An improved tabu-based vector optimal algorithm for design optimizations of electromagnetic devices

This paper introduces an improved tabu-based vector optimal algorithm for multiobjective optimal designs of electromagnetic devices. The improvements include a division of the entire search process, a new method for fitness assignment, a novel scheme for the generation and selection of neighborhood solutions, and so forth. Numerical results on a mathematical function and an engineering multiobjective design problem demonstrate that the proposed method can produce virtually the exact Pareto front, in both parameter and objective spaces, even though the iteration number used by it is only about 70% of that required by its ancestor.

A self-learning simulated annealing algorithm for global optimizations of electromagnetic devices

A self-learning simulated annealing algorithm is developed by combining the characteristics of simulated annealing and domain elimination methods. The algorithm is validated by using a standard mathematical function and by optimizing the end region of a practical power transformer. The numerical results show that the CPU time required by the proposed method is about one third of that using conventional simulated annealing algorithm.

A Non-Destructive Testing Based on Electromagnetic Measurements and Neural Networks for the Inspection of Concrete Structures

This paper presents a new non-destructive testing (NDT) for reinforced concrete structures, in order to identify the components of their reinforcement. A time varying electromagnetic field is generated close to the structure by electromagnetic devices specially designed for this purpose. The presence of ferromagnetic materials (the steel bars of the reinforcement) immersed in the concrete disturbs the magnetic field at the surface of the structure. These field alterations are detected by sensors coils placed on the concrete surface. Variations in position and cross section (the size) of steel bars immersed in concrete originate slightly different values for the induced voltages at the coils.. The values for the induced voltages were obtained in laboratory tests, and multi-layer perceptron artificial neural networks with Levemberg-Marquardt training algorithm were used to identify the location and size of the bar. Preliminary results can be considered very good.

Estudos teóricos e experimentais da operação conjunta de um supressor eletromagnético e de um filtro ativo de potência

Pós-graduação em Engenharia Elétrica - FEIS

An alternative formulation for guided electromagnetic fields in grounded chiral slabs - Summary

An alternative formulation for guided electromagnetic fields in grounded chiral slabs is presented. This formulation is formally equivalent to the double Fourier transform method used by the authors to calculate the spectral fields in open chirostrip structures. In this paper, we have addressed the behavior of the electromagnetic fields in the vicinity of the ground plane and at the interface between the chiral substrate and the free space region. It was found that the boundary conditions for the magnetic field, valid for achiral media, are not completely satisfied when we deal with chiral material. Effects of chirality on electromagnetic field distributions and on surface wave dispersion curves were also analyzed.

Experimental analysis and adherence test of the electromagnetic zero-sequence blocking model

This paper reveals new contributions to the analysis and development of mitigating harmonic distortion devices. Considering the variety of sequential distribution of harmonic current, in the use of passive filters, one can point out the electromagnetic blocking device, which have received particular attention due to its robustness and low cost of installation. In this context, aiming the evaluation of the reliability of the results obtained through mathematical modeling, experimental tests are carried out using a low-power prototype, highlighting particular aspects related to its function as a zero-sequence harmonic blocking. © 2011 IEEE.

Experimental analysis of an electromagnetic zero-sequence suppressor

The intent of this paper is to present contributions focused on the analysis and development of harmonic attenuator devices. Among these, highlights here the so-called electromagnetic zero-sequence suppressor. This arrangement consists of a filter and a blocker, both electromagnetic, whose combined operation provides paths for low and high impedance, respectively, which can be conveniently adjusted to the desired performance. In this context, here are present results related to experimental studies that show the behavior of the equipment in front of different operating conditions. The tests were performed on a low-power prototype (1kVA/220V) and the analysis results show the main motivator aspects for the use of these devices. © 2012 IEEE.