Eduardo Henrique da Rocha Coppoli

Induction Machines Modeling With Meshless Methods

Meshless Methods, also called Meshfree Methods, are a class of numerical methods to solve partial differential equations. The main characteristic of these methods is that they do not need a mesh like the one used in the Finite Element Method. In this sense meshless methods are very useful for modeling moving structures, such as electric machines, without a remeshing process. In this work the Element-Free Galerkin Method is used to simulate a three phase induction motor model including, for the first time, the field circuit coupling transient equations and the rotor movement.

Periodic Boundary Conditions in the Natural Element Method

The purpose of this paper is to introduce periodic and antiperiodic boundary conditions in the natural element method (NEM). It is shown that as the NEM shape functions verify the Kronecker delta property, the imposition of such boundary conditions can be done in an easy way as in the finite-element method (FEM). These boundary conditions are important because they allow exploitation of the inherent symmetry of the electromagnetic devices. Therefore, with these techniques the NEM can now easily take advantage of the symmetry of electrical machines. The proposed approach is evaluated, and its results are compared with those obtained by the traditional FEM.

Electromagnetic Scattering Analysis of Arbitrary Structures by the Natural Element Method Coupled With Absorbing Boundary Condition

The problem of determining the electromagnetic scattering of arbitrary structures consisting of both dielectric and conducting materials are analyzed in this paper by the natural-element method coupled with the absorbing boundary condition (NEM-ABC). By this method, the target is first enclosed by a fictitious boundary. Maxwells equations are then solved by NEM inside and ABC is applied on the fictitious boundary. The results are compared with analytical and finite-element method-ABC ones which show the robustness, applicability and relevance of the method.

A Meshless Approach Using EFG Interpolating Moving Least-Squares Method in 2-D Electromagnetic Scattering Analysis

In this paper, the element-free Galerkin method with special interpolating shape functions is used to solve an electromagnetic scattering problem. These shape functions make use of the interpolating moving least-squares method that guarantees the Kronecker delta property. This allows enforcing the absorbing boundary condition directly in the discrete system, consisting of a more practical way when compared with other methods, such as the Lagrange multipliers. The technique is applied to the analysis of electromagnetic scattering generated by an infinite dielectric cylinder illuminated by a TMZ plane wave and a sensibility analysis is done in which the numerical results are compared against the analytical solutions.

The electrical machine problem solved by a mixed finite and natural element method

In this paper, a Mixed Method using the Finite Element (FEM) and the meshless Natural Element Method (NEM) is used to determine the magnetic flux distribution in magnetic circuit of an electrical machine. In this solution, the NEM is applied exclusively in the gap of the machine where the largest deformations of the mesh are expected when the movement occurs. Due the use of anti-periodic boundary conditions, only 1/4 of machine is modeled reducing the computational cost. The error estimator and computational time by using the FEM, the NEM and the mixed FEM-NEM are obtained and compared.

Combined formulation for meshless-MoM hybrid method applied to 2D electromagnetic scattering

In this work a new formulation for the hybrid Meshless — Method of Moments is presented. The proposed approach employs the Interpolating Element Free Galerkin Meshless Method (IEFGM) and three different combinations of Electric Field Integral Equation (EFIE) and Magnetic Filed Integral Equation (MFIE). The technique is applied to solve the TMz scattering by an infinite dielectric cylinder and numerical and analytical results are compared.

The natural element method applied to solve an electrical machine problem

In this paper, the Constrained Natural Element Method (C-NEM) is used to determine the magnetic flux distribution in an electrical machine. Due the use of anti-periodic boundary conditions, only % of machine is modeled. The obtained results are compared with the traditional Finite Element Method (FEM) with good agreement.

FDTD-CPML method applied to analysis of a novel UWB microstrip antenna

The Ultra Wideband (UWB) technology is promising for data communications over short distances at high data rates. Since the antenna design is critical in the development of UWB systems, this paper proposes a new geometry for a microstrip UWB antenna. The modifications suggested are difficult to analyze because the proposed antenna is constructed using the high lossy FR4 fiber glass and the geometry does not conform with the FDTD mesh. Appropriate modifications on the FDTD method are done and the results are compared with the commercial software CST simulations and experimental results.

Field-circuit coupling with Element-Free Galerkin Method

This work presents a method which enables coupling between equations of electric circuits and a magnetic field for a time domain model making use of a meshless method. A three-phase induction machine is used as example and its field-circuit transient coupling equations are presented. With the Element-Free Galerkin Method (EFGM) the final system of equations is obtained and flux and currents are evaluated.