Patent ID: 8198840

Claim:
A method for operating a synchronous machine having a stator with three winding phases assigned to said stator, and a rotor, the method comprising: determining, by an observation unit, estimated values of motor currents of the synchronous machine in a coordinate system which rotates with the rotor, said step of determining estimated values being performed as a function of setpoint values of electrical voltages of the synchronous machine in the coordinate system which rotates with the rotor and as a function of motor inductances, the setpoint values of the electrical voltages of the synchronous machine being provided to a field attenuator unit which generates a set point value of at least one of the motor currents provided to a controller which determines pilot control values to form the setpoint values of the electrical voltages; determining the motor inductances as a function of the estimated values of the motor currents to operate the synchronous machine; and determining an ohmic equivalent resistance as a function of temperature; wherein the step of determining the estimated values of the motor currents is performed as a function of the determined ohmic equivalent resistance.