• Elastomers and Composites
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• 제52권4호
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• pp.317-325
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• 2017

Molding conditions can be described as factors that determine the quality of a product obtained from injection molding. Many studies have been performed on the injection molding pressure, injection temperature, packing pressure and other molding conditions related to part quality. However, the most accessible factor among the adjustable molding conditions during actual injection is the injection speed. In this study, we simulated the variation of the physical quantity according to injection speed and performed experiments to understand the effect of injection speed on the actual product. A CAE analysis program (Moldflow) was used to simulate and analyze the results using PC and PBT for two models. In order to compare these results with the experimental results, an actual injection molding was performed for each injection speed, and the correlation between simulation and injection molding, especially for the shrinkage of the molded article, was discussed.

• 전기학회논문지P
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• 제60권4호
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• pp.193-199
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• 2011

The next generation domestic high speed railway system is a power distributed type and uses vector control method for motor speed control. Nowadays, inverter driven induction motor system is widely used. However, recently PMSM drives are deeply considered as a alternative candidate instead of an induction motor driven system due to their advantages in efficiency, noise reduction and maintenance. The next-generation high-speed train is composed of 2 converter units, 4 inverter units, and 4 Traction Motor units. Each motor is connected to the inverter directly. In this paper, the effects of IPMSM parameter variation to the system operation characteristics of the multi inverter driven high speed train system are investigated. The parallel connected inverter input-output characteristics are analyzed to the parameter mismatches of the IPMSM in 1C1M control using Matlab/Simulink, then the reliability of the simulation results are verified through experimental results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.365-370
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• 2000

This study represents effect to attain to the exhaust gas and the exhaust noise by the inner shapes of automobile muffler, and obtained optimization-data for the inner muffler shapes by the temperature variation of the exhaust gas in muffler. The results of noise show to decrease in order of model-1, 2 and 3 under that the engine speed is 3500 R.P.M and similar values beyond it. CO represented good the model-2 at low engine speed and model-1 at high engine speed. The model-3 was show to tiny variation difference by the variables. HC decrease mostly by increase of the engine speed and expressed low values the model-2 at 3,000 R.P.M and the model-1 at high speed. Wholly, the model-2 expressed stable results. The temperature distributions expressed high distributions by increase of the engine speed, and the model-3 was express most good among three models.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.51-55
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• 2003

In this paper, the authors propose a new high performance Built-in Type spindle motor drive using vector-controlled technique at 15,000 r/min. Control method is changed by variation of motor speed in a conventional Built-in type spindle drive. In the drive system to be presented, the conventional vector control is used in the low-speed range, and the vector control without encoder is used in the high-speed range. Furthermore, in order to drive the motor from 0 to 15,000 rpm smoothly, the vector control with encoder in the low-speed range (from 0 to 8,000 rpm) is utilized and the vector control without encoder in the high-speed range (from 8,000 to 15,000 rpm) is utilized. This paper describes problem of control method in conventional spindle drive and proposes control method as variation of motor speed

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.808-811
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• 2002

유도전동기 센서리스 벡터제어의 안정성에 대하여 많은 연구가 되어지고 있다. 그 결과 유도전동기의 고정자 저항, 회전자 저항, 시스템 파라미터의 변화에 대하여 센서리스 방법이 속도 센서가 있는 경우와 비교하여 불안정하게 되기 쉽다는 것이 분명하다. 본 논문에서 속도 지령 $\omega$$_{r}$일 스텝 변화에 대하여 관성 모멘트 J 를 변화하는 경우, 유도전동기 회전자 저항 R$_{r}$,을 변화하는 경우에 대해 살펴보고, 전동기의 파라미터, 시스템 파라미터의 변화에 영향을 받지 않는 제어 방법으로 전동기 전압, 전류, 전동기 정수에 의한 속도 Observer를 구성하여 속도 추정을 행하는 방법에 대하여 제안하고 타당성을 입증하고자 한다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.24-34
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• 2021

This paper predicts the speed-power-rpm relationship in regular head waves using various indirect methods: load variation, direct powering, resistance and thrust identity, torque and revolution, thrust and revolution, and Taylor expansion methods. The subject ship is KVLCC2. The wave conditions are the regular head waves of λ/LPP = 0.6 and 1.0 with three wave steepness ratios at three ship speeds of 13.5, 14.5 and 15.5 knots (design speed). In the case of λ/LPP = 0.6 at design speed, two more wave steepness ratios have been taken into consideration. The indirect methods have been evaluated through comparing the speed-power-rpm relationships with those obtained from the resistance and self-propulsion tests in calm water and in waves. The load variation method has been applied to predict propulsive performances in waves, and to derive overload factors (ITTC, 2018). The overload factors have been applied to obtain propulsive efficiency and propeller revolution. The thrust and revolution method (ITTC, 2014) has been modified.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.1-4
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• 1996

The purpose of this treatise is to estimate speed of an induction motor and realize a robust speed control system with estimated speed in field-weakening region. A speed estimation is based on Model Reference Adaptive System(MRAS) technique and two flux estimator are designed to be robust against parameter variation. The MRAS-based overall control scheme has been implemented on 7.5kW Spindle induction motor control system. And it is verified that the proposed control scheme is very stable and robust in field-weakening region.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1750-1752
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• 2005

This paper presents a variable speed wind generation system where fuzzy logic controllers is used as efficiency optimizer. The fuzzy logic controller increments the machine flux by on-line search to improve the generator efficiency in case of light load. The speed of the induction generator is controlled according to the variation of the wind speed in order to produce the maximum output power The generator reference speed is adjusted according to the optimum tip-speed ratio. The complete control system has been developed by simulation study.

• 한국지구과학회지
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• 제32권2호
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• pp.180-189
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• 2011

엘니뇨/라니냐의 강도 변화에 따른 한반도의 풍력자원 변동성을 확인하기 위하여 20년간 장기 지상관측자료를 바탕으로 해석적인 분석을 실시하였다. 장기적으로 유라시아 대륙의 풍속 약화경향에도 불구하고 한반도는 최근 10년간 풍속 증가가 약하게 나타났다. 그리고 엘니뇨와 라니냐에 따른 한반도 풍속은 계절적으로 다양한 형태를 나타낸다. 지역적으로 음의 해수면 온도 아노말리를 나타내는 라니냐가 발생하면 한반도내 지상풍속이 빨라지는 경향을 가진다. 그리고 기후변화에 대한 풍속은 중규모의 강제력이 가장 미약한 산악지역에서 가장 민감하게 나타난다.

• 한국철도학회논문집
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• 제19권5호
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• pp.576-584
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• 2016

본 연구에서는 터널에서의 압력 변동값을 이용하여 차량의 기밀도를 측정하였다. 차량의 기밀도는 이명감과 깊은 관계가 있으므로, 차량의 기밀도를 추정하는 것은 실내 압력 변동을 파악하는데에 필수적이다. 차량의 기밀도를 알면, 실내압력 변동을 예측할 수 있다. 또한 이명감은 고속열차 뿐만아니라 급행 대심도 열차에서도 야기될 수 있는 문제이다. 본 연구에서는 각국의 다양한 이명감 기준을 비교 검토하였으며, ITX-청춘, KTX, KTX-산천(호남) 차량을 이용한 현차실험 데이터를 바탕으로 각 차량의 차량 기밀도를 추정하였다. 이 기밀도 값을 이용하여 차량 내부의 압력 변동값을 수치계산하였으며, 시험값과 비교하여 양호한 결과를 얻었다. 향후 고속차량 고속화를 위해서는 환기장치를 차단식이 아닌 연속환기 방식으로 할 필요가 있다.