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The aim of this paper is to simulate the performances of a ground fault circuit-breaker (GFCB) relay with new low-nickel-content alloys. Indeed, in the construction industry, the materials become more expensive as their nickel content increases. Moreover, the demand for nickel is particularly sensitive to the economic conjuncture. Therefore, an original electromagnetic relay model has been developed and validated in different working conditions (current amplitude, frequency, and temperature). A dedicated magnetic characterization of materials is needed, using basically a usual and industrial GFCB relay for reference and design data in modeling. First, the magnetic model of the relay is built and checked against experimental data. The simulation may predict the tripping current threshold of the relay. On the other hand, new low-nickel-content alloys for relay parts are studied in this framework, thanks to the developed model. The effects of temperature on the magnetic properties of the candidate materials and the electrical performances of the virtual relays are presented. The results, analysis, and conclusions are given. Finally, a first attempt to predict the economic gain obtained with a change of material is made. [ABSTRACT FROM AUTHOR]

This paper proposes an approach to systematically find the optimal geometry of electromagnetic energy harvesters through topology optimization. The energy harvesters designed herein have a pickup coil and permanent magnets (PMs) integrated with a magnetic back iron, completing a closed-loop magnetic circuit. The configuration and geometries of the PMs and back iron are simultaneously determined using topology optimization. The optimization goal is to maximize the root-mean-square (rms) value of the harvested output voltage, which is calculated based on the Lagrange polynomial interpolation with finite-element analysis. The sensitivity needed to solve the optimization problems is obtained using the adjoint variable method. The proposed optimization approach successfully determines the optimal design of the PMs and back irons. The optimized design consists of two PM pieces with opposite magnetization directions (to rapidly alternate the magnetic field direction) and shaped back irons (to minimize the magnetic reluctance). The optimized design significantly improves the electromagnetic performance of harvesters (a $42.5\times $ increase in the rms output voltage with decreases in the volumes of the PM and iron), compared with an initial benchmark design determined through intuition. [ABSTRACT FROM AUTHOR]

There has been increasing attention to the use of voice coil actuators (VCAs) for precision motion applications. In this paper, a detailed design of a cylindrical VCA is presented. Different options for the overall configuration are evaluated according to various criteria and design variables are defined for the chosen configuration. After that, optimization parameters are derived to maximize the performance in a precision motion application by maximizing the acceleration and minimizing the heat dissipation. Design parameters are optimized using finite element analysis to evaluate the magnetic properties. Optimization is carried out using the bulk volume of coil, which allowed electrical properties to be later characterized via the selection of wire gauge. Calculations for evaluating resistance, inductance, current drain, and voltage supply requirements for dc and dynamic cases are presented. Magnetic field predictions and formulations used in force calculations are verified in experiments. [ABSTRACT FROM AUTHOR]

Heat-assisted magnetic recording (HAMR) allows for data writing in hard disks beyond 1 Tb/in ^2 areal density, by temporarily heating the area of a single bit to its Curie temperature. The metallic optical antenna or near-field transducer (NFT), used to apply the nanoscale heating to the media, may self-heat by several hundreds of degrees. With the NFT reaching such extreme temperatures, demonstrations of HAMR technology experience write-head lifetimes that are orders of magnitude less than that required for a commercial product. Hence, heating of the NFT is of upmost importance. In this paper, we first derive fundamental limits on the temperature ratio NFT/Media to drive NFT design choices for low-temperature operation. Next, we employ inverse electromagnetic design software, which solves for unexpected geometries of the NFT and waveguide. We present computationally generated designs for the waveguide feeding the NFT that offer a 50% reduction in NFT self-heating ( \sim 220~^\circ \textC ) compared with typical industry designs. [ABSTRACT FROM AUTHOR]

In high voltage (HV) technology, the electrical field distribution can be improved using different field grading methods. These can be categorized into two groups: 1) capacitive or geometrical field grading and 2) resistive field grading. To obtain the optimized field grading effects, some geometrical or material parameters of the HV devices should be optimized. However, these devices are often nonrotationally symmetric and simulation is computationally very time consuming. In this paper, a multilevel surrogate method using co-Kriging methodology is proposed to optimize such large-scale 3-D HV devices. To compute the electrical field distribution of these HV devices, a finite-element method simulator can be run at different levels of complexity, i.e., by reducing the 3-D model into a 2-D model under certain additional assumptions. The co-Kriging method combines expensive runs of highly complex 3-D simulations with relatively inexpensive dimension reduced 2-D simulations. This approach is shown to allow for a faster optimization of a large-scale nonrotationally symmetric problem, while preserving a sufficiently high level of accuracy. [ABSTRACT FROM PUBLISHER]

Biomedical electrical impedance tomography (EIT) seeks to image the interior conductivity spatial distribution within a 3-D object. In this paper, we propose a novel excitation mode of 3-D EIT for generalized back projection algorithm (GBPA). The new injection configuration is optimized by particle swarm optimization making the equipotential distribution monotonic, so that the projection matrix of GBPA would be computed more accurate and available. In addition, the GBPA reconstruction results in the optimized mode are compared with those in multisection simultaneous adjacent excitation mode assessed by several metrics in simulation experiments. [ABSTRACT FROM PUBLISHER]

The magnetic nanoparticles (MNPs) in ac alternating magnetic fields will produce a sufficient amount of heats owing to the Néel and Brown relaxations. Magnetic fluid hyperthermia (MFH), based on this mechanism, is a new promising approach for tumor treatments. The temperature field distribution in the cancer and its neighbor regions have a significant effect on the therapeutic effect of MFH. As a result, it is generally required to maintain the temperature in the cancer in the range of 42 °C–90 °C while guaranteeing a sharp temperature gradient in the neighbor regions of the cancer and healthy tissues. This paper provides an automated shape and MNP volume fraction solid design optimization methodology with finite element analysis, coupled field analysis, and an enhanced multiobjective quantum particle swarm optimization, to realize the aforementioned two ultimate goals. Moreover, an optimal radial basis function approximation technique is proposed to approximate the distribution of the optimized nanoparticles volume fraction solids to give a smooth and implementable nanoparticles distribution. [ABSTRACT FROM PUBLISHER]

The selection of optimal parameters during the design of an electric motor is a multivariable and multimodal optimization problem that requires a considerable amount of computational calculation time. To solve this type of problem, this paper proposes a novel multimodal optimization algorithm that is assisted by a surrogate model using the newly developed compressed sensing theory. Its effectiveness is confirmed by comparing the optimization results for test functions with the results of conventional optimization methods. These results show that the proposed method has more rapid and accurate convergence characteristics than conventional approaches. To verify the feasibility of its application to electric motors, an in-wheel motor is designed using the proposed algorithm. [ABSTRACT FROM PUBLISHER]

This paper presents a fast shape optimization method for antennas using proper orthogonal decomposition (POD)-based model order reduction (MOR). In this method, the finite element region is subdivided into design and ambient regions. The former includes antennas, whose shapes are optimized, whereas the latter includes air and perfect matched layer. Since the electromagnetic fields significantly change in the design region during the optimization process, POD-based MOR is only applied to the ambient region. In addition, MOR for both shape and frequency responses is performed for optimization of wideband antennas. It is shown that the present method can effectively reduce the computational time without deteriorating performance in the optimization. [ABSTRACT FROM PUBLISHER]

In electromagnetic design, uncertainties in design variables are inevitable, thus in addition to pursuing the theoretical optimum of the objective function the evaluation of robustness of the optimum solution is also critical. Several methodologies exist to tackle robust optimization, such as worst case optimization and gradient index; this paper investigates the use of standard deviation and mean value of objective function under uncertainty of variables. A modified Kriging model with the ability of balancing exploration and exploitation is employed to facilitate the objective function prediction. Two TEAM benchmark problems are solved using different methodologies to compare the advantages and disadvantages of different robust optimization approaches. [ABSTRACT FROM PUBLISHER]

This paper presents a topology optimization method for multimaterial models based on the normalized Gaussian network. In this method, one can determine optimal shapes of machines that are composed of various materials, such as iron, magnetic, and non-magnetic material. The present method is applied to the optimization of the average torque for interior permanent magnet motor to determine the distributions of magnetic core and flux barrier as well as magnets. The optimization results show that average torque can be improved using as small amount of magnet as possible. In addition, the characteristic of the present method is discussed in detail. [ABSTRACT FROM PUBLISHER]

This paper presents the topology optimization of a synchronous reluctance motor using the normalized Gaussian network. In the optimization, the average torque and iron loss are considered. In the resultant motor, the area of the rotor surface adjacent to the stator is found to be reduced when the weight for the iron loss is sufficiently large. On the other hand, large flux barriers are present in the rotor when the average torque is maximized without considering the iron loss. [ABSTRACT FROM PUBLISHER]

This paper proposes a strategy for the optimal design of a synchronous motor with permanent magnets on the rotor surface. The proposed strategy includes several steps during which the general parameters of the rotor arrangements, currents in the stator windings, and the parameters of the slot tooth in the stator are consequently defined. The motor with the optimized cross section demonstrates significantly better performance than its initial prototype. All calculations are performed using industry-standard finite element method software. [ABSTRACT FROM PUBLISHER]

Permanent-magnet direct-drive generators (PMDDGs) running at low speed need large electromagnetic force to generate the necessary torque. This type of electromagnetic force is one of the sources for rotor mechanical stress. In actual operation, mechanical stress will be worsened by the rotor imbalance. In this paper, a joint optimization of electromagnetic and stress field analysis is developed for a PMDDG. The mechanical stress and deformation caused by rotor weight, eccentricity, and terminal fault conditions are optimized in transient structural analyses. The proposed method and model are employed to study electromagnetic forces acting on the rotor core of a 7 MW wind turbine generator. [ABSTRACT FROM PUBLISHER]

In this paper, hole sensitivity formula is analytically derived for topology optimization in magnetostatic system. With the concept of virtual hole, the hole sensitivity is obtained using continuum shape sensitivity. To demonstrate the validity of the hole sensitivity, topology optimization of synchronous reluctance motor is tested. Since the hole sensitivity formula is represented only with electromagnetic field, it is easily implemented for topology optimization. [ABSTRACT FROM PUBLISHER]

This paper presents parameter and topology optimizations of wideband antennas for microwave energy harvesters based on finite difference time-domain computations. The antenna shapes are optimized to reduce return losses in a specific frequency band using micro-genetic algorithm. The shape parameters of a two-arm planar spiral antenna are optimized. In addition, the topology optimization is performed using normalized Gaussian network, where spatial symmetries are assumed. It is shown that the return losses of the optimized antennas are <−10 dB from 1 to 2 GHz in which they have isotropic directivity. [ABSTRACT FROM PUBLISHER]

The nonlinear magnetic properties of an iron core should be considered when topology optimization (TO) is applied to a realistic problem. However, a scheme for introduction of the magnetic nonlinearity to material-density-based TO has not been rigorously established. In this paper, TO by using material density with magnetic nonlinearity is proposed. The numerical instability of the sequential linear programming method is a well-known topic. The stabilized sequential linear programming method, which realizes the stabilized convergence characteristics of an objective function, is proposed and investigated in the 3-D design problem of a magnetic circuit. [ABSTRACT FROM PUBLISHER]

Despite the surrogate-based two-level algorithms that have been proposed for accelerating the optimization procedures, it may be still expensive for large problems. Therefore, this paper proposes the exploration of the approximation characteristics of the wavelet functions to define a coarse subspace for this kind of approach with relatively few float point operations. The wavelet transform is used to create the coarse model in a two-level genetic algorithm (GA), which is applied to a set of benchmark test problems. Although the coarse model is simpler and less accurate than the fine model, it behaves similarly to this last one and the original function. Moreover, the approach prevented the convergence to local minima whenever the GA presented such behavior and it is faster than the use of principal components analysis. [ABSTRACT FROM PUBLISHER]

This paper discusses robust design issues in the multiobjective design of electromagnetic devices. A Pareto front of the worst cases of the solution due to the perturbation of the design variables is used to describe the robustness of a design. A robust dominance (r-dominance) relationship between two solutions of a multiobjective problem is defined. To reduce the computational cost of evaluating the robustness, a local response surface model is built on the uncertainty set. This robust multiobjective design scheme was applied to the design of an interior permanent magnet machine, where a tradeoff exists between the average torque and the torque ripple as the rotor angle is varied. The results show that the proposed r-dominance, when embedded in a multiobjective optimization search method, is able to find robust solutions to multiobjective design problems. [ABSTRACT FROM PUBLISHER]

This paper proposes a single-loop optimization strategy for efficient reliability-based electromagnetic design in the presence of uncertainty. Unlike conventional reliability-based optimization methods, optimization and reliability assessment are totally decoupled from each other during the overall design process. To achieve the desired design feasibility, constraint boundaries of an original design problem are shifted to feasible directions determined by the reliability information of a previous design. After all, the proposed single-loop method for reliability-based optimization performs a serial design of deterministic optimization with shifting constraints and reliability analysis. The proposed method is tested with a mathematical problem and the TEAM Workshop Problem 22, and its numerical accuracy and efficiency is examined by comparison with existing methods. [ABSTRACT FROM PUBLISHER]

Due to the existence of randomness and fuzziness in engineering problems, the reliable performance prediction is very complex. In addition, in the early design stage of a new product, the insufficient information on uncertainty further aggravates the difficulty of performance prediction and robustness evaluation. This paper suggests a new reliability analysis method using possibility theory to evaluate constraint feasibility even with insufficient uncertainty data in design variables. In order to save the computing time, two strategies of approximating performance constraints are proposed: 1) design sensitivity-based method and 2) dynamic Kriging-based method. Through applications to analytic example and engineering problem, the proposed methods are investigated and discussed. [ABSTRACT FROM PUBLISHER]

Harmony search (HS) algorithm is an evolutionary optimization algorithm developed in an analogy with an improvisation process where musicians try to polish their pitches to obtain a better harmony. In this paper, a modified HS (MHS) algorithm is adapted to multi-objective optimization using external archiving, ranking with crowding distance, and control parameters tuning based on Ricker map to solve a transformer design optimization (TDO) problem with two competing objectives. Simulations applied to a TDO problem demonstrate the effectiveness of the proposed multi-objective MHS algorithm. Results indicate that, compared with other multi-objective HS algorithm, in terms of output quality, the proposed MHS is able to find competitive solutions with a good tradeoff between the design objectives. [ABSTRACT FROM PUBLISHER]

This paper proposes a statistical probability approach to evaluate the quality loss function of electromagnetic design problems, which is expressed in terms of the first two statistical moments, mean and variance. A univariate dimension reduction method is employed to calculate the statistical moments of a performance function and their sensitivities accurately, and efficiently. Finally, the method is integrated into the robust design optimization algorithm. The proposed method explores an optimum design with statistical information so that it can provide a more accurate solution than other robust design methods. The proposed method is tested with a mathematical model and a blushless DC motor, and its numerical accuracy and efficiency are examined by comparison with existing methods. [ABSTRACT FROM PUBLISHER]

This paper presents a comparative study on different surrogate models for an application to multidimensional optimal design of electromagnetic devices. The surrogate model is combined with a heuristic optimization algorithm, which usually requires a lot of objective function calls. For this, various Kriging surrogate models, including dynamic Kriging (DK) and multiquadric radial basis function with optimal shape parameter, are investigated and discussed. In the DK surrogate model, the optimal combination of the basis functions is obtained using an improved binary particle swarm optimization algorithm. [ABSTRACT FROM PUBLISHER]

This paper proposes a sequential optimization methodology for designing an electrothermal polysilicon actuator in the presence of a fabrication tolerance. In the proposed method, a deterministic optimum is first sought from an initial design, and then a reliability-based robust design is obtained launching at the deterministic point. This serial design strategy can enhance numerical efficiency through minimizing the use of computationally expensive reliability-based design optimization. To effectively perform the robust design of very complex multiphysics problems, elaborate surrogate models based on the local window concept are exploited comprehensively. The proposed method is applied to an electrothermal polysilicon actuator with seven design random variables, and then three different nominal designs are examined in terms of maximum deflection, consumed power, and confidence level. [ABSTRACT FROM PUBLISHER]

The doubly fed dual-rotor flux-modulated (DFDRFM) machine is a promising electrical continuously variable transmission (E-CVT) concept for the hybrid electric vehicles as it has two mechanical ports and two electrical ports, which are highly desirable for E-CVT. In this paper, a novel DFDRFM machine is proposed. Compared with previous designs, the most prominent merits are its compactness and robustness. In addition, it is easy to manufacture. After introducing its structure and working principle, the influence of dimensions on its torque and loss is analyzed. A genetic algorithm and finite-element method-based design optimization method, which aims to increase the efficiency of the proposed machine, is presented. [ABSTRACT FROM PUBLISHER]

This paper focuses on the development of a low-cost system, based on Arduino, for the active shielding of magnetic fields generated by power systems at industrial frequency. The modeling of the source, the design and the optimization of the shielding loop, and, finally, the hardware (microcontroller, sensors, driven voltage source, etc.) and the control algorithm of a prototype system are described. A number of tests, developed through an experimental setup, are performed to validate the prototype. The main results are also discussed highlighting the capabilities of the proposed active shielding. [ABSTRACT FROM PUBLISHER]

Reducing the scattering and enhancing the bandwidth (BW) are two desirable aspects in cloak applications. In this paper, we propose their optimization using a simplified objective function, which avoids a costly detailed frequency sweep to get the BW at each iteration. The multi-objective characteristic of our optimization permits us to obtain a set of possible solutions (the Pareto-Front), which represents different compromises between the two objectives. Two examples of dielectric cloaks are presented and discussed. [ABSTRACT FROM PUBLISHER]

This paper presents robust topology optimization of electromagnetic machines by considering the magnetic degradation caused by mechanical and thermal stresses in punching, shrinking fitting, and other manufacturing processes. The topology optimization is performed using two methods: one is the robust genetic algorithm in which random noises are added to the magnetic characteristic parameters and the other takes the deviations in the objective and constraint functions due to the degradation into account. These methods are applied to optimization of the flux barrier shapes in an interior permanent magnetic motor to find that one can successfully realize robust design. [ABSTRACT FROM PUBLISHER]

Design optimization, favoring efficiency maximization, is the subject of extended current research in small electric traction motor applications, aiming the increase in efficiency to be achieved without compromising power density. This paper proposes a mixed technique based on a particular multi-objective, population-based optimization methodology, utilizing a strength Pareto evolutionary algorithm variant combined with the finite element method and analytical tools. The resultant motor design has been validated through measurements on a prototype in-wheel permanent magnet motor for a light electric vehicle. [ABSTRACT FROM PUBLISHER]

Both conformal mapping via Schwarz–Christoffel (SC) formulas and finite element methods (FEM) can provide accurate results in analyzing 2-D electric or magnetic fields. In the presence of curved boundaries with small radius of curvature, the first are normally constrained to introduce piecewise straight lines. The original contribution of this paper consists of presenting a reliable but simple procedure to smooth several sharp vertices of a polygonal boundary by the formula for rounded corners, and comparing the results with those obtained by replacing sharp corners with piecewise straight lines. Differences are perceived only in close proximity, and this quantitatively explains the similar results obtained from maps and from FEMs and provides reliable assessment of the obtainable results. Two approaches are followed. According to the first, sharp corner geometries are directly mapped into rounded corner ones, accepting small changes in the whole structure, and negligible only for small corner radii. According to the second, the simple optimization procedure of the SC prevertices allow us to match the original geometry in all details. [ABSTRACT FROM PUBLISHER]

In this paper, we optimize the size and position of silver hemispherical nanoparticles arranged in a regular array embedded in a thin-film heterojunction solar cell. The metallic nanoparticles are added in order to improve solar cell efficiency by exploiting the phenomenon of plasmon resonance. A finite-element code has been employed to compute the light scattered from the device and the optimization was performed at first by means of a genetic algorithm and then by means of the parallel self-adaptive low–high evaluation evolutionary algorithm. [ABSTRACT FROM PUBLISHER]

This paper presents the optimal design of a rotating eddy-current probe using the inverse problem method. The probe is dedicated to identify the electrical tensor conductivity of carbon fiber composite materials. A 3-D anisotropic shell elements model associated with annealing optimization algorithm is used to minimize the goal function. [ABSTRACT FROM PUBLISHER]

This paper describes a pulsed eddy current nondestructive evaluation of an annular groove dimensions using a simplex inversion method associated with a semianalytical direct model, in axisymmetric case. The proposed semianalytical formulation, used for direct calculations, is developed from coupled electric circuits modeling. It uses the current excitation allowing the determination of the sensor voltage. The feature of the variation of voltage provides information on the electromagnetic and geometrical properties of the device. The transient sensor voltage is then calculated, allowing the evaluation of the groove dimensions of the considered work piece. The peak’s amplitude and the zero and peak crossing times are used to determine these properties. [ABSTRACT FROM PUBLISHER]

This paper proposes a method to the model constraints from different models to run an optimization over models with different granularities. Through machine learning, the proposed method has proven to be able to accurately map the constraints and minimize the number of call to the model. It handles both continuous and discrete variables and mixes design rules to statistic approach to create a surrogate of the model. [ABSTRACT FROM PUBLISHER]

Brain storm optimization (BSO) is a novel population-based swarm intelligence algorithm based on the human brainstorming process. BSO has been proven feasible and has been successfully applied to benchmark problems in the electromagnetic field. In this paper, inspired by the mechanism of quantum theories, a novel variant of BSO algorithm, called quantum-behaved BSO (QBSO), is proposed to solve an optimization problem modeled for Loney’s solenoid problem. The new mechanism improves the diversity of population and also utilizes the global information to generate the new individual. Simulation results show that QBSO has better ability to jump out of local optima and perform better compared with the basic BSO. [ABSTRACT FROM AUTHOR]

In this paper, we present a method to solve inverse problems of electromagnetic circuit design, which are formulated as a topology optimization problem. Indeed, by imposing the magnetic field inside a region, we search the best material distribution into variable domains. To perform this, we minimize the quadratic error between the prescribed magnetic field and the one computed by a finite element method (FEM). A dedicated software was developed in MATLAB using fmincon routine and FEM Magnetics (FEMM) software; this code is named ATOP^TO for algorithm to optimization propulsion using topology optimization. To perform the first derivative of the objective function, we implemented an adjoint variable method. Indeed, this approach makes it possible to provide the derivative by only two uses of the finite element tool. Nevertheless, the problem is discrete because we take only two possibilities: with or without material. Thus, the solid isotropic material with penalization method was used to penalize intermediate values to have discrete solutions. Some numerical experiments with 40 and 800 variables concerning circuit designs validated our approach. This represents a first study to design a Hall effect thruster. [ABSTRACT FROM AUTHOR]

Backtracking search algorithm (BSA) is a novel evolutionary algorithm (EA) for solving real-valued numerical optimization problems. In this paper, an adaptive BSA (ABSA) is proposed to solve the optimization problem of an induction magnetometer (IM). In the adaptive algorithm, the probabilities of crossover and mutation are varied depending on the fitness values of the solutions to refine the convergence performance. The proposed ABSA will also be compared with basic BSA and other widely used EA algorithms. Simulation results show that ABSA is better able to solving the IM optimization problems. [ABSTRACT FROM AUTHOR]

In planar switched reluctance motors (PSRMs), the electromagnetic force ripple minimization is important to reduce the noise and vibration for high-precision motions. In this paper, an improved PSRM by optimization design for minimization of the electromagnetic force ripple is proposed. The structure, principle, and mathematical model of the PSRM are clarified. Based on Ansoft Maxwell, optimization design of the PSRM is performed by improved structure with smaller pole pitch and incremental number of mover poles. Experiments of the improved PSRM are implemented based on dSPACE. The experimental results verify that the improved PSRM effectively reduces electromagnetic force ripple with planar trajectory tracking. [ABSTRACT FROM AUTHOR]

This paper deals with design optimization of air-cored permanent magnet linear synchronous motors with overlapping windings to achieve high thrust per volume, high thrust per coils quantity, high motor constant, and low thrust ripple simultaneously for ultra-precise positioning stage with air-bearing. Based on accurate magnetic field model, motor parameters such as flux density, inductive electromotive force (EMF), thrust per volume, thrust per coils quantity, and thrust ripple are analyzed. A multiobjective optimization method with weight coefficients is proposed by applying the multiple population genetic algorithm. The design optimization is verified by 3-D finite element analysis and experimental results. [ABSTRACT FROM AUTHOR]

A kind of arc-structure permanent-magnet synchronous machine (AS-PMSM) used for scanning system, which requires high positioning accuracy, high response performance, and wide scanning range, is proposed and researched in this paper. The AS-PMSM is able to replace the traditional rotary motor plus gear box to realize the directly driving and limited angular movement. To ensure the high positioning accuracy and high response performance, the torque characteristics are researched. A new method is proposed to detach the torque \(T_{ \rm {slot}}\) caused by slotting and the end torque \(T_{ \rm {end}}\) caused by stator end effect for AS-PMSM. Considering the large torque \(T_{ \rm {end}}\) , the average torque and especially torque ripple are optimized from the aspects of stator central angle and permanent-magnet (PM) shape. Furthermore, the edge PM mounted on the end of the rotor is optimized by adopting asymmetry shape to improve the smooth scanning range. After all the optimization, the smooth scanning range with a satisfying torque ripple limited in 3% is much increased by 19.5%. [ABSTRACT FROM AUTHOR]

This paper presents a novel implementation of the sensitivity analysis with an improved Tabu search algorithm for the optimal design methodology of electromagnetic devices using finite-element method (FEM). A direct sensitivity formulation is proposed to calculate the sensitivity versus design variables by postprocessing the FEM result only once, and hence, it is expected to be very well received by the industrial users. The sensitivity analysis is also used as an indication of step vector to enhance the search performance during the optimization process. Further improvements, including a transition criterion for different current states and the introduction of a Tabu list with binary space partitioning tree, have been introduced to help obtaining the global optimum rapidly, as these are particularly useful for time-consuming optimal design problems. Optimal design examples of electromagnetic devices are reported to positively demonstrate the feasibilities and advantages of the proposed algorithm in practical engineering. [ABSTRACT FROM AUTHOR]

This paper proposes a new magnetic planetary geared permanent magnet brushless (MPG-PMBL) machine for hybrid electric vehicles. According to the dynamic performances in hybrid electric vehicles, the proposed machine needs to offer the advantages of high power density, high efficiency, and low torque ripple. To realize these goals, a multi-objective optimization design method based on the combined design of experiments approach and response surface method is presented, where three key optimization objectives of the efficiency, total loss, and cogging torque are selected. After the optimization, some reasonable key design variables are determined and the proposed MPG-PMBL machine is newly designed and built for evaluation. Both theoretical analysis and experimental results verify the validity of the proposed optimization method. [ABSTRACT FROM AUTHOR]

In order to optimize the preformation of the field free line (FFL) for human-targeted clinical magnetic particle imaging, an advanced design for the generation of FFL with two pairs of concentric circular coils is proposed in this paper. Simulation study using FEM software was performed to study the relationship between the coil geometric parameters and the FFL quality. Particle-swarm optimization algorithm was performed to optimize the coil topology to gain a highly homogenous gradient field. The results demonstrated that high quality FFL can be generated by the concentric circular coil pairs and the topology of the concentric circle coils is also promising for the human target clinical usage, with the rotation of the FFL just perpendicular to the movement direction of patients inside. [ABSTRACT FROM AUTHOR]

\(A~priori\) evaluations of inductance, stray capacitance, and dc resistance are important aspects in optimizations of inductors. In this paper, analytical formulas of the inductance (self and mutual), dc resistance (solid and litz wires), and the stray capacitances of coaxial inductors were derived for both hexagonal and orthogonal windings. Possible imperfections that occurred during the fabrication process were accounted by the inclusion of axial and azimuth filling factors into the formulations. The formulas presented here were validated using several coaxial coils with rectangular cross sections as reported in the literature and double tested by measurements. Discrepancies between estimated and measured values were less than 1%. The advantage of the present formulation is that optimization efforts are addressed at the earliest stages possible of inductor conception and construction. [ABSTRACT FROM PUBLISHER]

Five-phase surface-mounted permanent-magnet machines can inherently produce a smooth electromagnetic torque which can be increased when using third harmonic current injection. To really take advantage of these characteristics, the rotor magnets can be shaped to obtain a back electromotive force with large third harmonic term. This is the scope of this paper. For the design specifications of a low-speed marine propulsion machine, the following objective must be achieved: to significantly mitigate the pulsating torque without reducing the average torque bearing in mind the solution where the rotor is made with full pole-pitch magnets. An analytical field computation, called equivalent coil method, is developed to quickly explore the magnet geometries. Thus a procedure to optimize small trapezoid notches at the surface of the pole magnets is performed. Referring to the classical fully pole-pitch magnet shape, the solution found allows a substantial reduction of the pulsating torque without reducing the torque density. Furthermore, with regard to an equivalent three-phase machine, for the same copper losses, the average torque of the optimized five-phase machine can be potentially higher if the third harmonic current injection is implemented. [ABSTRACT FROM PUBLISHER]

In this paper, the design optimization of an interior permanent magnet synchronous machine is presented using lumped parameter model and genetic algorithms for 42 V integrated starter alternator application. The aim of the optimization is to increase starting torque while keeping torque ripple below 10% and increasing power output in generating mode at high speed and reducing the permanent magnet weight. A finite-element method is used to verify and compare the optimized machine characteristics. [ABSTRACT FROM PUBLISHER]

Harmony search (HS) is a novel heuristic algorithm that imitates the improvisation process of musicians. The feasibility of HS algorithm has already been proven on several benchmark problems. In this paper, HS is proposed to solve Loney's solenoid problem. To further enhance the convergence efficiency of HS, the improvisation with a Gaussian factor is employed. The newly developed algorithm, which is named Gaussian HS (GHS), can succeed in solving Loney's solenoid problem according to the numerical simulations. Comparative results show that our proposed GHS outperforms HS and particle swarm optimization in both the convergence speed and efficiency. [ABSTRACT FROM PUBLISHER]

From a computational point of view, the identification of Bouc-Wen (BW) hysteresis model is a hard task due to the large number of parameters to be found. This is one of the reasons for which it is rarely used for modeling magnetic hysteresis, where other hysteresis models are widely used (e.g., Preisach and Jiles–Atherton). However, the opportunities that the differential expression of BW model could offer for its use in more complex computation task (e.g., nonlinear inductors inserted into a circuit and so on) justify a deeper investigation on its adoption in ferromagnetism. In this paper, using a new hybrid heuristic called metric-topological–evolutionary optimization (MeTEO), the BW identification is presented. MeTEO is a powerful algorithm based on a synergic and strategic use of three evolutionary heuristics: 1) the flock-of-starlings optimization, which shows not only high exploration capability, but also a lack of convergence; 2) the particle swarm optimization, which has a good convergence capability; and 3) the bacterial chemotaxis algorithm, which has no collective behavior or exploration skill, but has high convergence capability. MeTEO is designed to use parallel architectures and exploits the fitness modification technique. Numerical validations are presented in comparison with the performances obtained using other approaches available in the literature. [ABSTRACT FROM AUTHOR]

The gravitational search algorithm (GSA) is a novel metaheuristics approach inspired by the laws of gravitation and motion. In GSA, a set of agents, called masses, searches the design space to find the optimal solution by simulation of Newtonian laws of gravity and motion. In this paper, a standard and an improved GSA (IGSA) approach based on a quasi-oppositional approach are presented and tested on a magnetic pole design benchmark. Results indicate that the performance of proposed IGSA on the magnetic pole design is better than that of classical GSA. [ABSTRACT FROM AUTHOR]