Tubular Linear Induction Motor Research Articles

Analysis of electromagnetic vibration of submerged tubular linear motors based on wave propagation approach

This paper presents the properties of electromagnetic vibration in a submerged tubular linear induction motor through an analytical model. Firstly, the spatial and temporal characteristics of electromagnetic force acting in the stator are analyzed. Subsequently, based on the wave propagation approach, an analytical model is established to calculate the vibration response of the stator, which is simplified as a finite-length cylindrical shell. The accuracy of the proposed model is verified by comparing natural frequencies of axial breathing modes and frequency response with the finite element method. Finally, the effects of the position of electromagnetic force, the spatial distribution of electromagnetic force, radial static pressure and structure parameters on vibration response are investigated and discussed. Some conclusions are outlined, which is of great importance to reduce electromagnetic vibrations by optimizing the structure design of the motor.

An alternative approach for the determination of electromechanical parameters of a tubular linear induction motor and its experimental validation

An alternative approach for the determination of electromechanical parameters of a tubular linear induction motor and its experimental validation

Modelling and analysis of electromagnetic vibration in long sheet secondary tubular linear induction motors

AbstractThis paper aims to clarify the behaviour and mechanism of electromagnetic vibration in long sheet secondary tubular linear induction motors (LSS‐TLIMs). Firstly, the spatial and temporal characteristics of electromagnetic force acting in the stator are analysed. Secondly, based on the wave propagation method, an analytical model is established to calculate the vibration response of the stator, which is simplified as a finite cylindrical shell. The accuracy of the proposed model, as well as the rationality of the simplification, are verified by 3D FEM simulation. It is indicated that the electromagnetic vibration response of LSS‐TLIMs mainly depends on the “axial breathing mode” (ABM) and corresponding “modal participation factor”. Moreover, the influences of the spatial distribution of electromagnetic force and the structural dimensions on the vibration are investigated. Finally, the “static vibration test” is performed to validate the above analysis. It is concluded that, compared with a rotary motor, the low‐frequency vibration of LSS‐TLIMs can be easily controlled since the natural frequency of ABMs tends to be much higher than that of the circumferential mode.

New 2-D Quasi-Analytical Computation of Eddy Currents in Axisymmetrical Problems: Application to Tubular Linear Induction Motor

In this article, an exact 2-D analytical magnetic field modeling in time harmonic mode of axisymetrical problems is proposed. It is applied for a tubular linear induction motor (TLIM) at locked rotor operation to calculate the magnetic field, eddy currents distributions, and thrust force. The proposed electromagnetic modeling combines the truncated region eigenfunction expansion method (TREEM) with the separation of variables technique to solve Maxwell’s equations in terms of the magnetic vector potential. The developed analytical model allows considering the finite length in the axial direction of both inductor and conductive parts of the investigated structure at the same time and also solves the nonlinear equation to compute the complex eigenvalues. The analytical results are in very good agreement with those obtained using a 2-D finite element method (FEM).

Prediction of Conductor Ratio for Tubular Linear Induction Motors using Finite Element Method and Response Surface Methodology

In many countries, the demand for motors has rapidly increased. For equipment automation and energy reduction, motors are efficient machines and play an important role in alleviating the current energy crisis. However, rotary machines have been studied instead of linear machines. Furthermore, tubular linear induction motors (TLIMs) have been developed for use in industry, but the characteristics of these machines have not been analyzed. In this study, using the finite element methodology (FEM), a TLIM was examined using the ratio of conductor thickness and back iron. The design of experiment (DOE) and response surface methodology were used to obtain this result. The TLIM is modeled to obtain thrust force in the steady state. Furthermore, conductor and back iron thickness are efficiently assigned using the DOE. The central composite design introduced in this study is used in various DOE methods. As a result, the conductor and back iron thickness ratio is obtained at an optimum value. This ratio can be used to design the TLIM for low voltages.

Optimised design, analysis, fabrication and experiments on a tubular linear induction motor prototype

Optimised design, analysis, fabrication and experiments on a tubular linear induction motor prototype

Mathematical Model of Tubular Linear Induction Motor

Problem of calculation of distribution of magnetic field induction in clearance of tubular linear induction motor (TLIM) is considered. Mathematical model is represented by Fredholm integral equations of second kind for complexes of electric field strength and density of coupled magnetization currents at interface of environments. Algorithm of calculation of distribution of magnetic field induction in TLIM clearance has been developed. Dependence of magnetic field induction in motor clearance on value of pole division is investigated. There is area of optimum pole pitch. Reliability of results of calculations on mathematical model is confirmed by their comparison with results obtained on physical model. Calculated dependence of induction on thickness of runner's iron circuit also has extreme character. Given model can be used at design stage of TLIM. Model allows calculating its optimal geometric dimensions based on criterion of maximum induction in motor clearance, taking into account physical properties of applied materials.

The development and testing of a linear induction motor being fed from the source with limited electric power

The report provides results of the research related to the tubular linear induction motors’ application. The motors’ design features, a calculation model, a description of test specimens for mining and electric power industry are introduced. The most attention is given to the single-phase motors for high voltage switches drives with the usage of inexpensive standard single-phase transformers for motors’ power supply. The method of the motor’s parameters determination, when the motor is being fed from the transformer, working in the overload mode, was described, and the results of it practical usage were good enough for the engineering practice.

Armature Structure Research of a Synchronous Induction Coil Launcher

Armature is very important for a synchronous induction coil launcher which can transform the electric energy to kinetic energy and push the load forward. The structure of the armature will influence the kinetic energy conversion efficiency directly. This paper analyzes the armature structure of a capacitor-driven synchronous induction coil launcher. Length and thickness of the armature are analyzed that how these parameters influence the maximum velocity and system efficiency of the launcher. Current filaments model is used to calculate the motion characteristics of a tubular linear induction motors, which is verified by an experiment and finite-element code. Genetic algorithm optimizer is used to calculate the best trigger times of the coils and the maximum velocity under the conditions of different length and thickness of the armature. It is shown that when the armature mass is fixed, length and thickness of the armature will greatly increase the velocity of the armature. The best length of the armature should be almost 2–2.5 times the length of the coil. The best thickness of the armature could be estimated by skin depth.

Experimental characterization and comparison of TLIM performances with different primary winding connections

This paper presents an experimental characterization and comparison of the performances achieved by a Tubular Linear Induction Motor (TLIM) prototype with different typologies of primary winding connections. More in detail, three different configurations have been considered, analyzed and discussed: full-pitch star, 5/6 shortened pitch star and 5/6 shortened pitch double star. For this purpose, an experimental test bench at the Sustainable Development and Energy Saving Laboratory (SDESLab), University of Palermo, Italy, has been set-up. The obtained results have allowed the identification of the best winding configuration for different applications intended for the motor. Moreover, in comparison with classic approaches that involve mathematical equations for winding design, the proposed experimental work is suitable for TLIM winding designs: indeed, more accurate results are obtained and approximation coefficients avoided.

Optimal Design of EMALS Based on a Double-Sided Tubular Linear Induction Motor

A novel evolutionary algorithm is used for the optimization of the thrust force of the stages of an electromagnetic aircraft launch system, based on a double-sided tubular linear induction motor. A semianalytical model allows for a fast and accurate prediction of all the electromagnetic quantities in the device, including the thrust force, the back electromotive force, the distribution of the induced current density, and the average magnetic flux density in the teeth. Using the semianalytical formulation, the characterization of the machine is greatly facilitated, so allowing a fast evaluation of the cost function and of the design constraints.

3-D FEM Analysis of a Novel Magnetic Levitation System

This paper deals with the 3-D finite element method (FEM) analysis of a novel magnetic levitation (maglev) train driven by an air-cored tubular linear induction motor. This new maglev system originates from electromagnetic launcher (EML) technology, especially linear induction launcher (LIL) type. Some 2-D magnetic analyses based on current sheet model or transmission line approach for the LIL type launchers are available in the literature, but this paper provides an alternative way to analyze LIL type of EMLs using 3-D FEM. The analysis examines the variation of propulsion, levitation, and guidance forces induced in the moving part. It is expected that the possible results of this magnetic analysis will lead to some new and important design considerations for the novel maglev system.

Force Optimization of a Double-Sided Tubular Linear Induction Motor

An innovative double-sided tubular linear induction motor is presented, and its optimal design in terms of thrust force is discussed. A dedicated semi-analytical model of the device is developed allowing for fast and accurate evaluation of all the electromechanic quantities in the device, including the thrust force, back-electromotive force, distribution of the induced current, and average magnetic flux density in the teeth. This provides a basis for the design optimization, which has been performed by a novel evolutionary algorithm based on the self-organizing maps. Using the semi-analytical formulation, the characterization of the machine is greatly facilitated, thus allowing a fast evaluation of the cost function and design constraints. Finally, the obtained optimal design is validated by comparison with finite elements method analysis.

Analysis and Optimization of Starting Characteristics of Tubular Linear Induction Motor

Traditional mechanical punching machines are mainly driven by rotary motors and a complete set of intermediate transformation mechanism is needed, which results in a reduction of the system efficiency. This paper focuses on the tubular linear induction motor (TLIM) with low cost and simple control structure which directly drives the punching machines. In order to provide a theoretical basis for its further control system, the finite element model of this TLIM is established. The starting performances, such as the trust force, phase current, velocity, displacement and the load force, are analyzed by the finite element analysis (FEA). Moreover, the optimization of the starting trust force is investigated.

Experimental Performance Investigation of a Novel Magnetic Levitation System

This paper deals with the design, construction, and especially the testing of a new magnetic levitation (maglev) train driven by an air-cored tubular linear induction motor. The proposed new design topology uses only one force-generating system (motor) to produce the three forces required in a maglev system: propulsion, levitation, and guidance, whereas classical maglev trains use separate motors or permanent magnets to produce each of these forces. Moreover, the system eliminates the need for control of the levitation and guidance forces. This paper presents a condensed design guideline, simply explains the implementation process of a laboratory-scale prototype, shows in detail the experimental test results—including the low-damping problem—and then addresses the advantages of the proposed system over existing maglev systems.

The Double-Sided Tubular Linear Induction Motor and Its Possible Use in the Electromagnetic Aircraft Launch System

In this paper, a double-sided stator tubular linear induction machine is presented, and its performance is discussed for possible use as a catapult in the electromagnetic acceleration of aircraft. Based on the use of the Fourier transform in the direction of the motion, a semianalytical model that is able to take into account the end effects due to the finite length of the stators is derived. The effectiveness of the model has been proven by comparison with a numerical analysis based on the finite-element method. The reported results obtained using the two methods show excellent agreement that makes the proposed model a valuable tool for a preliminary design of the device.

TUBULAR LINEAR INDUCTION MACHINE AS A FAST ACTUATOR: ANALYSIS AND DESIGN CRITERIA

In this paper, some design criteria for a Tubular Linear Induction Motor (TLIM) as a fast actuator are considered. The in∞uence of geometrical and physical parameters on the operating conditions of a TLIM are investigated by means a quasi-analytic model. The model is based on the application of the Fourier Transform both in space and in time. The Fourier transform in space is introduced to take into account the flnite length of the stator windings in the axial direction. The transient electrical response of the motor at standstill following the insertion of a three-phase system of voltage generators is performed by the Fourier transform in the time. Linear movements are very usual in mechanical engineering, especially in industrial robots, where linear speeds up to several meters per second are often required. These movements are usually obtained by using rotating motors in combination with rotation to translation mechanism. The resulting systems may have poor performance; in particular, an excessive time delay may prevent their use as fast actuators (1). The complexity of these systems can be overcome by using linear actuators. It is well known that tubular linear induction machines have the highest force to moving mass ratio when compared with other linear motors; this property makes these devices very attractive to be used as servo motors since they may have better performance in terms of reduction of delay times with respect to those of traditional systems. The simplest approach to model these linear motors is based on

A Novel Magnetic-Levitation System: Design, Implementation, and Nonlinear Control

This paper concerns the design, implementation, and nonlinear velocity-tracking control of a novel magnetic-levitation (maglev) system for magnetically levitated trains. The proposed system uses only one tubular linear induction motor to produce three forces required in a maglev system: propulsion, levitation, and guidance. Classical maglev systems, on the other hand, contain a separate force-generating system to build each of these three forces. Another benefit that the proposed system offers is that there is no need to control the guidance, and particularly, the levitation forces, one of the most challenging tasks in maglev systems. The system always centers the moving part during operation and eliminates the necessity for control of the levitation and guidance forces. However, the propulsion force strongly requires some control efforts because a linear induction motor has nonlinear system dynamics. This paper gives a condensed design guideline based on the mature theory of electromagnetic launchers, particularly the linear induction launcher type. It explains the implementation process, shows experimental test results, and finally, presents a nonlinear partial state-feedback controller for the proposed system.

New Concept for Lifting in Onshore Oil Wells

This paper presents the development of a prototype of a tubular linear induction motor applied to onshore oil exploitation, named MATAEligOS (which is the Portuguese acronym for Tubular Asynchronous Motor for Onshore Oil Exploitation). The function of this motor is to directly drive the sucker-rod pump installed in the down hole of the oil well. Considering the drawbacks and operational costs of the conventional oil extraction method, which is based on the walking beam and rod string system, the developed prototype is intended to become a feasible alternative from both technical and economic points of view. At the present time, the MATAEligOS prototype is installed in a test bench at the Applied Electromagnetism Laboratory at the Escola Politecnica da Universidade de Sao Paulo. The complete testing system is controlled and supervised by special software, enabling good flexibility in operation, data acquisition, and performance analysis. The test results indicate that the motor develops a constant lift force along the pumping cycle, as shown by the measured dynamometric charts. Also, the evaluated electromechanical performance seems to be superior to that obtained by the traditional method. The system utilizing the MATAEligOS prototype allows the complete elimination of the rod string sets required by the conventional equipment, indicating that the new system may advantageously replace the surface mechanical components presently utilized.

Transient Modeling of Multiparallel Tubular Linear Induction Motors

In this paper, we model single and multiparallel generator driven tubular linear induction motors by the current filament method, in transient and dynamic states. Using a previously written code for transient and dynamic modeling of a single motor, we simulate a sample motor noted in a reference paper and compare the results with those obtained by using our current filament method. This comparison confirms the accuracy of our method. Finally, we model a system of two or more parallel motors and show that it is feasible to achieve greater muzzle velocities by paralleling certain designs of motors