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1

Influence of the stator current reconstruction method on direct torque control of induction motor drive in current sensor postfault operation

Adamczyk Michal, Orlowska-Kowalska Teresa

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 1

art. no. e140099

EN

Modern induction motor (IM) drives with a higher degree of safety should be equipped with fault-tolerant control (FTC) solutions. Current sensor (CS) failures constitute a serious problem in systems using vector control strategies for IMs because these methods require state variable reconstruction, which is usually based on the IM mathematical model and stator current measurement. This article presents an analysis of the operation of the direct torque control (DTC) for IM drive with stator current reconstruction after CSs damage. These reconstructed currents are used for the stator flux and electromagnetic torque estimation in the DTC with space-vector-modulation (SVM) drive. In this research complete damage to both stator CSs is assumed, and the stator current vector components in the postfault mode are reconstructed based on the DC link voltage of the voltage source inverter (VSI) and angular rotor speed measurements using the so-called virtual current sensor (VCS), based on the IM mathematical model. Numerous simulation and experimental tests results illustrate the behavior of the drive system in different operating conditions. The correctness of the stator current reconstruction is also analyzed taking into account motor parameter uncertainties, especially stator and rotor resistances, which usually are the main parameters that determine the proper operation of the stator flux and torque estimation in the DTC control structure.

2

MRAS-super twisting sliding modeo observer for speed sensorless vector control of induction motor drive

Kouriche Lilia, Messlem Youcef

Przegląd Elektrotechniczny

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2021

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R. 97, nr 4

121--127

EN

This article proposes a high-order super-twisting sliding mode observer associated to MRAS method applied to an induction motor fed by a power voltage source without speed sensor. Based on the vector control principle, high-order super-twisting sliding mode observer in speed loop and flux loop are designed respectively. The super-twisting sliding mode observer is utilised to improve the speed estimation and robustness of motor control systems. Meanwhile, high-order sliding modes are adopted to eliminate the chattering phenomenon at variable state observation. We also present the mechanism of adaptive super-twisting speed and rotor flux observers with the only assumption that from stator voltages and currents are measurable. The objective is to improve the sensorless speed control, the rotor flux control under load torque disturbances, inversion of rotor speed and zero speed operation. The simulation results prove clearly a good robustness against load torque disturbances, the estimated fluxes and the rotor speed converge to their real values. Our study is close to reality; all the simulations are based on real models simulated within the Matlab SymPower System environment in continuous time. To analyze our approach, a prototype is modeled, simulated and can be realized in an experimental test setup

PL

W artykule zaproponowano obserwator super-skrętnego poślizgu wysokiego rzędu, powiązany z metodą MRAS, zastosowany do silnika indukcyjnego zasilanego ze źródła napięcia bez czujnika prędkości. W oparciu o zasadę sterowania wektorowego zaprojektowano odpowiednio obserwator przesuwu super-skrętnego wysokiego rzędu w pętli prędkości i pętli strumienia. Obserwator trybu przesuwu super skręcającego jest wykorzystywany do poprawy szacowania prędkości i odporności systemów sterowania silnikiem. Przedstawiamy również mechanizm adaptacyjnych obserwatorów super-skręcania i strumienia wirnika z jedynym założeniem, że z poziomu stojana mierzalne są napięcia i prądy. Celem jest poprawa bezczujnikowej kontroli prędkości, sterowania strumieniem wirnika pod wpływem zakłóceń momentu obciążenia, inwersji prędkości wirnika i pracy przy zerowej prędkości. Wyniki symulacji wyraźnie dowodzą dobrej odporności na zakłócenia momentu obciążenia, oszacowane strumienie i prędkość wirnika są zbieżne z ich rzeczywistymi wartościami. Nasze badanie jest bliskie rzeczywistości; wszystkie symulacje oparte są na rzeczywistych modelach symulowanych w środowisku Matlab SymPower System w czasie ciągłym. Aby przeanalizować nasze podejście, modeluje się prototyp, przeprowadza symulację i może zostać zrealizowany w eksperymentalnej konfiguracji testowej.

3

Technical and economical comparison of different autotransformer based 36 pulse AC-DC Converters

Abdollahi Rohollah

Journal of Power Technologies

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2019

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Vol. 99, nr 4

281--288

EN

Three-phase multipulse ac–dc converters (MPC) are being developed to improve power quality to reduce harmonics in ac mains and ripples in dc output. This study, based on technical and economic factors, compares different autotransformer based 36 pulse AC-DC Converters. This paper presents a comparison of tapped delta, polygon and T connected autotransformer based 36-pulse AC-DC converters. These converters were implemented and simulations were made using Matlab/Simulink software for similar ratings under different load conditions. A set of power quality indices on input ac mains and on a dc bus for a DTCIMD fed from different 36-pulse ac-dc converters is given to compare their performance. The economic comparison of 36 pulse ac–dc converters is based on the apparent power (kVA) ratings of the different autotransformers for 36 pulse AC-DC converters. Also, a prototype is developed and the experimental measurements obtained are presented to validate the feasibility and operability of the 36-pulse AC-DC converter. The 36-pulse AC-DC converter offers a total harmonic distortion of 4% and can operate at near-unity power factor, in compliance with IEEE and IEC standards.

4

The application of the finite element method in diagnostics of electrical drives

Fiser R., Ferkolj S.

Journal of Technical Physics

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2002

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Vol. 43, no 4

399-403

EN

The paper presents the application of the finite element method for predicting the performance of induction motor having asymmetry of stator and/or rotor winding due to the different combination and propagation of faults gained during heavy-duty operation. Quantities like magnetic vector potential, flux density, force components, rotor and stator currents, mutual and leakage inductance are determined very precisely. The detailed insight in magnetic field distribution of a squirrel cage induction motor, forms the basis for further evaluation of its operational behaviour. Increasing anomaly in magnetic field distribution due to the increasing stage of faults propagation results in a degradation of steady-state and dynamic performance of the induction motor and can be evaluated with computer simulation eliminating expensive and time-consuming laboratory tests.

5

Calculation of electromagnetic field in a disk-type induction motor using a 3-D reluctance network method

Ciosk K.

Journal of Technical Physics

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2002

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Vol. 43, no 4

383-387

EN

The paper presents an analysis of the magnetic field in a disk-type induction motor with double-sided stator and twin rotors. The magnetic flux density was found in a 3-D space using the reluctance network method (RNM). The results were compared with the measurements carried out on the real object.