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T. Wolbank:
"High dynamic low frequency filtering of flux-angle in field-oriented control of induction motors without speed- and position Sensor";
Poster: International Conference on Electrical Machines, Vigo, SPAIN; 1996-09-10 - 1996-09-12; in: "Proceedings", (1996), 7 - 11.

To realize an induction motor drive that is able to produce full torque even at zero flux frequency and at low speed usually a mechanical Sensor is necessary to estimate the position of the rotor flux linkage for field oriented control. In this paper the flux position at low stator frequency is detected with the INFORM ("Indirect flux detection by on-line reactance measurement") flux model. In some parts of the operating range the performance of the drive can be improved by low frequency filtering of the flux angle. Usually low frequency filtering leads to a deteriorate dynamic behavior of the drive. In this paper a new technique is presented, which enables the low frequency filtering of the estimated flux angle without making the dynamic behavior of the drive worse. To achieve this the well-known voltage flux model is modified by feeding back the reference value of the rotor flux magnitude and the flux angular position detected with the INFORM flux detection method to a parameter adaptation algorithm. Thus the voltage flux model does not lose its dynamic behavior, but with the slowly modified parameters does a low frequency filtering of the estimated flux angle. The applicability of the proposed method is verified by simulation results.