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Article
Publication date: 7 September 2012

Slawomir Wiak, Anna Firych‐Nowacka and Paolo Di Barba

The purpose of this paper is to create computer models of magnetic micro‐ and nano‐fibres. The fibres are the base of textronics devices, such as sensors and actuators…

Abstract

Purpose

The purpose of this paper is to create computer models of magnetic micro‐ and nano‐fibres. The fibres are the base of textronics devices, such as sensors and actuators. The authors show how one can avoid painstaking work during manufacture process by initial preparing of computer models.

Design/methodology/approach

The paper presents correspondence between finite element method (FEM) and reluctance network method (RNM). The smooth transition is possible, due to homogeneous models of magnetic micro fibres based on FEM.

Findings

The paper describes the solution to accelerated designing and manufacturing process of magnetic micro‐fibres; it describes also how magnetic permeability of such fibers can be calculated and how to perform a homogenisation in models.

Originality/value

The authors present a new way of modelling magnetic micro‐fibers by combining FEM with RNM. So far, only calculations for the B/H curve of magnetic micro‐fibers have been performed, yet authors propose an innovative way for determination of magnetic micro‐fibers' parameters. Homogenisation of finite element models is the crucial part in the process of combining two different numerical methods.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 7 September 2012

Slawomir Wiak, Dieter Gerling and Marcin Pyc

The purpose of this paper is to describe the optimization process of a homopolar machine. The work has been focused on a reduction of axial forces acting on the rotor.

Abstract

Purpose

The purpose of this paper is to describe the optimization process of a homopolar machine. The work has been focused on a reduction of axial forces acting on the rotor.

Design/methodology/approach

A novel machine design has been proposed and a detailed FEM analysis has been performed.

Findings

The source of the axial force in the homopolar machine has been indicated and a new method of axial force reduction has been presented.

Originality/value

A detailed comparison shows that the applied changes lead to a significant axial force reduction and allow the usage of cheaper and less prone to axial forces bearings.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 24 July 2019

Anna Firych-Nowacka, Krzysztof Smolka and Sławomir Wiak

Electrospinning is a method of the polymer super thin fibres formation by the electrostatic field. The distribution of electrostatic field affects the effectiveness of the…

Abstract

Purpose

Electrospinning is a method of the polymer super thin fibres formation by the electrostatic field. The distribution of electrostatic field affects the effectiveness of the electrospinning.

Design/methodology/approach

This paper presents various computer models that can improve the electrospinning process. The possibilities of modelling the electrostatic field in the design of electrospinning equipment are presented.

Findings

In the research part, the one focussed on finding a cylinder-shaped collector structure to limit the adverse effect of an uneven distribution of the electric field intensity on the collector.

Originality/value

The paper concerns the improvement of the electrospinning process with the use of electrostatic field modelling. In the first part, several possible applications of electrostatic models have been indicated, thanks to which the efficiency of the process has been improved. The original solution of the collector geometry was presented, which according to the authors, in comparison with previous models, gives the most promising results. In this solution, it was possible to obtain an even distribution of the electric field intensity while removing the unfavourable effect of the field strength increase on the outer edges of the collector. The most important aspect in this paper is electric field strength analysis.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 2 March 2015

Maria Dems, Krzysztof Komeza, Slawomir Wiak and Sara Fernández Coya

– The purpose of this paper is to present the distribution of the magnetic field and additional losses analysis of the induction motors (IM) with opened and closed rotor slots.

Abstract

Purpose

The purpose of this paper is to present the distribution of the magnetic field and additional losses analysis of the induction motors (IM) with opened and closed rotor slots.

Design/methodology/approach

In the field-circuit approach the distribution and changes of magnetic flux density in the motor are computed using a time-stepping finite element method. The additional losses in each element are evaluated at different frequencies.

Findings

An approximate analytical formulation is derived for rapid losses computation confirmed by the results of field-circuit method. For high-voltage motors due to the size ratios of the core and relatively deep stator and rotor slots major role in causing loss of higher harmonics play a fundamental slot harmonics. Higher harmonics order bigger than 100 cause only small part of total higher harmonics core losses. Closed rotor slots construction influenced significantly on no-load losses mainly due to reduction of losses at slot upper part. For nominal load condition that influence is not so strong according to the saturation of slot tips by rotor leakage flux. Nevertheless, core losses at load are several times higher as at no-load.

Research limitations/implications

In future research authors will take into account motors feed from PWM inverter, working in the frequency range up to 400 Hz.

Practical implications

The results of investigation will be used in more detailed design of IMs especially for motors with closed rotor slots.

Originality/value

The methods presented in the paper was not used before. Also results of additional losses in the motor core calculation, especially according motors with closed slots at no load and load conditions are new.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 11 July 2008

Renata Sulima and Slawomir Wiak

The main aim of this paper is to build an equivalent circuit model of a comb drive microactuator, while the phenomenon of generating the electric fringing field at…

Abstract

Purpose

The main aim of this paper is to build an equivalent circuit model of a comb drive microactuator, while the phenomenon of generating the electric fringing field at electrode edges is taken into consideration.

Design/methodology/approach

The approach to the comb drives design requires the “leakage capacitance” (appearing at electrode edges) to be introduced to the complex equivalent circuit model. Introducing these capacitances leads to defining the circuit model properly.

Findings

Such a complex approach by use of the equivalent circuits model could make it possible to reduce the discrepancy between the field and circuit models. These results were obtained after comparing both field and circuit models.

Originality/value

MEMS microdrives are in the area which is being developed very dynamically. Improvements in the mathematical models would permit more precise microdrive design, leading to optimal structure.

Details

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

Keywords

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Article
Publication date: 5 May 2015

Robert-Leon Chereches, Paolo Di Barba and Slawomir Wiak

Fostered by the development of new technologies, micro-electro-mechanical systems (MEMS) are massively present on board of vehicles, within information equipment, as well…

Abstract

Purpose

Fostered by the development of new technologies, micro-electro-mechanical systems (MEMS) are massively present on board of vehicles, within information equipment, as well as in medical and healthcare equipment. The purpose of this paper is to approach here the shape design of MEMS in terms of the optimization of a vector objective function, subject to a set of constraints. Objectives and constraints are non-linear, dependent on the unknown device shape. When multiple objective functions should be optimized simultaneously, the set of solutions minimizing the degree of conflict (Pareto front) can be searched for.

Design/methodology/approach

This paper proposes an automated optimal design method based on connecting the MATLAB surrogate modeling (SUMO) toolbox with COMSOL Multiphysics finite element analysis tool, and the evolutionary algorithm NSGA-II as well.

Findings

The efficiency of the optimization method proposed is approximately doubled in terms of runtime (5 vs 10 h for the referred platform), when compared with the same computational job without using surrogate models. This way, a cost-effective and accurate approximation of the Pareto front, trading off drive and levitation force components in a comb-drive electrostatic microactuator, was found.

Research limitations/implications

More in-depth models of MEMS devices could be obtained by simulating multi-domain physical processes, i.e. encompassing a coupled-field analysis in the multiphysics sense.

Originality/value

Under this framework, the proposed approach lays the ground for a very general method devoted to the optimal shape design of any MEMS configuration; in fact, the application of multiobjective optimizations to these kind of devices is quite new.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Content available
Article
Publication date: 1 July 2006

Slawomir Wiak

Abstract

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 5 July 2013

Slawomir Wiak and Krzysztof Smółka

This paper aims to focus on the hybrid numerical method for effective design of silicon micromotor.

Abstract

Purpose

This paper aims to focus on the hybrid numerical method for effective design of silicon micromotor.

Design/methodology/approach

In this work, the authors introduced finite element methods combined with LUA and Matlab. The paper focuses on analysis of electrostatic micromotor and uses computer simulation procedure leading to new structure design.

Findings

This strategy enables changing of all parameters of the micromotors MEMS. Moreover, this strategy allows for taking advantage of FEM, namely possibility of calculations of complicated geometries (different electromagnetic devices too) without additional operations.

Originality/value

A novel strategy in computer modeling of micromotor MEMS, based on the fast and very efficient hybrid method for analysis and design, is proposed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 7 September 2012

Rafal M. Wojciechowski, Cezary Jedryczka, Piotr Lukaszewicz and Dariusz Kapelski

The purpose of this paper is to investigate application possibilities of soft magnetic composites (SMC) in the design of high speed permanent motors for home appliances.

Abstract

Purpose

The purpose of this paper is to investigate application possibilities of soft magnetic composites (SMC) in the design of high speed permanent motors for home appliances.

Design/methodology/approach

The design of high speed permanent magnet motor (HSPM) with core made of SMC has been proposed. The governing information about SMC has been presented. The possible advantages and disadvantages of applying magnetic powder materials in the design of electrical machines have been studied. To solve the partial differential equations describing magnetic vector distribution in considered HSPM, the edge element method (EEM) has been applied. The formulas of permanent magnet and winding descriptions, and electromagnetic torque calculations have been presented and studied. To verify accuracy of methodology and functionality of the elaborated software, a prototype of the considered motor has been built and the experimental setup for testing torque and electromotive force has been elaborated. The comparison between measured and simulated motor characteristics have been presented and discussed.

Findings

Comparison between measured and simulated motor characteristics proves the model accuracy. The obtained results show that the designed HSPM motor has sinusoidal electromotive force waveforms, low cogging torque value and the sinusoidal torque versus rotor angle characteristics. Moreover, it has been indicated that the application of SMC materials can reduce power losses in the high speed motors.

Originality/value

The paper describes the development of the numerical method and software for analysis of HSPM with core made of powder materials.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article
Publication date: 7 September 2012

P. Di Barba, F. Dughiero and E. Sieni

The purpose of the paper is to propose a cost‐effective method of non‐parametric optimisation in order to explore shapes of a magnetic pole, in the search for the optimal…

Abstract

Purpose

The purpose of the paper is to propose a cost‐effective method of non‐parametric optimisation in order to explore shapes of a magnetic pole, in the search for the optimal one fulfilling a prescribed objective function.

Design/methodology/approach

The boundary of the magnetic field region to synthesize is considered as a moving boundary separating two materials (air and ferrite). An objective‐function dependent velocity field is defined, in order to update the position of nodes located along the unknown boundary. Specifically, a uniform magnetic field within the controlled region is aimed at.

Findings

The application of the proposed method to the design of a magnet for magnetic‐fluid hyperthermia made it possible to reduce the field deviation with a little computational effort.

Practical implications

Instead of using a standard algorithm of numerical minimisation to find the optimal search direction, a field‐dependent velocity proportional to the objective function value is exploited. This way, the motion of the boundary towards the optimal shape is automatically driven: in principle, in fact, the velocity reaches the zero value at the optimum.

Originality/value

Thanks to the kinematic law governing the movement of the boundary to synthesize, the overall computational cost is low. Moreover, the non‐parametric approach to the shape synthesis preserves the advantage of a broad search space.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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