K.J.W. Pluk

Modeling and Measurements on a Finite Rectangular Conducting Plate in an Eddy Current Damper

This paper concerns the modeling of an eddy current damper with a finite conducting plate. In the eddy current damper, a finite rectangular conducting plate is moving between cuboidal magnets. The first step of the modeling method is based on an infinite conducting plate. For this infinite conducting plate, the eddy current density is derived using two different methods, the scalar potential method and the vector potential method. The finite boundaries of the conducting plate are included by means of the method of images in two dimensions and, therewith, complete the model. By applying the method of images, the accuracy of the models for calculating the damping coefficient is significantly improved. The assumption of an infinite conducting plate gives less than 15% error for a conducting plate with at least twice the dimensions of the permanent magnet. Applying the method of images reduces the modeling error for a conducting plate with two times the permanent-magnet dimensions to less than 3% in respect to a finite-element model. For the verification of the semianalytical model, measurements are performed. For a variation of the plate width, the presented semianalytical model has less than 5% discrepancy with respect to the measurements.

Hybrid Analytical Modeling: Fourier Modeling Combined With Mesh-Based Magnetic Equivalent Circuits

This paper presents a hybrid analytical modeling (HAM) method, which integrates a mesh-based magnetic equivalent circuit model with the Fourier modeling approach. This HAM is capable of correctly predicting the electromagnetic field distributions for various 2-D geometries. The generalized approach of the presented hybrid modeling concept makes the modeling technique applicable to a wide range of electromagnetic devices. By only meshing the parts of the domain in the vicinity of the high-permeable materials, the increase in computational effort is limited compared with the sole use of Fourier modeling. The proposed HAM method predicts the force in the geometry with ≥97[%] accuracy with respect to finite-element analysis.

3-D Hybrid Analytical Modeling: 3-D Fourier Modeling Combined With Mesh-Based 3-D Magnetic Equivalent Circuits

This paper presents a novel 3-D hybrid analytical modeling (HAM) method that integrates a mesh-based 3-D magnetic equivalent circuit model into 3-D Fourier modeling. This HAM is capable of predicting the electromagnetic field distributions for Cartesian 3-D structures. A generalized approach of the hybrid-modeling concept is presented. The modeling technique is applicable to a wide range of electromagnetic devices, such as linear and planar actuators. In only a fraction of the calculation times of 3-D finite-element approaches, the 3-D HAM calculates the magnet field distributions and forces with approximately 90% accuracy.

Fourier Modeling of Magnetic Shields With Linear Permeable Material and Finite Dimensions

This paper describes a semianalytical modeling method capable of calculating the magnetic flux density in presence of a magnetic shield with finite dimensions and a linear permeability. The modeling method is based on Fourier modeling extended with mode-matching. The error of the semianalytical model with respect to a finite element solution is less than 1 (%), except for the area near the tangential edges of the magnetic sheet. The described model is compared with a model where an infinite permeability is assumed and a clear difference in behavior is found.

Field Calculations for Magnetic Shielding: Fourier Modeling Extended With Mode-Matching Technique Applied on a Shield With Finite Dimensions

In this paper, a semi-analytical model is derived to calculate the magnetic flux density around a magnetic shield with finite dimensions. The proposed modeling is based on Fourier modeling, which is extended with mode-matching. The described model has less than 0.2(%) error with respect to finite element modeling for the given configuration. Furthermore, the paper shows that assuming a magnetic shield with infinite dimensions introduces a significant error with respect to a magnetic shield with finite dimensions.

Force measurements on a shielded coreless linear permanent magnet motor

This paper compares force measurements on a shielded coreless linear permanent magnet motor with 2-D models. A 2-D semianalytical modeling method is applied, which is based on Fourier modeling and includes force calculations. The semianalytical modeling correctly predicts the behavior found in the measurements, disregarding the saturation effects in the shield. The proposed semianalytical modeling method gives a good preliminary indication of the forces, which makes it a valuable modeling technique during design.

Magnetic Shielding for Coreless Linear Permanent Magnet Motors

This paper concerns the local reduction of the magnetic flux density by means of magnetic shielding. Using a spatial frequency description, a 2-D semi-analytical periodic model is obtained for a coreless single-sided linear permanent magnet motor. The magnetic shield is included in the modeling using mode-matching. The obtained magnetic flux density is compared to a finite element model and is verified with measurements. The results show a reasonable agreement between the semi-analytical model and the measurements. Some large deviations occur due to the modeling assumption that the shield has a linear permeability, while the used shields are saturated. However, the semi-analytical modeling method is accurate enough for design purposes and initial calculations, especially when being aware of the possible saturation of the shield.

Optimization and measurement of eddy current damping applied in a tuned mass damper

This paper describes the optimization of the eddy current damping, applied in a tuned mass damper. A semi-analytical model based on scalar potential formulation is extended for different permanent magnet topologies. Optimal design parameters are acquired by particle swarm optimization. Measurements are performed for validating the semi-analytical model and optimization routine. Furthermore, an experiment is carried out to test a tuned mass damper with two optimal permanent magnet topologies.

Three-Dimensional Modeling of Shielding of Magnetic Stray Fields Based on Superposition of 2-D Models

This paper concerns the superposition of 2-D semianalytical models to model 3-D shielding configurations. The 2-D semianalytical models are used to describe the effect of magnetic shielding on the stray field of a single-sided coreless linear permanent-magnet motor. The modeling results are compared to 3-D finite-element analysis and to measurements. It is found that an accurate description of the tendencies and the order of magnitude is given. Furthermore, the comparison of the superposition of 2-D semianalytical models with the measurements shows that saturation and neglecting the 3-D effects cause the deviation between model and measurement.

3-D modeling of shielding of magnetic stray fields based on superposition of 2-D models

This paper concerns the superposition of two-dimensional semi-analytical models to model three-dimensional shielding configurations. The 2-D semi-analytical models are used to describe the effect of magnetic shielding on the stray field of a single-sided coreless linear permanent magnet motor. The modeling results are compared to 3-D finite element analysis and to measurements, it is found that an accurate description of the tendencies and the order of magnitude is given. Furthermore, the comparison of the superposition of 2-D semi-analytical models with the measurements shows that saturation and neglecting the 3-D effects cause the deviation between model and measurement.