| 摘要 |
PROBLEM TO BE SOLVED: To detect metallic foreign matter on the basis of a change in inductance of a primary coil and a change in input impedance of an inverter due to the metallic foreign matter.SOLUTION: A wireless power transmission device includes: a primary L-Cresonator comprising a coil Land a capacitor Cconnected in series; a drive power supply which switches DC power at a fixed drive frequency ωto drive the primary L-Cresonator; voltage detection means for detecting the voltage V(L) across the coil Land the voltage V(C) across the capacitor Cduring driving of the primary L-Cresonator; voltage ratio calculation means for calculating a voltage ratio V(L)/V(C) from the detected voltage V(L) across the coil Land the detected voltage V(C) across the capacitor C; and determination means for determining the presence or absence of metallic foreign matter on a mounting surface of a device to be charged, from the calculated voltage ratio V(L)/V(C) and a predetermined threshold. |
