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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]

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]

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]

Automatic differentiation (AD) is introduced as a powerful technique to compute derivatives of functions given in the form of computer programs in high-level programming languages such as FORTRAN, C, or C++. This paper applies AD to compute error-free gradients of electromagnetic device sizing models. Then, the obtained gradients are exploited in optimization to size electromagnetic devices by means of minimizing a cost function with constrained parameters and performances. Often, the electromagnetic devices models have to be described not only by analytical formulas, but also by algorithms. This paper proposes an electromagnetic model of a linear actuator dealing with implicit equations solved by numerical algorithms. The ADOL-C package is considered for automatic differentiation. [ABSTRACT FROM PUBLISHER]

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]

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]

In order to reduce the thrust ripple of linear servo system, a double-sided air core permanent magnet linear servo motor with trapezoidal shape permanent magnets (TDAPMLSM) is proposed in this paper. An analytical model of the motor for predicting the magnetic field in the air-gap at no-load is introduced. This model is derived based on the equivalent magnetization intensity method, and its accuracy is validated by using the results obtained from the finite-element method. The key dimensions that affect the air-gap magnetic field are analyzed based on the analytical model, and the design is optimized by using genetic algorithm. A thrust ripple reduction of 70.6% is achieved by optimization. The proposed analytical model may be used for a quick and reliable design and design optimization of the TDAPMLSM. [ABSTRACT FROM AUTHOR]

Magnetic resonant wireless power transfer (MRWPT) technology has great potential in delivering power to bio-implantable devices as it obviates the need to have expensive battery replacement surgery. However, no systematic design method has been reported in this important area. In this paper, a design method of MRWPT system for bio-implantable devices, including detailed procedures, is proposed to realize maximum power transfer efficiency. Considerations on the basic dimensions of the system are outlined, and ways to express the impedance coefficients matrix of equivalent circuit model as functions of system variables are given. Experiment is carried out to verify the validity and effectiveness of the proposed design method. [ABSTRACT FROM AUTHOR]

In this paper, a synthesis of design methodologies for electromagnetic devices made with soft magnetic composite (SMC) material is presented. To realize efficient and low-cost SMC devices, it is necessary to benefit from interesting isotropic SMC material properties such as 3-D flux circulation path. In this case, the best approach is to carry out a topological structure research and perform a global optimization using physical models. However, the iterative optimization process can be computationally intensive and some compromises should be found between accuracy and computation time. One way is to use coarse models with important simplifying hypotheses but the optimal solution is often not valid. In this case, one can perform a limited number of finite element (FE) simulations to compute some correction coefficients and improve optimization convergence to a valid optimal solution. Another way is to perform the device optimization by using directly FE models with low mesh density and several simplifications of the device geometry. Such design approaches are illustrated by three concrete realizations with SMC material. [ABSTRACT FROM AUTHOR]

In this paper, the actual synthesis of the thermal field is proposed and solved as an inverse problem, considering a fully coupled magnetic-thermal analysis as for the direct problem. Reference is made to an air-cored inductor for magnetic fluid hyperthermia (MFH). [ABSTRACT FROM PUBLISHER]

Magnet segmentation is an effective and simple technique for cogging torque reduction in high power permanent-magnet (PM) synchronous machines; however, it deteriorates air gap flux density and decreases the output torque. Therefore, a multiobjective optimization framework is necessary for cogging torque minimization, and to diminish its adverse effect on the output torque in segmented-pole permanent-magnet synchronous machines (PMSMs). This can be fulfilled by proper selection of widths and displacements of the magnet segments. Finite-element analysis (FEA) is an accurate method for this purpose. However, it is very time consuming where finding optimal configuration needs a lot of simulations. Thus, an analytical based design optimization is very useful and eases the design process. In this paper, a novel semianalytical model for cogging torque computation in PMSMs is proposed. Based on the proposed model, a multiobjective optimization framework is developed. The particle swarm optimization (PSO) method is applied to find the optimum machine design. To show the effectiveness of the proposed method, two prototype segmented magnet PMSMs with two and three PM blocks per pole are optimized respectively. Performance characteristics are compared to the initial machine design and segmented PMSMs with design parameters chosen according to previous analytical models and initial uniform pole machines using FEA. [ABSTRACT FROM PUBLISHER]