146 research outputs found
Core Loss Estimation in Electric Machines With Flux-Controlled Core Loss Tester
No full textTsukerman, Igor/0000-0001-8318-3225; Tekgun, Burak/0000-0003-2720-8816; Sozer, Yilmaz/0000-0003-3971-3967The complexity of core loss estimation is a serious challenge in the design of high-efficiency electric machines. Current estimation methods based on the Steinmetz equation and loss separation are not accurate enough, even at the rated conditions. This paper describes a loss estimation technique combining finite-element analysis (FEA) and actual core loss measurements. First, flux density waveforms in various parts of the electric machine are determined using FEA. Second, the same waveforms are generated in a wound toroidal core made of the same material as used in the machine. The loss is measured per unit mass, and then the total motor core loss is calculated by integrating the measured W/kg loss values for predefined sections of the motor. These estimation results are compared with those of the Bertotti method. The proposed procedure is shown to improve the accuracy of loss estimation.ABB US Corporate Research; U.S. National Science Foundation [DMS-1620112]This work was supported by fellowships from ABB US Corporate Research. The work of I. Tsukerman was supported in part by the U.S. National Science Foundation under Grant DMS-1620112. (Corresponding author: Yilmaz Sozer.
A priori error indicator in the transformation method for problems with geometric uncertainties
No full textVersion éditeur de cette publication à l'adresse suivante : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514655To solve stochastic problems with geometric uncertainties, one can transform the original problem in a domain with stochastic boundaries and interfaces to a problem defined in a deterministic domain with uncertainties in the material behavior. The latter problem is then discretized. There exist infinitely many random mappings that lead to identical results in the continuous domain but not in the discretized domain. In this paper, an a priori error indicator is proposed for electromagnetic problems with scalar and vector potential formulations. This leads to criteria for selecting random mappings that reduce the numerical error. In an illustrative numerical example, the proposed a priori error indicator is compared with an a posteriori estimator for both potential formulationsThis work is supported by the program MEDEE funded by the Nord Pas de Calais council and the European Community and supported in part by the National Science Foundation under Grant No. 1216927
Effective constitutive parameters of plasmonic metamaterials: Homogenization by dual field interpolation
No full textWe introduce a general implementation of the recently proposed homogenization theory [Tsukerman, J. Opt. Soc. Am. B 28, 577 (2011)] allowing one to retrieve all 36 linear constitutive parameters of any 3D metamaterial with parallelepipedal unit cells. The effective parameters are defined directly as linear relations between pairs of coarse-grained fields, in contrast with methods where these parameters are obtained from reflection and transmission data or other indirect considerations. The method is applied to plasmonic metamaterials with spherical gold particles and split-ring resonators (SRR), respectively. In both cases, the expected physical behavior is reproduced almost perfectly, with no unphysical artifacts
Modeling of Nanostructured Magnetic Field Sensors
No full textA panoramic view of recent nanostructured magnetic field sensors has been provided, focusing on the modeling of some examples of device concepts, with possible applications in high-tech sectors including automotive, aerospace, Information and Communications Technology (ICT), and medical fields. In particular, this chapter provides a description, from physical basic principles to numerical simulation, of magnetoresistive nanosensors based on anisotropic magnetoresistance (AMR) or planar Hall effect (PHE), novel sensing elements exploiting ferromagnetic resonance (FMR) in nanopatterned magnetic thin films, and miniaturized Hall probes. Specific attention has been devoted to their application in the detection of magnetic nanoparticles or microbeads for biomedical and biochemistry applications, sectors in which very high-sensitivity and submicrometric resolution are required
Homogenization of laminated magnetic cores and the role of surface charges
No full textDue to its theoretical and practical significance, homogenization of laminated magnetic cores has been studied by several research groups. Recently, Tsukerman and Markel proposed non-asymptotic and nonlocal homogenization theories for periodic electromagnetic structures at high frequencies. This paper explores the applicability of these theories to laminated magnetic cores at power frequencies. Particular attention is paid to the boundary condition for the electric current density: its normal component does not have to be zero and may produce surface charges. The eddy current problem inside conducting elements must be coupled with the quasi-static problem outside. The importance of the boundary condition for the current density extends far beyond the simulation of laminated cores - to a variety of eddy current and coupled field-circuit problems
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