Method and device for controlling a synchronous machine without a position sensor by means of one-to-one assignment of the admittance or inductance to the rotor position

A method for assigning an inductance or an admittance to a rotor position of a synchronous machine having a stator and a rotor with or without permanent magnets, the method comprising:

• actuating the synchronous machine via clocked terminal voltages;
• measuring electric current of the synchronous machine responsive to the synchronous machine being actuated via the clocked terminal voltages;
• determining an inductance or an admittance from each pair of clocked terminal voltage and measured current response;
• and
• using a pattern of the inductance or the admittance as a function of rotation of the rotor, under a boundary condition of an at least two-dimensional electric current vector that is unchanged in coordinates of the stator, to assign respective inductances or admittances to positions of the rotor.