• 한국신뢰성학회지:신뢰성응용연구
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• 제14권4호
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• pp.213-219
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• 2014

Wind turbine, which is attracting part of the renewable energy and is researching continuously, is going to be large size for high efficiency. There is a yaw system rotating the nacelle, weighted about 600 tons, to be perpendicular with the wind direction blowing in the large wind turbine. The wind turbine is focusing on the reliability improvement because working environment effect is bigger than any other points and specially, the reliability improvement of the yaw drive is required by the customer because it is the key component of the wind turbine. Because of this, the establishment of criteria for yaw drive is required because yaw drive system is the part of the wind turbine closely related with ensuring the reliability. So, this study did the failure analysis of the yaw drive system, which is consisted with 10 sets of yaw drives through researching and analyzing the site conditions. Also this study designed the life test method based on the failure analysis and working condition of the yaw drive. To design the accelerated life test of the yaw drive, this study reviewed the torque, lubrication condition, and frequency of use and etc. Finally, this selected the torque as the acceleration factor which is affected mainly to the system and also, the test equipment was developed based on the requirement of the life and performance test.

• 한국가스학회지
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• 제26권2호
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• pp.21-26
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• 2022

사륜구동은 구동력을 4바퀴에 모두 전달하기 때문에 노면과의 접지력이 상승하여 구동력이 상승한다. 하지만 그로 인해 연비가 저하되는 단점을 가지고 있다. 따라서 평소에 이륜구동으로 주행하다가 필요에 의해 선택적 사륜구동으로 변환하는 방법으로 사륜구동을 많이 사용한다. 이러한 선택적 사륜구동은 운전자가 보내는 전기적 신호를 Transfer case에서 기계적으로 바꿔서 구동력을 변환시킨다. 본 연구에서는 전기적 신호를 기계적으로 바꿔주기 위해 모터에 감속기를 적용하여 토크를 증대시켜 기능을 수행하였다. 따라서, 본 연구에서는 구동을 변환시켜주기 위해 적용되는 Transfer case내부에 있는 모터에 적용할 수 있는 감속메커니즘을 도출하고 그에 따른 유성기어형태를 적용한 감속비를 최적화하였다. 그리고 도출된 감속비를 토대로 링기어를 공통으로 사용하는 유성기어 2세트를 적용하여 입력축과 출력축이 동일상에서 감속이 진행되는 유성기어 기어치형의 개발 및 Transfer csae 내에 있는 구동변환장치 구동부의 최적화 설계를 진행하였다.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4111-4124
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• 2022

The control rod drive system is critical to the reactor's reliable operation. The performance of its control system and mechanical system will gradually deteriorate because of operational and environmental stresses, thus increasing the reactor's operational risk. Currently there are few researches on the aging-related degradation of the entire control rod drive system. Because it is difficult to quantify the effect of various environmental stresses and establish an accurate physical model when multiple mechanisms superimposed in the degradation process. Therefore, this paper investigates the aging-related degradation of a control rod drive system by integrating Dynamic Object-Oriented Bayesian Network and Hidden Markov Model. Uncertainties in the degradation of the control system and mechanical system are addressed by using fuzzy theory and the Hidden Markov Model respectively. A system which consists of eight control rod drive mechanisms divided into two groups is used to demonstrate the method. The aging-related degradation of the control rod drive system is analyzed by the Bayesian inference algorithm based on the accelerated life test data, and the impact of different operating schemes on the system performance is also investigated. Meanwhile, the components or units that have major impact on the system's performance are identified at different operational phases. Finally, several essential safety measures are suggested to mitigate the risk caused by the system degradation.

• Journal of Power Electronics
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• 제14권1호
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• pp.74-81
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• 2014

In this study, a brain emotional learning-based intelligent controller (BELBIC) is developed for the speed control of an interior permanent magnet synchronous motor (IPMSM). A novel and simple model of the IPMSM drive structure is established with the intelligent control system, which controls motor speed accurately without the use of any conventional PI controllers and is independent of motor parameters. This study is conducted in both real time and simulation with a new control plant for a laboratory 3 ph, 3.8 Nm IPMSM digital signal processor (DSP)-based drive system. This DSP-based drive system is then compared with conventional BELBIC and an optimized conventional PI controller. Results show that the proposed method performs better than the other controllers and exhibits excellent control characteristics, such as fast response, simple implementation, and robustness with respect to disturbances and manufacturing imperfections.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1392-1397
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• 2003

This paper deals with a control technique of eliminating the transient vibration of a twin-drive geared mechanical system. This technique is based on a model-based control in order to establish the damping effect at the driven machine part. The control model is composed of reduced-order electrical and mechanical parts. This control model estimates a load speed converted to the motor shaft. The difference between the estimated load speed and the motor speed is calculated dynamically and it is added to the velocity command to suppress the transient vibration generated at the load. This control technique is applied to a twin-drive geared system with backlash. In the previous work, the performance of this control method is examined by simulations. In this paper, the effectiveness of this control technique is verified by experiments. The settling time of the residual vibration generated at the loading inertia can be shortened down to about 1/2 of the uncompensated vibration level.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권4호
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• pp.441-446
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• 2013

A thermal model of power modules based on the physical dimension and thermal properties is proposed in this paper. The heat path in the power module is considered as a one-dimensional heat transfer in the model. The method of the parameters extraction for the model is given in the paper. With high speed and accuracy, the thermal model is suit for electrothermal simulation. The proposed model is verified by experimental results.

• 동력기계공학회지
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• 제21권1호
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• pp.5-10
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• 2017

Pitch drive system in wind turbine is composed by the planetary gear system to satisfied its required performance such as long life and light weight for gear train. When the planetary gear system can reduce its volume and weight, the power consumption of the wind turbine can be reduced. In this study, the planetary gear system of the pitch drive system in medium-sized wind turbine is obtained for weight reduction by shape optimization method. And the planetary gear system is verified for their strength by the structural analysis.

• 한국전자파학회논문지
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• 제17권9호
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• pp.852-859
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• 2006

본 논문에서는 위성통신용 EHF(Extremely High Frequency) 대역 진행파관 증폭기(TWTA: Traveling Wave Tube Amplifier)의 개발 방안을 제안한다. RF(Radio Frequency) 특성 및 이득 향상을 위해 증폭기 설계 및 구현시 선형화기(linearizer)와 구동 증폭기(drive amplifier)를 활용하였다. 80 W급 EHF 대역 진행파관 증폭기의 구현 및 시험을 통하여 제안한 방안이 설계 규격을 만족시키는 결과를 얻었다. 따라서 본 논문에서 제안한 방안은 매우 유용하며, 차후 EHF 대역 유사 장비 개발시 적용 가능할 것으로 판단된다.

• Journal of Advanced Marine Engineering and Technology
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• 제27권5호
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• pp.590-599
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• 2003

In this study. object transport method based on ultrasonic flexural vibration is presented. Ultrasonic vibration generates ultrasonic traveling waves on the surface of elastic medium. Objects are transported through the interaction with traveling waves propagating in medium. Two types of transport methods are studied： frictional drive and acoustic levitation. With frictional drive, objects are transported in contact with the beam in the opposite direction of wave propagation whereas with acoustic levitation, objects are acoustically levitated above the beam surface and transported in the wave propagation direction. Transport characteristics are experimentally investigated using objects of different shapes and sizes. The transition from acoustic levitation mode to frictional drive mode is also examined. and it is found to occur when the ratio of mass to area of an object exceeds the threshold ratio of mass to area. It is envisaged that this feasibility study will serve as a stepping-stone for ultrasonic vibration to become an effective industrial material handling device in the future.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.591-595
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• 2000

In this paper we proposed a new sensorless drive system for the trapezoidal type brushless DC motor which does not use any mechanical position or speed sensor and applicable to the systems requiring a constant speed and torque such as Fan. For this a novel indirect rotor position sensing technique based on a detailed analysis of the terminal voltage characteristics is proposed in this paper. And a sensorless drive system for the brushless DC motor is implemented using a 87c196mc fo the main microprocessor and a power FET for the inverter. The experimental results will show the validity of the proposed indirect sensing method and the practical use of the sensorless drive