Controlling a polyphase machine

A rotating field machine comprises a plurality of phases, each phase comprising a plurality of parallel-connected windings. A control device for the rotary field machine comprises a half-bridge for each phase, a processing device for controlling the half-bridge in response to a current flowing through one of the phases phase current and a current sensor. In this case, the current sensor to determine a current flowing through one of the windings of the phase winding current is set up and the processing means is adapted to determine the phase current on the basis of the winding current.