METHOD FOR DETECTING FOREIGN MATERIAL, AND DEVICE AND SYSTEM THEREFOR

A wireless power receiver that receives power from a wireless power transmitter, the wireless power receiver including a communication unit configured to communicate with the wireless power transmitter; and a main controller, wherein the main controller generates a plurality of packets including a foreign object detection (FOD) status packet, wherein the communication unit transmits the FOD status packet to the wireless power transmitter, and the communication unit receives, from the wireless power transmitter, a response signal indicating whether a foreign object is present in a charging area of the wireless power transmitter, wherein the response signal is determined using a measured peak frequency of a power signal transmitted by the wireless power transmitter and a reference peak frequency included in the FOD status packet received from the wireless power receiver, wherein each of the plurality of packets includes a preamble, a header, a message, and a checksum for identifying whether an error occurs in each packet, and wherein the header is configured to identify a type of the each packet.