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  • 1
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Compel 17 (1998), S. 171-176 
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: The paper presents a comparison of performance of a number of selected optimization procedures when applied to solving electromagnetic field problems. The optimization techniques assessed encompass simulated annealing and genetic algorithms, as well as deterministic methods, including the Levenberg-Marquardt procedure. The comparison is performed using a number of test functions followed by a study of two simple configurations relevant to problems encountered in electromagnetics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: The paper presents a novel method of utilising neural networks for optimisation systems. First, a conventional magnetic circuit model of the device is developed to create a set of sensitivity rules which guide the optimisation. The rules are coded in a knowledge-based neural network. Second, an error network is developed to correct the approximations inherent in the magnetic circuit approach and this combines with the first network to generate realistic outputs. Finally, the error network can be trained on-line with a finite element system. Over time, the network replaces the finite element analysis, thus speeding up the optimisation process.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Compel 18 (1999), S. 215-224 
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: The paper presents an extension to previous work on modelling AC losses in high-temperature superconducting tapes as a highly non-linear diffusion process. Following successful formulation for a bulk superconductor the presence of silver in a tape has now been included, using a "sandwich" model, to represent more realistically the practical arrangement. The results of the extended 1-D model are included and a new 2-D scheme is described using finite difference formulation. Effects of non-linearity are emphasised.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: When dealing with problems entailing time consuming finite element solutions alternative methods are sought which can reduce the number of function calls whilst preserving solution accuracy. Two different strategies for practical electromagnetic design and optimisation are presented and compared. The main features and performance of each are described and evaluated on an analytical and a physical problem.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: This paper presents the initial stage of a 3D finite element (FE) model of the electromagnetic field in the arc chamber of a current limiting miniature circuit breaker (MCB). The final objective of the model is to compute the magnetic forces on the arc, and predict the position of the arc at a series of discrete time steps. The trajectory of the arc calculated from the model will then be compared with experimental data recorded by a high speed arc imaging system (AIS) on a flexible test apparatus (FTA) designed to simulate the operation of a commercial MCB under laboratory conditions. By comparing the FE model of the arc behaviour with the actual arc images generated from the AIS an insight into the factors governing the motion of the arc can be gained. In particular the relative importance of the average flux density across the arc chamber is compared with the local flux density distribution at the arc roots. An understanding of the influence of the magnetic flux distribution can then be used to improve the magnetic design of the MCB to promote low immobility times and effective current limiting operation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Compel 17 (1998), S. 749-756 
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: The paper reports on a development of an automated CAD optimization system which interfaces an external design routine with a general purpose finite element software. The magnetic analysis is performed using a parameterized model and the process is controlled from within procedures written in MATLAB programming environment. Results are shown for a permanent magnet brushless DC motor.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Compel 23 (2004), S. 159-172 
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Design and optimisation of many practical electromechanical devices involve intensive field simulation studies and repetitive usage of time-consuming software such as finite elements (FEs), finite differences of boundary elements. This is a costly, but unavoidable process and thus a lot of research is currently directed towards finding ways by which the number of necessary function calls could be reduced. New algorithms are being proposed based either on stochastic or deterministic techniques where a compromise is achieved between accuracy and speed of computation. Four different approaches appear to be particularly promising and are summarised in this review paper. The first uses a deterministic algorithm, known as minimal function calls approach, introduces online learning and dynamic weighting. The second technique introduced as ES/DE/MQ - as it combines evolution strategy, differential evolution and multiquadrics interpolation - offers all the advantages of a stochastic method, but with much reduced number of function calls. The third recent method uses neuro-fuzzy modelling and leads to even further economy of computation, although with slightly reduced accuracy of computation. Finally, a combined FE/neural network approach offers a novel approach to optimisation if a conventional magnetic circuit model could also be used.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Compel 17 (1998), S. 146-150 
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: The main purpose of this paper is to discuss ways in which magnetic performance of electromechanical transducers can be simulated accurately using a series of finite-element models. Of particular interest is the usage of multivariable interpolation techniques which enable significant reduction of the number of finite-element computations necessary to fully model all relevant cases. This is particularly important in the case when a shift of the zero position of the coil occurs. Moreover, this type of modelling provides a good insight into the physical behaviour of the device and aids understanding of its performance characteristics. Finally, the paper presents briefly how a significant reduction in harmonic content has been achieved by improving the linearity of the magnetic circuit. These improvements have been confirmed experimentally.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Compel 17 (1998), S. 36-46 
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: The purpose of this paper is to examine the current situation in numerical field computation, paying special attention to the role of education in developing new ideas to meet the ever growing demands of industry.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Bradford : Emerald
    Compel 17 (1998), S. 427-438 
    ISSN: 0332-1649
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: The paper presents a historical review, the state of the art and recent advances in the field of computational electromagnetics at leading universities and research institutes in Poland. Contributions made by Polish scientists to the development of fundamental electromagnetism, as well as to computational methods, are emphasized, and some conclusions are drawn regarding expected future developments.
    Type of Medium: Electronic Resource
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