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공간고조파해석법을 이용한 영구자석 선형 동기전동기의 특성해석
尹相伯,洪正杓,玄東石,鄭因城 창원대학교 공작기계기술연구센터 1999 연구업적집 Vol.1 No.1
This paper presents a two dimensional analytical method of a permanent Magnet Linear Synchronous Motor(PMLSM) based on the concept of space harmonic The air gap flux densities due to permanent magnets and primary current are calculated separately, and the resultant air gap flux density is obtained by superposition of those, Maxwell's stress tensor is used to calculate thrust and normal force. The static thrutst and normal force according to exciting current and power angle are calculated, and the harmonics of the thrust are analyzed using discrete Fourier transform In order to verify the validity of the proposed analytical method, we make a test facility and compare the analysis results with the experimental ones.
주행속도에 따른 부상마그네트의 특성을 고려한 상전도 자기부상시스템의 부상제어에 관한 연구
玄東石,洪正杓,鄭因城,許眞,尹相伯 창원대학교 공작기계기술연구센터 1999 연구업적집 Vol.1 No.1
A collective controller for electromagnetic suspension (EMS) system considering the speed characteristics of electromagnets is presented. The speed characteristics of the electromagnet are analyzed by finite element method (FEM) and Neural Network algorithm is used for the controller considering speed. The proposed controller is examined and the dynamic characteristics are compared with those of other controllers. The simulation results show that proposed controller has a better performance at high speed.
Radiological Spectrum of Hepatic Mesenchymal Hamartoma in Children
Kim, Soung Hee,Kim, Woo Sun,Cheon, Jung-Eun,Yoon, Hye-Kyung,Kang, Gyeong Hoon,Kim, In-One,Yeon, Kyung Mo The Korean Radiological Society 2007 KOREAN JOURNAL OF RADIOLOGY Vol.8 No.6
<P><B>Objective</B></P><P>A hepatic mesenchymal hamartoma is an uncommon benign tumor in children and little is known about the spectrum of its radiological features. The purpose of this study is to describe the spectrum of radiological features of a hepatic mesenchymal hamartoma in children.</P><P><B>Materials and Methods</B></P><P>Thirteen children with a pathologically confirmed hepatic mesenchymal hamartoma (M:F = 7:6; mean age, 3 years 2 months) were included in our study. Ultrasonography (US) was performed in nine patients including color and power Doppler US (n = 7). CT scans were performed in all patients. We evaluated the imaging findings of the hepatic mesenchymal hamartomas and the corresponding pathological features.</P><P><B>Results</B></P><P>Each patient had a single tumor (mean diameter: 13 cm [1.8-20 cm]). On CT and/or US, four patients (31%) had a 'multiseptated cystic tumor', five patients (38%) had a 'mixed solid and cystic tumor', and four patients (31%) had a 'solid tumor.' The septa of the cystic portion were thin in the multiseptated cystic tumors and irregularly thick in the mixed solid and cystic tumors as seen on US. On a post-contrast CT scan, solid portions or thick septa of the tumors showed heterogeneous enhancement. The amount of hepatocytes was significantly different among the three tumor groups according to the imaging spectrum (<I>p</I> = 0.042).</P><P><B>Conclusion</B></P><P>A hepatic mesenchymal hamartoma in children can show a wide spectrum of radiological features, from a multiseptated cystic tumor to a mixed solid and cystic tumor, and even a solid tumor.</P>
Development of BLDC Motor Drive for Automotive Water Pump Systems
Park, Joon-Sung,Gu, Bon-Gwan,Choi, Jun-Hyuk,Jung, In-Soung The Korean Institute of Electrical Engineers 2011 The Journal of International Council on Electrical Vol.1 No.4
In order to save resources and prevent global warming, there has been a pressing need in recent years to reduce the volume of CO2 emissions, and to improve the fuel consumption of automobiles. The trend in the automotive application is to improve efficiency and to reduce volume and weight. Under these circumstances, the mechanical parts in the automobile industry are being replaced by electronic methods. Especially, to improve vehicle engine efficiency, power transmission and around the field of devices according to driving conditions need to be properly cooled. Conventional mechanical water pump is directly connected by the engine belt. For this reason, regardless of coolant circulation, the conventional mechanical water pump is always operated. The way which the mechanical water pump is replaced by electric water pump could reduce energy consumption.
Design and Analysis of Slotless Brushless DC Motor
Jung-Moo Seo,Joo-Han Kim,In-Soung Jung,Hyun-Kyo Jung IEEE 2011 IEEE transactions on industry applications Vol.47 No.2
<P>This paper presents a design method for a small-sized slotless brushless dc motor. Distributed hexagonal windings are employed for achieving a high torque density and for ease of manufacture. Numerical approaches with an analytic model are used to analyze the magnetic and output characteristics of the motor. The proposed motor is manufactured, and the empirical results are compared with the results of the simulation.</P>
Jung-Moo Seo,In-Soung Jung,Hyun-Kyo Jung,Jong-Suk Ro IEEE 2014 IEEE transactions on magnetics Vol.50 No.5
<P>This paper presents a magnetic field analysis of a surface-mounted permanent magnet machine with an overhang structure wherein the rotor axial length exceeds that of the stator. A 2-D analytic method using a lumped magnetic circuit model (LMCM) is proposed for more rapid computation of the overhang effect compared with a conventional 3-D or quasi-3-D finite element analysis (FEA). In the LMCM, the effective overhang length is calculated, and a leakage flux generated in the overhang region is estimated. The accuracy and usefulness of the proposed analytic method is confirmed through the 3-D FEA and the experimental results according to the diverse overhang length, the number of slot/pole, and stator core length.</P>
Bon-Gwan Gu,Jun-Hyuk Choi,In-Soung Jung IEEE 2014 IEEE transactions on power electronics Vol.29 No.4
<P>In this study, interturn short fault models of permanent magnet synchronous motors (PMSMs) employing series and parallel winding connections are developed using deformed flux models based on both fault winding flux information and inductance variations caused by cross flux linkages that depend on the distribution of same phase windings. As these models take into account fault winding within a three-phase winding dynamics analysis, they constitute fourth-order assessments. In the parallel-winding model, an additional dynamical analysis is used to describe variations in current distribution caused by the parallel connection between fault and healthy windings. Based on deformed flux modeling and positive sequence current assumptions, the proposed model is derived in both positive and negative sequence synchronous reference frames. A finite-element method-based simulation is applied to validate the proposed PMSM model.</P>
Flux filter LSPM Motor for the Prevention of Demagnetizing in Permanent Magnet
Jeong-Jong Lee,Young-Kyoun Kim,Se-Hyun Rhyu,In-Soung Jung 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6
In this paper, we proposed the flux filter LSPM motor in order to reduce the demagnetizing flux in the rotor magnet at starting condition. Line start permanent magnet motors have high efficiency and simple driving circuit. LSPM motor is needed the conductor bar in the rotor instead of power electric operating system for rotating. LSPM rotor is complex than general synchronous motor because of its conductor bar. But, LSPM motor is big problem to use in the industrial motor. The starting current is too large, it is occur the demagnetizing of permanent magnet. Proposed flux filter decrease the opposite flux against magnetizing direction. In order to analyze the effect of magnetizing, time-stepping finite element analysis is used. We verify the performance of the flux filter LSPM with ferrite magnet and compared with neodymium magnet LSPM.