report the power information; and

receiving, from the wireless power receiver, a report signal including the power information of the wireless power receiver in response to the command signal.

6. The method of claim 5 , wherein the command signal comprises at least one piece of information about a session IDentifier (ID) of the wireless power receiver, a sequence number, a network ID of the wireless power transmitter, a command type, and extra information of the command type.

7. The method of claim 6 , wherein the command type indicates that the command signal is an instruction to report the power information of the wireless power receiver.

8. The method of claim 5 , wherein the report signal includes at least one of a session IDentifier (ID) of the wireless power receiver, a sequence number, a network ID of the wireless power transmitter, the voltage at the input end of the DC to DC converter of the wireless power receiver, the voltage at the output end of the DC to DC converter of the wireless power receiver, and a current passing through the output end of the DC to DC converter of the wireless power receiver.

9. The method of claim 1 , wherein determining whether to adjust the charging power comprises determining whether a new wireless power receiver is registered in the wireless power transmitter and the wireless power transmitter transmits a command signal to start charging to the new wireless power receiver.

10. The method of claim 1 , wherein determining whether to adjust the charging power comprises determining whether the wireless power receiver is rearranged or withdrawn and a corresponding load change is detected by the wireless power transmitter.

11. The method of claim 1 , wherein determining whether to adjust the charging power comprises determining whether the wireless power transmitter has a wireless power transmission efficiency with respect to the wireless power receiver that is less than a predetermined threshold.

12. The method of claim 1 , wherein determining whether to adjust the charging power comprises determining whether a voltage at an input end or output end of a DC to DC converter of the wireless power receiver is less than a predetermined threshold.

13. The method of claim 2 , wherein decrementing the first power step by step comprises maintaining an optimal wireless power transmission efficiency by performing impedance matching of the wireless power transmitter.

14. The method of claim 2 , wherein decrementing the first power step by step comprises decreasing power applied to an amplifier of the wireless power transmitter.

15. The method of claim 1 , further comprising:

transmitting, for each cycle, a notice signal to the wireless power receiver, the notice signal having at least one of information of a protocol version of the wireless power transmitter, a sequence number, a network IDentifier (ID), information about wireless power receivers reporting to the wireless power transmitter, and information about a number of managed wireless power receivers.

16. The method of claim 2 , wherein decrementing the first power step by step comprises decrementing a voltage of the first power by a step for a predetermined period of time.

17. The method of claim 2 , wherein a voltage of the first power is two steps higher than a voltage of the charging power.

18. A wireless power transmitter for wirelessly transmitting power to a wireless power receiver, the wireless power transmitter comprising:

a power transmitter for transmitting charging power to the wireless power receiver;

a communication unit for receiving power information of the wireless power receiver; and

a controller for determining whether to adjust a size of the charging power applied to the power transmitter based on the power information of the wireless power receiver, and adjusting, upon determining whether to adjust the size of the charging power, the charging power.

19. The wireless power transmitter of claim 18 , wherein the controller increases the charging power to a first power upon determining to adjust the size of the charging power, decrements a voltage at the first power step by step until a voltage at the wireless power receiver meets a predetermined threshold, and when the voltage at the wireless power receiver meets the predetermined threshold, fixes the decreased charging power.

20. The wireless power transmitter of claim 19 , wherein the voltage at the wireless power receiver comprises a voltage at an input end or an output end of a Direct Current (DC) to DC converter of the wireless power receiver.

21. The wireless power transmitter of claim 18 , further comprising:

an impedance matching unit for maintaining an optimal wireless power transmission efficiency by performing impedance matching of the wireless power transmitter.

22. The wireless power transmitter of claim 21 , wherein the impedance matching unit includes at least one of at least one switch, at least one coil, and at least one capacitor.

23. The wireless power transmitter of claim 18 , further comprising:

a power supplier for supplying power; and

an amplifier for amplifying the power with a predetermined gain,

wherein the controller decreases the power applied to the amplifier.

24. The wireless power transmitter of claim 18 , wherein the communication unit transmits, for each cycle, a notice signal to the wireless power receiver, the notice signal having at least one of information of a protocol version of the wireless power transmitter, a sequence number, a network IDentifier (ID), information about wireless power receivers reporting to the wireless power transmitter, and information about a number of managed wireless power receivers.

25. The wireless power transmitter of claim 19 , wherein the controller decrements a voltage of the first power by a step for each of a predetermined period of time.

26. The wireless power transmitter of claim 19 , wherein a voltage of the first power is two steps higher than a voltage of the charging power.

27. A method for applying wireless power for charging a wireless power receiver by a wireless power transmitter, the method comprising:

applying at least one detection power to a resonator of the wireless power transmitter;

detecting a change in impedance of the wireless power transmitter caused by a placement of the wireless power receiver during applying the at least one detection power;

applying driving power, in response to detecting the change;

registering the wireless power receiver in a wireless power network managed by the wireless power transmitter; and

applying charging power for the wireless power receiver.

28. A wireless power transmitter for wirelessly transmitting power to a wireless power receiver, the wireless power transmitter comprising:

a resonator; and

a controller configured to:

apply at least one detection power to a resonator of the wireless power transmitter;

detect a change in impedance of the wireless power transmitter caused by a placement of the wireless power receiver during applying the at least one detection power;

apply driving power, in response to detecting the change;

register the wireless power receiver in a wireless power network managed by the wireless power transmitter; and

apply charging power for the wireless power receiver.