Model Of Induction Motor Research Articles

Model of Dynamic Modes of an Asynchronous Drive Taking into Account Motor Steel Saturation and Variables of Power Source

A model of squirrel cage induction motor has been developed and implemented in the MATLAB/Simulink software. The proposed model takes into account saturation of magnetic core at high currents in windings of electric motor, as well as current displacement in rotor conductors and internal resistance of power source. The model structure allows to simulate steel saturation according to dependences of physical machine. An equation with coefficients obtained by approximation of experimental data has been proposed for simulation of mutual inductance between stator and rotor as a function of mutual induction flux linkage. The model has been verified in the MATLAB/Simulink environment and on a laboratory test rig by experimental validation of predicted data. The developed model can be used for investigation into dynamic modes of an asynchronous motor. Various drive starting modes have been simulated; in addition, together with electric and mechanic variables, the model determines energy performances. The model has been applied in practice to detect the possibility of using starting currents and voltages of a motor for experimental determination of power source variables.

Stator Fault Detection on DTC-Driven IM via Magnetic Signatures Aided by 2-D FEA Co-Simulation

This paper investigates the online fault detection (FD) of the inter-turn short-circuit (ITSC) fault in direct torque control (DTC)-driven induction motors (IMs). We conducted the investigations of harmonic, inter-harmonic, and sub-harmonic contents for FD purposes. The harmonics in the flux leakage spectrum appear as a result of diverse causes including stator fault, DTC reaction to the fault, switching activities, and core saturation effect. Physics-based co-simulation was held through the coupling between a finite-element model (FEM) of the faulty IM and the circuit simulation of DTC. Its advantages are: 1) the IM harmonic contents including stator slots, rotor slots, saturation, switching activity, and fault are simulated and 2) dangerous experimentations of a faulty IM can be avoided. Therefore, we can safely study all the characteristics on a faulty IM. We exploited FEM for the verification of the experimental harmonic signatures of the scattered magnetic field. We verified the online FD technique based on the radiated magnetic field’s spectrum through the co-simulation and experimental results. This indicated that the method is able to correctly detect the ITSC faults with 1% severity factor.

A Decoupling Estimation Scheme for Rotor Resistance and Mutual Inductance in Indirect Vector Controlled Induction Motor Drives

Coupling between the two parameter estimation loops, for rotor resistance and mutual inductance of an induction motor (IM), is presented and the resulting negative effects are discussed in this paper. To solve this problem, an online estimation scheme, estimating these two parameters in a decoupled way, is proposed for indirect vector controlled IM drives. The estimation scheme is implemented with a model reference adaptive system for the rotor flux. The reference model is taken by two sliding mode observers (SMOs) operating in series, i.e., a high-order terminal SMO, observing the defined back-electromotive force (EMF), and a first-order SMO, observing the rotor flux itself with the obtained back-EMF as its reference. Meanwhile, the current model of IM depending on both of these two parameters is chosen as the adaptive model. The error signal, driving each of the adaptive mechanisms, originates from the errors in magnitude and phase of the fluxes obtained in above two ways. The coupling between these two estimation loops are compensated by designing the weighting factors assigned to these two errors properly. Thus, the proposed scheme is decoupling, resulting in a significantly improved dynamic performance of the estimation. With the estimated parameter values, the slip speed can be calculated correctly and the field orientation can be achieved. Moreover, the torque tracking accuracy can be guaranteed. All of the analysis and design are validated through numerical simulations and laboratory experiments.

RTC (reaction torque compensated) induction motor and its open-loop control

Rapid change of the rotating speed of an induction motor causes large reaction torque or excessive vibration of the system base. This paper proposes a passive reaction torque compensated (RTC) induction motor considering the dynamic characteristic of open-loop speed control with a variable frequency drive. RTC mechanism converts the reaction torque into the dissipative inertial energy of the rotary stator and the potential energy of the torsion spring torque so that a part of the reaction torque or the spring torque is transmitted to the system base. First, dynamic equation and simulation model for the RTC induction motor are introduced and verified with experiments. The acceleration response of an induction motor with variable speed drive is approximated as first-order ordinary differential equation. Then, the RTC mechanism such as spring and additional inertia are designed considering derived acceleration response or torque profile. Then, an experimental set-up and its control system for the RTC induction motor are built. Finally, effectiveness of the RTC induction motor is verified comparing open-loop speed control of both RTC and conventional induction motor.

Dynamic controller design for an IVCIM

A dynamic output feedback (DOF) controller design is proposed for an indirect vector-controlled induction motor (IVCIM). The proposed controller is an alternative to the conventional proportional integral (PI) one and can be used for improving the dynamic performance of the IVCIM system. A sequential design method is used in which, first, the inner-loop controllers are designed. Then, the designed inner-loop controller is employed to design the outer speed-loop controller. The procedure incorporates the iron loss dynamics of the induction motor model to fetch the benefit of better performance than conventional controller designs neglecting the same. The DOF controller is designed in an H ∞ control framework by solving the iterative linear matrix inequality that makes stator currents and speed response to be robust against load disturbances and parameter variations. A first-order dynamic controller is tested to highlight its superiority over the PI controller. Comparison between the proposed dynamic and conventional PI controller is shown through several experimental results. It depicts enhanced performance by the proposed controller and suitability to industrial use.

Sensorless field oriented control for five-phase induction motors with third harmonic injection and fault insensitive feature

The paper presents a solution for sensorless field oriented control (FOC) system for five-phase induction motors with improved rotor flux pattern. In order to obtain the advantages of a third harmonic injection with a quasi-trapezoidal flux shape, two vector models, α1–β1 and α3–β3, were transformed into d1– q1, d3– q3 rotating frames, which correlate to the 1st and 3rd harmonic plane respectively. A linearization approach of the dual machine model in d – q coordinate frames is proposed by introducing a new additional variable “x” which is proportional to the electromagnetic torque. By applying the static feedback control law, a dual mathematical model of the five-phase induction motor was linearized to synthesize a control system in which the electromagnetic torque and the rotor flux can be independently controlled. The results shows the air gap flux shape in steady as well transient states under various load conditions. Moreover, the implemented control structure acquires fault tolerant properties and leads to possible emergency running with limited operation capabilities. The fault-tolerant capability of the analyzed machine was guaranteed by a special implemented control system with a dedicated speed observer, which is insensitive to open-phase fault situation. The experimental tests have been performed with single and double-open stator phase fault. A torque measurement was implemented to present the mechanical characteristics under healthy and faulty conditions of the drive system.

Substantiation of the parameters of short-circuited rings for integrated design of an asynchronous motor using quasi-three-dimensional field analysis and modeling

Purpose. To justify and apply an improved mathematical model of induction motors for solving problems of increasing their energy efficiency as part of electromechanical systems. To investigate the effect of increasing the cross-sectional area of the short-circuited rotor rings on the efficiency in the operating mode of the electromechanical system of the engine-mechanism, the multiplicity of starting current and torque. Methodology. The use of a refined mathematical model of the engine when integrating it into a simulation model of an electromechanical system that takes into account the nonlinear dependencies of the parameters of the equivalent circuit calculated from the results of a quasi-three-dimensional field analysis. Results. Originality. With reduced requirements for starting torque, it is reasonable to use an improved mathematical model of the engine when determining the parameters of the rings of a short-circuited rotor. Practical value. The effect of increasing the cross-sectional area of the short-circuited rotor rings on the engine operating and starting characteristics is investigated. The approximation dependences of the electromagnetic parameters as a function of the magnitude of the design parameters are substantiated.

MODERNIZATION OF LUENBERGER OBSERVER FOR CONTROL SYSTEM OF HERMETIC COMPRESSOR ELECTRIC DRIVE

Context. The analysis of existing systems of sensorless control of hermetic compressor electric drives is carried out. The main requirements for control systems of automated electric drives of small refrigerating units’ hermetic compressors are determined. The topology of the adaptive Luenberger observer, which allows real-time estimation of the current value of the rotational speed and load torque on the shaft of the hermetic compressor electric motor, is proposed. Objective. The object of the study is the coordinates observer as a part of control system of the hermetic compressor electric drive. The purpose of the work is to develop a mathematical model of the coordinates observer as a part of control system of the hermetic compressor electric drive. Method. Based on the linearized model of a three-phase induction motor, the Luenberger observer is synthesized by the modal method with the distribution of the roots of the characteristic polynomial according to the standard linear Bessel form. Results. The characteristic polynomial of the observer is obtained and the coefficients of the Luenberger matrix and the mean geometric root of the characteristic polynomial are calculated. To ensure the necessary accuracy the structure of the observer on the basis of the complete mathematical model of a three-phase induction motor executed in the fixed coordinate system is proposed. In the Matlab/Simulink simulation environment an imitation model of the Luenberger observer, which includes a complete mathematical model of the hermetic compressor electric motor in the fixed coordinate system, is constructed. By means of simulation modeling the work of the projected Luenberger observer is studied using the example of the modernized three-phase induction motor of the domestic refrigerator’s hermetic compressor. Conclusions. The efficiency of the proposed method for identifying the rotational speed and the load torque of the compressor motor by the adaptive observer based on the calculation of the motor’s electromagnetic moment from the measured data of the phase voltage and current sensors is confirmed. The error of the researching observer does not exceed 0.5% at the rotation speed and 10% at the load torque. The obtained structure of the adaptive Luenberger observer makes it possible to build closed control systems for the electric drive of a small refrigerating unit’s hermetic compressor.

Design of Motor Controller New Energy Vehicle Based on DSP

For the AC Induction Motor (ACIM) has the characteristics of simple structure, high power factor and high overload rate, the drive controller of the new energy vehicle induction motor is researched and designed. According to the d-q axis coefficient model of induction motor, the controller model of induction motor based on vector control is constructed. The controller consists of Digital Signal Processor (DSP) TMS320F28035, power drive circuit, control circuit and current detection circuit. The digital signal processor (DSP) TMS320F28035 produced by TI is the core of the whole control system. With the help of more precise digital vector field oriented control (FOC) algorithm, DSP enhanced PWM (EPWM) module is used to generate high precision flexible space vector pulse width modulation (SVPWM) signal this allows the motor to maintain high efficiency over a wide range of speeds.

Resistances and Speed Estimation in Sensorless Induction Motor Drives Using a Model With Known Regressors

This paper addresses the problem of stator and rotor resistances identification in speed sensorless induction motor (IM) drives. The IM model that is transformable into the adaptive observer form is sought, for which the speed and rotor resistance adaptive observer can be established with rigorous stability arguments under the assumption of constant unknown parameters. However, further inclusion of stator resistance estimation leads to the overparameterization problem. As a result, the adaptive observer based on the first-order approximation of the error dynamics is proposed. This is feasible because the regressors of the adopted IM model consist of known signals only. An experiment is carried out to verify the effectiveness of a sensorless drive with the proposed adaptive observer. Compared with the existing methods, estimation of speed and resistances during a regeneration mode as well as successful slow-speed reversal operation is found possible in the experiments.

Influence of variable slip frequency control strategy on tractiv e performance

In order to improve the current situation of poor traction ability of medium-low speed maglev train, a variable slip frequency control (VSFC) strategy is proposed based on the constant slip frequency control (CSFC) of linear induction motor (LIM). The control frequency of the starting stage of the vehicle is selected low on the premise of no obvious influence on the levitation performance. After reaching the maximum power point, the traction of the motor is always the maximum that can be exerted under the corresponding speed. Firstly, the mathematical model of linear induction motor is established, and the analytical expressions of traction and normal force are listed; Then the influence of slip frequency on vehicle tractive performance is analyzed by traction calculation, the VSFC strategy is proposed and its advantages are analyzed. The results show that the VSFC strategy can fully suppress the influence of normal force on levitation stability at low speed, and can give full play to the tractive performance of the motor in the whole process.

The Sensorless Speed Controller of Induction Motor in DFOC Model Based on the Voltage and Current

This paper presents the Sensorless Speed control of the Induction Motor (IM) in Direct Field Oriented Control (DFOC) modeling based on the mathematical model of the voltage and current parameter. The first is DFOC controlled modeling of IM, the second presents sensorless speed controller base on RF-MRAS, the third describes the model of the sensorless speed controller based on measured values directly from the induction motor as the voltage and current. The last is simulation results in the Matlab-Simulink environment. These results indicate that this proposed method can determine accurately, very quickly the speed of the induction motor and can be applied in the practice with high reliability, and low cost.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

Modeling and Analytical Calculation of a Multiphase Induction Motor in the Phase Loss Asymmetrical Transient Process

The multiphase independent winding induction motor (MIWIM) has wide application in AC drive systems of high control redundancy necessary to ships and coal mines. An accurate analysis of its phase loss transient process is a prerequisite for the phase loss fault-tolerant control. When a phase loss occurs, the internal magnetic fields of the MIWIM are asymmetric. In this case, conventional coordinate transformation or resultant space vector cannot be used to reduce the mathematical model of the motor phase loss to a lower order. Using a five-phase induction motor as an object of study, this paper presents a full-order mathematical model suitable for the asymmetric state in the α–β–z1–z2–z3 coordinate system. The factor analysis of the frequency domain and no consideration of its small value make it possible to reduce the order of the analytical model. According to the constraint relationship between voltage and current, an analytical analysis is made of the motor dynamic characteristics after a phase loss. The results are in agreement with those of numerical simulation and experiment, which verify that the phase loss asymmetric transient model and analytic method of the MIWIM are feasible and effective.

Mathematical model of a two-machine induction motor with rotating inductor

Mathematical model of a two-machine induction motor with rotating inductor

Transient and steady‐state modelling of healthy and eccentric induction motors considering the main and third harmonic saturation factors

This paper deals with the modelling of magnetic saturation in induction motors (IMs) with particular focus on the equivalent or fictitious air-gap permeance technique. Besides, an improved version of this technique is provided so as to account for the transient starting process and the third harmonic saturation factor in addition to the fundamental one. This is for the symmetric case. Under air-gap eccentricities, extension of both saturation models is proposed using the varying saturation factor solution. The 2D-modified winding function approach (2D-MWFA) is the base of the inductance calculation and the state equations are derived from the well-known multiple coupled circuit model (MCCM). Thanks to such considerations, skew effect, rise of the magneto-motive force (MMF) across the slots, all winding harmonics, and many faulty states can be judiciously taken into account. In summary, five derived saturation models are discussed in favour of a good handling of the saturation phenomenon in cage IMs. The work is supported by extensive simulation and experimental results of eccentricity, broken rotor bar, and combined faults.

A STUDY OF MRAS BASED SPEED ESTIMATION OF SENSORLESS INDUCTION MOTOR USING MATLAB AND SIMULINK MODELLING

Model reference adaptive system(MRAS) based techniques are one of the best method to estimate the rotor speed due to its performance and straight forward stability approach.These techniques use two different models which have made the speed estimation a reliable scheme especially when the variations.The scheme use the stator equation and rotor equation as the reference model and the adjustable model respectively.The output error from both models is tuned using a PI controller yielding the estimated rotor speed.It presents the identification and parameter estimation of an induction motor model with parameters varying as functions of the operating conditions. A Sensorless torque control system for induction motors is developed. The system allows for fast and precise torque tracking over a wide range of speed.The induction motor is controlled through field orientation techniques that require knowledge of the rotor speed.Since speed sensors decrease the reliability of a drive system (and increase its price), a common trend in motor control is to use an observer to estimate speed.

A STUDY OF MRAS BASED SPEED ESTIMATION OF SENSORLESS INDUCTION MOTOR USING MATLAB AND SIMULINK MODELLING

Model reference adaptive system(MRAS) based techniques are one of the best method to estimate the rotor speed due to its performance and straight forward stability approach.These techniques use two different models which have made the speed estimation a reliable scheme especially when the variations.The scheme use the stator equation and rotor equation as the reference model and the adjustable model respectively.The output error from both models is tuned using a PI controller yielding the estimated rotor speed.It presents the identification and parameter estimation of an induction motor model with parameters varying as functions of the operating conditions. A Sensorless torque control system for induction motors is developed. The system allows for fast and precise torque tracking over a wide range of speed.The induction motor is controlled through field orientation techniques that require knowledge of the rotor speed.Since speed sensors decrease the reliability of a drive system (and increase its price), a common trend in motor control is to use an observer to estimate speed.

Discrete and Continuous Model of Three-Phase Linear Induction Motors “LIMs” Considering Attraction Force

A fifth-order dynamic continuous model of a linear induction motor (LIM), without considering “end effects” and considering attraction force, was developed. The attraction force is necessary in considering the dynamic analysis of the mechanically loaded linear induction motor. To obtain the circuit parameters of the LIM, a physical system was implemented in the laboratory with a Rapid Prototype System. The model was created by modifying the traditional three-phase model of a Y-connected rotary induction motor in a d–q stationary reference frame. The discrete-time LIM model was obtained through the continuous time model solution for its application in simulations or computational solutions in order to analyze nonlinear behaviors and for use in discrete time control systems. To obtain the solution, the continuous time model was divided into a current-fed linear induction motor third-order model, where the current inputs were considered as pseudo-inputs, and a second-order subsystem that only models the currents of the primary with voltages as inputs. For the discrete time model, the current-fed model is discretized by solving a set of differential equations, and the subsystem is discretized by a first-order Taylor series. Finally, a comparison of the continuous and discrete time model behaviors was shown graphically in order to validate the discrete time model.

Bayesian Estimation on Load Model Coefficients of ZIP and Induction Motor Model

Parameter identification in load models is a critical factor for power system computation, simulation, and prediction, as well as stability and reliability analysis. Conventional point estimation based composite load modeling approaches suffer from disturbances and noises, and provide limited information of the system dynamics. In this work, a statistics (Bayesian Estimation) based distribution estimation approach is proposed for both static and dynamic load models. When dealing with multiple parameters, Gibbs sampling method is employed. The proposed method samples all parameters in each iteration and updates one parameter while others remain fixed. The proposed method provides a distribution estimation for load model coefficients and is robust for measuring errors. The proposed parameter identification approach is generic and can be applied to both transmission and distribution networks. Simulations using a 33-feeder system illustrated the efficiency and robustness of the proposal.

Comparison Study of Induction Motor Models Considering Iron Loss for Electric Drives

In a variety of motor models, the effects of iron-loss (ILS) on motor control accuracy and efficiency are generally ignored. This makes it difficult for the motor control system to obtain accurate control parameters (especially on high speed and low load conditions), and limits the improvement of motor control accuracy. This paper aims to clarify the influence of different ILS modeling and observation methods on motor control performance. Three equivalent models of motors with iron losses are compared. These models are: A parallel model, a series model and the simplified traditional model. Three tests are conducted to obtain the effect of ILS perturbation on ILS estimation results, and then to derive the sensitivity of the motor state and torque to the perturbation. These test conditions include: Ideal no-load, heavy-load, locked-rotor, and ILS perturbations during speed regulation. Simulation results show that the impedance and excitation characteristics of the series model and the parallel model are similar, and the traditional model has the best speed regulation smoothness. The ILS estimation errors of the series model is nearly constant and easy to compensate. For accurate ILS observation results, the series model can achieve better control accuracy.