Sung-Won Seo

Core Loss Analysis of Permanent Magnet Linear Synchronous Generator Considering the 3-D Flux Path

This paper presents an analysis of the core loss observed in the stator of a permanent magnet linear synchronous generator. Core loss is usually calculated using the classical Steinmetz equation, but it leads to erroneous results. Consequently, several researchers have proposed modified versions of this equation, taking into account the hysteresis loss, eddy current loss, and excess loss. In this paper, we calculated all loss coefficients from the Epstein test data using a curve fitting method. Moreover, we separated the rotating and alternating fields based on the time harmonics observed with changes in the magnetic flux density. In addition, we considered the 2-D and 3-D plane flux paths that cause magnetic flux leakage. Finally, the core loss of the linear machine was calculated using a modified Steinmetz equation that considers the flux path.

Analytical torque calculation and experimental verification of synchronous permanent magnet couplings with Halbach arrays

This paper presents analytical torque calculation and experimental verification of synchronous permanent magnet couplings (SPMCs) with Halbach arrays. A Halbach array is composed of various numbers of segments per pole; we calculate and compare the magnetic torques for 2, 3, and 4 segments. Firstly, based on the magnetic vector potential, and using a 2D polar coordinate system, we obtain analytical solutions for the magnetic field. Next, through a series of processes, we perform magnetic torque calculations using the derived solutions and a Maxwell stress tensor. Finally, the analytical results are verified by comparison with the results of 2D and 3D finite element analysis and the results of an experiment.

Electromagnetic analysis and experimental verification of double- permanent magnet linear synchronous generator with slotted stator using analytical method

Linear generators are considered to have higher efficiency and better performance compared to rotary generators, because they do not require any transmission device.

Characteristic analysis and experimental verification of generating performance in double-sided permanent magnet synchronous linear generator considering three-dimensional effects for ocean wave energy converter

For generating performance analysis and experimental verification of a double-sided permanent magnet linear synchronous generator (PMLSG) with a slotless stator as shown in Fig. 1(a), this paper utilized a three-dimensional (3D) analysis method and manufactured model.

Comparative study and experiment of a double-sided permanent magnet linear synchronous generator according to magnetization pattern

This paper presents a comparison of efficiency and mover mass on a double-sided permanent magnet linear synchronous generator (PMLSG) according to its magnetization pattern. When a PMLSG has a lighter mover, it has advantages such as lower cost and other aspects regarding mechanical losses. In general, PMLSGs are used with a vertical PM pattern, but we propose a horizontal PM pattern in this paper because the horizontal PM mover does not need a back-iron for the magnetic path. Electromagnetic field analysis is especially essential when analyzing the characteristics of PMLSGs. For this type of analysis, commercial finite element analysis tools are widely used because they offer convenient user interfaces that provide very accurate analytical results. Based on two-dimensional finite element analysis, we got results for two different patterns and compared them with our experimental results. Finally, the results of this analysis and the test results obtained confirm the validity of the model and the superiori...

Eddy current loss in double-sided cored slotless type permanent magnet linear synchronous generator using analytical method

This paper describes the eddy current loss analysis of a double-sided cored slotless-type permanent magnet linear synchronous generator using the space harmonic method. To calculate the eddy current, an analytical solution was derived by applying the Maxwell equation, magnetic vector potential, and Faraday’s law in a two-dimensional (2-D) Cartesian coordinate system. Based on the armature reaction field distribution produced by the armature winding current, we obtained an analytical solution for the eddy current density distribution. Then, an analytical solution for eddy current loss induced in a permanent magnet (PM) was derived using the equivalent electrical resistance calculated from the PM’s volume and eddy current density distribution solution. Finally, the resulting current was determined based on analysis of the eddy current loss. The analytical results produced using this application of the space harmonic method were validated extensively through comparison with finite element method results.

Open circuit and armature reaction field analysis of permanent magnet linear synchronous generator

This paper presents a comparative analysis of a double-sided permanent magnet linear synchronous generator (PMLSG) with different magnetic circuits using electromagnetic transfer relations. The magnetizations for vertical and Halbach arrays are derived using a Fourier series expansion. Based on Maxwells equations, governing equations are derived for each case, and transfer relation matrices are obtained. The magnetic fields produced by PMs and the armature reaction are calculated. In order to analyze the generating behavior, an equation for calculating the induced voltage is derived, and equivalent circuit parameters are calculated. The analytical results are validated by comparing them with finite element analysis (FEA) results.

Comparison of characteristic of a double-sided permanent magnet linear synchronous generator according to magnetization pattern

This paper compares the characteristics of a double-sided small-scale permanent magnet linear synchronous generator (PMLSG) operating with three different magnetization patterns. First, in this paper, we determine the characteristics of a vertical array. Second, we derived the characteristics of the Halbach and horizontal array. Finally, the analysis results are verified by using results from experiments.

Characteristic Analysis for the Reduction Detent Force of Double-sided Slotted Type Permanent Magnet Linear Generator for Wave Energy Conversion

This study considered the reduction of the detent force of a permanent magnet linear synchronous generator (PMLSG). The PMLSG has a relatively large magnetic air gap. Thus, a slotted type of stator structure is generally employed. Furthermore, the detent force, which is caused by energy imbalances owing to the interaction between tooth-slot structures and the permanent magnets (PMs), must be minimized for start-up operation. Therefore, in this paper, the methods of auxiliary teeth and a notch in the teeth are applied to reduce the detent force.