Modeling and experimental validation of field distributions due to eddy currents in slitted conducting plates

The paper describes a 3D semi-analytical harmonic modeling technique, which is capable to model eddy current distributions in conducting structures and the associated fields. The induced current density and magnetic fields in the spectral domain are described, where a spatially varying conductivity of a conducting region is incorporated in the solutions of magnetic-field quantities. An experimental setup is used to measure the field distribution above differently shaped conducting plates, placed on top of a coil, in which eddy currents are induced. The measurement results are compared to simulation results and the perturbations are analyzed.</p

Semianalytic harmonic modeling of segmented structures

The paper concerns the semianalytical modeling of parasitic forces in electromagnetic devices. The Fourier analyses technique is extended to incorporate a position dependent relative permeability and conductivity into the solutions of electromagnetic quantities. The spatial distribution of these material properties are described using Fourier series. As a result, the parasitic reluctance and eddy current force can be accurately modeled. To model transient behavior of the device, multiple time harmonics have been incorporated in the solutions. To validate the developed method, it is applied to a coreless linear motor and compared to finite element results. The paper concerns the semianalytical modeling of parasitic forces in electromagnetic devices. The Fourier analyses technique is extended to incorporate a position dependent relative permeability and conductivity into the solutions of electromagnetic quantities. The spatial distribution of these material properties are described using Fourier series. As a result, the parasitic reluctance and eddy current force can be accurately modeled. To model transient behavior of the device, multiple time harmonics have been incorporated in the solutions. To validate the developed method, it is applied to a coreless linear motor and compared to finite element results

Static decoupling of force and torque components in a moving-magnet planar motor

The paper describes simulations and measurements performed on the double-layer planar motor (DLPM), in order to analyze the static decoupling of the machine. By standstill levitation of the translator above the stator, the static coupling of force and torque components can be obtained. Possible sources of cross-coupling are predicted using an electromagnetic model and the obtained results are used to improve the static decoupling on the DLPM prototype. The performed measurements show the average cross-coupling over a grid can be minimized to less than one percent for all force and torque components

Modeling and experimental validation of field distributions due to eddy currents in slitted conducting plates

The paper describes a 3D semi-analytical harmonic modeling technique, which is capable to model eddy current distributions in conducting structures and the associated fields. The induced current density and magnetic fields in the spectral domain are described, where a spatially varying conductivity of a conducting region is incorporated in the solutions of magnetic-field quantities. An experimental setup is used to measure the field distribution above differently shaped conducting plates, placed on top of a coil, in which eddy currents are induced. The measurement results are compared to simulation results and the perturbations are analyzed

Memory efficient harmonic method for electromagnetic models using scattering matrices

In design and optimization of electrical machines, accurate models of the electromagnetic fields are important to predict the performance of the machine. The finite element method (FEM) is often used, because of its ability to produce accurate results when it is correctly utilized. However, the method can be demanding in terms of memory and relatively slow in terms of computation time. Therefore, semi-analytical models have been proposed over the years for increasingly complex structures in both 2D and 3D. One of the semi-analytical models is the harmonic modeling technique [1], [2], [3], which uses a Fourier bases to describe the solutions to electromagnetic field quantities. In many electromagnetic configurations, accurate results are obtained using a relatively low number of harmonics. However, for more complex structures, the number of harmonics has to be increased to retain accuracy. This leads to a proportional increase in the required memory. As a result, especially in 3D models, the advantage in terms of memory of the harmonic model in comparison to FEM is reducing. In this paper an alternative solving method for 3D harmonic models with position dependent material properties is presented. Using the scattering matrix approach, the memory required to obtain the solutions of the model is significantly reduced

Validation of a harmonic model for eddy currents in slitted conducting plates

The paper describes a 3D semi-analytical harmonic modeling technique that is capable of modeling eddy current distributions in segmented conducting structures, such as slitted conducting plates, and the associated magnetic fields. The spatially varying conductivity of a conducting region is incorporated into the solutions of magnetic-field quantities and the induced current density. The harmonic model is compared to results obtained with finite element analysis. An experimental setup is used to measure the field distribution above differently slitted conducting plates, in which eddy currents are induced by a coil. The measurement results are compared to simulation results, and the perturbations are analyzed

2D semi-analytical modeling of eddy currents in segmented structures

The paper concerns the semi-analytical modeling of eddy currents in segmented structures of electromagnetic devices. A Fourier series is used to describe the spatial distribution of the conductivity and included in the magnetic field solutions. By incorporating multiple time harmonics in the solution, transient behavior of forces due to eddy currents can be obtained. To validate the developed method, it is applied to a coreless linear motor and compared to finite element results. The eddy currents in segmented conducting structures of motors, such as permanent magnet arrays, can be accurately determined with this method

2D semi-analytical modeling of eddy currents in segmented structures

The paper concerns the semi-analytical modeling of eddy currents in segmented structures of electromagnetic devices. A Fourier series is used to describe the spatial distribution of the conductivity and included in the magnetic field solutions. By incorporating multiple time harmonics in the solution, transient behavior of forces due to eddy currents can be obtained. To validate the developed method, it is applied to a coreless linear motor and compared to finite element results. The eddy currents in segmented conducting structures of motors, such as permanent magnet arrays, can be accurately determined with this method

3D harmonic modeling of eddy currents in segmented conducting structures

Purpose: The purpose of this paper is to describe a semi-analytical modeling technique to predict eddy currents in three-dimensional (3D) conducting structures with finite dimensions. Using the developed method, power losses and parasitic forces that result from eddy current distributions can be computed. Design/methodology/approach: In conducting regions, the Fourier-based solutions are developed to include a spatially dependent conductivity in the expressions of electromagnetic quantities. To validate the method, it is applied to an electromagnetic configuration and the results are compared to finite element results. Findings: The method shows good agreement with the finite element method for a large range of frequencies. The convergence of the presented model is analyzed. Research limitations/implications: Because of the Fourier series basis of the solution, the results depend on the considered number of harmonics. When conducting structures are small with respect to the spatial period, the number of harmonics has to be relatively large. Practical implications: Because of the general form of the solutions, the technique can be applied to a wide range of electromagnetic configurations to predict, e.g. eddy current losses in magnets or wireless energy transfer systems. By adaptation of the conductivity function in conducting regions, eddy current distributions in structures containing holes or slit patterns can be obtained. Originality/value: With the presented technique, eddy currents in conducting structures of finite dimensions can be modeled. The semi-analytical model is for a relatively low number of harmonics computationally faster than 3D finite element methods. The method has been validated and shown to be computationally accurate