| 摘要 |
A metal foreign-object detection apparatus (7) for a non-contact electric power feeding system comprises an antenna coil (AT2), an oscillation circuit (7a) for making high-frequency current flow through the antenna coil (AT2), and a detection circuit (7b) for detecting changes in the voltage or current to be observed at either the oscillation circuit or the antenna coil. The oscillation circuit (7a) comprises components set to design values that will make oscillation be generated in oscillation conditions ranging from the condition just after an oscillation is started being generated, to just before the condition becomes a stable oscillation-continuing condition. The metal foreign-object detection apparatus (7) detects, with the detection circuit (7b), stopping of the oscillation or attenuation of the oscillation amplitude of the oscillation circuit (7a), on the basis of changes in the electrical characteristics of the antenna coil (AT2) due to a metal foreign-object being placed on an electric power feeding apparatus (1). |
