Simple Technique of Initial Speed Identification for Speed-Sensorless Predictive Controlled Induction Motor Drive
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Warsaw University of Technology
Electrotechnical Institute Warsaw
Marian P. Kazmierkowski   

Warsaw University of Technology
Power Electronics and Drives 2020;5 (40)
The paper presents a simple initial speed identification technique and its application in model predictive flux control (MPFC) scheme for three-level inverter-fed sensorless induction motor (IM) drive operated in wide speed region including field weakening. For speed estimation compensated Current-Model Reference Adaptive System (C-MRAS) were applied and also further extended for initial speed identification necessary for fast IM restarting. The proposed technique consists of two steps during each the short pulse of flux reference is generated. First, for the initial estimator speed set to zero, the short (40ms) flux generation is initiated. If the initial speed is incorrect, the torque impulse appears. Direction of this torque impulse determines whether the set speed is lower or higher than the current one. In the second step the initial speed is set to the half of nominal one with the sign corresponding to estimated sign of torque, and the procedure is repeated. This allows fast restarting of the IM with limitation that the difference between real and estimated speed is in the range up to 25%. The experimental results measured on 50kW drive that illustrate operation and performances of the system are presented.
ISSN (print):2451-0262