• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.82-84
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• 2009

최근 널리 사용되고 있는 BLDC Motor는 코깅 토크 문제점을 가지고 있다. 본 연구에서는 4극 24슬롯 BLDC Motor를 Flux 2D로 시뮬레이션 하였고, 문제점을 파악하여 Magnet Pole Cover를 이용한 모터를 설계하고 분석하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.736_737
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• 2009

본 논문은 전기자전거용으로 쓰이는 500W급 매입형 영구 자석 동기전동기의 자석 형태에 따른 특성 변화에 대해 연구하였다. 전기자전거의 경우 낮은 코깅토크 특성을 필요로 하며, 부하의 변화 시에도 고출력 고효율 특성을 지니는 정특성 운전이 요구된다. 이를 위해 높은 관성력을 얻을 수 있는 외전형 타입의 모터가 필요로 하며, 많은 부하가 요구되는 지점에서 고출력 토크를 위해서는 매입형 영구자석 동기전동기가 요구되고 있다. 본 논문에선 500W급 매입형 영구자석 동기전동기의 특성 향상을 위하여 자석 형태에 따른 모터 특성을 비교 분석하였으며, 실제 최적화 모델을 제작 및 성능실험을 통해 제안된 모델의 타당성을 검증하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.196-201
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• 2008

This paper is about electromagnetic vibration source in outer rotor type of BLDC motors. Experiments are carried out with three pole-slot combinations which are 6 slots, 12 slots, and 24 slots with 4 poles rotor. According to results, vibration sources separate into electromagnetic and mechanical factors. Using the finite element method (FEM), It is analyed that vibration characteristics of electromagnetic source in each type. This paper shows electromagnetic sensitivity to vibration, and introduces necessary point in lower vibration motors. Also rotor balance is important to prevent uneven distribution of magnetic flux between rotor and stator.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.798-799
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• 2015

본 논문에서는 영구자석의 형상을 변화시켜 표면 부착형 동기 전동기(Surface Permanent Magnet Synchronous Motor, SPMSM)의 토크리플을 저감하였다. 교류전동기의 경우 공극에 자속이 정현적으로 분포할수록 역기전력 파형이 정현파에 가까워지고, 토크리플이 작아진다. 위의 조건을 바탕으로, 자석의 사용 양을 동일하게 유지하면서 공간고조파를 최소화하기 위해 공극에 자속이 정현적으로 분포할 수 있도록 자석 형상에 모깎기를 적용하여 SPMSM의 최적설계를 진행하였다. 2D 유한요소해석법(Finite Element Method)을 이용하여 각 형상별 토크, 역기전력 등의 모터의 기본 특성들을 해석하여 영구자석 형상이 SPMSM의 성능에 어떠한 영향을 미치는지 분석하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.316-322
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• 2007

The EHA(Electro-hydrostatic Actuator) reveals completely different characteristics from the conventional valve-controlled Electro-hydraulic actuators. In this paper, its mathematical model including nonlinear elements was derived to be verified by experiments. Based on this, a simulation program was developed for the EHAs consisting of an electric motor driven hydraulic pump, pipe lines and a cylinder. The influence of important design parameters such as peak motor torque and rotational inertia moment of the hydraulic pump on control performance was investigated, where the test condition was intentionally selected so that the motor torque was saturated during the transient phase. As a result, design requirements for improving the control accuracy under full speed operation conditions of the EHAs were investigated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.35-42
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• 2019

Nut fasteners that require ultra-precise control are required in the overall manufacturing industry including electronic products that are currently developing with the automobile industry. Important performance factors when tightening nuts include loosening due to insufficient fastening force, breakage due to excessive fastening, Tightening torque and angle are required to maintain and improve the assembling quality and ensure the life of the product. Nut fasteners, which are now marketed under the name Nut Runner, require high torque and precision torque control, precision angle control, and high speed operation for increased production, and are required for sophisticated torque control dedicated to high output BLDC motors and nut fasteners. It is demanded to develop a high-precision torque control driver and a high-speed, low-speed, high-response precision speed control system, but it does not satisfy the high precision, high torque and high speed operation characteristics required by customers. Therefore, in this paper, we propose a control technique of BLDC motor variable speed control and nut runner based on vector control and torque control based on coordinate transformation of d axis and q axis that can realize low vibration and low noise even at accurate tightening torque and high speed rotation. The performance results were analyzed to confirm that the proposed control satisfies the nut runner performance. In addition, it is confirmed that the pattern is programmed by One-Stage operation clamping method and it is tightened to the target torque exactly after 10,000 [rpm] high speed operation. The problem of tightening torque detection by torque ripple is also solved by using disturbance observer Respectively.

• Journal of the Korean Geotechnical Society
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• v.23 no.7
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• pp.57-64
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• 2007

This study proposes a method to estimate drilling torque during ground boring with an aid of electrical energy required for rotating a boring-auger. Ground boring is commonly used in geotechnical engineering such as preboring precast pile installation, soil-cement grouting, ground exploration and so forth. In order to understand the correlation between required electrical energy to rotate the boring auger and the drilling torque, a small laboratory apparatus was designed and a pilot study was performed. The apparatus rotates common drill bits of $D=5{\sim}25mm$ in CBR specimens. The velocity of a bit is 19 RPM and predefined using a reduction gear which connects a main rotation axis to a 25 Watts AC electrical motor shaft. In the middle of drilling the motor current increments and the drilling torque were measured and the correlation between the current and the torque was obtained through linear square fits. Based on the correlation the acquired motor current during drilling was applied to predict the drilling torque in consequent testing and the prediction results were compared to the measured torque. The comparison leads a conclusion that the motor current during drilling using electrical power may be a good indicator to estimate/determine strength characteristics of the ground.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.814_815
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• 2009

본 논문은 로봇관절 구동 및 제어에 활용될 중공모터의 설계 및 특성해석에 대해 연구하였다. 로봇관절에 사용될 중공모터의 경우고 토크출력이 요구될 뿐만 아니라, 저속에서 제어 및 구동 신뢰성이 높은 운전특성이 요구된다. 또한 로봇 관절에 활용하기 위하여 배선처리가 간편한 중공타입의 구조가 요구된다. 따라서 우리는 로봇 구동 및 경량화가 가능하도록 유성기어와 결합이 가능한 외전형 타입의 영구자석 동기전동기의 설계 및 특성해석을 하였다. 먼저 로봇 관절에 적합하도록 FEA 기법을 이용하여 설계하였으며, 실제 시작기 모델을 제작하여 성능실험을 통해 제안된 모터의 특성을 분석하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1682-1683
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• 2007

본 논문은 시변 파라미터를 갖는 직류 모터의 적응 제어를 위한 온라인 상태궤환 제어시스템을 구성한다. 모터의 전기자 저항은 공칭값에 대하여 가우시안 랜덤변수로 가정하고 온라인 최소자승 추정법을 이용하여 실시간으로 추정한다. 모터의 부하 토크 또한 시변 특성을 가지며 이런 시스템 환경의 변화에 대해서도 설정치를 잘 추종하는 특성을 갖도록 한다. 컴퓨터 시뮬레이션을 통해 제어기법의 타당성을 검증하며 기존의 상태궤환 제어기법과 비교분석하여 성능의 우수성을 입증한다.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.1-6
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• 2018

The torque ripple that is generated by the irregularity of magnetic flux density on the BLDC motor in a satellite actuator degrades the satellite attitude control performance. In this paper, the performance analysis of permanent magnet configurations (shape, arrangement, and air gap) is simulated by the Finite Element Method (FEM) to find the appropriate combination of the configuration. The configuration is chosen by comparing between rectangular and arc-shaped permanent magnets and single-arrangement and dual-arrangement magnets. The performance is verified by a prototype.