Power control method for considering situation of wireless power receiver in wireless power transmitter and the wireless power transmitter thereof

The present invention suggests a method to prevent an excessive voltage in a power receiver to transmit power required by the power receiver to start a charging step. To do so, the present invention determines whether power transmission to the power receiver is possible based on the power data the power receiver if there is an entry request from the power receiver to enter a wireless power network controlled by a power transmitter, notifies the start of step-by-step power transmission to the power receiver if the power transmission is determined possible, increases the amount of the power transmission until a request to stop the voltage increase from the power receiver is received, stops increasing the amount of the power transmission when the stop request is received, and starts to charge by sending a charge start command. By doing so, an excessive voltage can be prevented in transmitting power required by the power receiver to start the charging step. [Reference numerals] (300) Nothing on TX;(305) RX on TX;(310) Notoify the operation as level-up;(315) Rx requests to stop the voltage increase;(320) Tx informs Rx of the start of power transmission;(AA) Power of the power transmitter (PTx)[W];(BB) Standby state;(CC) Charging state;(DD,HH) Load detection;(EE) Power tracking;(FF) Power stabilization;(GG) Hold time;(II) Search & register;(JJ) Time