Wireless power transmitting and charging system

1. A method for operating a wireless power transmitter, comprising:

maintaining a ping value table having a plurality of ping signal conditions that are mapped to different heights of a power receiver;

varying a ping signal according to the ping value table;

detecting the power receiver when the ping signal matches one of the plurality of ping signal conditions recorded in the ping value table; and

controlling a charge mode according to a message received from the power receiver.

2. The method of claim 1 , wherein the ping signal condition is at least one of a frequency of the ping signal collected at each height, a voltage level of the ping signal and a duty ratio of the ping signal.

3. The method of claim 1 , wherein detecting the power receiver includes storing a previous ping signal condition which was successful in detecting the power receiver, wherein the previous ping signal condition which was successful in detecting the power receiver is set as an initial value for varying the ping signal.

4. The method of claim 1 , wherein controlling the charge mode includes:

identifying an initial driving condition mapped to the ping signal condition successful in detecting the power receiver; and

performing wireless charge based on the initial driving condition.

5. The method of claim 4 , wherein the initial driving condition mapped to the ping signal condition is identical to a previous ping signal condition which was successful in detecting the power receiver.

6. The method of claim 4 , wherein the initial driving condition mapped to the ping signal condition is at least one of a driving frequency for wireless charge, voltage level and a constant value of Proportional Integral Differential (PID) algorithm.

7. The method of claim 4 , wherein the initial driving condition mapped to the ping signal condition is identified by a look-up table in which an optimized value measured in advance for each height of the power receiver is recorded.

8. The method of claim 4 , wherein performing wireless charge includes starting wireless charge with the initial driving condition, performing a driving condition varying procedure which varies at least one of a driving frequency and a voltage level, and terminating or continuing the driving condition varying procedure according to whether a power transmission efficiency is improved.

9. A device for transmitting wireless power via a power transmitter of a charge system, comprising:

a memory storing a ping value table having a plurality of ping signal conditions that are mapped to different heights of a power receiver;

a detecting unit configured to:

vary a ping signal according to the ping value table, and

detect the power receiver when the ping signal matches one of the plurality of ping signal conditions recorded in the ping value table; and

a charge mode control unit for controlling a charge mode according to a message received from the power receiver.

10. The device of claim 9 , wherein the ping signal condition is at least one of a frequency of the ping signal collected at each height, a voltage level of the ping signal and a duty ratio of the ping signal.

11. The device of claim 9 , wherein the detecting unit is further configured to store a previous ping signal condition which was successful in detecting the power receiver, and set the previous ping signal condition as an initial value for varying the ping signal.

12. The device of claim 9 , wherein the charge mode control unit identifies an initial driving condition mapped to a previous ping signal condition which was successful in detecting the power receiver and performs wireless charge based on the initial driving condition.

13. The device of claim 12 , wherein the initial driving condition mapped to the ping signal condition is identical to the previous ping signal condition which was successful in detecting the power receiver.

14. The device of claim 12 , wherein the initial driving condition mapped to the previous ping signal condition is at least one of a driving frequency for wireless charge, voltage level and a constant value of Proportional Integral Differential (PID) algorithm.

15. The device of claim 12 , wherein the memory further includes a look-up table in which an optimized value of a driving condition mapped to the ping signal condition for each height of the power receiver is stored.

16. The device of claim 12 , wherein the charge mode control unit performs a driving condition varying procedure which varies at least one of a driving frequency and a voltage level, and terminates or continues the driving condition varying procedure according to whether a power transmission efficiency is improved.