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Article

Arash Kiyoumarsi, Abolfazl Nazari, Mohammad Ataei, Hamid Khademhosseini Beheshti and Rahmat‐Allah Hooshmand

The purpose of this paper is to present a 3D finite element model of the electromagnetic fields in an AC three‐phase electric arc furnace (EAF). The model includes the…

Abstract

Purpose

The purpose of this paper is to present a 3D finite element model of the electromagnetic fields in an AC three‐phase electric arc furnace (EAF). The model includes the electrodes, arcs, and molten bath.

Design/methodology/approach

The electromagnetic field in terms of time in AC arc is also modeled, utilizing a 3D finite element method (3D FEM). The arc is supposed to be an electro‐thermal unit with electrical power as input and thermal power as output. The average Joule power, calculated during the transient electromagnetic analysis of the AC arc furnace, can be used as a thermal source for the thermal analysis of the inner part of furnace. Then, by attention to different mechanisms of heat transfer in the furnace (convection and radiation from arc to bath, radiation from arc to the inner part of furnace and radiation from the bath to the sidewall and roof panel of the furnace), the temperature distribution in different parts of the furnace is calculated. The thermal model consists of the roof and sidewall panels, electrodes, bath, refractory, and arc. The thermal problem is solved in the steady state for the furnace without slag and with different depths of slag.

Findings

Current density, voltage and magnetic field intensity in the arcs, molten bath and electrodes are predicted as a result of applying the three‐phase AC voltages to the EAF. The temperature distribution in different parts of the furnace is also evaluated as a result of the electromagnetic field analysis.

Research limitations/implications

This paper considers an ideal condition for the AC arc. Non‐linearity of the arc during the melting, which leads to power quality disturbances, is not considered. In most prior researches on the electrical arc furnace, a non‐linear circuit model is usually used for calculation of power quality phenomena distributions. In this paper, the FEM is used instead of non‐linear circuits, and calculated voltage and current densities in the linear arc model. The FEM results directly depend on the physical properties considered for the arc.

Originality/value

Steady‐state arc shapes, based on the Bowman model, are used to calculate and evaluate the geometry of the arc in a real and practical three‐phase AC arc furnace. A new approach to modeling AC arcs is developed, assuming that the instantaneous geometry of the AC arc at any time is constant and is similar to the geometry of a DC arc with the root mean square value of the current waveform of the AC arc. A time‐stepping 3D FEM is utilized to calculate the electromagnetic field in the AC arc as a function of time.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

G. Krebs, A. Tounzi, F. Piriou, B. Pauwels and D. Willemot

Electromagnetic actuators, with very specific features for industrial processes, are needed much more for an increase in reliability and dynamic. To reach the wanted…

Abstract

Purpose

Electromagnetic actuators, with very specific features for industrial processes, are needed much more for an increase in reliability and dynamic. To reach the wanted features, the actuator has to be designed and its performance has to be quantified with good accuracy and reasonable computation time. The purpose of this paper is to present the design and the study of a permanent magnet linear actuator.

Design/methodology/approach

The first design of the permanent magnet linear actuator has been introduced from electromechanical considerations. Then, both models utilized to study the actuator are presented: the permeance network model (PNM) and the 3D finite element model. These models are used to quantify the performance of the prototype. Owing to its speed, the influence of geometric parameters on the performances are studied by the PNM. Then, both models are used to perform calculations on global variables. A prototype of the designed actuator has been built up and the results obtained by both models are compared with the measurements.

Findings

The developed model has been used to study the behaviour of the designed actuator. Using the 3D‐FEM, the local phenomena have been highlighted as the magnetic flux density and the induced current. Then, global variables as the no load fluxes and the forces at load have been determined. The results obtained by both models have been compared together and show a good agreement. They are also very close to the measurements achieved on the prototype constructed.

Originality/value

This paper shows that it is possible to use a PNM model to design a permanent magnet linear actuator with a relative good accuracy. The PNM developed does not permit one to calculate the cogging forces and does not take into account the induced currents but it gives accurate results when the interest is focused only on the magnetostatic load operating. The comparison with the results given by 3D‐FEM and to the measurements shows a good agreement.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 26 no. 4
Type: Research Article
ISSN: 0332-1649

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Article

Takashi Abe, Ryohei Ohba and Tsuyoshi Higuchi

Recently, considerable attention has been attracted to the development of the new concept motor for EV or HEV. Wider torque and speed controllable operating range and high…

Abstract

Purpose

Recently, considerable attention has been attracted to the development of the new concept motor for EV or HEV. Wider torque and speed controllable operating range and high efficiency under driving area are needed for traction motor. The purpose of this paper is to realize the new concept variable field flux motor with claw pole rotor and brushless robust structure for high-speed range.

Design/methodology/approach

In the previous paper, the authors proposed a half-wave rectified brushless variable field flux method with a diode inserted into the field winding. This paper presents a designing for a novel claw pole rotor type motor using the variable field flux method (CP-HVFM). The claw pole type rotor has simple and robust structure for high-speed operation. This paper describes a first prototype design result for CP-HVFM using 3D-FEM. And the authors report the torque and efficiency characteristic results using 3D-FEM.

Findings

The authors have studied the designing for CP-HVFM using 3D-FEM. The designed prototype CP-HVFM reached a rated power of 2 kW or more at a rated speed 1,800 rpm under design restrictions of experimental equipment and initial specifications. In addition, the authors found the ratio of the tip and root embrace of the claw pole shape for maximum average torque and minimum torque ripple. Finally, the authors revealed an influence of the armature current on the torque and the efficiency characteristic results for the designed prototype CP-HVFM using 3D-FEM.

Originality/value

The half-wave rectified brushless variable field flux method proved to be effective for the claw pole rotor type motor. And also the authors found the best claw pole shape for torque characteristic. This results are applied to another concept motor for EV or HEV.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 2
Type: Research Article
ISSN: 0332-1649

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Article

Byung‐Jun Lee, Byoung‐Kuk Kim, Yun‐Hyun Cho, Yon‐Do Chun and Dae‐Hyun Koo

The purpose of this paper is to present the performance characteristics analysis of a new type axial flux permanent magnet (AFPM) machine according to the geometric…

Abstract

Purpose

The purpose of this paper is to present the performance characteristics analysis of a new type axial flux permanent magnet (AFPM) machine according to the geometric structure of rotor such as permanent magnet dimension, the air‐gap length and so on.

Design/methodology/approach

The 3D finite element method (FEM) is used to analyse electromagnetic fields with the aid of an ANSYS software package. The FEM is based on the magnetic vector potential and the governing equation can be obtained from the Maxwell equation. Using the dynamometer system, the characteristics of the AFPM machine were estimated according to load torque.

Findings

The AFPM machine characteristics with static torque, cogging torque and flux density according to rotor geometric dimensions are analyzed using a 3D FEM software package. And then, the prototype of an AFPM machine and several rotors with different PM structure are manufactured and tested. Resulting from the experiment, the characteristics such as EMF waveform, speed and efficiency curves according to load torque, and efficiency curves according to PM thickness, are obtained. The measured performance results verified the overhang effects and improved the efficiency of the motor.

Originality/value

The paper proposes a new type AFPM machine structure with T‐shape teeth and laminated back yoke and two types of rotor with fan‐shaped permanent magnets. It presents the results of characteristics of the proposed AFPM machine throughout the simulation and experiment.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 4
Type: Research Article
ISSN: 0332-1649

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Article

Francisc Bölöni, Abdelkader Benabou and Abdelmounaïm Tounzi

Electrostatic microelectromechanical systems are characterized by the pull‐in instability, associated to a pull‐in voltage. A good design requires an accurate model of…

Abstract

Purpose

Electrostatic microelectromechanical systems are characterized by the pull‐in instability, associated to a pull‐in voltage. A good design requires an accurate model of this pull‐in phenomenon. The purpose of this paper is to present two approaches to building finite element method (FEM) based models.

Design/methodology/approach

Closed form expressions for the computation of the pull‐in voltage, can provide fast results within reliable accuracy, except when treating cases of extreme fringing fields. FEM‐based models come handy when high accuracy is needed. In the first model presented in this paper, the FEM is used to solve the electrostatic problem, while the mechanical problem is solved using a simplified Euler‐Bernoulli beam equation. The second model is a pure FEM model coupling the electrostatic and mechanical problems iteratively through the electrical force. Results for both scalar and vector potential formulations for the FEM models are presented.

Findings

In this paper a comparative study of simple pull‐in structures is presented, between analytical and 3D FEM‐based models. A comparison with analytical models and experimental results is also realized.

Research limitations/implications

The coupling between the electrostatic and mechanical problem in the presented approaches, is iterative. Therefore, to improve the accuracy of the presented model, a strong coupling is needed.

Originality/value

In the presented FEM‐analytical model, the electrostatic problem is solved in both, scalar and vector electric potential formulations. This allows defining an upper and a lower limit for the electrostatic force and consequently for the pull‐in voltage.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Irma Hajdarevic and Hansjörg Köfler

Switched reluctance motors are promising candidates for a wide variety of drive applications. The theoretical description of such motors is often reduced to the rather…

Abstract

Switched reluctance motors are promising candidates for a wide variety of drive applications. The theoretical description of such motors is often reduced to the rather simple, but clear concept of ΨI‐characteristics. In contrast to this, the machine itself is a real electrical machine and must therefore be analysed as is done with conventional machines although the experimental machine is constructed as simple as possible. The paper will first describe some well known basics connected to very short machines and flux. In the next step, the calculation of stray flux quantities aided by 3D‐FEM is discussed and finally a comparison of calculation and experimental measurements is given.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 22 no. 4
Type: Research Article
ISSN: 0332-1649

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Article

Hanhua Zhang, Jun Li, Jun Zou, Zhixin Wang and Jin Yang

The track impedance is one of the most important parameters in designing the track circuit which is widely used in the railway signal control system to detect the presence…

Abstract

Purpose

The track impedance is one of the most important parameters in designing the track circuit which is widely used in the railway signal control system to detect the presence of a train. This paper aims to calculate the ballastless track impedance by taking account of the influence of reinforcement bars.

Design/methodology/approach

This paper proposes a two-step decomposition approach to calculate the ballastless track impedance. The basic idea is evaluating the track impedance without the reinforcement bars by using two-dimensional (2D) finite element method (FEM), and the incremental impedance, because of the reinforcement bar, is calculated by the partial element equivalent circuit (PEEC) method.

Findings

The numerical examples show that the proposed approach can guarantee the accuracy and largely reduce the computing time, at least 20 times, compared with the direct three-dimensional (3D) FEM method.

Research limitations/implications

The study provides a fast approach to calculate the ballastless track impedance. However, compared with the 3D FEM method, the results are less accurate because of the approximation and assumption adopted in the method. A future study should pay more attention to improve accuracy of the model.

Originality/value

A fast approach is proposed to calculate the ballastless track impedance taking account of the influence of the reinforcement bars. The computing time can be largely reduced by using the method. With the proposed approach, the influence of insulation of the reinforcement bars on track impedance can be analyzed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 1
Type: Research Article
ISSN: 0332-1649

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Article

Daoyu Hu and Maochun Zhai

The purpose of this paper is to analyze the influence of different parameters on the characteristics of the superconducting electrodynamic suspension (EDS) system.

Abstract

Purpose

The purpose of this paper is to analyze the influence of different parameters on the characteristics of the superconducting electrodynamic suspension (EDS) system.

Design/methodology/approach

The authors used an analytical model based on the dynamic circuit theory to perform the analysis. The authors proposed an inductance criterion to improve the calculation accuracy. They also proposed a three-dimension finite element method (FEM) to verify the validity of the analytical model.

Findings

The levitation force and guiding force increase with the superconducting magnet (SCM) speed and show a saturated trend, while the drag force decreases with the SCM speed. The vibration characteristic is the inherent characteristic of the superconducting EDS. The frequency and amplitude are affected by the gap between adjacent null-flux coils. The levitation force first increases and subsequently decreases with the levitation height. The total levitation force of the SCM increases with the superconducting coil (SC) number, while the average levitation force of an SC decreases with the SC number. The total levitation force nonlinearly increases with the SC number.

Originality/value

The authors introduced an inductance criterion for better understanding and using the analytical model, and they also proposed a 3D FEM method. The 3D FEM method could be extended to simulate the other EDS systems with more complex structures which the numerical model is no longer applicable. The results of the parameter study could deepen people’s understanding of EDS.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 40 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Abdoulaye Ba, Huu Kien Bui, Gérard Berthiau, Didier Trichet and Guillaume Wasselynck

This paper aims to present a lightened 3D finite element model (FEM) for coupled electromagnetic thermal simulation of the induction thermography non-destructive testing…

Abstract

Purpose

This paper aims to present a lightened 3D finite element model (FEM) for coupled electromagnetic thermal simulation of the induction thermography non-destructive testing (NDT) technique to reduce the computation time.

Design/methodology/approach

The time harmonic electromagnetic problem is expressed in Aϕ formulation and lightened by using the surface impedance boundary condition (SIBC) applied to both the massive induction coil surface and the surface of conductor workpiece including open cracks. The external circuit is taken into account by using the impressed voltage or the impressed current formulation. The thermal diffusion in the workpiece is solved by using surface electromagnetic power density as thermal source.

Findings

The accuracy and the usefulness of the method for the design of the induction thermography NDT technique have been shown with acceptable deviation compared with a full FEM model. It is also observed that at high frequency, when the ratio between the local radius of the conductor and the skin depth is high, a very good accuracy can be obtained with the SIBC methods. At lower frequency, the effect of the curvature of the surface becomes significant. In this case, the use of the Mitzner’s impedance can help to correct the error.

Originality/value

The SIBC can be used for both massive coil and workpieces with open cracks to alleviate 3D FEMs of the coupled electrothermal model. The implementation in matrix form of the coupled electrothermal formulation is given in details. The comparisons with reference analytical solution and full 3D FEM show the accuracy and performance of the method. In the test case presented, the computation time is 6.6 times lower than the classical model.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Gui-Yu Zhou, He Hao, Meng-Jia Jin and Jian-Xin Shen

The purpose of this paper is to investigate the effect of the interlocking process on the iron loss in the lamination core and to increase the efficiency of electrical…

Abstract

Purpose

The purpose of this paper is to investigate the effect of the interlocking process on the iron loss in the lamination core and to increase the efficiency of electrical machines.

Design/methodology/approach

A 3D electromagnetic model of the interlocking dowels is proposed in order to simulate the eddy current distribution in the lamination core. Considering the time-consuming of the 3D finite element method (FEM), a 2D electromagnetic model is then proposed based on the 3D model. Influence of the interlocking process on the motor performances is analyzed with 2D FEM, considering the electrical connection of the dowels and the magnetic property deterioration of the electrical steel sheets.

Findings

The interlocking process removes the insulation between the laminations at the cut-edges of the interlocking dowels, causing extra eddy current loss in the lamination core. The effect of the interlocking process is dependent on the number, location and size of the interlocking dowels.

Practical implications

The interlocking dowel model is established in order to simulate the effects of the interlocking process. By using the FEM calculation, optimal solution is discussed to minimize the undesired effect of the interlocking dowels.

Originality/value

In this paper, the FEM model of the induction motor with interlocked stator core is first established, then simulation analysis is implemented. Results shows that choosing a proper number of interlocking dowels with suitable location and size can reduce the extra loss.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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