Emerald | COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering | Table of Contents http://www.emeraldinsight.com/0332-1649.htm Table of contents from the most recently published issue of COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering Journal en-gb Tue, 29 Apr 2014 00:00:00 +0100 2013 Emerald Group Publishing Limited editorial@emeraldinsight.com support@emeraldinsight.com 60 Emerald | COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering | Table of Contents http://www.emeraldinsight.com/common_assets/img/covers_journal/compelcover.gif http://www.emeraldinsight.com/0332-1649.htm 120 157 Guest editorial: Optimization and inverse problems in electromagnetism http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108515&show=abstract <strong>Abstract</strong><br /><br />Not available. Article literatinetwork@emeraldinsight.com (Guillaume Crevecoeur, Luc Dupre) Thu, 03 Apr 2014 00:00:00 +0100 Topology optimization of rotor poles in a permanent-magnet machine using level set method and continuum design sensitivity analysis http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108575&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - In this paper, a numerical approach to the topology optimization is proposed to design the permanent magnet (PM) excited machines with improved high-speed features. For this purpose the modified multi level set method (MLSM) was proposed and applied to capture the shape of rotor poles on the fixed mesh using FE analysis.<B>Design/methodology/approach</B> - This framework is based on theories of topological and shape derivative for the magnetostatic system. During the iterative optimization process, the shape of rotor poles and its evolution is represented by the level sets of a continuous level set function f. The shape optimization of the iron and magnet rotor poles is provided by combining continuum design sensitivity analysis with level set method (CDSA).<B>Findings</B> - To obtain an innovative design of the rotor poles composed of different materials, the modified MLSM is proposed. An essential advantage of the proposed method is its ability to handle a topology change on a fixed mesh by nucleating a small hole in design domain that leads to more efficient computational scheme then standard level set method.<B>Research limitations/implications</B> - An essential advantage of the MLSM-based algorithm is its ability to handle a topology change on a fixed mesh by nucleating a small hole in design domain that leads to more efficient computational scheme then standard level set method. <B>Originality/value</B> - The novel aspect of the proposed method is the incorporation of The Total Variation regularization in the MLSM, which distribution is additionally modified by the gradient derivative information, in order to stabilize the optimization process and penalize oscillations without smoothing edges. Article literatinetwork@emeraldinsight.com (Piotr Putek, Piotr Paplicki, Ryszard Palka) Thu, 03 Apr 2014 00:00:00 +0100 Bi-objective optimization of induction machine using interval-based interactive algorithms http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108583&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Discrete highly-constrained optimization of induction machine taking into consideration two objective functions: efficiency and total costs of production.<B>Design/methodology/approach</B> - Interactive and semi-interactive interval-based optimization methods were used. Two concepts of multi-objective discrete optimization were proposed.<B>Findings</B> - Proposed methodology and algorithms allow decision maker participate in the process of optimal design and therefore decrease the total time of optimization process. The search procedure is straightforward and it does not require special skills of decision maker. Presented methods were successfully versified for the problem of optimal design with discrete variables. <B>Research limitations/implications</B> - Three interval algorithms suitable for inverse problems are researched and verified. It generally can be used for multi-objective problems. The dominance principles for interval boxes are showed in the article. Proposed algorithms are based on the idea of hybridization of exact and evolutionary methods. <B>Practical implications</B> - Proposed approaches were successfully implemented within computer-aided application which is used by manufacturer of high power induction machine.<B>Originality/value</B> - The concept of pareto-domination using the interval boxes can be treated as original. We researched several elimination rules and discuss the difference between different approaches. Article literatinetwork@emeraldinsight.com (Dmitry Samarkanov) Thu, 03 Apr 2014 00:00:00 +0100 Framework for the optimization of online computable models http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108560&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The main idea is to make easily accessible models to test and compare the optimization algorithms we develop. <B>Design/methodology/approach</B> - For this, we propose an optimization framework based on software component, web-service, and plug'in to exploit these models in different environments.<B>Findings</B> - We illustrate our discussion with optimizations in Matlab™ and R (www.r-project.org) of a transformer described and exploitable from the Internet.<B>Originality/value</B> - The originality is to make easy implementation of simulation model and optimization algorithm coupling using software component, web-service, and plug'in. Article literatinetwork@emeraldinsight.com (Benoit Delinchant, Frédéric Wurtz, Joao Vasconcelos, Jean-Louis Coulomb) Thu, 03 Apr 2014 00:00:00 +0100 A modified lambda algorithm for optimization in electromagnetics http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108539&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - To show with the help widely used analytical and application-oriented benchmark problems that a novel and relatively uncommon optimization method, lambda optimization, can be successfully applied to the solution of optimization problems in electromagnetics. Furthermore an improvement to the method is proposed and its effectiveness is validated.<B>Design/methodology/approach</B> - An adaptive probability factor is used within the framework of lambda optimization.<B>Findings</B> - It is shown that in the framework of lambda optimization the use of an adaptive probability factor can provide high-quality solutions with small standard deviation on the selected benchmark problem.<B>Research limitations/implications</B> - Although the chosen benchmarks are considered to be representative of typical electromagnetic problems, different test cases may give less satisfactory results.<B>Practical implications</B> - The proposed approach appears to be an efficient general purpose stochastic optimizer for electromagnetic design problems.<B>Originality/value</B> - This paper introduces and validates the use of adaptive probability factor in order to improve the balance between the explorative and exploitative characteristics of the lambda optimization algorithm. Article literatinetwork@emeraldinsight.com (Piergiorgio Alotto, Leandro dos Santos Coelho, Viviana Cocco Mariani) Thu, 03 Apr 2014 00:00:00 +0100 Simple sensitivity calculation for inverse design problems in electrical engineering http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108517&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The paper presents a simple approach for calculation of the sensitivities in the free-form inverse design problems. The approach is based on the analogy with the similar tasks used in the signal-processing analysis. In the proposed case it is not required to solve an adjoint problem as in the most of the similar optimization tasks. The simulation engine used in the background is a Fast Boundary Element Method. The approach is validated on some known benchmark problems<B>Design/methodology/approach</B> - Invers design is recognized nowadays as a crucial scientific grand challenge. Contrary to the conventional approach ("Given the structure, find the properties") it purses a new paradigm ("Given the desired property, find the structure"). Inverse class of problems has a broad application area, from the material-, medical-, bio- to the engineering-class of problems. When dealing with the inverse design in free-form optimization of the engineering problems the typical approach is to calculate the adjoint problem. Calculation of the adjoint problem mostly requires the costly calculation of the gradients, which makes the whole optimization procedure rather expensive due to the high computational burden required for their solution. In this paper it is proposed a novel Simple Sensitivity Approach (SSA) to get in a fast way the response (sensitivity) function of the analyzed structure. The simulation engine used in the background is the Fast Boundary Element Method <B>Findings</B> - Invers design is recognized nowadays as a crucial scientific grand challenge. Contrary to the conventional approach ("Given the structure, find the properties") it purses a new paradigm ("Given the desired property, find the structure"). Inverse class of problems has a broad application area, from the material-, medical-, bio- to the engineering-class of problems. When dealing with the inverse design in free-form optimization of the engineering problems the typical approach is to calculate the adjoint problem. Calculation of the adjoint problem mostly requires the costly calculation of the gradients, which makes the whole optimization procedure rather expensive due to the high computational burden required for their solution. In this paper it is proposed a novel Simple Sensitivity Approach (SSA) to get in a fast way the response (sensitivity) function of the analyzed structure. The simulation engine used in the background is the Fast Boundary Element Method <B>Originality/value</B> - Novel apprach for inverse desing when performing the free-form optimization of engineering problems Article literatinetwork@emeraldinsight.com (Zoran Andjelic) Thu, 03 Apr 2014 00:00:00 +0100 Optimal household energy management using V2H flexibilities http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108591&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The use of energy storage devices helps the consumers to utilize the benefits and flexibilities brought by smart networks. One of the major energy storage solutions is using electric vehicle batteries. This paper develops an optimal energy management strategy for a consumer connected to the power grid equipped with V2H power supply and renewable power generation unit (PV).<B>Design/methodology/approach</B> - The problem of energy flow management is formulated and solved as an optimization problem using a linear programming model. The total energy cost of the consumer is optimized. The optimal values of decision variables are found using CPLEX solver. <B>Findings</B> - The simulation results demonstrated that if the optimal decisions are made regarding the V2H operation and managing the produced power by solar panels then the total energy payments are significantly reduced. <B>Originality/value</B> - The gap that the proposed model is trying to fill is the holistic determination of an optimal energy procurement portfolio by using various embedded resources in an optimal way. The contributions of this paper are in threefold as: • The introduction of mobile storage devices with a periodical availability depending on driving schedules. • Offering a new business model for managing the generation of PV modules by considering the possibility of grid injection or self consumption. • Considering Real Time Pricing (RTP) in the suggested formulation. Article literatinetwork@emeraldinsight.com (Ardavan Dargahi, Stéphane Ploix, Alireza Soroudi, Frédéric Wurtz) Thu, 03 Apr 2014 00:00:00 +0100 Optimization of EMI filters for electrical drives in aircraft http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108523&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The paper deals with the design of passive filter for power electronics voltage inverters used in aircraft electrical drives (a permanent magnet synchronous machine fed by a 6-phase voltage inverter with PMW control), using optimization for both sizing and sensibility analyses.<B>Design/methodology/approach</B> - The approach is generic. An aid allows to modify easily the frequency model and so to check various study cases, and to carry out the filter optimization for different topologies or control strategies.<B>Findings</B> - The approach is generic. An aid allows to modify easily the frequency model and so to check various study cases, and to carry out the filter optimization for different topologies or control strategies.<B>Research limitations/implications</B> - The power electronics load is supposed to be a set of predefined harmonic sources, obtained by experiment or time simulation plus FFT before the optimization process.<B>Practical implications</B> - The problem has numerous constraints on the components, mainly technological constraints. The volume is minimized, respecting electromagnetic standards and an EMI filter prototype has been made. <B>Originality/value</B> - The frequency model is automatically generated. A complex aircraft application has been studied thanks to the approach. Several sensibility analyses have been carried out. An EMC filter has been sized and an experimental prototype has been made, comforting the sizing by optimization. Article literatinetwork@emeraldinsight.com (Laurent Gerbaud, Baidy Touré, Jean-Luc Schanen, Régis Ruelland) Thu, 03 Apr 2014 00:00:00 +0100 Adaptive level set method for accurate boundary shape in optimization of electromagnetic systems http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108550&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - This paper presents a new numerical technique, called adaptive level set method, for use with the finite element method.<B>Design/methodology/approach</B> - A conventional level set method using the smeared Heaviside function has been employed for shape and topology optimizations. The smeared Heaviside function yields an indistinct interface boundary, and so can increase computational time and cause numerical errors. The adaptive level set method does not use the smeared Heaviside function. To coincide with the material interface, it processes the zero level as the boundary data of element meshing.<B>Findings</B> - Usefulness and accuracy of shape optimization using the adaptive level set method are shown by comparison to the conventional level set method. A shape optimization procedure using the adaptive level set method is introduced. Numerical examples are employed to explain how the adaptive level set method is applied.<B>Originality/value</B> - The adaptive level set method is proposed to relieve the interface problem of the conventional level set method. Shape variation in the optimization is calculated from the continuum sensitivity analysis. Article literatinetwork@emeraldinsight.com (Kang Hyouk Lee, Seung Geon Hong, Myung Ki Baek, Hong Soon Choi, Young Sun Kim, Il Han Park) Thu, 03 Apr 2014 00:00:00 +0100 A MODIFIED IMMUNE ALGORITHM WITH SPATIAL FILTERING FOR MULTIOBJECTIVE TOPOLOGY OPTIMIZATION OF ELECTROMAGNETIC DEVICES http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108602&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - In the development of electromagnetic devices, multiobjective topology optimisation is effective to obtain diverse design candidates for production models. However, multiobjective topology optimisation has not widely been performed because it is difficult to obtain resultant shapes for engineering realisation due to large search spaces. This paper presents a new multiobjective topology optimisation method.<B>Design/methodology/approach</B> - This paper presents a new multiobjective topology optimisation method in which the Immune Algorithm is modified for multiobjecrive optimisation and a shape modification process based on spatial filtering is employed.<B>Findings</B> - The present method shows that better Pareto solutions can be found in comparison with the conventional methods.<B>Originality/value</B> - A new effective multiobjective topology optimization is presented. This method enables to diverse design candidates for production models. Article literatinetwork@emeraldinsight.com (Takahiro Sato, Kota Watanabe, Hajime Igarashi) Thu, 03 Apr 2014 00:00:00 +0100 Use of Compensation Theorem for the Robustness Assessment of Electromagnetic Devices Optimal Design http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108579&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - This paper aims at presenting the use of the Compensation Theorem, well known in the analysis of linear electric networks, to compute sensitivity of the performance functions used in the robust design or tolerance analysis of electromagnetic devices.<B>Design/methodology/approach</B> - The Compensation Theorem is first illustrated in the case of a simple field analysis problem. Then, using numerical simulations, the effectiveness of Compensation approach for assessing impact of the small modification of material properties is shown. The numerical simulations are performed with a finite elements code based on an integral formulation. <B>Findings</B> - The complexity of additional computations to assess the effect of small variations involved in sensitivity analysis can be reduced. <B>Research limitations/implications</B> - The method can be applied only to linear systems; in addition, although compensation applies to any variations, the reduction of computational complexity is achieved only for small variations, giving localized effects.<B>Practical implications</B> - The method proposed in the paper can speed up the computations of sensitivity arrays in the robust design and tolerance analysis of electromagnetic device, when numerical methods are applied. <B>Originality/value</B> - The use of Compensation Theorem in field computations is not new, but its adoption in the sensitivity computation is new to the best knowledge of authors. Article literatinetwork@emeraldinsight.com (Alessandro Formisano, Raffaele Fresa, Raffaele Martone) Thu, 03 Apr 2014 00:00:00 +0100 Multi-physics optimisation of an energy harvester device for automotive application http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108545&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Supplying remote wireless sensors is not an easy task if the site where the device is located is not easily accessible. In order to obtain direct measurements of the road-vehicle interactions, sensors must be placed inside the tyre environment thus a power supply must be available for their working there without any wire connection with the car main power. <B>Design/methodology/approach</B> - An electro-mechanical energy harvester has thus been developed for supplying an automotive wireless sensor of pressure, temperature and acceleration to be placed on the inner line of a tyre. The primary energy source is the vibrations or variable accelerations imposed to the device and induced in the tyre by the wheeling. <B>Findings</B> - The harvester has been designed by means of a multi-physics optimisation based on an integrated electromagnetic-mechanical-circuit simulator. Thus an automated optimisation of the device with respect to volume constraints, magnets dimensions, induction coils placement and size have been performed to increase the average power extracted from the device at different wheeling speeds.<B>Originality/value</B> - The use of the multi-physics environment together with automated optimization technique has been tested for the first time on the electromagnetic harvester structure. Article literatinetwork@emeraldinsight.com (Repetto Maurizio) Thu, 03 Apr 2014 00:00:00 +0100 Stochastic modeling error reduction using Bayesian approach coupled with an adaptive Kriging based model http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108578&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Magnetic material properties of an electromagnetic device can be recovered by solving a coupled experimental numerical inverse problem. In order to ensure the highest possible accuracy of the inverse problem solution, all physics of the electromagnetic device need to be perfectly modeled using a complex numerical model. However, these fine models demand a high computational time. Alternatively, less accurate coarse models can be used with a demerit of the high expected recovery errors. The purpose of this paper is to present an efficient methodology to reduce the effect of stochastic modeling errors in the inverse problem solution. <B>Design/methodology/approach</B> - The recovery error in the electromagnetic inverse problem solution is reduced using the Bayesian approximation error approach coupled with an adaptive Kriging based model. The accuracy of the forward model is assessed and adapted a priori using the cross-validation technique.<B>Findings</B> - The adaptive Kriging based model seems to be an efficient technique for modeling electromagnetic devices used in inverse problems. Moreover, using the proposed methodology, the recovery error in the electromagnetic inverse problem solution is largely reduced in a relatively small computational time and memory storage. <B>Originality/value</B> - The proposed methodology is capable of not only improving the accuracy of the inverse problem solution, but also reducing the computational time as well as the memory storage. Furthermore, to the best of our knowledge, it is the first time to combine the adaptive Kriging based model with the Bayesian approximation error approach for the stochastic modeling error reduction. Article literatinetwork@emeraldinsight.com (Ahmed Abdallh, Luc Dupre) Thu, 03 Apr 2014 00:00:00 +0100 n-level output space mapping for electromagnetic design optimization http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108522&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The aim of this paper is to reduce the evaluations number of the fine model within the output space mapping technique in order to reduce their computing time.<B>Design/methodology/approach</B> - In this paper, n-level output space mapping is proposed and expected to be even faster than the conventional output space mapping. The proposed algorithm takes advantages of the availability of n models of the device to optimize, each of them representing an optimal trade-off between the model error and its computation time. Models with intermediate characteristics between the coarse and fine models are inserted within the proposed algorithm to reduce the number of evaluations of the consuming time model and, then the computing time. The advantages of the algorithm are highlighted on the optimization problem of superconducting magnetic energy storage.<B>Findings</B> - A major computing time gain equals to 3 is achieved using the n-level output space mapping algorithm instead of the conventional output space mapping technique on the optimization problem of superconducting magnetic energy storage.<B>Originality/value</B> - The originality of this paper is to investigate several models with different granularities within output space mapping algorithm in order to reduce its computing time without decreasing the performance of the conventional strategy. Article literatinetwork@emeraldinsight.com (Ramzi Ben Ayed, Stéphane Brisset) Thu, 03 Apr 2014 00:00:00 +0100 High speed functionality optimization of five-phase PM machine using 3rd harmoniccurrent http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108549&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Some surrogate-assisted optimization techniques are applied in order to improve the performances of a 5-phase Permanent Magnet (PM) machine in the context of a complex model requiring computation time.<B>Design/methodology/approach</B> - An optimal control of four independent currents is proposed in order to minimize the total losses with the respect of functioning constraints. Moreover, some geometrical parameters are added to the optimization process allowing a co-design between control and dimensioning.<B>Findings</B> - The optimization results prove the remarkable effect of using the freedom degree offered by a 5-phase structure on iron and magnets losses.The performances of the 5-phase machine with concentrated windings are notably improved at high speed (16 000 rpm).<B>Originality/value</B> - The effectiveness of the method allows solving the challenge which consists in taking into account inside the control strategy the eddy-current losses in magnets and iron. In fact, magnet losses are a critical point to protect the machine from demagnetization in flux-weakening region. Article literatinetwork@emeraldinsight.com (Jinlin GONG, Bassel Aslan, eric semail, Frederic Gillon) Thu, 03 Apr 2014 00:00:00 +0100 Topology optimization of magnetostatic shielding using multistep evolutionary algorithms with additional searches in a restricted design space http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108516&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The main object is an improvement of multistep algorithm using evolutionary algorithm for the topology optimization of magnetostatic shielding, and we reveal the effectiveness of methodology by comparison with conventional optimization method. Furthermore, the design target is to obtain the novel shape of magnetostatic shielding.<B>Design/methodology/approach</B> - The evolutionary algorithms based on random search allow engineers to define general-purpose objects with various constraint conditions; however, many iterations are required in the FEA for the evaluation of the objective function, and it is difficult to realize a practical solution without island and void distribution. Then, we proposed the multistep algorithm with design space restriction, and we improved the multistep algorithm in order to get better solution than the previous one.<B>Findings</B> - The variant model of optimized topology derived from improved multistep algorithm is defined to clarify the effectiveness of the optimized topology. The upper curvature of the inner shielding contributed to the reduction of magnetic flux density in the target domain.<B>Research limitations/implications</B> - Because the converged topology has many pixel element unevenness, the special smoother to remove the unevenness will play an important role for the realization of practical magnetostatic shielding.<B>Practical implications</B> - The optimized topology will give us useful detailed structure of magnetostatic shielding.<B>Originality/value</B> - 1. While the conventional algorithm could not find the reasonable shape, the improved multistep optimization can capture the reasonable shape. 2. An additional search is attached to the multistep optimization procedure. It is shown that the performance of improved multistep algorithm is better than that of conventional algorithm. Article literatinetwork@emeraldinsight.com (Yoshifumi OKAMOTO, Yusuke TOMINAGA, Shinji WAKAO, Shuji SATO) Thu, 03 Apr 2014 00:00:00 +0100 Adaptive unscented transform for uncertainty quantification in emc large-scale systems http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108544&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The purpose of this paper is to introduce a novel methodology for uncertainty quantification in large-scale systems. It is a non-intrusive approach based on the Unscented Transform but it requires far less simulations from a EM solver for certain models.<B>Design/methodology/approach</B> - The methodology of uncertainty propagation is carried out adaptively instead of considering all input variables. First, a ranking of input variables is determined and after a classical unscented transform is applied successively considering each time one more input variable. The convergence is reached once the most important variables were considered.<B>Findings</B> - The adaptive Unscented Transform can be an efficient alternative of uncertainty propagation for large dimensional systems.<B>Originality/value</B> - The classical unscented transform is unfeasible for large-scale systems. This paper presents one new possibility to use this stochastic collocation method for systems with large number of input dimensions. Article literatinetwork@emeraldinsight.com (Moises FERBER, Christian Vollaire, Laurent Krahenbuhl, João Antonio Vasconcelos) Thu, 03 Apr 2014 00:00:00 +0100 Ant colony optimization for the topological design of interior permanent magnet (IPM) machines http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108584&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - In this paper, an Ant Colony Optimization (ACO) approach is applied for the solution of the topological design of Interior Permanent Magnet (IPM) machines.<B>Design/methodology/approach</B> - The IPM motor design domain is discretized into a suitable equivalent graph representation and an Ant System (AS) algorithm is employed to achieve an efficient distribution of materials into this graph.<B>Findings</B> - The single-objective problems associated with the maximization of the torque and with the maximization of the shape smoothness of the IPM are investigated. The rotor of the device is discretized into a 9 x 18 grid in both cases, and three different materials are considered: air, iron and permanent magnet.<B>Research limitations/implications</B> - The graph representation used enables the solution of topological design problems with an arbitrary number of materials, which is relevant for 2 and 3D problems.<B>Originality/value</B> - From the numerical experiments, the AS algorithm was able to achieve reasonable shapes and torque values for both design problems. The results show the relevance of the mechanism for multi-domain topology optimization of electromagnetic devices. Article literatinetwork@emeraldinsight.com (Lucas Batista, Felipe Campelo, Frederico Guimarães, Jaime Ramirez, Min Li, David Lowther) Thu, 03 Apr 2014 00:00:00 +0100 Drive optimisation of a pulsatile Total Artificial Heart http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108596&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Total Artificial Hearts (TAHs) are required for the treatment of cardiovascular diseases. In order to replace the native heart a TAH must provide a sufficient perfusion of the human body, prevent blood damage and meet the implantation constraints. Until today there is no TAH on the market which meets all constraints. So the purpose of this paper is to design a drive in such a way that the operated TAH meets all predefined constraints. <B>Design/methodology/approach</B> - The drive is designed in terms of weight and electric losses. In setting up a cost function containing those constraints, the drive design can be included in a optimization process. When reaching the global minimum of the cost function the optimum drive design is found. In this paper the optimisation methods manual parameter variation and Differential Evolution are applied. <B>Findings</B> - At the end of the optimisation process the drive's weight amounts to 460g and its mean losses sum up to 10 W. This design meets als predefined constraints. Further it is proposed to start the optimisation process with a parameter variation to reduce the amount of optimisation parameters for the time consuming Differential Evolution algorithm. <B>Practical implications</B> - This TAH has the potential to provide a therapy for all patients suffering from cardiovascular diseases as it is independent of donor organs. <B>Originality/value</B> - The optimisation based design process yields an optimum drive for a TAH in terms of weight and electrical losses. In this way a TAH is developed which meets all implantation constraints and provides sufficient perfusion of the human body at the same time. Article literatinetwork@emeraldinsight.com (Andre Pohlmann, Kay Hameyer) Thu, 03 Apr 2014 00:00:00 +0100 Multiobjective approach developed for optimizing the dynamic behaviour of incremental linear actuators http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108580&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Through this paper an optimal approach is developed for optimizing the dynamic behavior of incremental linear actuators. <B>Design/methodology/approach</B> - First a parameterized design model is built. Second, a dynamic model is implemented. This model takes into account the thrust force computed from a Finite Element model. Finally, the multiobjective optimization approach is applied to the dynamic model to optimize control as well as design parameters. <B>Findings</B> - The Pareto front resulting from the optimization approach, (or the parallel optimization approach,) is better than the Pareto, which is obtained from the only application of MOGA method (or parallel MOGA with the same number of optimization approach objective function evaluations). The only use of MOGA can reach the region near an optimal Pareto front, but it consumes more computing time than the multiobjective optimization approach. At each flowchart stage, parallelization leads to a significant reduction of computing time which is halved when using two-core machine.<B>Originality/value</B> - In order to solve the multiobjective problem, a hybrid algorithm based on MultiObjective Genetic Algorithm is developed. Article literatinetwork@emeraldinsight.com (Imen AMDOUNI, Lilia El AMRAOUI, Frederic Gillon, Mohamed BENREJEB, Pascal Brochet) Thu, 03 Apr 2014 00:00:00 +0100 Radial output space mapping for electromechanical systems design http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108559&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - This paper aims to set a relation through adaptive multilevel optimization between two physical models with different accuracies; a fast coarse model and a fine time consuming model. The use case is the optimization of a permanent magnet axial flux electrical machine.<B>Design/methodology/approach</B> - The paper opted to set the relation between the two models through Radial Basis Function (RBF). The optimization is held on the coarse model. The deduced solutions are used to evaluate the fine model. Thus, through an iterative process a residue RBF between models responses is built to endorse an adaptive correction. <B>Findings</B> - The paper shows how the use of a residue function permits, to diminish optimization time, to reduce the misalignment between the two models in a structured strategy and to find optimum solution of the fine model based on the optimization of the coarse one. The paper also provides comparison between the proposed methodology and the traditional approach (Output Space Mapping) and shows that in case of large misalignment between models the Output Space Mapping fails.<B>Originality/value</B> - This paper proposes an original methodology in electromechanical design based on building a surrogate model by means of radial basis function on the bulk of existing physical model. Article literatinetwork@emeraldinsight.com (Maya HAGE HASSAN, Ghislain Remy, Guillaume Krebs, Claude Marchand) Thu, 03 Apr 2014 00:00:00 +0100 Minimum energy control of descriptor positive discrete-time linear systems http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108590&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The purpose of this paper is to formulate and solve the minimum energy control problem of descriptor positive discrete-time linear systems.<B>Design/methodology/approach</B> - A procedure for computation of the optimal input sequences and the minimal value of the performance index is proposed.<B>Findings</B> - Necessary and sufficient conditions for the positivity and reachability of descriptor positive discrete-time linear systems and sufficient conditions for the existence of solution to the minimum energy control problem are given.<B>Originality/value</B> - A method for solving of the minimum energy control problem of descriptor positive discrete-time linear systems is proposed. Article literatinetwork@emeraldinsight.com (Tadeusz Kaczorek) Thu, 03 Apr 2014 00:00:00 +0100 Current spectrum estimation using Prony’s estimator and coherent resampling http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108553&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - A highly accurate method of current spectrum estimation of a nonlinear load is presented in this paper. Using the method makes it possible to evaluate the current injection frequency domain model of a nonlinear load from previously recorded time domain voltage and current waveforms.<B>Design/methodology/approach</B> - The method incorporates the idea of coherent resampling (resampling synchronously with the base frequency of the signal) followed by the DFT to obtain the frequency spectrum. When DFT is applied to a synchronously resampled signal, the spectrum is free of negative DFT effects ( the spectrum leakage for example). However, to resample the signal correctly it is necessary to know its base frequency with high accuracy. To estimate the base frequency, the first order Prony’s frequency estimator was used.<B>Findings</B> - It has been shown that the presented method may lead to superior results in comparison with WIFTA (window interpolated FFT) and TDQS (time-domain quasi synchronous sampling) algorithms.<B>Research limitations/implications</B> - The method was designed for steady state analysis in the frequency domain. The voltage and current waveforms across load terminals should be recorded simultaneously to allow correct voltage/current phase shift estimation.<B>Practical implications</B> - The proposed method can be used in case when the frequency domain model of a nonlinear load is desired and the voltage and current waveforms recorded across load terminals are available. The method leads to correct results even when the voltage/current sampling frequency has not been synchronised with the base frequency of the signal. It can be used for off-line frequency model estimation as well as in real-time DSP systems to restore coherent sampling of the analysed signals.<B>Originality/value</B> - The method proposed in the paper allows to estimate a nonlinear load frequency domain model from current and voltage waveforms with higher accuracy than other competitive methods, while at the same time its simplicity and computational efficiency is retained. Article literatinetwork@emeraldinsight.com (Michal Lewandowski, Janusz Walczak) Thu, 03 Apr 2014 00:00:00 +0100 Optimal shape design of flux barriers in IPM synchronous motors using the phase field method http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108526&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - In this study, we present an optimization method for flux barrier designs in interior permanent magnet synchronous motors that aims to produce an advantageous sinusoidal flux density distribution in the air-gap.<B>Design/methodology/approach</B> - The optimization is based on the phase field method using an Allen-Cahn equation. This approach is a numerical technique for tracking diffuse interfaces like the level set method based on the Hamilton-Jacobi equation.<B>Findings</B> - The optimization results of IPM motor designs are highly dependent on the initial flux barrier shapes. We solve the optimization problem using two different initial shapes, and the optimized models show considerable reductions in torque pulsation and the higher harmonics of back-EMF.<B>Originality/value</B> - This paper presents the optimization method based on the phase field for the design of rotor flux barriers, and proposes a novel interpolation scheme of the magnetic reluctivity. Article literatinetwork@emeraldinsight.com (Jae Seok Choi, Takayuki Yamada, Kazuhiro Izui, Shinji Nishiwaki, Heeseung Lim, Jeonghoon Yoo) Thu, 03 Apr 2014 00:00:00 +0100 Conformal antennas arrays radiation synthesis using immunity tactic http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108561&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The paper was written in order to introduce to scientific community a new optimization technique and its application to the radiation synthesis case. <B>Design/methodology/approach</B> - The immunity tactic is a new powerful optimization tool inspired by immune system. It was used with success to achieve the conformal antenna radiation synthesis in an acceptable processing time.<B>Findings</B> - Radiation synthesis of conformal antenna arrays based on immunity tactic generates very good results compared with other optimization methods. The comparison is very satisfactory as regards accuracy and processing time.<B>Research limitations/implications</B> - The improvement of convergence and accuracy will be done certainly by use of other variants of the technique or combination with others.<B>Originality/value</B> - The paper exposes with details a new optimization technique based on immune system and its behaviour. The results, for the special case of conformal antenna arrays radiation synthesis, are very satisfactory and very encouraging. The impact of the new technique will be, without doubt, positive on optimization field. Article literatinetwork@emeraldinsight.com (Sidi Ahmed DJENNAS, Belkacem BENADDA, Lotfi MERAD, Fethi Tarik BENDIMERAD) Thu, 03 Apr 2014 00:00:00 +0100 Multi-level design of an isolation transformer using Collaborative Optimization http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108505&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - The purpose of this paper is to present an application of a multidisciplinary multi-level design optimization methodology for the optimal design of a complex device from the field of electrical engineering throughout discipline-based decomposition. The considered benchmark is a single-phase low voltage safety isolation transformer.<B>Design/methodology/approach</B> - The multidisciplinary optimization of a safety isolation transformer is addressed within this paper. The bi-level collaborative optimization (CO) strategy is employed to coordinate the optimization of the different disciplinary analytical models of the transformer (no-load and full-load electromagnetic models and thermal model). The results represent the joint decision of the three distinct disciplinary optimizers involved in the design process, under the coordination of the CO’s master optimizer. In order to validate the proposed approach, the results are compared to those obtained using a classical single-level optimization method – sequential quadratic programming (SQP) – carried out using a multidisciplinary feasible (MDF) formulation for handling the evaluation of the coupling model of the transformer.<B>Findings</B> - Results show a good convergence of the CO process with the analytical modeling of the transformer, with a reduced number of coordination iterations. However, a relatively important number of disciplinary models evaluations were required by the local optimizers.<B>Originality/value</B> - The CO multi-level methodology represents a new approach in the field of electrical engineering. The advantage of this approach consists in that it integrates decisions from different teams of specialists within the optimal design process of complex systems and all exchanges are managed within a unique coordination process. Article literatinetwork@emeraldinsight.com (Alexandru Claudiu Berbecea, Frederic Gillon, Pascal Brochet) Thu, 03 Apr 2014 00:00:00 +0100 Model-free discrete control for uncertain robot manipulators using a fuzzy estimator http://www.emeraldinsight.com/journals.htm?issn=0332-1649&volume=33&issue=3&articleid=17108500&show=abstract <strong>Abstract</strong><br /><br /><B>Purpose</B> - Discrete control of robot manipulators with uncertain model is the purpose of this paper.<B>Design/methodology/approach</B> - The proposed control design is model-free by employing an adaptive fuzzy estimator in the controller for the estimation of uncertainty as unknown function. An adaptive mechanism is proposed in order to overcome uncertainties. Parameters of the fuzzy estimator are adapted to minimize the estimation error using a gradient descent algorithm.<B>Findings</B> - The proposed model-free discrete control is robust against all uncertainties associated with the model of robotic system including the robot manipulator and actuators, and external disturbances. Stability analysis verifies the proposed control approach. Simulation results show its efficiency in the tracking control.<B>Originality/value</B> - A novel model-free discrete control approach for electrically driven robot manipulators is proposed. An adaptive fuzzy estimator is used in the controller to overcome uncertainties. The parameters of the estimator are regulated by a gradient descent algorithm. The most gradient descent algorithms have used a known cost function based on the tracking error for adaptation whereas the proposed gradient descent algorithm uses a cost function based on the uncertainty estimation error. Then, the uncertainty estimation error is calculated from the joint position error and its derivative using the closed-loop system. Article literatinetwork@emeraldinsight.com (Mohammad Mehdi Fateh, Siamak Azargoshasb, Saeed Khorashadizadeh) Thu, 03 Apr 2014 00:00:00 +0100