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This paper describes a new method aiming at the multi-objective optimization of a transverse flux machine with a claw-pole and flux-concentrating structure (CPTFM). Considering the 3-D main magnetic flux in the CPTFM, the time-consuming 3-D finite-element method (FEM) should be used to accurately analyze the performance of the machine. In order to reduce the calculation time for the optimization of the complex CPTFM, the Taguchi method is first applied to evaluate the importance of all the design parameters in the consideration of the predefined five objectives. Subsequently, a mathematical model is developed to replace the 3-D FEM, so that the objectives depending on the selected four critical parameters can be analytically calculated. With its help, the four parameters are further optimized with the multi-objective particle swarm optimization method and nondominated sorting genetic algorithm 2. Finally, the optimal design of the CPTFM is selected from all the searched Pareto solutions with the help of fuzzy logic. It can be concluded that the developed method is effective and efficient, which can make an appropriate compromise between the calculation time and the improvement of the machine performance. [ABSTRACT FROM PUBLISHER]

Following a study on the optimal write head design for perpendicular magnetic recording, this paper aims at optimizing the design of write head for shingled magnetic record by applying the Taguchi method and the response surface methodology. The criteria for the evaluation of the write head design are to maximize the signal-to-noise ratio (SNR) and minimize the bit error rate (BER) in the shingled magnetic recording (SMR). In this paper, the magnetic fields of the write head designs are modeled using finite-element analysis, the SMRs are simulated by applying micromagnetic modeling based on Landau–Lifshitz–Gilbert equation, and the SNR and the BER are characterized using the grain flipping probability model. An optimal design of the write head is obtained to achieve the maximum SNR and the minimum BER. A discussion on the erasure band width is also carried out in this paper. Furthermore, the SNR and the BER at different bits and track densities in SMR are compared and discussed. [ABSTRACT FROM PUBLISHER]

In this paper, a novel algorithm “firework optimization” (FO) is introduced, as well as its hybridization with generating set search (GSS). FO is an exploration algorithm, which intends to explore a vast region within the search space in order to determine regions that may contain a regional optimum. As the regions with potential are defined, GSS, the exploitation algorithm is applied to determine whether regions determined by FO contain a local or a global optimum. The validity of FO and GSS hybridization algorithm is verified using Branin and Six-Hump Camel test functions, and the hybridization algorithm is applied to an interior permanent magnet synchronous motor, in order to minimize torque ripple. [ABSTRACT FROM AUTHOR]

In this paper, an exact analytical solution based on Fourier analysis is proposed to compute the cogging torque in a surface-mounted permanent magnet synchronous machine. The analytical solutions are derived by solving the field-governing equations in each simple and regular subdomain, i.e., permanent magnet (PM), air, slot opening, and slot, and then by applying the boundary conditions to the interfaces between these subdomains. Based on these solutions, the cogging torque is also determined analytically. In order to verify the analytical results of the proposed method, an experimental system was implemented on a servomotor and a torque sensor. All analytical results were extensively validated using nonlinear 2-D finite-element analysis and experimental results. Using the proposed method, we investigated the influence on the cogging torque, according to the machine parameters. Therefore, the proposed method should be very useful in the initial design and cogging torque optimization of PM machines. [ABSTRACT FROM AUTHOR]

This paper introduces a new approach to kriging surrogate model sampling points allocation. By introducing the second (dual) kriging during the model construction, the existing sampling points are reallocated to reduce overall memory requirements. Moreover, a new algorithm is proposed for selecting the position of the next sampling point by utilizing a modified expected improvement criterion. [ABSTRACT FROM AUTHOR]

Using the finite-element model (FEM) to achieve the optimal design of electromagnetic devices is a complex and time-consuming process. Space-mapping techniques reduce computation cost by aligning two models with different granularities, namely, a coarse model and a fine model. In this paper, Kriging output space mapping (OSM), an original space-mapping technique based on adaptive nonlinear corrective projection, is proposed and compared with a conventional OSM technique. The device for optimal sizing is a five-phase linear induction motor, which is represented through two modeling levels: 1) coarse (Kriging model) and 2) fine (2-D FEM). An advantage of this new technique is its ability to provide a sufficiently accurate model for each objective and constraint function and make the coarse model converge effectively toward the fine model. [ABSTRACT FROM AUTHOR]

This paper proposes an enriched performance measure approach to significantly improve computational efficiency of reliability-based design optimization when applied to electromagnetic products. To achieve the goal, three improvements are made over the original performance measure approach: 1) as a way to launch reliability-based design optimization at a deterministic optimum; 2) as a probabilistic feasibility check; and 3) as a fast reliability analysis under the condition of design closeness. Each of the improvements makes a unique contribution to improving numerical efficiency while maintaining stability in the design optimization process. Finally, the proposed method is tested with a mathematical model and the TEAM Workshop Problem 22, and three improvement effects on the reliability-based optimization process are investigated from a numerical efficiency and accuracy point of view. [ABSTRACT FROM AUTHOR]

In this paper, a novel approach to numerically design a microwave (MW) shield is proposed. The strategy is based upon the interplay between a reduced model, formed by three periodical element teeth in a waveguide, and a full model composed of an entire shield, a metallic cavity, and the open space. A correlation criterion is implemented to avoid the divergence between the physical responses of the models. In order to save computational time, the evaluation of less influent design variables is included, and preoptimization is performed. The compact range method has been experimentally applied to test the optimized MW shield. A comparison between computed and measured electromagnetic leakages is presented and discussed. Measured scattering parameter S21 is lower than −30 dB over the industrial, scientific, and medical frequency band, confirming the adequacy of the strategy. [ABSTRACT FROM AUTHOR]

Multidisciplinary optimization strategies are widely used in the static case and can be extended to a problem with a time-domain model in order to reduce optimization time. The waveform relaxation method is a fixed-point approach applied to waveforms, which allows the coupling of dynamic models. Using the individual discipline feasibility strategy, the coupling is transferred to the optimization problem and leads to a high decrease of the number of model evaluations compared with the multidisciplinary feasibility strategy. The drawback of this approach might be the increased number of optimization variables, but it is coped through an efficient way to compute the derivatives of time-dependent variables. [ABSTRACT FROM AUTHOR]

The surrogate-based optimization is largely used in engineering design to find optimal performance characteristics of computational expensive simulations such as the finite element method. An original multiple surrogate-based optimization criterion is proposed. The approach was tested on the Zakharov benchmark function and on the Loney solenoid benchmark problem. Simulation results and comparisons with some traditional Kriging-based global optimization methods show that the proposed method can be used very effectively in electromagnetic design optimization. [ABSTRACT FROM PUBLISHER]

A kriging-based optimization approach is proposed for problems with large data sets and high dimensionality. Memory usage is maintained via model centering aided by minimizing the impact of information loss on accuracy of new point prediction using points aggregation techniques. The eight-parameter TEAM problem 22 is revisited in the context of computational efficiency and accuracy. [ABSTRACT FROM AUTHOR]