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Copyright of SDU Journal of Engineering Sciences & Design / Mühendislik Bilimleri ve Tasarım Dergisi is the property of Journal of Engineering Sciences & Design and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is important to detect the faults of induction motors in an accurate manner due to their widespread use in industrial production processes. Broken rotor bars and eccentricity faults are the common faults of induction motor. The simultaneous occurrence of these two types of faults is often encountered in industrial facilities. Therefore, it is important to properly detect characteristic harmonic components of these types of faults. It is difficult to detect these components at low loading and noisy conditions. In this paper, the simultaneous broken rotor bars and static eccentricity faults are investigated based on the stator current and vibration signals. Hilbert envelope analysis was applied to the stator current and vibration signals under four different loading levels (25%, 50%, 75% and 100%) of induction motor. The frequencies and amplitudes of characteristic harmonic components have been successfully detected in envelope spectrum. The results show that the proposed method can be used to diagnose the simultaneous broken rotor bars and eccentricity faults of induction motors. [ABSTRACT FROM AUTHOR]

The purpose of the study is to develop a high-performance speed sensorless indirect field oriented control for induction motors (IMs). The proposed method is a novel Model Reference Adaptive System (MRAS) and needs only steady-state stator q-axis voltage equation to estimate rotor speed. And also, the proposed speed estimator algorithm removes the voltage transducer requirement in calculations since the algorithm compares the current requlator PI controller output with the calculated q-axis stator voltage. So the system does not need a reference loop since the calculated voltage I adaptive sub-model is directly compared with controller output. This simple equation does not require any rotor parameter and this makes the system immune to the variation of rotor parameters. Moreover, this unique calculation eliminates the requirement of flux estimation thus, the method is less sensitive to pure integration problems. This makes the estimator quite accurate at very low and zero speeds. Moreover, the suggested MRAS technique eliminates the voltage transducer measurement noises so, the low speed accuracy of the speed estimator is increased. Which are validated in simulations using MATLAB/SIMULINK. [ABSTRACT FROM AUTHOR]

In this study, the design of the adaptive extended Kalman filter (AEKF) based direct torque controlled drive system with constant switching frequency (DTCD-CSF) is performed for speed-sensorless control of induction motor (IM). The system noise covariance matrix, which directly affects the estimation performance of EKFs and is assumed as constant in conventional EKFs, is updated online according to the operating conditions by the AEKF, which uses stator flux-based IM model. The reason why the proposed algorithm is included on a DTCD-CSF, instead of a conventional DTCD, is to reduce the torque ripples in the traditional direct torque control and the switching losses caused by the variable switching frequency. The load torque and the stator stationary axis components of stator currents in addition to the stator stationary axis components of stator fluxes and the rotor mechanical speed required for the DTCD-CSF are estimated by the proposed AEKF-based observer. By the load torque estimation, it is ensured that the proposed speed-sensorless drive system is robust to changes in load torque. Finally, the proposed AEKF-based speedsensorless DTCD-CSF is verified under simulation studies. [ABSTRACT FROM AUTHOR]

The effects of nonlinear load models on the system are an important issue in terms of power quality. In this study, the effect of nonlinear load models in the grid-connected Doubly Fed Induction Generator (DFIG) based wind turbine was investigated. Exponential, constant impedance, constant current, constant active power (ZIP) and induction motor are used as nonlinear load model. Composite load modeling is consist of exponential-ZIP-induction motor. Composite load modeling is turn on and turns off system within different times. Analysis and stability analysis of the composite load modeling were examined. This simulation study was carried out in MATLAB / SIMULINK environment. 34.5 kV bus voltage, DFIG terminal voltage, DFIG electrical torque, DFIG d-q axis stator current variations and DFIG d-q axis rotor current variations in composite load model analysis are examined. As a result of, it has been seen that composite load modeling which is activated as short time is effective on the power system. [ABSTRACT FROM AUTHOR]

Copyright of SDU Journal of Engineering Sciences & Design / Mühendislik Bilimleri ve Tasarım Dergisi is the property of Journal of Engineering Sciences & Design and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Induction motors, due to the extensive use in industrial applications, are dominant factor in terms of energy consumption in many countries. Especially in recent years, many studies have been realized to achieve higher energy savings in induction motors. Thus, even if a small percentage increases in efficiency would result in a huge amount of energy savings in a global scale. In this work, a new design for the core is proposed to increase the induction motor performance. In the proposed design, slits are inserted between the stator and the rotor teeth. In the slitted models proposed, the slit depth and width are optimized using Finite Element Method in F.E.M.M. (Finite Element Method Magnetics) software. Saturation points, variation of flux leakage and zigzag flux obtained from both proposed and original motor are given in comparison. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the Institute of Science & Technology of Dumlupinar University / Dumlupinar Üniversitesi Fen Bilimleri Enstitüsü Dergisi is the property of Dumlupinar University, Institute of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Asynchronous motors are the machines which are preferred mostly when the electrical energy is converted to the mechanical energy. Efficiency during the energy conversions is of the uttermost importance for preferences. In addition, the motors are expected to be cheaper and give long life service under working conditions. Some of the factors affecting the conditions are the stator windings. Stator windings of the motors, while differs from the point of laboring, they are important parts effecting their performances. In this study, a 36 slots, 4 poles, 1.1 kW 90 S-4 type asynchronous motor with single and double layer windings are tested and the types of the windings on the performance of the motor are examined by comparing the results obtained. The motors are fed by 380 V, 50 Hz grid supply. [ABSTRACT FROM AUTHOR]

In this study a projectile monitoring and control system for multistage induction coil gun has been designed, and relevant prototype is produced. Synchronization between the projectile coil and stator coil becomes more important, especially, as the number of stages increases. Both the absence of a mechanical or electrical contact between the coils and presence of only magnetic coupling between the projectile and stator coils also render solving the problem of synchronization between these two coils difficult. A new microcontroller monitoring and control system is proposed to minimize timing error for multistage coil guns up to 6000m/s. The control system produced and the related software prepared have been elaborated within the context of this study. [ABSTRACT FROM AUTHOR]