Patent ID: 8907606

Claim:
A method for determining a rotor position of a two-phase synchronous machine having a first winding phase and a second winding phase for electronically commutating the synchronous machine, the method comprising: driving each of the first and second winding phases alternately in a first drive time window with a drive variable of positive polarity and in a second drive time window with a drive variable of negative polarity, the first drive time window and the second drive time window directly following one another alternately; applying a drive variable of 0 to the first winding phases during a measurement time window, which is provided within at least one of the drive time windows of a winding phase; applying a measurement pulse to the first winding phase within the measurement time window; determining a winding phase inductance of the first winding phase caused by the measurement pulse; determining the rotor position based on the determined winding phase inductance of the first winding phase, changing the drive variable to the first winding phase when the determined winding phase inductance of the first winding phases exceeds or falls below a predetermined threshold value, and wherein, during the measurement time window, a drive current is applied to the second winding phase, the drive current being selected in such a way that a torque of the synchronous machine generated during the measurement time window corresponds to a torque which is generated by application of drive variables unequal to 0 to the first and second winding phases.