Patent ID: 8587250

Claim:
A method for the identification of magnetomechanical characteristic quantities without a shaft encoder, the quantities including the mass moment of inertia J and the permanent magnetic flux Ψ PM between the rotor ( 11 ) and the stator ( 13 ) of a three-phase synchronous motor ( 09 ), comprising at least the steps: applying a constant voltage U 1d in d-direction of axial flux of the rotor ( 11 ) by impressing a direct current I d =I DC to bring about an alignment of the rotor ( 11 ) opposite the stator ( 13 ), whereby no torque is exerted on the rotor ( 11 ) after the rotor ( 11 )assumes a standstill position; applying a test signal voltage U 1q in q-transverse axial direction of the rotor ( 11 ), whereby the d-direction of axial flux remains with DC current; detecting a measurement signal current I 1q of the q-transverse axial direction; identifying magnetomechanical characteristic quantities of the synchronous motor ( 09 ) based on the test signal voltage U 1q and on the measurement signal current I 1q ; whereby the applying of a test signal voltage into the synchronous motor ( 09 ) takes place in such a manner that the rotor ( 11 ) can execute deflection movements ( 75 ) with pre-definable maximal amplitudes based on the applying of test signals, so that no complete rotation of the rotor ( 11 ) can take place and the rotor ( 11 ) remains aligned in a definable angular range relative to the stator ( 13 ).