A POWER TRANSMITTER, SYSTEM AND METHOD THEREFOR

A power transmitter () provides wireless power transfer to a power receiver () via a wireless inductive power transfer signal. The power transmitter () comprises transmitter coil () for generating the power transfer signal and a driver () generating a drive signal for this. A communicator () communicates with the power receiver () via a communication channel that does not use the power transfer signal as a communication carrier. A power loop controller () implements a power control loop by adapting a power level of the power transfer signal in response to power control error messages received from the power receiver (). A generator () introduces a power level variation sequence to the power transfer signal and a validity detector () detects data received by the communicator () to be invalid data for the power transfer in response to a comparison of the power level variation sequence and power change requests of the power control error messages.