Electricity: motive power systems – Induction motor systems
Reexamination Certificate
2000-06-27
2001-11-13
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
Induction motor systems
C318S804000, C318S805000, C318S806000
Reexamination Certificate
active
06316904
ABSTRACT:
TECHNICAL FIELD
The invention relates to powertrains having an electric induction motor, including hybrid powertrains that include an internal combustion engine.
BACKGROUND ART
U.S. Pat. No. 6,014,006 discloses a method for controlling torque output for an electric induction motor using estimations of rotor flux angle and rotor speed. The speed is estimated based on motor dynamics represented by equations for which the speed is a control variable to be estimated, the other variables being measurable. Rotor flux is estimated directly from rotor speed using a set of motor control equations, and rotor flux angle is determined from rotor flux for controlling motor torque.
The accuracy of speed estimation of an induction motor without rotational transducers can be affected by rotor resistance variation during operation.
A rotor parameter identification technique for the purpose of updating control gains of an induction motor vector controller by introducing a separate high frequency carrier signal is described by Matsuo et al in a paper entitled “A Rotor Parameter Identification Scheme For Vector-Controlled Induction Motor Drives”, (IEEE Transactions On Industry Applications, Vol. IA-21, No. 4, May/June 1985). An adaptive scheme for simultaneous speed and rotor resistance identification derived by using Lyapunov's function is analyzed by Kubota et al in a paper entitled “Speed Sensorless Field-Oriented Control of Induction Motor with Rotor Resistance Adaptation” (IEEE Transactions on Industry Applications, Vol. 30, No. 5, 1994). The approach of Kubota et al is implemented by superimposing AC components on the field current command.
Robust nonlinear control of the speed of induction motors that uses measurements of the rotor position and stator current with on-line adaptation of the rotor resistance is described by Aloliwi et al in a paper entitled “Robust Speed Control of Induction Motors Using Adaptive Observer” (Proceedings of American Control Conference, pp. 931-935, June 1999). A paper written by Shishkin et al entitled “Discrete-Time Method for Robust Global Stabilization of Induction Motor” (Proceedings of American Control Conference, 1999), describes how the rotor resistance is updated at a prescribed instant by minimizing a nonlinear scalar function, which is monotonic and has a well defined solution when &ohgr; and/or load are small.
Zheng et al describe in a paper entitled “Adaptive Flux and Speed Estimation for Induction Motors” (Proceedings of American Control Conference, June 1999), an adaptive estimator for rotor resistance that considers the rotor speed and rotor resistance as slowly varying unknown parameters of a model reference adaptive system. Under persistent excitation, it is explained by Zheng et al that estimated flux and rotor speed converge to their true values.
A paper by Bondarko and Zaremba (one of the inventors of the present invention), entitled “Speed and Flux Estimation for an Induction Motor Without Position Sensor” (Proceedings of American Control Conference, June 1999) describes a speed sensorless torque control of an induction motor.
DISCLOSURE OF INVENTION
The rotor resistance observer used in the present invention is a further development of the approach, mentioned above, for speed sensorless torque control of electric motors. By assuming that rotor resistance and speed variation are slow, compared to flux and current changes, a linear algebraic system is developed with rotor resistance and speed being the only unknown parameters. The inputs to the observer are pseudo current and pseudo voltage signals and their observable derivatives. The rotor resistance and speed observer is complemented with an accurate, discrete time flux observer, which is based on an analytical solution of the rotor flux equation over a sampling interval. Knowing flux estimation, a standard field orientation control technique is applied.
The method and strategy of the invention provides estimates of rotor resistance and speed for motor torque control by computing a rotor slip gain as a function of measurable stator current and voltage, computing orientation and magnitude of rotor flux as a function of stator current, estimated speed and rotor slip gain, computing rotor slip speed as a function of slip gain and calculating electrical rotor speed as a function of the number of pole pairs, estimated rotor speed and rotor slip speed.
REFERENCES:
patent: 4445080 (1984-04-01), Curtiss
patent: 4926105 (1990-05-01), Mischenko et al.
patent: 4962339 (1990-10-01), Schauder
patent: 5032771 (1991-07-01), Kerkman et al.
patent: 5272429 (1993-12-01), Lipo et al.
patent: 5334923 (1994-08-01), Lorenz et al.
patent: 5476158 (1995-12-01), Mann et al.
patent: 5510689 (1996-04-01), Lipo et al.
patent: 5541488 (1996-07-01), Bansal et al.
patent: 5594670 (1997-01-01), Yamamoto
patent: 5729113 (1998-03-01), Jansen et al.
patent: 5796236 (1998-08-01), Royak
patent: 5903129 (1999-05-01), Okuno et al.
patent: 6008618 (1999-12-01), Bose et al.
patent: 6014006 (2000-01-01), Stuntz et al.
Bondarko et al, “Speed and Flux Estimation for an Induction Motor Without Position Sensor”, Proc. Amer. Contr. Conf., San Diego, CA, Jun. 1999.
Matsuo et al, “A Rotor Parameter Identification Scheme for Vector-Controlled Induction Motor Drives”, IEEE Transaction on Industry Applications, vol. IA-21, No. 4, May/Jun. 1985.
Kubota et al, “Speed Sensorless Field-Oriented Control of Induction Motor with Rotor Resistance Adaptation”, IEEE Transactions on Industry Applications, vol. 30, No. 5, 1994.
Aloliwi et al, “Robust Speed Control of Induction Motors Using Adaptive Observer”, Proc. Amer. Contr. Conf., pp. 931-935, San Diego, CA, Jun. 1999.
Shishkin et al, “Discrete-Time Method for Robust Global Stabilization of Induction Motor”, Proc. Amer. Contr. Conf., San Diego, CA, Jun. 1999.
Zheng et al, “Adaptive Flux and Speed Estimation for Induction Motors”, Proc. Amer. Contr. Conf., San Diego, CA, Jun. 1999.
Leonard, “Control of Electrical Drives”, Springer, 2nd Edition, 1996.
Novotny et al, “Vector Control and Dynamics of AC Drives”, Clarendon Press, Oxford, 1996.
Zaremba et al, “Active Damping of Engine Speed Oscillations Based on Learning Control”, Proc. Amer. Contr. Conf., Philadelphia, PA, 1998.
Zaremba et al, “Performance and Control Issues in an Electric Power Steering System”, Proc. Amer. Contr. Conf., Philadelphia, PA, 1998.
Davis, “Engine and Vehicle Model for Starter/Alternator Active Flywheel Development”, Ford Technical Report, SRR-1998-0048, 1998.
Semenov Sergey Gennadievich
Zaremba Alexander Timofeevich
Ford Global Technologies Inc.
Leykin Rita
Nappi Robert E.
Stec Jennifer
LandOfFree
Speed and rotor time constant estimation for torque control... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Speed and rotor time constant estimation for torque control..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Speed and rotor time constant estimation for torque control... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2588991