Electricity: motive power systems – Induction motor systems – Primary circuit control
Patent
1995-06-01
1998-08-18
Martin, David S.
Electricity: motive power systems
Induction motor systems
Primary circuit control
318701, 318254, H02P 534
Patent
active
057962359
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method and arrangement for determining machine-specific electromagnetic and mechanical status variables for electrodynamic rotary field machines supplied via inverters, such as, for example, asynchronous machines, synchronous machines and reluctance machines.
2. Discussion of Background and Relevant Information
Due to progress made in the field of power and information processing electronics, inverter supplied asynchronous, synchronous and reluctance machines are gaining increasing significance in drive technology.
Asynchronous machines are distinguished from synchronous machines and direct current machines by their greater sturdiness and lower production costs. When performing closed-loop control algorithms for dynamically high-quality field-oriented control concepts, the necessity arises, at low rpm of the asynchronous machines, of having a mechanical transducer detect the rotor position or rotor speed. Asynchronous machines can be dynamically operated without the use of position transducers and tachometers if the rpm exceeds a certain minimum predetermined value, in which case, the magnetic flux can be calculated from electrical variables from an induced voltage. However, this has not yet been successfully achieved when the asynchronous machine is operating in the low rpm range. Thus, ongoing research is attempting to replace mechanical transducers with mathematical models and/or to utilize physical phenomena.
An article at pages 349-351 of "etzARCHIV", No. 11, Vol. 12 (1990), entitled "Determination of the Stator Flux Space Vector of Saturated AC Machines" addresses these problems. The article describes a method in which an alternating current machine that is supplied via a pulse-width modulated alternating converter stage, carries out a real-time determination of the stator voltage vector once each oscillation period. According to this method, measurement errors in the values of the phase currents and phase voltages needed for the calculations can be kept small. Thus, there is no need for obtaining rotor speed measurements.
One disadvantage of this method is that inductances are calculated. Thus, voltage measurements need to be constantly obtained.
In a dissertation entitled "Entwurf und Aufbau Eines Nichtlinearen Zustands--Und Parameterbeobachters Fur Transient Betriebene Parameter Observer for Transient Operation Asynchronous Machines!, by Vienna!, 1987, page 14f.), the author discusses how to determine a rotor flux from a stator equation in a rotary current machine. According to the dissertation, a "voltage model" is used as an aid, which is based on a formula: ##EQU1## in which the symbols have the following meanings: .psi..sub.R . . . rotor flux space vector
According to this model, the flux can be determined solely by measuring electrical variables, eliminating the need for an electrical transducer. Additionally, when voltage space vector amounts are high--which is equivalent to a high rpm--the current-dependent terms, especially at a low load, only weakly influence the flux value. Accordingly, a good accuracy can be expected in these operating ranges.
A disadvantage of such a measuring method is that the influence of measurement errors and temperature-dependent stator resistance, and in the case of an analog construction, the drift of the integrators, increasingly worsen the quality of the model because of the lack of any feedback.
Synchronous machines have become popular because of improvements in the field of magnetic materials. Compared with asynchronous machines, synchronous machines have a simpler structure in terms of closed-loop control technology, and, because of very low rotor losses, operate with a higher efficiency as compared to asynchronous machines.
In order to carry out the control algorithms in dynamically high-quality field-oriented closed-loop concepts (or magnet-wheel-oriented closed-loop control concepts), a mechanical transducer must be employed that detects the magnet wheel positi
REFERENCES:
patent: 4240020 (1980-12-01), Okuyama et al.
patent: 4267499 (1981-05-01), Kurosawa
patent: 4268781 (1981-05-01), Kawada et al.
patent: 4400655 (1983-08-01), Curtiss et al.
patent: 4611157 (1986-09-01), Miller et al.
patent: 4642543 (1987-02-01), MacMinn
patent: 4767976 (1988-08-01), Mutoh
patent: 4780650 (1988-10-01), Miyazaki et al.
patent: 4961038 (1990-10-01), MacMinn
patent: 5003243 (1991-03-01), Tadakuma et al.
patent: 5166593 (1992-11-01), De Doncker et al.
patent: 5296793 (1994-03-01), Lang
IEEE Transactions On Industrial Electronics And Control, vol. 38, No. 2, Apr. 1991, New York, NY. pp. 95 -100 (Sanjib Kumar Panda and Gehan Amaratunga), "Comparison of Two Techniques for Closed-Loop Drive of VR Step Motors Without Direct Rotor Position Sensing".
Fourth International Conference On Power Electronics And Variable Speed Drives, Jul. 17, 1990, London, United Kingdom, pp. 249 -252 (N.H. Mvungi et al.), "A New Sensorless Position Detector for SR Drives".
etzARCHIV, vol. 12 (1990), No. 11, pp. 349 -351 (Manfred Depenbrock et al.), "Determination of the Stator Flux Space Vector of Saturated AC Machines".
Dissertation entitled "Entwurf und Aufbau eines nichtlinearen Zustands-und and construction of a nonlinear status and parameter observer for transien-operation asynchronous machines!, by Manfred Schrodl of the +.
A chapter entitled "Algorithmus zur rechnerischen Erfassung der Polradlage for computer detection of the magnet wheel position of a permanent-magnet-excited synchronous machine without position transducer!, by M. Schrodl and T. Stefan, in the Proceedings (pp. 48 -54) of the ETG/VDE Conference, Antriebssysteme fur die Gerate-und industry!, held in Bad Nauheim, Germany, in 1988.
A chapter entitled "Detection of the rotor position of a permanent magnet synchronous machine at standstill", by M. Schrodl, included in the proceedings published for the International Conference on Electrical Machines in Pisa, Italy in 1988.
Dissertation entitled "Die permanenterregte umrichtergespeiste permanently excited inverter-spplied synchronous machine without magnet wheel transducer, as an rpm-regulated drive!, by H. Vogelmann of the University of Karlsruhe, Germany, 1986.
An article entitled "PWM-Based Position Sensorless Control of Variable Reluctance Motor Drives", by Michael G. Egan et al., in the Proceedings of the EPE-European Power Electronics Conference in Florence, Italy, 1991, pp. 4-024 to 4-029.
An article entitled "A Torque Angle Calculator for Sensorless Reluctance Motor Drives", by Silverio Bolognani, in the Proceedings of the EPE-European Power Electronic Conference in Florence, Italy, 1991, pp. 4-013 to 4-017.
An article entitled "Accurate Sensorless Rotor Detection in an SR Motor", by N.M. Mvungi et al., in the Proceedings of the EPE-European Power Electronic Conference in Florence, Italy, 1991, pp. 1-390 to 1-393.
Ensbacher Richard
Schrodl Manfred
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