Ki-Chan Kim

Review of maglev train technologies

This paper reviews and summarizes Maglev train technologies from an electrical engineering point of view and assimilates the results of works over the past three decades carried out all over the world. Many researches and developments concerning the Maglev train have been accomplished; however, they are not always easy to understand. The purpose of this paper is to make the Maglev train technologies clear at a glance. Included are general understandings, technologies, and worldwide practical projects. Further research needs are also addressed.

The Shape Design of Permanent Magnet for Permanent Magnet Synchronous Motor Considering Partial Demagnetization

This paper presents a study on shape design of permanent magnets that is focused on robustness for cogging torque, sinusoidal back emf, and partial demagnetization of the permanent magnet of the outer rotor permanent magnet synchronous motor (PMSM). The simulation method for partial demagnetization is proposed and performed with four kinds of permanent magnet shape models at the fault current and two kinds of load angles corresponding to maximum torque operation and short circuit operation by finite-element method (FEM). The robust shape model of permanent magnets for large-sized hybrid electric vehicles is presented. The characteristics after partial demagnetization are analyzed and compared with experimental results for verification of the partial demagnetization effect

A Study on the Characteristics Due to Pole-Arc to Pole-Pitch Ratio and Saliency to Improve Torque Performance of IPMSM

In this paper, the design methodology of a rotor for the interior permanent magnet motor (IPMSM) considering pole-arc to pole-pitch ratio and saliency parameter owing to PM and duct structure is proposed in order to improve the characteristics such as average torque, torque ripple, cogging torque and back EMF waveform. Especially, demagnetization effect due to duct design is analyzed by using the finite element method (FEM)

A Study on the Optimal Design of SynRM for the High Torque and Power Factor

This paper presents the optimal design method of synchronous reluctance motor (SynRM) for the high torque and power factor. It is difficult to design optimal barrier shape of rotor by analytical method because of leakage flux between barriers and saturation in the core. Therefore, the optimal design of SynRM including rotor structure is proposed in this paper by using finite element method (FEM) and simulation design of experiment (DOE). Finally, the characteristics of optimal model are compared with those of the worst one

Analysis of electromagnetic force distribution on end winding for motor reliance

The design of electrical rotating machine is required to have high capacity and electrical loading without comparable increase in size. In this paper, we looked into the electromagnetic force of end winding part of electrical motor by using 3D finite element method to analyze distribution of end winding forces more exactly. And we also performed stress analysis of end windings by using the force distribution calculated by 3D electromagnetic field FEM. Finally, the design of support ring surrounding end windings and preventing the insulation fault is presented by comparing the stress distribution of supporting ring with the yield stress of ring material.

Analysis on the direct-driven high power permanent magnet generator for wind turbine

In this paper, the permanent magnet synchronous generator of 1.5 MW output power which is driven directly without gear system is designed by conventional magnetic equivalent circuit method and analyzed by finite element method for verification of design. We analyzed the characteristics of generator like no load, rated load, short circuit condition and demagnetization of permanent magnet. The last, the analysis results of two kinds of rotor types are compared with each other. Especially the THD (total harmonic distortion) of output voltage is examined for the comparison.

The Study on the Overhang Coefficient for Permanent Magnet Machine by Experimental Design Method

This paper presents a study on the overhang coefficient which represents the extent of air-gap flux concentration owing to overhang. The overhang coefficients are derived by experimental design method and 3-D magneto-static finite-element analysis (FEM) according to permanent magnet rotor types. Finally, the application method for overhang coefficient is proposed when we design and analyze the permanent magnet (PM) motor with overhang parameter by equivalent circuit and 2-D transient FEM

The dynamic analysis of a spoke-type permanent magnet generator with large overhang

In this paper, we examined overhang effects based on overhang length and material of rotor core by using 2D and 3D static FEM analysis, and proposed 2D dynamic FEA method considering overhang parameter which gives good and rapid results. The proposed method is verified by the experimental results of no load and short-circuit test. The PMG has 13 mm overhang length, spoke type ferrite permanent magnet and 1800 rpm speed.

Dynamic Analysis Of A Reciprocating Linear Actuator For Gas Compression Using Finite Element Method

This paper presents the dynamic analysis of a reciprocating actuation system based on moving magnet actuator for gas compression. For the analysis of the linear actuator, an axisymmetric finite element method (FEM) considering the saturation effect of the magnetic material is used, and electrical circuit equation, mechanical dynamic equation and pressure dynamics are coupled. In the FE analysis, we adopt a moving line technique to save computation time and to perform the process efficiently. The pressure dynamics of the gas in the compressor is modeled by using the law of thermodynamics. The analysis results compare fairly well with experimental ones.

Characteristic Analysis of Permanent-Magnet-Type Stepping Motor With Claw Poles by Using 3 Dimensional Finite Element Method

This paper analyzed the characteristics of the permanent magnet (PM)-type claw pole stepping motor by using 3D finite element method (FEM). In the case of analyzing this type of motor, 3D FEM is necessary for an accurate analysis due to the magnetizing component of the z-axis direction. As a main design variable, the magnetizing pattern and PM area were selected. The variation of the detent torque and the holding depending on the shape of the pole is also shown. Finally, the results are verified as to compare with the experimental results