Patent ID: 8571609

Claim:
A method of a wireless power transmission device for wirelessly transmitting power to a terminal, the method comprising: transmitting a Broadcast Message (BM) while the wireless power transmission device is in an idle state; receiving a connection request message from the terminal, and in response, transitioning from the idle state to a plug-in state; transmitting a test power to the terminal, and in response, receiving an efficiency information message comprising a comparison to an amount of the test power transmitted by the wireless transmission device and an amount of the test power actually received by the terminal; establishing a connection with the terminal during which power is wirelessly transmitted to the terminal, in response to the amount of test power actually received by the terminal being greater than a reference value; and transitioning from the power transmission state to a plug-out state in which the connection to the terminal is terminated, in response to a charging completion message being received from the connected terminal.