Check of the anisotropy of the inductance of an electric motor during end-of-line commissioning

A method for verifying an anisotropy of an inductance of an electric motor during end-of-line commissioning, comprising:

• a) providing an electric machine having a stationary rotor,
• b) determining a d-axis, in particular a minor semi-axis, of an ellipse by means of an iterative method and setting an angular offset Gamma_q1,
• c) determining a q-axis, in particular a major semi-axis, of the ellipse by means of an iterative method and setting an angular offset Gamma_d1, wherein the d-axis and the q-axis are found by a sign change in the iterative method,
• d) analyzing the amplitude of the current response of the injected signal in the d-direction and the q-direction,
• e) ascertaining a ratio of the current response in the d-direction and the q-direction, and
• f) transforming the phase currents in d−45°, d+45°, d+0° and in q−45°, q+45° and q+0°, wherein the ellipse is formed in a d-q plane with a circular excitation in a voltage in the current.