• Industrial Engineering and Management Systems
• /
• 제15권2호
• /
• pp.148-155
• /
• 2016

Existing power plants may consume significant amounts of fuel and require high operating costs, partly because of poor electrical power output estimates. This paper suggests a continuous conditional random field (C-CRF) model to predict more precisely the full-load electrical power output of a base load operated combined cycle power plant. We introduce three feature functions to model association potential and one feature function to model interaction potential. Together, these functions compose the C-CRF model, and the model is transformed into a multivariate Gaussian distribution with which the operation parameters can be modeled more efficiently. The performance of our model in estimating power output was evaluated by means of a real dataset and our model outperformed existing methods. Moreover, our model can be used to estimate confidence intervals of the predicted output and calculate several probabilities.

• 전기학회논문지
• /
• 제59권10호
• /
• pp.1718-1726
• /
• 2010

Utilization of renewable energy is becoming increaingly important from the viewpoints of environmental protection and conservation of fossil fuel. However, the generating power of renewable energy is always fluctuating due to the environmental status. This paper presents a scheme for supervisory control of wind generation system with the energy storage and STATCOM to reduce the power variation. In this paper, we especially concentrate on constant power output control of wind generation system. In order to achieve this purpose, the coordinated control strategy between different types of energy storage system and reactive power compensation device. The proposed control scheme has been validated by PSCAD/EMTDC simulation. As a result, the proposed scheme can handle the power output of wind generation system with a constant value.

• 대한전자공학회논문지SD
• /
• 제39권8호
• /
• pp.42-45
• /
• 2002

낮은 전력선 잡음과 피드쓰루 전류를 갖는 저전력 SDRAM 출력 버퍼가 소개된다. 다수의 I/O를 갖는 SDRAM 출력 버퍼에 있어서, 제안된 언더슈트 방지 회로를 통하여, 피드쓰루 전류의 감소뿐 아니라, 전력소모의 감소가 가능하다. 효율적인 피드백 방법을 사용한 풀다운 드라이버를 사용하여, 접지선 잡음을 감소시킬 수 있다. 기존의 회로에 비하여 접지선 잡음은 66.3%, 순간 전력소모는 27.5%, 평균 전력 소모는 11.4% 감소되었다.

• 전기학회논문지
• /
• 제58권10호
• /
• pp.2028-2037
• /
• 2009

This paper presents the simulator for dynamic modeling of a MT(micro turbine) during start-up period. The simulator is implemented by modeling a dynamic power of main components of a MT including compressor, combustor and turbine. A modeling for a MT under steady state operation can be accurately built from thermodynamics analysis. But dynamic modeling during start-up period is very difficult because efficiency of main components is very low and the designed value has big error and nonlinear characteristics during start-up. In this paper, new method without using thermodynamics analysis during start-up is proposed for the simulator. The power models of main components are derived from analysis of the experimental operation data by test motoring using a electric starter under constant power output. The simulator is developed using MATLAB/Simulink. For constant power output control, sensorless vector inverter is designed and algorithms for starting from stall and method for controling a output power are proposed. The performance of developed simulator is verified by comparing experimental and simulation start-up results.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2012년도 전력전자학술대회 논문집
• /
• pp.498-500
• /
• 2012

According to the climatic characteristics of the wind power output is difficult to predict and a severe strain due to a change in output has been very influential in the grid. Jeju Hangwon wind farm, many of the wind generator is installed in a wide area because it is not have this device that artificially Smoothing is needed. In addition, By the requirements of the power company active power supply / control and improve power system reliability and energy storage during the peak demand for electricity using the energy stored in the power supply is needed. In this paper, Unit 12 in Jeju Hangwon demonstrated 0.5MW PCS and energy storage system associated with the wind through the stabilization of output and the leveling of output and test results will be introduced.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
• /
• pp.337-340
• /
• 2000

In this paper, I compared some characteristics between HPA and LPA using Feedforward method. Feedforward method is known for best IMD correction. HPA generated 46.5㏈c at 45.5㏈m output power. But, using feedforward linearing method, I could improve IMD to 67.17㏈c at the same output power. IMD could be improved 20.67㏈ at 45.5㏈m output power. I measured average power, IMD, total current, and efficiency of two amplifier at many different power levels. I could get about 70d3c IMD using feedforward method.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2012년도 전력전자학술대회 논문집
• /
• pp.242-243
• /
• 2012

In this paper, 200 W power supply for LED driver has been designed, analyzed, simulated and tested. Input AC voltage of 100VAC-240VAC was converted to DC voltage by high power factor converter. Output voltage was controlled, and output current was controlled by constant current when output current was reached to LED maximum rated current. By simulation and experimental test, voltage and current control and high power factor characteristics are verified.

• 전기학회논문지P
• /
• 제66권4호
• /
• pp.158-162
• /
• 2017

This paper did basic study on the vertical-axis wind turbine. Namely, This paper was try to find the optimum conditions by using the ANSYS CFX simulation program through the changes of the main-blade angle and sub-blade angle. Main-blade Shape #4 angle $45^{\circ}$ compared to others Shape angle $0^{\circ}$ was increased by 157.2[%] to 263.2[%] in the power output and was increased by 110[%] to 250[%] in the power coefficient. Also, when the Shape #5 Fin length of main-blade doubles, because the power output was 70.8[%] compared to Shape #1 and 27.5[%] compared to Shape #4, and the power coefficient was 60[%] compared to Shape #1 and 28.6[%] compared to Shape #4, the power output and the power efficiency were rather reduced. The output current of Shape #4 was increased 109.9[%] compared to Shape #1 and increased 250[%] compared to Shape #5, and The output voltage of Shape #4 was increased 22.5[%] compared to Shape #1 and increased 3.7[%] compared to Shape #4.

• 에너지공학
• /
• 제28권2호
• /
• pp.47-54
• /
• 2019

복합화력발전소 에너지절감 사업으로 폐열회수용 흡수식 히트펌프가 설치됨에 따라 부분부하(Partial Load)에서의 성능 데이터 확인을 위해 성능시험을 실시하였다. 부분 부하에서 히트펌프 가동에 따른 운전 데이터 변화는 다음과 같다. 기기냉각수(CCW) 배열 및 배열회수열교환기(HRSG)로부터 공급되는 저압증기(LP STM)의 일부가 히트펌프의 열원으로 공급되므로 지역난방열 생산이 증대된다. 그러나 증기터빈으로 공급되는 저압증기의 유량감소에 따라 증기터빈 출력이 감소된다. 또한 고압 지역난방열교환기(HP-DH) 및 저압 지역난방열교환기(LP-DH)로 공급되는 고압터빈(HPT) 배기증기의 유량 저하에 따라 HP-DH 및 LP-DH의 열생산량도 감소한다. 부분부하에서는 정격부하 대비 히트펌프에 운전에 따른 터빈 출력 저하가 큰 것으로 나타났으며, 이에 따라 부분 부하에서는 발전소 전체의 열 생산 증가량, 전기출력 감소량을 종합적으로 고려하여 히트펌프 운전 여부를 결정해야 한다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.201-205
• /
• 1998

In this paper, the charge control with the input voltage feed forward is proposed for the input series-output parallel connected converter configuration for high voltage power conversion applications. This control scheme accomplishes the output current sharing for the output-parallel connected modules as well as the input voltage sharing for the input-series connected modules for all operating conditions including the transients. It also offers the robustness for the component value mismatches among the modules.