• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권10호
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• pp.701-707
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• 2000

This paper proposes a tension control to compensate friction loss using on-line friction torque observer for a continuous strip processing line. Friction loss of roller results in significant deviation of strip tension, accordingly it has an influence on the operation of other adjacent rolls. To avoid tension variation of the strip, a friction torque observer is designed in adjacent roll, which operates in speed control mode. The observed torque is added to the torque limit reference of the pay-off reel for on-line compensation of both friction loss and acceleration/deceleration torque at the same time. The simulation and experimental results show improvement of tension control performance by the proposed friction compensation method.

• 한국기계가공학회지
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• 제9권3호
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• pp.8-18
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• 2010

A total stroke of an opening or closing motion of a hinge mechanism for a folder-type mobile phone is composed of two portions. In the first portion, human fingers act a torque to open or close the folder. In this portion, the rotating folder compresses the coil spring installed in the hinge mechanism. In the last portion, this compressed coil spring generates a torque to rotate the folder. In this study, we have developed an algorithm to design a hinge mechanism to be operated by an arbitrary continuous torque in the first portion of the total stroke. Consequently, we can design hinge mechanisms that satisfy various demands of consumers. A pair of contours installed in the mechanism plays an important role. It transforms the folder's rotational motion into translation to compress the coil spring in the first portion; on the other hand, it transforms translational motion into the folder's rotation in the last portion. Using this algorithm we have designed the pair of the contour curves operated by an arbitrary continuous torque.

• Journal of Electrical Engineering and Technology
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• 제6권5호
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• pp.640-646
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• 2011

The current study presents the design and performance of a novel 4/2 switched reluctance motor (SRM) for a high-speed air blower. With a comparative study of some rotor structures for a high-speed drive, a stepper-type rotor is optimized to produce a continuous torque and a low torque ripple. Rotor pole arc is modified to have a wide continuous output torque region, and air gap is determined to develop less torque ripple. The rotor radius is determined to reduce torque ripple with a reiterative FEM analysis. The designed rotor has three regions: short uniform, long uniform, and nonuniform air-gap region. The positive torque region is wider than a conventional 4/2 SRM without any torque dead zone. A prototype is tested and the efficiency is up to 72[%] at 30,000[rpm], 600[w] output.

• Smart Structures and Systems
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• 제23권4호
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• pp.319-327
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• 2019

Continuous rotating SMA actuators require motion conversion mechanisms, so their structure is relatively complex and difficult to realize the miniaturization. Here, a new type of continuous rotating actuator driven by SMA is proposed. It combines the movable tooth drive with SMA drive. The structure and working principle of the integrated movable tooth drive system is introduced. The equations of temperature, stress and strain of memory alloy wires, and the output torque of drive system are given. Using these equations, the temperature, the output forces of the SMA wires, and output torque of the drive system are studied. Results show that the compact drive system could give large output torque. To obtain large output torque plus small fluctuation, large eccentricity and small diameter of the SMA wire should be taken. Combined application of ventilation cooling and high current can increase the rotary speed of the drive system.

• 전력전자학회논문지
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• 제7권2호
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• pp.186-193
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• 2002

연속 공정 라인을 구성하는 롤러들의 속도뿐만 아니라 토크를 적적히 제어할 수 있는 통합형 제어기를 제안하였다. 여러 대의 롤러들이 동시에 가감속 할 때 발생하는 속도 편차는 소재의 장력을 유발하여 가공중인 제품의 품질에 나쁜 영향을 미치게 된다. 제안된 통합형 제어기를 사용하면 속도 기준값 편차나 속도제어 기 특성차이가 존재하더라도 토크 및 속도 기준값을 잘 추종하도록 제어하는 것이 가능하다 제안된 제어기는 가감속 등의 과도상태에는 속도 기준 값을 추종하는 것을 위주로 하고 정상 운전속도에서는 토크 기준값에 따라 제어함으로서 인접한 롤러간의 부하를 분담하도록 설계되었다 특히 제안된 제어기는 인접한 롤러의 제어 정보를 필요로 하지 않으므로 각각의 롤러 제어기 유닛에 쉽게 구현될 수 있다는 장점이 있다. 연속 공정 라인 모의 실험장치에서 제안된 제어기의 토크 및 속도 제어 특성을 비교 검토하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.212-213
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• 2013

This paper proposes the algorithm of torque distribution in the electric wheel-chair using 2D joystick for drive safety. For the accurate driving performance, the specific and precise torque distribution is required in both wheels depending on signals of X-Y axis that is generated from 2D joystick. The signals of X-Y axis from joystick are transformed into the propulsion force and the torque reference. And the torque reference can be generated through the dynamic model of wheel-chair. The optimal dynamic characteristics of the electric powered wheelchair can be obtained, by adjusting the sensitivity coefficients of propulsion force and torque reference, In addition, the system takes smooth and stable control characteristics due to continuous torque output at all directions of joystick. The several simulations verify the usefulness of the proposed algorithm about torque distribution.

• 조명전기설비학회논문지
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• 제18권3호
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• pp.74-80
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• 2004

연속 주조 공정에서 설정한 속도로 주편을 인발하는 스트랜드 구동롤에 인발력이 적절하게 분배가 되지 않으면 주형 레벨의 주기적인 변동을 유발시킴과 동시에 주편의 품질을 저하하게 된다. 따라서 본 논문에서는 주편의 속도를 제어함과 동시에 각 구동롤에 운전자가 원하는 비율로 인발력을 분배할 수 있는 알고리즘을 제안한다. 제안된 방법은 전동기에 작용하는 토크 전류를 상위 제어기로 귀환하여 평균 토크 전류를 산출하고 각 구동롤 전동기의 토크 전류와 비교하여 전동기의 속도 기준값을 미소하게 변경함으로써 각 구동롤 전동기의 토크 전류가 평균 토크 전류에 추종하도록 하여 인발력을 분배한다. 그리고 과도상태 개선을 위하여 안티와인더업(anti-wind up) 제어기를 가진 인발력 제어기를 적용하였으며, 제안된 알고리즘의 확인을 위하여 포스코의 시험연주기에 적용하여 우수성을 입증하였다.

• Journal of Magnetics
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• 제17권3호
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• pp.200-205
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• 2012

Recently, applications of the reluctance torque motor have been quite limited due to their inherent limitation of noise and vibration and thus, researches on the reluctance motor have been limited as well. However, with the tremendous increase in the cost of rare earth material magnets, studies of the reluctance torque motor are being conducted more and more. In principle, reluctance torque is generated when the inductance is changed. Therefore, in order to generate continuous torque in the switched reluctance motor, it is necessary to figure out the exact inductance level corresponding to the rotor position and the current level to be applied in that rotor position, respectively. If the current level or the rotor position is not accurately determined, then the generated reluctance torque becomes unstable and undesirable torque ripples prevail to eventually cause noise and vibrations. In this research, a flux switched reluctance motor (FSRM), which is classified into the switched reluctance motor (SRM), was studied. A methodology using the current shaping control according to the rotor position was proposed. Based on the proposed methodology, the optimal current waveform and the torque distribution function for the FSRM to minimize torque ripple was established and demonstrated in this paper.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.94-103
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• 2011

This paper presents a novel bearingless switched reluctance motor (BLSRM) with decoupled torque and suspending stator poles. BLSRM is different from conventional bearingless switched reluctance motors (SRMs) because its suspending poles are separated from the torque poles. Perpendicularly placed suspending poles are designed to produce a continuous radial force to suspend the rotor. Due to the independent suspending and torque poles, BLSRM produces a suspending force with excellent linearity according to the rotor position and independent characteristics of the torque current. The air-gap is easier to control than in conventional SRMs with their linear and independent characteristics. Furthermore, to verify the proposed structure, a mathematical model for the suspending force is derived. Finite element analysis is also employed to compare BLSRM and conventional SRMs expressions of suspending force. A prototype motoris designed and manufactured to verify the effectiveness of the proposed bearingless structure.

• 전기학회논문지
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• 제65권12호
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• pp.2183-2188
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• 2016

This paper deals with the design process for an outer-rotor-type surface-mounted permanent magnet synchronous motor (SPMSM) used in continuous variable valve timing (CVVT) systems in automobiles with internal combustion engines. When the same size, outer-rotor-type SPMSMs generate larger torque and more stable than inner-rotor-type SPMSMs. For the initial design, space harmonic analysis (SHA) is used. In order to minimize the cogging torque, an optimization was conducted using Response Surface Methodology (RSM). At the end of the paper, Finite Element Analysis (FEA) is performed to verify the performance of the optimum model.