Electricity: motive power systems – Constant motor current – load and/or torque control
Reexamination Certificate
2007-09-07
2010-06-15
Duda, Rina I (Department: 2837)
Electricity: motive power systems
Constant motor current, load and/or torque control
C318S400020
Reexamination Certificate
active
07737652
ABSTRACT:
A method for safely limiting the torque of a frequency-converter-fed three-phase motor operated under field-oriented control (controlled torque) is disclosed. Actual phase current values of the three-phase motor are used to calculate a sum current signal on two channels which is checked for a sum current value of zero. A rotor position angle is determined on the two channels, and torque-forming current components of the two orthogonal field-oriented current components of a stator current space vector are calculated on the two channels as a function of the measured phase currents and the rotor position angle. The three-phase motor is switched on the two channels without applying a torque if the sum value is not equal to zero and/or if the torque-forming current components calculated on the two channels are not equal. This produces a safety function “safe torque limiting” which can be integrated in commercially available frequency converters.
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“Saftey in Bewegung—Sicherheitsfunktionen für Antriebssteuerungen in der Praxis”. abgedruckt in der DE-Zeitschrift “elektrotechnik”, Heft 9, 2003, p. 34-36.
Day Ursula B.
Duda Rina I
Feiereisen Henry M.
Siemens Aktiengesellschaft
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