1,721,046 research outputs found
Simple Extraction of the First Resonant Frequency via Integral Equation Method
No full textThe accurate determination of the first resonant frequency (FRF) is important for the design of electromagnetic (EM) devices and for establishing safety margins for their operation. However, the numerical extraction of the FRF typically involves a costly parametric sweep across operational frequencies. This article introduces a method for extracting the FRF based on energetic considerations and the PEEC scheme for the solution of EM problem. Despite its simplicity, the proposed approach significantly reduces the computational cost while maintaining a good accuracy compared to conventional methods. This advancement promises to enhance the efficiency and accuracy of FRF extraction in EM device characterization
Extending the Unstructured PEEC Method to Magnetic, Transient, and Stochastic Electromagnetic Problems
Full text linkL’obiettivo principale di questa tesi è di estendere e migliorare l’applicabilità e l’accuratezza del metodo Partial Element Equivalent Circuit (PEEC) non strutturato (Unstructured PEEC). L’interesse riguardo tale argomento è stimolato dalla crescente necessità di metodi numerici rapidi ed efficienti, che possono aiutare gli ingegneri durante la progettazione e altre fasi della produzione di componenti elettrici ed elettronici di nuova generazione. Durante la prima fase della tesi, il metodo PEEC (nella sua forma non strutturata) è esteso ai mezzi magnetici. A questo proposito, vengono sviluppate e confrontate due formulazioni: la prima, basata sull’interpretazione amperiana dei fenomeni di magnetizzazione, deriva dalla letteratura esistente relativa alla versione standard (strutturata) del metodo PEEC; il secondo, basato sull’interpretazione coulombiana dei fenomeni di magnetizzazione, è proposto dall’autore con l’obiettivo di collocare il metodo PEEC nel contesto dei metodi di integrali di volume (Volume Integral Equation). Successivamente, la ricerca si focalizza sull’utilizzo di tecniche di compressione a basso rango al fine di risolvere problemi PEEC in maniera computazionalmente efficiente, salvaguardando tempo e memoria di calcolo. A tal proposito, vengono applicati due metodi diversi: il primo si basa su matrici gerarchiche (matrici H e H2) mentre il secondo si basa su matrici gerarchiche-semi-separabili (HSS). I due metodi vengono confrontati e vengono analizzati i principali problemi numerici che emergono applicando tali tecniche di compressione a basso rango al metodo PEEC. In seguito, il metodo PEEC non strutturato viene combinato con l’approccio Marching On-In Time (MOT) per lo studio di fenomeni transitori rapidi con un ricco contenuto armonico. Infine, sono stati sviluppati due diversi metodi PEEC stocastici per la quantificazione dell’incertezza. Il primo si basa sull’espansione Polynomial Chaos, mentre il secondo si basa sulla tecnica di riduzione d’ordine parametrica (Parametric Model Order Reduction) unita all’espansione spettrale
Una formulazione PEEC 3−D bastata sul Metodo delle Celle per l’analisi di problemi full-wave in presenza di mezzi conduttori, dielettrici e magnetici
Full text linkA Fast Integral Equation of J−φe Formulation for Superconducting Structures
No full textThis article presents an integral equation method based on the current–potential ( J−φe ) formulation, for the solution of the eddy currents problem in superconducting structures. Two efficient methods for storing and manipulating the fully populated matrices resulting from the discretization of the integral equation are proposed in this work. These approaches leverage hierarchical ( H ) matrices and the fast Fourier transform technique, tailored for voxelized structures. These techniques drastically reduce the computational cost of the numerical simulations. The proposed approach is compared to existing methods, as the H−φm formulation, and is efficiently applied to calculate the power losses for a realistic high-temperature superconductor coil
The proposed approach is compared to existing methods, as the formulation, and is efficiently applied to calculate the power losses for a realistic High-Temperature Superconductor (HTS) coil
Design of Magnetic Flux Concentrator Plates Using SMC and Ferrite With Topology Optimization for WPT Systems in Industrial Forklifts
No full textWireless power transfer (WPT) is increasingly adopted in industrial applications. However, components such as the magnetic flux concentrator plates in ferrite are susceptible to challenges common in industrial environments, such as vibrations and shocks. Recent studies have investigated soft magnetic composites (SMCs) as alternatives to ferrite, taking advantage of their superior mechanical strength and machinability. Despite these advantages, the lower relative magnetic permeability of SMCs prevents them from fully replacing ferrite in WPT systems. To address this, a mixed strategy was adopted in this work, incorporating ferrite inserts into the SMC plate to leverage the benefits of both materials. This work employs topology optimization, specifically the Solid Isotropic Material with Penalization approach, to optimize the distribution of ferrite and SMC in the plates of a WPT system for charging industrial electric forklifts. The proposed solution achieves a reduced ferrite volume while maintaining performance comparable to a full ferrite design, resulting in a lighter and more robust system
High-Performance PEEC Analysis of Electromagnetic Scatterers
No full textLow-rank approximation techniques are useful approaches to reduce the computational effort required by integral equations methods. Here, two different libraries based on hierarchical-matrices and hierarchically semi-separable matrices are applied to the partial element equivalent circuit method for the study of high-frequency electromagnetic problems. The academic case of a dielectric sphere and the study of a complex device used in thermonuclear fusion science are considered in order to compare the performances of the two libraries
A fast tool for the parametric analysis of human body exposed to LF electromagnetic fields in biomedical applications
Full text link: A numerical procedure for analyzing electromagnetic (EM) fields interactions with biological tissues is presented. The proposed approach aims at drastically reducing the computational burden required by the repeated solution of large scale problems involving the interaction of the human body with EM fields, such as in the study of the time evolution of EM fields, uncertainty quantification, and inverse problems. The proposed volume integral equation (VIE), focused on low frequency applications, is a system of integral equations in terms of current density and scalar potential in the biological tissues excited by EM fields and/or electrodes connected to the human body. The proposed formulation requires the voxelization of the human body and takes advantage of the regularity of such discretization by speeding-up the computational procedure. Moreover, it exploits recent advancements in the solution of VIE by means of iterative preconditioned solvers and ad hoc parametric Model Order Reduction techniques. The efficiency of the proposed tool is demonstrated by applying it to a couple of realistic model problems: the assessment of the peripheral nerve stimulation, performed in terms of evaluation of the induced electric field, due to the gradient coils of a magnetic resonance imaging scanner during a clinical examination and the assessment of the exposure to environmental fields at 50 Hz of live-line workers with uncertain properties of the biological tissues. Thanks to the proposed method, uncertainty quantification analyses and time domain simulations are possible even for large scale problems and they can be performed on standard computers and reasonable computation time. Sample implementation of the method is made publicly available at https://github.com/UniPD-DII-ETCOMP/BioMOR
PEEC-based analysis of complex fusion magnets during fast voltage transients with H-matrix compression
No full textPEEC-based methodology appears very attractive for the analysis of fast voltage transients which may appear across and inside magnets in fusion devices in case of off-normal events. In this paper, we aim at illustrating how Adaptive Cross Approximation coupled with hierarchical matrix (H-matrix) arithmetics can provide an effective method to allow the solution of large scale problems typical of real devices
TopIE: An Integral Equation Tool for Topology Optimization in Electromagnetics
Full text linkTopology optimization for the design of electromagnetic devices has recently garnered significant interest, thanks to advancements in additive manufacturing techniques that enable the fabrication of intricate geometries. This has opened up new possibilities for utilizing integral equation methods to solve electromagnetic (EM) problems, particularly in the analysis of Inductive Power Transfer (IPT) devices. In this context, we introduce a novel topology optimization tool called TopIE, which is built upon the Integral Equation method for EM problem solutions. TopIE adopts the logic of Topology Optimization of Binary Structures (TOBS), a sensitivity-based approach that leverages binary design variables to clearly differentiate the material properties within the design domain. The tool is specifically employed for optimizing IPT devices, and sample implementations of the method are made publicly available. By combining the power of topology optimization and integral equation methods, TopIE offers a promising avenue for enhancing the design and performance of EM devices
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