WIRELESS INDUCTIVE POWER TRANSFER

A power transmitter () of a wireless power transfer system comprises a resonance including a transmitter coil () for generating a power transfer signal for wirelessly transferring power to a power receiver (). Further, a driver () generates a drive signal for the resonance circuit () and a message receiver () is arranged to receive messages from the power receiver (). A power loop controller () implements a power control loop by adapting the power of the drive signal in response to power control messages received from the power receiver (). However, the regulation is subject to a constraint of at least one of a current or voltage of the resonance circuit and a power of the drive signal being below a maximum limit. Further, the power transmitter () comprises an adapter () which adapts the maximum limit in response to a load indication indicative of a loading of the power transfer signal by the power receiver ().