FOREIGN OBJECT DETECTION IN INDUCTIVE COUPLED WIRELESS POWER TRANSFER ENVIRONMENT USING THERMAL SENSORS

摘要

A device for detecting presence of a foreign object in an inductively coupled power transfer environment is disclosed. The device is provided with a thermal conducting sheet on the charging unit. A device to be charged can be coupled to the primary for charging only if it is within the area of the thermal conducting sheet. When a metallic foreign object is placed in the charging region it acts as a parasitic load and its temperature starts to increase. Since the object is in contact with the thermal conducting sheet, the temperature of the sheet will also increase. This is detected by temperature sensors provided to the thermal conductive sheet and triggers a controller to switch off the primary coil and stop the charging.