Apparatus and method for rotating-sensor-less identification of magneto-mechanical parameters of an AC synchronous motor

1. 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 ).

2. The method according to claim 1 ,

characterized in that

given knowledge of the position of the d/q rotor axis directions opposite the α/β stator axial directions, an appropriate U 1α , U 1β supply takes place, so that a constant stator magnetic field can be carried out in the d direction of axial flux and a test signal can be carried out in the q direction of axial flux.

3. The method according to claim 2 ,

characterized in that

supplying a constant voltage U 1α in the α axial direction of the stator ( 13 ) brings about an alignment of the d flux axis of the rotor ( 11 ) relative to the α axis of the stator ( 13 ) by impressing a direct current I 1α =I DC , and

applying a test signal voltage U 1β in the β axial direction, whereby the α axial direction remains supplied with DC current so that a measurement signal current that measures I 1β of the β axial direction can be detected.

4. The method according to claim 3 ,

characterized in that

the ratio of constant voltage U 1d to test signal voltage U 1q is selected in an optimal manner for achieving maximal amplitudes of the deflection movement ( 75 ) at a height such that magnetomechanical characteristic quantities of an adjustable spring-mass system ( 77 ) are determined with a pre-determinable accuracy.

5. The method according to claim 3 ,

characterized in that

further characteristic quantities of equivalent circuit characteristic quantities L 1 , R 1 ( 03 , 05 , 15 ) as well as mechanical structural magnitudes of pole pair number p or electrical measuring magnitudes I 1α , I 1β , or I 1α =I DC of the synchronous motor ( 09 ) are taken into account or also identified.

6. The method according to claim 3 ,

characterized in that

the test signal is a pseudo-noise binary signal.

7. The method according to claim 3 ,

characterized in that

the identification of the magnetomechanical characteristic quantities comprises a Fourier transformation of time-discrete signals according to a Welch method.

8. The method according to claim 3

characterized in that

the identification of the magnetomechanical characteristic quantities comprises a transmission function-parameter determination according to a Levenberg-Marquardt algorithm.

9. The method according to claim 3

characterized in that

the identified magnetomechanical characteristic quantities are used in an adjustment or optimization of inverter control parameters or for motor monitoring.

10. An identification apparatus ( 39 ) for the identification of magnetomechanical characteristic quantities without shaft encoder of a three-phase synchronous motor ( 09 ), the apparatus comprising an inverter interface unit ( 39 ) that is connected to an inverter control apparatus ( 37 ) for a controlling communication and for determining rotor standstill,

characterized in that

the identification apparatus ( 39 ) furthermore comprises

a test signal generation apparatus ( 51 ) for generating a d/q test signal, the test signal comprising a direct current I 1d =I DC to brine about an alignment of the rotor ( 11 ) opposite the stator ( 13 ), whereby no torque is exerted on the rotor ( 11 );

a U/V/W transformation unit ( 43 ) for transformation of the d/q test signal into a U/V/W control test signal,

a d/q transformation unit ( 41 ) for transformation of detected U/V/W measurement signal currents into d/q measurement signal currents and

a parameter identification unit ( 67 ) for identification of the magnetomechanical characteristic quantities under the assumption of a standstill position of the rotor ( 11 ).

11. The apparatus according to claim 10 ,

characterized in that

the parameter identification unit ( 67 ) comprises a Fourier transformation means ( 45 ) for the Fourier transformation of discontinuous d/q scanning signal values according to the Welch method and comprises a parameter determination means ( 47 ).

12. The apparatus according to claim 10 ,

characterized in that

furthermore the apparatus comprises, a monitoring and optimization unit ( 49 ) that is set up to determine, optimize or monitor control parameters of an inverter control apparatus ( 37 ) on the basis of the identified magnetomechanical characteristic quantities.

13. A motor control device ( 35 ) for controlling a three-phase synchronous motor ( 09 ) without a shaft encoder, and comprising

(a) an identification apparatus ( 39 ) for the shaft-encoderless identification of magnetomechanical characteristic quantities of a three-phase synchronous motor ( 09 ), the identification apparatus ( 39 ) furthermore comprising a test signal generation apparatus ( 51 ) for generating a d/q test signal, the test signal comprising

a direct current I 1d =I DC to bring about an alignment of the rotor ( 11 ) opposite the stator ( 13 ), whereby no torque is exerted on the rotor ( 11 );

a U/V/W transformation unit ( 43 ) for transformation of the d/q test signal into a U/V/W control test signal,

a d/q transformation unit ( 41 ) for transformation of detected U/V/W measurement signal currents into d/q measurement signal currents and

a parameter identification unit ( 67 ) for identification of the magnetomechanical characteristic quantities under the assumption of a standstill position of the rotor ( 11 ) and

(b) an inverter interface unit ( 39 ) that is connected to an inverter control apparatus ( 37 ) for a controlling communication and for determining rotor standstill,

whereby the identified characteristic quantities are used for the determination, optimization and monitoring of the motor ( 09 ) or of the motor control.

14. The device according to claim 13 ,

characterized in that

the device is arranged in such a manner that an automated identification of the magnetomechanical characteristic quantities is carried out at least during the first startup, whereby an error signal is initiated upon a demonstrable deviation of the magnetomechanical characteristic quantities from previously determined, stored or model-related characteristic quantities.

15. The use of a method according to claim 1 for the determination, optimization and monitoring of motor regulator parameters for the control of electrical drives.