• 한국정밀공학회지
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• 제22권6호
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• pp.47-54
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• 2005

A dangerous event occurred at the field industry and mechanical system. At developed by SUNGGOKNANOTECH corp. a R-L clutches of a small and high capacity serves safety device from a variety environment of mechanical system, it permits transmission of driving torque from input to output shaft in both directions of rotation, but restrains any feedback torque of the driven load from rotating the output shaft in either direction. This study was carried out to demonstrate through finite element method and durability estimation for safety of the R-L clutches without sliding during the engagement process. As results, we organized about endurance test method when applied rated torque.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권5호
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• pp.283-294
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• 2004

This paper introduces the new Direct Torque Control(DTC) method based on the estimated torque in Switched Reluctance Motor(SRM) and applies the proposed DTC to SRM for the instantaneous torque ripple reduction. The nonlinear characteristics of SRM is considered in the calculation of the estimated torque and the theory is described in this paper. Current control is one of the kernel elements of torque controller and the performance of the current control should be high for this work. But the conventional PI current control has a weak point in SRM application because of motional EMF. Consequently, this paper makes up for the weakness of PI controller through present of new current controller, that is termed the non-interference current control. The ability of proposed torque and current controller is verified through simulation and experiment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.319-322
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• 1997

In vector control technique, stator currents of an induction motor are transformed to equivalent d-q currents in reference frame consist of d and q axis, each of which is coincide with flux and torque direction respectively. In this paper, the new algorithm is suggested where the stator current through an induction motor torque is monitored by using a vector control method where an additional equipment is not need. The G-programming is used to apply the suggested algorithm in the experiment and this is applied to an actual system to monitor the torque value of an induction motor on real time. To solve the vibration trouble of estimated torque caused from an unbalanced real rotating speed of an induction motor and measured rotating speed by suggesting the reconstructed in a method based on measurement current signal. This produced system testifies an accuracy of an induction motor through the experiment by comparing the reference value of the control method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1190-1193
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• 2004

The purpose of this study is to evaluate the possibility of identifying joint damping property through commercially available isokinetic ergometer (BIODEX). The proposed method is to estimate the damping torque of the knee joint from the difference between the external joint torque for maintaining isokinetic movement and the gravity torque of the lower leg. The damping torque was estimated at various joint angular velocities, from which the damping property would be derived. Measurement setup was composed of the BIODEX system with an external force sensor and Labview system. Matlab was used in the analysis of the damping property. The experimental result showed that the small variation in angular velocity due to acceleration and deceleration of the crank arm resulted in greater change of inertial torque than the damping torque, so that the estimation of damping property from the isokinetic movement is difficult.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2172-2174
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• 1998

In this paper, a speed estimation based on the quick torque control is proposed to realize speed sensorless control in a full range of induction motors. The proposed method can be formulated simply from a motor circuit equation and conducted easily by detecting primary motor currents and a voltage command at every sampling time. Since the method need not the differential values of primary currents in an arithmetic of a speed, it can be expected to improve the precision of speed estimation in a very low speed area, especially. Some numerical simulations were conducted with the assumption of using a Pulse Width Modulation voltage source inverter.

• Wind and Structures
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• 제21권4호
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• pp.443-460
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• 2015

In this paper, an integrator based method to estimate the effective wind speed in wind turbine systems is proposed. First, the aerodynamic torque was accurately estimated through a proportional gain based observer where the generator speed is the measured output of the system. The torque signal contains not only useful frequencies of the wind, but also high frequencies and the ones due to structural vibration. The useful information of the wind signal is low frequency. A spectral analysis permitted the determination of the useful frequencies. The high frequencies were then filtered before introducing the torque signal in the wind speed observer. The desired effective wind speed was extracted through an integrator based observer using the previously estimated aerodynamic torque. The strength of the method is to avoid numerical solutions used in literature of the wind speed estimation. The effectiveness of the proposed wind speed estimator and its use to control the generator speed has been tested under turbulent situations using the FAST software (Fatigue, Aerodynamics, Structures, and Turbulence), for large scale Megawatt turbine.

• 한국산학기술학회논문지
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• 제20권4호
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• pp.517-522
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• 2019

본 논문은 전동기 상수 추정 방법을 제안한다. 제안하는 기법은 전동기 전압방정식을 차동식 형태로 전개한 수식에 기반한다. 차동식 형태를 이용함으로써 전동기 상수 추정시 사용되는 전압 정보에 존재하는 크기 오차인 데드타임의 영향을 배제한다. 전동기의 상수값은 전동기 제어 성능 향상을 위해서 필요할 때가 있다. 예를 들면 DTC(Direct Torque Control) 제어 기법에는 토오크 및 자속 크기의 연산시 전동기의 상수를 알아야한다. 다른 예로서 예측제어의 경우 지령치 전압 생성을 위해서는 정확한 전동기의 상수 값의 정보가 필요하다. 전동기의 상수는 구동 환경에 따라 변동하는 값이므로 부정확한 전동기 상수 사용시 제어 성능의 저하를 가져온다. 따라서, 정확한 전동기 상수의 추정이 필요하다. 제안하는 기법에서 전압차동식에 기초하여 추정되는 전동기 상수는 RLS(Recursive Least Square) 기법에 의해 구해진다. 본 연구에서는 단순 수식에 의한 형태로 전동기의 상수를 추정하지 않고, RLS 알고리즘을 적용하여 노이즈에 강인하게 전동기 상수를 추정한다. 표면 부착형 영구자석 전동기의 제어시스템에 적용하여 제안하는 기법의 타당성을 보인다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1991년도 제2차 학술발표초록집
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• pp.76-76
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• 1991

• 재활복지공학회논문지
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• 제7권2호
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• pp.7-12
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• 2013

본 논문에서는 동력의지를 위한 브러쉬리스 DC 모터 구동 시스템과 DC 링크단의 전류를 이용하여 상전류를 추정하는 기법을 제안한다. 토크제어를 위해서는 전류 측정이 매우 중요하며 전류 측정 시 스위칭 노이즈를 최소화하기 위해 전류 센싱 시점은 스위칭 전압 명령에 동기화 되어야 한다. 저가의 시스템, 공간의 절약 그리고 제어의 단순화하기 위해 DC 링크단 전류를 사용한 제어를 실시하였다. 또한 환류 다이오드를 통해 흐르는 전류에서 발생하는 DC 링크단 전류와 상전류간의 오차를 줄이기 위해 Analog MUX를 이용한 상전류 추정방법을 사용하였다. 실험 결과를 통해 제안한 시스템의 유효성을 검증하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.850-853
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• 2006

This paper presents a primary study for a new method of enhancing measurement using impedance analysis method, which is widely used for structure health monitoring. Many of skyscrapers, bridges, tunnels, which have been built up several years, and nearly reached their operating life due to aging crack, material deterioration, and so on. therefore, the health monitoring technique has obtained considerable attention. The usage of the PZT sensor is proposed, and the coupling torque of bolt-connection overlapping beam is assumed. By using the torque wrench, it is easy to apply torque of different values to each bolt. The coupling torque is adjusted gradually from $3N{\cdot}m\;to\;0N{\cdot}m$ with the decrement of $1N{\cdot}m$. Simultaneously, the impedance peak variation is measured. The peak frequency variation can be determined through the change of bolt coupling torque.