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, and wherein the plurality of packets further include at least one of a signal strength packet, an end power transfer packet, a power control hold-off packet, a configuration packet, an identification packet for transmitting receiver identification information, an extended identification packet, a general request packet, a special request packet, a control error packet, a renegotiation packet, a 24-bit received power packet, an eight-bit received power packet, and a charging status packet.