• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.70-79
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• 2005

In this paper, improvement method of control performance by a full-order observer using reduced-order state equation is proposed in the low speed range. Full-order observer using reduced-order state equation is the motor speed and the disturbance torque observer. The proposed algorithm is very stable in the low speed range about 1.9[rpm]. The disturbance torque in the motor drive system degrades speed control performance in the low speed range. The proposed algorithm estimated both motor speed and disturbance torque. The estimated disturbance torque is used as a feedforward value in output of the speed controller, As a result, it improves the response of load torque in the low speed range(1.9rpm).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.105-111
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• 2013

The spindle is the main component in machine tools. The static and dynamic characteristics of the spindle directly affect the machining accuracy of workpieces. The characteristics of the spindle depend on the shaft size, bearing span, built-in motor location, and so on. Therefore, the appropriate selection of these parameters is important to improve the spindle characteristics. This paper presents the analysis of the static and dynamic characteristics and optimization design of a 40,000-rpm high-speed spindle. Statistical analysis for optimization and finite element analysis were performed. This study uses the response surface method to optimize the objective function and design factors. The targets are the natural frequency and displacement. The design factors are the shaft length, shaft diameter, bearing span, and motor location. The optimized design provides better results than the initial model, and these results are expected to improve the static and dynamic characteristics of the spindle.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.252-257
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• 1998

레이저 프린터에 사용되는 스케너 모터의 안정적인 베어링을 개발하기 위해서 함유소결 베어링과 빗살무늬 유체베어링을 개발하였다. 함유소결베어링은 9,000~20,000 rpm까지에서 매우 우수한 마찰 및 접촉특성을 나타내었으며, 빗살무늬 유체베어링에서는 35,000rpm까지 우수한 특성을 나타내었다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.416-417
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• 2018

Brushless DC(BLDC) 모터는 브러시가 없어 고속 회전에 유리하기 때문에 핸드피스 모터에 많이 적용하는 추세이다. 핸드피스 모터는 부피가 작을수록 유리하여 홀 센서를 장착하지 않은 경우가 많기 때문에 센서리스 제어를 하여야 한다. BLDC 모터의 상 역 기전력 zero crossing 감지 방법을 이용한 센서리스 제어를 할 시 40,000rpm에 달하는 고속 회전에서 상 전압 floating 구간이 $250{\mu}s$밖에 안되기 때문에 샘플링이 부족하고 스위칭 노이즈도 강해 zero crossing에 대한 감지가 어려울 수 있다. 이 논문에서는 역 기전력에 대한 비선형 필터인 majority function을 응용함으로써 모터 상 역기전력의 zero crossing을 감지해내고 고속 BLDC 모터 센서리스 제어를 하는 방법을 소개한다.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.234-236
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• 2001

자동차 산업의 활성화로 인하여 차량의 연료 소비의 고효율화 및 구동모터의 고정밀 설계 기술의 향상이 대두되고 있는 실정이다. 특히, LPG 차량의 연료 펌프 모터의 고속화, 저진동, 저 소음화의 추세로 인하여 기존의 Brush타입의 DC모터를 대체하기 위한 Brushless DC 모터의 개발이 증대되고 있다. 본 논문에서는 이러한 Brushless DC모터의 고정밀 속도제어 및 빠른 응답 특성을 가지는 제어기를 개발하였으며, 회전자의 위치를 파악하기 위하여 역기전력을 이용한 센서리스형 제어기를 개발하였다. 본 논문에서 개발한 제어기는 가변속도제어범위를 가지며. 2000rpm에서 정격 속도를 가진다. 제어기의 성능 검증을 위하여 정격 속도에서의 단위스텝 응답 특성 실험을 하였으며, 각각의 게인 설정에 따른 제어 성능 실험을 하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.9
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• pp.789-799
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• 2012

In this research, a high temperature superconducting(HTS) motor is designed which is adequate for an electrical aircraft by generating high power density and the potentiality of its application to an aircraft is studied. The designed motor is based on YBCO plates, HTS coils composed of Bi-2223, and ironless air cooled resistive armature. The HTS motor is designed to generate power equivalent to O-360 engine with 180HP at 2700RPM which is used for Cessna and equivalent to CFM56 engine with 18000HP at 5000RPM which is used for B-737. Also, power densities of HTS motors are compared with power densities of aircraft engines so that we can estimate the potentiality of the HTS motor as an aircraft engine.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.561-569
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• 2000

The purpose of this study is to construct a testing equipment with which several characteristics of the domestically developed swashplate type axial piston motor can be tested and to develop a software with which the data from experiment can be stored and can be applied. The results of the study are as follows; 1) The leakage flow and the torque of the motor being stopped is propotional to supply pressure and their relation can be showed by linear equations. 2) The motor movement is not smooth below 50 rpm but it moves smoothly up 170 rpm. 3) When the motor starts or stops, the pressure rise ratio effects decisively to the max. torque.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.61-67
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• 2012

The in-wheel motor used in green car was designed and constructed for an electric direct-drive traction system. It is difficult to connect cooling water piping because the in-wheel motor is located within the wheel structure. In the air cooling structure for the in-wheel motor, a outer surface on the housing is provided with cooling grooves to increase the heat transfer area. In this study, we carried out the analysis on the fluid flow and thermal characteristics of the in-wheel motor under the effects of motor speed and heat generation. In order to check the problem of heat release, the analysis has been performed using conjugate heat transfer (conduction and convection). As a result, flow fields and temperature distribution inside the in-wheel motor were obtained for base speed condition (1250 rpm) and maximum speed condition (5000 rpm). Also, the thermo-flow characteristics analysis of in-wheel motor for vehicles was performed in consideration of ram air effect. Therefore, we checked the feasibility of the air cooling for the housing geometry having cooling grooves and investigated the cooling performance enhancement.

• Tribology and Lubricants
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• v.15 no.1
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• pp.108-115
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• 1999

The electrical and frictional properties of oil-impregnated sintered-metal bearing (OSB) and herringbone-grooved fluid bearing (HFB) with varying loads and speeds were measured. OSB shows very good performance up to 20,000 rpm and 0.05 N, and HFB successfully works up to 35,000 rpm and 0.05 N. From the endurance tests on start-stop and continuous operation, it was confirmed that those bearings could be mass-produced fur use on scanner motor in a laser scanner unit.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.326-333
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• 2004

This paper presents the structural characteristics analysis of a high-speed horizontal machining center with spindle speed of 50, 000rpm and feedrate of 120m/min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motor and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guide. The structural analysis model of the high-speed horizontal machining center is constructed by the finite element method, and the validity of structural design is estimated based on the structural deformation of the high-speed horizontal machining center and spindle nose caused by the gravity and inertia forces.