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Showing 7 results for Induction Motor

A. Ebadi, M. Mirzaie, S. A. Gholamian,
Volume 8, Issue 2 (6-2012)

Induction motor is the most popular load in the industry, it is very important to study about the effects of voltage quality on induction motor performance. One of the most important voltage quality problems in power system is voltage unbalance. This paper evaluates and compares two methods including finite element method (FEM) and equivalent electrical circuit simulation for investigation of the effects of voltage unbalance conditions on the performance of a three- phase induction motor. For this purpose, a threephase squirrel cage induction motor is simulated using Finite Element Method and equivalent electrical circuit parameters of the FEM model is estimated by genetic algorithm. Then, some unbalanced voltages are applied on the FEM model of the Motor and the resulted power and losses are compared with calculated values using equivalent electrical circuit simulation in same voltage conditions.
S. M. Mousavi Gazafroodi, A. Dashti,
Volume 10, Issue 4 (12-2014)

In this paper, a novel stator current based Model Reference Adaptive System (MRAS) estimator for speed estimation in the speed-sensorless vector controlled induction motor drives is presented. In the proposed MRAS estimator, measured stator current of the induction motor is considered as a reference model. The estimated stator current is produced in an adjustable model to compare with the measured stator current, where rotor flux identification is needed for stator current estimation. In the available stator current based MRAS estimator, rotor flux is estimated by the use of measured stator current, where the adjustable model and reference model depend on each other since measured stator current is employed in both of them. To improve the performance of the MRAS speed estimator, both the stator current and rotor flux are estimated in the adjustable model by using the state space equations of the induction motor, adjusted with the rotor speed calculated by an adaptation mechanism. The stability of the proposed MRAS estimator is studied through a small signal analysis. Senorless induction motor drive along with the proposed MRAS speed estimator is verified through computer simulations. In addition, performance of the proposed MRAS is compared with the available stator current based MRAS speed estimator
B. Yassine, Z. Fatiha, L. Chrifi-Alaoui,
Volume 16, Issue 1 (3-2020)

This paper suggests novel sensorless speed estimation for an induction motor (IM) based on a stator current model reference adaptive system (IS-MRAS) scheme. The IS-MRAS scheme uses the error between the reference and estimated stator current vectors and the rotor speed. Observing rotor flux and the speed estimating using the conventional MRAS technique is confronted with certain problems related to the presence of the pure integrator and the rotor resistance causing offsets at low speeds, as proved by the most recent publications. These offsets are disastrous in sensorless control since these signals are no longer suitable to calculate of park angle (θs). This paper discusses the new MRAS approach (IS-MRAS) for on-line identification of the rotor resistance suitable for compensating offsets and solving problems of ordinary MRAS at low speed. This new MRAS approach used to estimate the components of the rotor flux and rotor speed without using the voltage model with on-line Setting parameters (Kp, K1) based on Type-2 fuzzy Logic. The results of the simulation and the experimental results are presented and show the effectiveness of the proposed technique.

H. Shadfar, H. R. Izadfar,
Volume 16, Issue 1 (3-2020)

Single-phase induction motors have a wide range of domestic and industrial applications. These motors have a squirrel cage rotor and their stator usually has two windings: main and auxiliary. The use of auxiliary winding in the structure of single-phase induction motors creates two unbalance and asymmetric phases. This causes to increase the spatial harmonics of the field in the air gap, and also useless electromagnetic forces. The purpose of this paper is the reduction of the electromagnetic forces in single-phase induction motors, focusing on the effect of the stator winding distribution. For this purpose, two new and different winding distributions for the motors used in the water coolers will be provided. The produced electromagnetic forces in several conventional single-phase induction motors will be compared with new and conventional windings by means of numerical methods. Numerical analysis is performed by Maxwell software. The results of this analysis indicate improvements in the quality of the performance of these motors in the presence of the provided windings.

M. Ghaseminezhad, A. Doroudi, S. H. Hosseinian, A. Jalilian,
Volume 17, Issue 1 (3-2021)

Nowadays study of input voltage quality on induction motors behavior has become a controversial subject due to the wide application of these motors in the industry. The impact of grid voltage fluctuations on the performance of induction motors can be included in this area. The majority of papers devoted to the influence of voltage fluctuations on the induction motors are focusing only on the solving of d-q state equations or steady-state equivalent circuit analysis. In this paper, a new approach to this issue is investigated by field analysis which studies the effects of voltage fluctuations on the magnetic fluxes of induction motors. New analytical expressions to approximate the airgap flux density and the torque under-voltage fluctuation conditions are presented. These characteristics are also calculated directly by the finite-element method considering the magnetic saturation and the harmonic fields. Finally, experimental results on a typical induction motor are employed to validate the accuracy of analytical and simulation results.

A. Ghayebloo, S. Shiri,
Volume 17, Issue 4 (12-2021)

In this paper, a conceptual study on switching intervals in the classic direct torque control (DTC) method and a novel modified method have been proposed. In the switching table of classic DTC, the switching vectors have been changed in sectors with 60 degrees intervals and their boundaries are fixed. In this study, these fixed boundaries and length of switching intervals have been challenged and proved that the performance of the classic DTC can be improved with modified intervals with different lengths and boundaries. The final proposed switching table not also benefits simplicity of implementation as classic DTC switching table, but also it offers better performance especially in the aspect of low torque ripples. The proposed final switching table has been derived by a two-stage optimization process and the results have been proved by simulation results.

S. M. Ahmed, K. S. Ahmed, Y. M. Shuaib,
Volume 19, Issue 1 (3-2023)

This article discusses the operating principle and simulation of closed loop control of a three phase induction motor (IM) powered by five level diode clamped multilevel inverter (DCMLI) using direct torque control (DTC) technique. The main purpose of this article is to regulate the torque and speed of an IM and to decrease total harmonic distortion (THD). In this article, a five-level inverter's direct modulation approach with the dc link voltage self-balancing is presented. To reduce capacitor voltage variation, the redundancies of various switch topologies for the creation of intermediate voltages are also used. The use of LC filter results in lower output voltage and current distortion. A multicarrier PWM control technique is used for DCMLI to provide high quality sinusoidal output voltage with decreased harmonics. This can be obtained by employing Sinusoidal Pulse Width Modulation (SPWM) method for speed and torque control. This demonstrates that the recommended method of controlling the motor's speed and torque is effective. The simulation result reveals that DTC for the five-level inverter fed IM drive gives a rapid dynamic response, lower voltage and current THDs, and much less flux and torque distortion. The simulation is carried out in MATLAB Simulink (R2014).

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