| 摘要 |
<p>To reliably detect the setting down of a foreign object on a charging platform using a simple circuit configuration. To efficiently transmit power from a power transmission coil to a power receiving coil while charging a device. In this non-contact charging method, a battery-powered device (50) is set down on a charging platform (10), a power receiving coil (51) in the battery-powered device (50) is electromagnetically coupled to a power transmission coil (11) in the charging platform (10), power is transmitted from the power transmission coil (11) to the power receiving coil (51) by electromagnetic induction, and a battery (52) in the battery-powered device (50) is charged. In this non-contact charging method, the charging current of the battery (52) is detected on the battery-powered device (50) side, the transmission efficiency is detected from the detected charging current, the detected transmission efficiency is compared to an efficiency threshold value, it is determined that a foreign object has been set down on the charging platform (10) when the detected charging efficiency is less than the efficiency threshold value and it is determined that a foreign object has not been set down on the charging platform (10) when the detected charging efficiency is greater than the efficiency threshold value, and foreign object detection is suspended during a time period including a fluctuation in the charging current.</p> |
