Method and device for load-free determining of load-dependent positioning parameters of a synchronous machine without a position sensor

A method for load-free determination of load-dependent position assignment parameters of a synchronous machine without using a position sensor, the 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 admittance from each pair of clocked terminal voltage and measured electric current response;
• determining a load-free lowest differential inductance and a load-free highest differential inductance from the clocked terminal voltages and the measured electric current responses;
• predicting a magnetic saturation behavior of an absolute inductance and/or of a magnetic anisotropy of the synchronous machine under load based on the load-free lowest differential inductance, the load-free highest differential inductance, and a short-circuit electric current, wherein the short-circuit electric current is calculated as the quotient of a permanent magnet flux linkage and a combination of the load-free lowest differential inductance and the load-free highest differential inductance;
• and
• using the predicted magnetic saturation behavior of the absolute inductance and/or of the magnetic anisotropy of the synchronous machine under load in a position sensor-free control operation for position assignment.

A method for load-free determination of load-dependent position assignment parameters of a synchronous machine without using a position sensor, the 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 admittance from each pair of clocked terminal voltage and measured electric current response;
• determining a load-free lowest differential inductance and a load-free highest differential inductance from the clocked terminal voltages and the measured electric current responses;
• predicting a magnetic saturation behavior of an absolute inductance and of a magnetic anisotropy of the synchronous machine under load based on the load-free lowest differential inductance, the load-free highest differential inductance, and a short-circuit electric current, wherein the absolute inductance is calculated in such a way that, starting from its value of the load-free highest differential inductance that is valid at zero electric current, with increasing electric current it drops so that upon reaching the short-circuit electric current it is equal to the average value of the load-free lowest differential inductance and the load-free highest differential inductance;
• and
• using the predicted magnetic saturation behavior of the absolute inductance and/or of the magnetic anisotropy of the synchronous machine under load in a position sensor-free control operation for position assignment.