Behavior Of Induction Motor Research Articles

Modeling and Control of Low Switching Frequency High-Performance Induction Motor Drives

Complex state variables are used to study the dynamic behavior of induction motors considering the propagation in space of the distributed magnetic field inside the machine. The objective of this paper is to improve the dynamics of pulsewidth modulation inverters in medium-voltage drive systems. To keep the dynamic losses of the power devices at a tolerable level, the switching frequency must be below 1 kHz. The sampling rate of the digital signal processing system is then low which introduces considerable signal delay. The delay has an adverse influence on the dynamic behavior of the current control system. It introduces undesired cross coupling between the current components $i_{d}$ and $i_{q}$ . The degree of cross coupling is described by a cross-frequency transfer function. It is shown that the mechanism of cross coupling is different and more adverse than the conventional theory discloses. A current controller structure having poles and zeroes of the single-complex type is synthesized. Cross coupling is completely eliminated at any low switching frequency. Experimental results demonstrate that high dynamic performance and zero cross coupling is achieved even at very low switching frequency.

Design and Implementation of an Automatic Electrical Motor Protection

The purpose of this paper was to design and implement an automatic motor protection system prototype. The system designed made use of sensors to measure and provide protection to the motors against temperature, overcurrent, overvoltage and under voltage using an arduino as the controller. Units to monitor temperature, overcurrent, overvoltage and under-voltages were designed and integrated. The temperature and current tolerance of the motor were set at 50ºC and 0.26A respectively. The system could respond accordingly to temperature and current changes by way of stopping the motor when set conditions were exceeded. The data measured was stored on a memory card and could be retrieved at any time to analyse the induction motor behaviour. The system if incorporated on motors, could minimize potential damages to electric motors’ windings, hence reducing electric motor maintenance costs for companies.

The impact of the rotor slit number on the behavior of high-speed induction motor

The impact of the rotor slit number on the behavior of high-speed induction motor

Simulation of Start-Up Behaviour of Induction Motor with Direct Online Connection

In this paper, a simulation of dynamical start-up behaviour of induction motor with direct online connection to the network has been carried out using COMSOL Multiphysics software. The simulated model of the motor mainly consists of a basic FEM model, an electrical model with stator and rotor circuits and a~mechanical model. The chosen motor parameters both electrical and mechanical have been studied and their results presented in this paper. An experimental measurement of the start-up transient of the no-loaded motor was carried out and some its results have been compared to the results from the simulated motor model and analysed.

A simplified equivalent thermal circuit for the substitution of a stator in an induction motor

Based on a review of investigations of the thermal behavior of induction motors, it has been established that the stator winding of an induction motor is subject to very high values of temperature in most applications and work regimes. The analysis of techniques to determine the temperatures of different units of an induction motor helped us to propose the use of equivalent thermal circuits, in particular, a simplified substitution circuit for the determination of winding and a magnetic conductor of a stator. The thermal equilibrium equations were found. A technique to calculate the thermal resistances of a stator by means of a laboratory setup was developed. The setup considers the features of cooling specific types of motors; thus, it is unnecessary to observe an induction motor as an aerodynamic system. The technique was tested using a setup containing a 14-kW short-circuited induction motor. The temperatures in different units of a motor were measured using chromel–copel thermocouples, and its load simulated the load of a traction electric drive of transport vehicles. The results of the experimental investigation are presented to show the influence of the rotor speed and the cooling air flow on the thermal resistances.

Finite Element Analysis in the Estimation of Air-Gap Torque and Surface Temperature of Induction Machine

This paper presents electromagnetic and thermal behavior of Induction Motor (IM) through the modeling and analysis by applying multiphysics coupled Finite Element Analysis (FEA). Therefore prediction of the magnetic flux, electromagnetic torque, stator and rotor losses and temperature distribution inside an operating electric motor are the most important issues during its design. Prediction and estimation of these parameters allows design engineers to decide capability of the machine for the proposed load, temperature rating and its application for which it is being designed ensuring normal motor operation at rated conditions. In this work, multiphysics coupled electromagnetic – thermal modeling and analysis of induction motor at rated and high frequency has carried out applying Arkkio’s torque method. COMSOL Multiphysics software is used for modeling and finite element analysis of IM. Transient electromagnetic torque, magnetic field distribution, speed-torque characteristics of IM were plotted and studied at different frequencies. This proposed work helps in the design and prediction of accurate performance of induction motor specific to various industrial drive applications. Results obtained are also validated with experimental analysis. The main purpose of this model is to use it as an integral part of the design aiming to system optimization of Variable Speed Drive (VSD) and its components using coupled simulations.

Approach to measure the degree of the unbalanced power in induction motor for energy‐efficient use

This study utilises the power unbalance factors (PUFs) to determine the output precisely of the induction motor (IM) subjected to unbalanced supply voltage, and use them to analyse motor performance [i.e. copper losses, motor efficiency, power factor, input active and reactive powers, electromagnetic torque and derating factor (DF)]. The analysis of IM is applied using the approach of symmetrical component. Furthermore, MATLAB/Simulink is used to examine the behaviour of IM during balanced and unbalanced operations. Results illustrate that the reactive PUF ( K Q ) provides accurate assessment for the machine performance. Three cases of the unbalanced condition were selected to provide various scenarios, which may IM subjected to them. The influence of cases on electromagnetic torque, rotor speed, stator and rotor current, active and reactive input powers has been investigated. DF is investigated and tuned to improve energy efficiency during unbalanced operations.

An Investigation of Induction Motor Saturation under Voltage Fluctuation Conditions

Nowadays power quality effects on induction motors have gained significant attention due to wide application of these motors in industry. The impact of grid voltage fluctuations on the induction motor behavior is one of the important issues to be studied by power engineers. The degree of iron saturation is a paramount factor affecting induction motors performance. This paper investigates the effects of voltage fluctuations on motor magnetic saturation based on the harmonic content of airgap flux density by finite element method (FEM). It is clarified that the saturation harmonics under normal range of voltage fluctuations have not changed significantly with respect to pure sinusoidal conditions. Experimental results on a 1.1 ㎾, 380 V, 50 ㎐, 2 pole induction motor are employed to validate the accuracy of the simulation results.

Angular-based modeling of induction motors for monitoring

Understanding the occurrence of bearing defects in electrical current signals using Motor Current Signal Analysis (MCSA) requires the implementation of numerical models. In this paper, an electro-magnetic-mechanical model is proposed to describe the dynamic behavior of a squirrel cage induction motor coupled to a rotating shaft supported by elastic foundations. The aim of this research work is to gain understanding of the interaction between multiphysics subsystems, mainly in faulty cases, to decipher the transfer path from the defect to its manifestation in stator currents. A new method of writing dynamic equations for simplified simulations of an induction motor is developed using an angular approach. In addition to its capacity to extend the modeling to non-stationary operating conditions, the model proposed highlights the angular periodicity of the rotating motor’s geometry. The electromagnetic field of the motor is redistributed periodically when a geometric defect occurs on a rotating part of the global system. In this case, the electromagnetic torque of the induction motor may present angularly-periodic variations. After having presented the electromagnetic-mechanical coupling methodology, the influence of torque variations is investigated and the importance of the angle-time function is highlighted.

Analysis of voltage fluctuation impact on induction motors by an innovative equivalent circuit considering the speed changes

The most commonly used motor in industries is induction motor. This motor is exposed to various power quality disturbances. A frequent power quality disturbance which has an adverse effect on induction motor is voltage fluctuations. In this study, the behaviour of three-phase induction motors under voltage fluctuation conditions is studied. By using the theory of dynamic phasor, an innovative equivalent circuit in which the speed fluctuations are taken into account is presented. The currents, efficiency and power factor under voltage fluctuation conditions are evaluated by the proposed equivalent circuit. The variations of these quantities due to different voltage fluctuation characteristics are also investigated. The simulation results are validated by measurements on the laboratory test setup which comprises a 1.1 kW induction motor excited by a programmable power supply unit.

Modeling and Simulation of Induction Motor based on Finite Element Analysis

<p>This paper presents the development of a co-simulation platform of induction motor (IM). For the simulation, a coupled model is introduced which contains the control, the power electronics and also the induction machine. Each of these components is simulated in different software environments. So, this study provides an advanced modeling and simulation tools for IM which integrate all the components into one common simulation platform environment. In this work, the IM is created using Ansys-Maxwell based on Finite Element Analysis (FEA), whereas the power electronic converter is developed in Ansys-Simplorer and the control scheme is build in MATLAB-Simulink environment. Such structure can be useful for accurate design and allows coupling analysis for more realistic simulation. This platform is exploited to analyze the system models with faults caused by failures of different drive’s components. Here, two studies cases are presented: the first is the effects of a faulty device of the PWM inverter, and the second case is the influence of the short circuit of two stator phases. In order to study the performance of the control drive of the IM under fault conditions, a co-simulation of the global dynamic model has been proposed to analyze the IM behavior and control drives. In this work, the co-simulation has been performed; furthermore the simulation results of scalar control allowed verifying the precision of the proposed FEM platform.</p>

Voltage support in industrial distribution systems in presence of induction generator-based wind turbines and large motors

Industrial loads are usually composed of large induction motors (IM). These motors present a critical behavior under some circumstances, e.g. during starting and faults in the system. Currently, induction generator-based wind turbines are also connected to distribution systems. Essentially, these generators present the same behavior of large IM and, when directly connected to the system, their interaction can increase voltage sag levels or even lead the system to a voltage collapse. These generators, however, are usually provided with specific controls or power electronic-based equipment to comply with the voltage ride-through capability required by the grid codes. These resources, however, can be used to minimize the impact of large motors in the grid or even minimize their impact on voltage sags caused by faults in the system. In this context, this paper has the objective of analyzing the impact of different technologies used in induction generator-based wind turbines during disturbances in distribution systems in the presence of large IM. The analysis aims to clarify the potential benefit of wind turbine allocation at the demand side of an industrial power distribution system. Based on the results, an adapted control scheme, considering the control strategies currently available, is proposed for the grid side converter of the doubly fed induction generators to improve power quality.

Impact of Number of Poles on the Steady-State Performance of Induction Motors

A simplified analysis of influence of pole pairs on the steady-state behavior of induction motors is presented. The analysis makes simplifying assumptions to express relationship between key steady-state performance parameters of 2-pole reference motor compared to its multiple pole counterparts. The analysis is performed using considerations of fixed geometrical dimensions on one hand and fixed output power on the other hand. Available manufacturer catalog data of medium voltage (MV) induction machines from one manufacturer are used to evaluate the soundness of the analysis. Also test and catalog data analyses of commercially manufactured low-voltage (LV) machines from different manufacturers are evaluated to determine extent to which they conform to the theoretical considerations of the analyses. The preliminary findings indicate more agreement with the MV motors than the LV motors.

Modeling Induction Motor for Prediction of High frequency problems

In this paper a novel high-frequency model of Induction motor is presented for investigating induction motor behavior in a wide electromagnetic interference (EMI)-frequency range from 100 Hz to 30 MHz. This model is suitable for prediction of common mode current, EMI problems and terminal over-voltage analysis. The model parameters are estimated by asymptotical method using novel differential and common-mode impedance measurements. The values of parameters are limited in a specified range and then optimized using genetic algorithm (GA). A least mean square method is used with GA optimization to solve the identification problem. The proposed model can also be used to predict the high-frequency problems and design EMI filters to improve electromagnetic compatibility limitation in cable fed motor-drive system. In order to validate the proposed high-frequency motor model, novel common-mode and differential-mode measuring tests have been carried out on the 9.3 kW industrial induction motor using a network analyzer in a wide frequency range as described. Very good agreement was seen between the experimental and simulation results of the proposed model in both magnitude and phase.

Broken bar and end-ring faults: analysis of their effects on the rotor cage currents

Purpose – The purpose of this paper is to investigate the effects of different faulty scenarios on the induction motor (IM) operation with emphasis on the currents in the rotor bar and end rings. Design/methodology/approach – The modeling of the IM followed by a graphical representation-based analysis of the rotor steady-state currents under healthy operation is treated. Then, a case study is considered in order to investigate different faulty scenarios with a focus on the rotor cage currents. Findings – It has been found that the rotor faults greatly affect the currents in the bars and in the end rings both in amplitude and in harmonic content. These vary according to the relative positions with respect to the fault such that: the currents in the bars adjacent to the faulty one(s) have the highest amplitudes with the lowest harmonic content; and the ones in the ring portions adjacent to the faulty one have the lowest amplitudes with the highest harmonic content. Research limitations/implications – Although the simulated model has confirmed the well known IM behavior under healthy operation, it would be appreciated if the obtained results under faulty operation would be validated by finite element analysis. Practical implications – It is of great interest to investigate the effects of faulty scenarios on the rotor cage currents, in order to take appropriate actions starting from the design of the IM. Originality/value – A deep investigation (including the waveforms, the phasor diagrams and the harmonic content) of the effects of different faulty scenarios on the IM rotor cage currents represents the major contribution of this work.

Behavior of Induction Motor at Voltage Unbalanced

Behavior of Induction Motor at Voltage Unbalanced

Classification of voltage sags according to the severity of the effects on the induction motor

In this paper, symmetrical and unsymmetrical voltage sags are classified according to the severity of the effects produced on the behavior of induction motors, using the double-cage rotor model. The analyzed variables are: current and torque peaks, and speed loss in transient and steady states. The severity of these effects is analyzed with 14640 voltage sags, both at the beginning of the voltage sag and when the voltage is recovered, by changing the type, magnitude, duration, and initial-point-of-wave. Four mechanical torque loads were used for the analysis, three with constant behavior and one with quadratic behavior. The results show the durations and initial-point-of-wave with more severe effects for each type of voltage sag. Finally, a classification that depends on the type of voltage sag and the variable of interest is obtained.

Direct torque controlled space vector modulated method for line start permanent magnet synchronous and induction motors

This paper presents a thorough comparison of Direct Torque Controlled Space Vector Modulated (DTC-SVM) method for a three-phase four-pole Induction Motor and its equal Line-Start Permanent Magnet Synchronous Motor (LSPMSM), which is amended from an actual induction motor. For this reason, both nominal voltage and voltage sag conditions are tested for line-fed and voltage source inverter-fed of both motors, and a comparison between induction motor and LSPMSM behavior shows that synchronization problems of LSPMSM during line-fed conditions are obviated by DTC-SVM method. In addition, a superior transient and steady-state performance of the LSPMSM drive is observed rather than an induction motor, especially for voltage sag conditions.

Variational Iteration Method for the Solution of Seventh Order Boundary Value Problems using He’s Polynomials

The induction motor behaviour is represented by a fifth order differential equation model. Addition of a torque correction factor to the model accurately reproduces the transient torques and instantaneous real and reactive power flows of the full seventh order differential equation model. The variational iteration method using He’s polynomials is employed to solve the seventh order boundary value problems. The approximate solutions to the problems are obtained in terms of a rapidly convergent series. Several numerical examples are given to illustrate the implementation and the efficiency of the method.

A New Hybrid "Park's Vector - Time Synchronous Averaging" Approach to the Induction Motor-fault Monitoring and Diagnosis

Induction motors are critical components in industrial processes since their failure usually lead to an unexpected interruption at the industrial plant. The studies of induction motor behavior during abnormal conditions and the possibility to diagnose different types of faults have been a challenging topic for many electrical machine researchers. In this regard, an efficient and new method to detect the induction motor-fault may be the application of the Time Synchronous Averaging (TSA) to the stator current Park’s Vector. The aim of this paper is to present a methodology by which defects in a three-phase wound rotor induction motor can be diagnosed. By exploiting the cyclostationarity characteristics of electrical signals, the TSA method is applied to the stator current Park’s Vector, allowing the monitoring of the induction motor operation. Simulation and experimental results are presented in order to show the effectiveness of the proposed method. The obtained results are largely satisfactory, indicating a promising industrial application of the hybrid Park’s Vector-TSA approach.