METHOD FOR DETECTING FOREIGN MATERIAL, AND APPARATUS AND SYSTEM THEREFOR

A wireless power receiver that receives power from a wireless power transmitter, the wireless power receiver including a wireless communication unit configured to communicate with the wireless power transmitter; and a controller, wherein the wireless communication unit transmits a first foreign object status packet and a second foreign object status packet to the wireless power transmitter, wherein the wireless communication unit receives, from the wireless power transmitter, a first foreign object detection indicator including a positive response signal or a negative response signal to the first foreign object status packet, wherein the wireless communication unit receives, from the wireless power transmitter, a second foreign object detection indicator including a positive response signal or a negative response signal to the second foreign object status packet, and wherein the controller is configured to proceed to a first power transmission procedure when both the first foreign object detection indicator and the second foreign object detection indicator include the positive response signal, or is configured to proceed to a second power transmission procedure that requests termination of power transmission or proceed to a third power transmission procedure different from the termination of the power transmission when at least one of the first foreign object detection indicator and the second foreign object detection indicator includes the negative response signal.