Patent ID: 11070095

Abstract:
The present invention relates to a method for detecting a foreign material, and a device and system therefor. The method for detecting a foreign material in a wireless power transmitter provided with a resonance circuit for wirelessly transmitting power according to an embodiment of the present invention comprises: a step of detecting an object disposed in a charging area; a step of measuring a quality factor value of a resonance circuit, following the detection of the object; a step of identifying a wireless power receiver by sending out a detection signal; a step of determining a critical value for detecting a foreign material, on the basis of a reference quality factor value received from the identified wireless power receiver; and a step of judging whether or not the foreign material exists, by comparing the measured quality factor value and the determined critical value, wherein the critical value may be determined by applying a weight which increases in accordance with the reference quality factor value. Accordingly, the present invention has the advantage of detecting a foreign material more effectively and accurately.