DEVICE AND METHOD FOR WIRELESS POWER TRANSFER

A wireless power transmitter () or power receiver () comprises a power transfer coil () for receiving or generating a power transfer signal and a controller () for controlling the device to perform power transfer during a power transfer phase. The power transfer phase comprises power transfer intervals where power is transferred and foreign object detection time intervals during which a power level of the power transfer signal is reduced. A magnetic shielding element () is positioned between the power transfer coil () and a power transfer coil of a complementary device. The magnetic shielding element () comprises a magnetic shield material having a saturation point such that it operates in a saturated and non-saturated mode during respectively power transfer intervals and foreign object detection time intervals. The saturation point is above a magnetic field strength generated by the power transfer signal during the power transfer time intervals and below that generated during the foreign object detection time intervals.