• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.91-97
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• 2010

In this paper, we present simulation results of Dynamic Matrix Control (DMC) to a Once-through boiler steam temperature. In order to control the steam temperatures, we choose spray and damper as two input variables. Then, the step response model is generated for the two major output variables by step test. After that, on-line optimization is performed using $(2\times2)$ step response model. Proposed controller is applied to the APESS (Doosan company's boiler model simulator) and the simulation results show satisfactory performance of proposed control.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.1
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• pp.73-80
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• 2004

In this paper, a maximum output power control of stand-alone cage-type induction generator systems for wind power generation is proposed. The induction generator is operated in a vector-controlled mode, which is excited with d-axis current and of which torque is controlled with q-axis current. The generator speed is controlled by this torque, along which speed the generator produces the maximum output power. The generated power charges the battery bank for energy storage through an ac/dc PWM converter. The proposed scheme has been verified for the wind turbine simulator system which consists of M-G set.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.201-204
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• 2004

In this study, the GSP and in-house numerical codes have been used for analyses of the on-design, static off-design and dynamic off-design performances. Through the various missions including altitude, velocity, and power variations static engine performance have been investigated. The dynamic engine performances based on these complicated variations have been also analysed. Especially, the power, engine rpm and heat overload characteristics of a turbine have been estimated with the response time through the control of a throttle setting rather than a power setting. It could be applied to the FADEC system as an engine control device.

• Journal of Wind Energy
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• v.15 no.2
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• pp.10-22
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• 2024

This research is a comprehensive analysis of wind power prediction sensitivity using a Long Short-Term Memory (LSTM) deep learning neural network model, accounting for the inherent uncertainties in wind speed estimation. Utilizing a year's worth of operational data from an operational wind farm, the study forecasts the power output of both individual wind turbines and the farm collectively. Predictions were made daily at intervals of 10 minutes and 1 hour over a span of three months. The model's forecast accuracy was evaluated by comparing the root mean square error (RMSE), normalized RMSE (NRMSE), and correlation coefficients with actual power output data. Moreover, the research investigated how inaccuracies in wind speed inputs affect the power prediction sensitivity of the model. By simulating wind speed errors within a normal distribution range of 1% to 15%, the study analyzed their influence on the accuracy of power predictions. This investigation provided insights into the required wind speed prediction error rate to achieve an 8% power prediction error threshold, meeting the incentive standards for forecasting systems in renewable energy generation.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.46-52
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• 2011

A study on the improvement for cycle efficiency of closed-type ocean thermal energy conversion (OTEC) was studied to obtain the basic data for the optimal design of cycle. For that, OTEC cycle with a generator, a reheater and a multi-turbine was simulated and analyzed. The basic thermodynamic model for OTEC is Rankine cycle and the surface seawater of $26^{\circ}C$ and deep seawater of $5^{\circ}C$ were used for the heat source of evaporator and condenser, respectively. Ammonia is used as the working fluid. The cycle efficiency increased when generator is added with 0.9 generator effectiveness. When the reheater and multi-turbine are applied in the basic cycle, the cycle efficiency showed 3.14% and the capacity of heat exchanger decreased for same total cycle power. For the OTEC cycle with the generator, the reheater and the multi-turbine showed the highest cycle efficiency and increased the efficiency by more than 6.5% comparing with the basic OTEC cycle.

• Journal of Energy Engineering
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• v.19 no.1
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• pp.8-15
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• 2010

As environmental friendly energy system, distributed micro gasturbine is focused on new energy source for overcoming brand new construction area of power generation. This distributed micro gasturbine system has the powerful characteristics as belows; 1) environmental friendly features NOx < 9 ppm, noise < 65 db 2) various fuel flexbility which is used such as natural gas, diesel, low calory new & renewable fuel, kerosene. 3) high specific output power based on small area and is avilable for very easy and compact installation. There are many new installation sites in USA and Japan from 1998. On the other hand the exhisting large power system was constructued by the sea side, this compact power system is now installed by enduser in downtown area and supplying combined heat & power, has the various apllication on-site power generation. In recently, there is the very important issue for new & reliablbe energy development and spreading out. This paper represent as belows for important system characteristics; 1) grid connection modeling 2) system operation characteristics 3) on-site operation result and evaluation output of power quality analysis.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.145-151
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• 2010

In this study, an absorption power cycle, which can be used for a low-temperature heat source driven power cycle such as geothermal power generation, was investigated and optimized in terms of power by the simulation method. A steady-state simulation model was adopted to analyze and optimize its performance. Simulations were carried out for the given heat source and sink inlet temperatures, and the given flow rates were based on the typical power plant thermal-capacitance-rate ratio. The cycle performance was evaluated for two independent variables: the ammonia fraction at the separator inlet and the maximum cycle pressure. Results showed that the absorption power cycle can generate electricity up to about 14 kW per 1 kg/s of heat source when the heat source temperature, heat sink temperature, and thermal-capacitance-rate ratio are $100^{\circ}C$, $20^{\circ}C$, and 5, respectively.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.4
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• pp.327-333
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• 2015

Wind turbines, in the case of less than rated wind speed, is controlled to achieve maximum power. MPC(Maximun Power Control) method, by controlling the rotational speed of the generator, is a method to achieve maximum power but should know the wind speed. However, for several reasons, there have been proposed methods of estimating the wind speed rather than measuring wind speed. TSR(Tip Speed Ratio) is needed to know to estimate the wind speed. However, a complex interaction formula has to be solved to find a TSR. Therefore, many methods have been suggested to solve a complex interaction formula. In this paper, the new method has been proposed to simplify the complicated interaction formula by using the regression method. Matlab/Simulink is used to simulate and to verify the proposed method.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.179.1-179.1
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• 2010

포항공과대학교 풍력특성화대학원에서는 3MW급 외전형 영구자석 동기발전기 설계를 진행하고 있다. 여기서 외전형이란 RFPM 발전기에서 회전자가 바깥에서 회전하는 형태로 기존의 RFPM 발전기와 비교하여 같은 공극직경에 더 많은 자석을 채택할 수 있고, 회전자와 터빈 블레이드를 직접 연결이 가능하다. 또한, 회전자를 외부에 노출 시킬 수 있으므로 냉각에 유리한 면이 있다. 설계 변수 중 출력과 회전수를 고정시키고 각 극수와 공극 직경, 전압을 변화함에 따른 전기적 특성을 비교하고, 그 중 최적의 모델을 선택한다. 선택된 모델의 전자기장 해석, 손실 계산, 열분석을 수행한다. 본 논문에서는 각 경우에 따른 결과를 비교하고 최적 모델에 대한 해석 결과에 대해 요약한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1370-1377
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• 2002

This study analyzed the design performance of the bottoming system of combined cycle power plants using a once-through heat recovery steam generator. For a parallel arrangement of the main heater and reheater, parametric analyses were carried out to present the criteria for determining the reheater pressure and the location of the starting point of the reheater in the HRSG. The performance of the bottoming system was presented fer a range from high subcritical to supercritical pressure. The steam turbine power is as high as that of conventional triple-pressure bottoming systems. The serial arrangement of heat exchangers with division of each heater into several segments can achieve similar power level.