An exemplary inductive power transfer system having a transmitter coil and a receiver coil. A transmitter-side power converter having a mains rectifier stage powering a transmitter-side dc-bus and controlling a transmitter-side dc-bus voltage U1,dc. A transmitter-side inverter stage with a switching frequency fsw supplies the transmitter coil with an alternating current. A receiver-side power converter having a receiver-side rectifier stage that rectifies a voltage induced in the receiver coil and powering a receiver-side dc-bus and a receiver-side charging converter controlling a receiver-side dc-bus voltage U2,dc. Power controllers that determine from a power transfer efficiency of the power transfer, reference values U1,dc*, U2,dc* for the transmitter and receiver side dc-bus voltages. An inverter stage switching controller controls the switching frequency fsw to reduce losses in the transmitter-side inverter stage.