WIRELESS POWER TRANSFER

A power transmitter () comprises a transmitter coil () for generating the power transfer signal during a power transfer phase. A driver () generates a drive signal for the transmitter coil () to generate the power transfer signal during the power transfer phase. A communicator () receives messages from the power receiver () and a controller () is arranged to, during the power transfer phase, generate a reduced power time interval during which a power level of the power transfer signal is reduced where the reduced power time interval is generated in response to the communicator () receiving a reduced power time interval request message from the power receiver (). The power receiver () may generate a request message when e.g. a change in operating mode occurs. The power receiver () may ensure that a request message, and thus a reduced power time interval, is only generated when the power receiver can handle a power interruption for the power transfer signal.