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Author: search.filters.author.Lefley, Paul

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    Synthesis and analysis of a high‐performance low‐cost permanent magnet brushless DC motor
    (Emerald, 2012-09-07)
    Petkovska, Lidija
    ;
    Lefley, Paul
    ;
    Cvetkovski, Goga
    The paper presents design development of a novel high‐performance low‐cost 6/4 pole permanent magnet brushless DC (PMBLDC) motor. The objective is to show how the cogging torque of this new design is minimised by determining the optimum stator pole arc length and the best shoe thickness. At the beginning a step‐by‐step design synthesis of a reference 6/4 pole PMBLDC motor with concentrated 3‐phase windings and asymmetric stator pole arcs is presented. It is followed by a full performance analysis of the reference motor. The FEM for electromagnetic field computation is employed. The characteristics of the motor are calculated and analysed. By simple variation of the stator pole geometry, two‐stage design optimisation for cogging torque minimisation is performed, and an optimised motor model is proposed. The comparative analyses of the reference and optimised motor models show the advantages of the proposed novel design. The focus is to show the sensitivity of the cogging torque due to changes in the stator pole shoe design parameters, such as arc length and thickness, which are discretely changed inside the prescribed constraints, and the solution matrix is derived. It was found the optimised stator pole design, providing minimum cogging torque, has the original arc length 85° and pole shoe thickness 4 mm. Thus, the peak‐cogging torque from 0.294 Nm is reduced to respectable value 0.142 Nm. The paper presents an original approach to synthesis of 6/4 PMBLDC new structured motor. A two‐step design procedure is introduced and optimised stator geometry is defined, minimising the cogging torque and, at the same time, improving the profile of back electromotive force (EMF) of the motor.
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    Optimal design of single phase permanent magnet brushless DC motor using particle swarm optimisation
    (Emerald, 2014-10-28)
    Cvetkovski, Goga
    ;
    Petkovska, Lidija
    ;
    Lefley, Paul
    The purpose of this paper is to perform an optimal design of single phase permanent magnet brushless DC motor (SPBLDCM) using efficiency of the motor as objective function. In the design procedure performed on SPBLDCM, particle swarm optimisation (PSO) as an optimisation tool is used. The created computer programme for optimal design of electrical machines is based on the PSO. According to the design characteristics of SPBLDCM, some of the motor parameters are chosen to be constant and others variable. A comparative analysis of both motor models based on the value of the objective function, as well as the values of the optimisation parameters, is performed. From the comparative data analysis of both motor models, it can be concluded that the main objective of the optimisation is realised, and it is achieved by an improvement of the efficiency of the motor. An optimisation technique based on PSO has been developed and applied to the design of SPBLDCM. According to the results it can be concluded that the PSO is a very suitable tool for design optimisation of SPBLDCM and electromagnetic devices in general. The quality of the PSO model has been proved through the data analysis of the prototype and optimised solution. At the end, the quality of the PSO solution has been again proved by comparative analysis of the two motor models using FEM as a performance analysis tool.
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    Finite element analysis of a novel single phase permanent magnet brushless DC motor
    (IEEE, 2010-09)
    Lefley, Paul
    ;
    Petkovska, Lidija
    ;
    Ahmed, Saeed
    ;
    Cvetkovski, Goga
    This paper is an extension and continuation of the previous authors’ work, where a practical solution for a novel single phase PM BLDC motor model has been developed, utilising an asymmetrical stator pole design. An accurate 2D finite element simulation was employed to numerically analyse the magnetic field distribution inside the motor. The results are used to prove the selected stator/rotor arc length ratio combination that produces a flat back EMF shape, at a reduced cogging torque.
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    Specific power based optimal design of novel single phase PM BLDC motor using GA
    (IEEE, 2014-09)
    Cvetkovski, Goga
    ;
    Petkovska, Lidija
    ;
    Lefley, Paul
    In this paper a genetic algorithm based optimal design of a single-phase permanent magnet brushless DC motor (SPMBLDCM) is proposed. This approach employs a genetic algorithm (GA) technique as a search tool for the optimization process of the SPMBLDCM. The specific power of the motor is selected as an objective function. At the end of the optimisation a best solution is proposed based on the values of the optimisation parameters, as well as other important motor parameters. An overall comparison of the best optimal solution and the basic model of the motor is presented.
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    Analysis of the stator topology impact on cogging torque for surface permanent magnet motor
    (Emerald, 2015-03-02)
    Petkovska, Lidija
    ;
    Cvetkovski, Goga
    ;
    Lefley, Paul
    The purpose of this paper is to investigate the impact of the stator core design for a surface permanent magnet motor (SPMM) on the cogging torque profile. The objective is to show how the cogging torque of this type of motor can be significantly reduced by implementing an original compound technique by skewing stator slots and inserting wedges in the slot openings.
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    Shaping the topology of a single phase BLDC motor for reduced cogging torque and improved performance
    (EDP Sciences, 2022-06-21)
    Petkovska, Lidija
    ;
    Lefley, Paul
    ;
    Cvetkovski, Goga
    In the paper is presented a step-by-step development of the topology for a novel single phase permanent magnet (PM) brushless DC (BLDC) motor, aiming to improve its operation with more efficient utilisation of the active materials. The studied motor is based on a generic design, where asymmetrical stator poles and respective shaping of the permanent magnets is applied. Accurate 2D finite element simulations were employed for numerical prototyping of the motor design, until the expected results were obtained. Based on FEA, cogging and static torque waveforms, along with other relevant performance characteristics were determined and examined. The results show that the motor topology, and in particular, the detailed shape of the stator poles has the most important impact on the smooth operation of the single phase BLDC permanent magnet motor.