• Journal of Power Electronics
• /
• 제19권1호
• /
• pp.288-295
• /
• 2019

Rectifiers are widely used in industrial applications. Although detailed models of rectifiers are usually used to evaluate their performance, they are complex and time-consuming. Therefore, the Average Value Model (AVM) has been introduced to meet the demand for a simple and accurate model. This type of rectifier modeling can be used to simplify the simulations of large systems. The AVM of diode rectifiers has been an area of interest for many electrical engineers. However, healthy diode rectifiers are only considered for average value modeling. By contrast, faults occur frequently on diodes, which eventually cause the diodes to open-circuit. Therefore, it is essential to model bridge rectifiers under this faulty condition. Indeed, conventional AVMs are not appropriate or accurate for faulty rectifiers. In addition, they are significantly different in modeling. In this paper, a novel application of the parametric average value of a three-phase line-commutated rectifier is proposed in which one diode of the rectifier is considered open-circuited. In order to evaluate the proposed AVM, it is compared with experimental and simulation results for the application of a brushless synchronous generator field. The results clearly demonstrate the accuracy of the proposed model.

• 한국정보통신학회논문지
• /
• 제14권7호
• /
• pp.1557-1564
• /
• 2010

감성신호는 개인에 따라 그 패턴이 매우 다르게 나타나므로, 본 논문에서는 감성신호의 개인별 특징을 고려한 최대 엔트로피 기반 감성 인식 모델을 제안한다. 제안하는 모델은 보다 정확하게 사용자의 감성을 인식하기 위해서, 단순히 주어진 입력 감성 신호 값만을 사용하지 않고, 긍정 감성 신호 값의 평균과 부정 감성 신호 값의 평균을 입력 감성 신호의 값과 비교하여 활용한다. 또한, 감성 인식에 대한 전문적인 지식이 없이도 감성 인식 모델의 구축이 용이하도록, 제안하는 모델은 성능이 높다고 잘 알려진 기계학습기법의 하나인 최대 엔트로피 모델을 이용한다. 감성 신호의 수치 값을 그대로 사용하면 기계 학습에 필요한 학습 패턴 자료를 충분히 확보하기 어렵다는 점을 고려하여, 제안하는 모델은 평균차를 수치 값 대신 +(양수)와 -(음수)로 단순하게 표현하며, 감성 반응 전체 시간인 10초 대신 초단위로 분할하여 학습 패턴 자료의 양을 늘렸다.

• 전기학회논문지
• /
• 제63권11호
• /
• pp.1497-1502
• /
• 2014

Electric load forecasting is essential for stable electric power supply, efficient operation and management of power systems, and safe operation of power generation systems. The results are utilized in generator preventive maintenance planning and the systemization of power reserve management. Development and improvement of electric load forecasting model is necessary for power system maintenance and operation. This paper proposes daily maximum electric load forecasting methods for the next 4 weeks with a seasonal autoregressive integrated moving average model and an exponential smoothing model. According to the results of forecasting of daily maximum electric load forecasting for the next 4 weeks of March, April, November 2010~2012 using the constructed forecasting models, the seasonal autoregressive integrated moving average model showed an average error rate of 6,66%, 5.26%, 3.61% respectively and the exponential smoothing model showed an average error rate of 3.82%, 4.07%, 3.59% respectively.

• Journal of Electrical Engineering and Technology
• /
• 제9권5호
• /
• pp.1562-1568
• /
• 2014

Based on the average method and the geometrical technique to calculate the average value, the average model of the open-loop step-up converter in CCM operation is established. The DC equilibrium point and corresponding small signal model is derived. The control-to-output transfer function is presented and analyzed. The theoretical analysis and PSIM simulations shows that the control-to-output transfer function includes not only the DC input voltage and the DC duty cycle, but also the two inductors, the two energy-transferring capacitors, the switching frequency and the load. Finally, the hardware circuit is designed, and the circuit experimental results are given to confirm the effectiveness of theoretical derivations and analysis.

• Journal of Power Electronics
• /
• 제11권1호
• /
• pp.59-63
• /
• 2011

This paper presents the modeling of the sampling effect in the p-type average current mode control. The prediction of the high frequency components near half of the switching frequency in the current loop gain is given for the p-type average current mode control. By the proposed model, the prediction accuracy is improved when compared to that of conventional models. The proposed method is applied to a buck converter, and then the measurement results are analyzed.

• 대한교통학회지
• /
• 제20권3호
• /
• pp.159-168
• /
• 2002

미국 도로용량편람(HCM)은 감응식 신호운영의 평가를 위하여 감응식 현시의 평균녹색시간 추정을 요구하고 있고 그 부록에서 제시한 평균녹색시간 추정모형을 적용할 것을 권장하고 있다. 이 모형은 감응식 신호운영의 기능적 특징을 반영하는 유일한 분석모형이지만 그 모형식에는 (1)대기행렬처리시간의 추정, (2)적신호우회전 교통량(Right turn on red)의 영향, (3)공유차로 비보호 좌회전의 영향에 있어 개선요소를 포함하고 있다. 본 연구는 이러한 HCM모형의 개선요소를 분석하고 수정하여 새로운 평균녹색시간추정모형을 제시한다. 다양한 교통상황, 기하구조상황, 현시조합상황을 가상 설정하여 총 234개의 감응식 신호운영시나리오를 구축하고 이로 파생되는 1,196개의 감응현시를 실험자료로 사용하였다. 각각의 시나리오를 Corridor Simulation(CORSIM)모형으로 모의실험한 결과를 기준으로 삼아 HCM 분석모형과 본 연구에서 제시하는 분석모형의 추정력을 비교하였다. 제시된 모형의 전산적용은 Average Green time Estimation(ACE) 프로그램을 개발하여 적용하였고, HCM모형은 미국 University of Florida에서 개발된 ACT348 프로그램을 사용하여 적용하였다. 예측된 결과는 비보호좌회전이 허용되지 않는 신호현시 집단(1,118개)과 허용되는 신호현시 집단(78개)으로 나누어서 비교하였다. HCM모형의 경우 각각의 집단에 대한 설명력이 0.56, 0.57로 결과된 반면 본 연구를 통해 새롭게 제시된 모형의 설명력은 각각 0.90. 0.86으로 결과되었다.

• 자동차안전학회지
• /
• 제14권1호
• /
• pp.62-67
• /
• 2022

This study is to construct the simple estimating model for the HIC15 of the driver dummy using the frontal impact test results. Test results of 9 vehicles of Hyundai Sonata from the MY2002~MY2020 USNCAP are utilized for constructing the linear regression model. The average accelerations extracted from the vehicle crash pulses are handled as the main factors. The average accelerations of 10 ms interval within 0~100 ms are calculated from the crash pulse data of 9 vehicles. The present estimating model of the HIC15 using the average accelerations of 10 ms interval in the 0~80 ms range shows good agreement with the tested value within 2.4% maximum error.

• 한국해양공학회지
• /
• 제23권2호
• /
• pp.47-52
• /
• 2009

A Lagrangian particle tracking model coupled with the Princeton Ocean Model were used to estimate the average residence time of coastal water in Masan Bay, Korea. Our interest in quantifying the transport time scales in Masan Bay was stimulated by the search for a mechanistic understanding of this spatial variability, which is consistent with the concept of spatially variable transport time scales. Tidal simulation was calibrated through a comparison with the results of semi-diurnal current and water elevation measured at the tidal stations of Masan, Gadeokdo. In the model simulations, particles were released in eight cases, including slack before ebb, peak ebb, slack before flood, and peak flood, during both spring and neap tides. The averaged values obtained from the particle release simulations were used for the average residence times of the coastal water in Masan Bay. The average residence times for the southeastern parts of Somodo and the Samho River, Masan Bay were estimated to be about 20~50days and 70~80days, respectively. The spatial difference for the average residence time was controlled by the tidal currents and distance from the mouth of the bay. Our results might provide useful for understanding the transport and behavior of coastal water in a bay and might be used to estimate the dissimilative capacity for environmental assessment.

• 한국농공학회지
• /
• 제35권3호
• /
• pp.36-46
• /
• 1993

The purposes of this study are to develop three-layered Green-Ampt infiltration model considering temporal variation of physical properties of soil and to evaluate the model with field experiment on bare-tilled and soybean-growing soil plots under natural rainfalls. Infiltration tests were conducted on a sandy loam soil. The model has three-layered soil profile including a surface crust, a tilled layer, a subsoil and considers temporal variation of porosity, hydraulic conductivity, capillary pressure head on a tilled layer by natural rainfalls and canopy density variation of crop. Field measurement of porosity, average hydraulic conductivity and average capillary presure head on a tilled layer were conducted by soil sampler and air-entry permeameter at regular intervals-after tillage. It was found that temporal variation of porosity and average hydraulic conductivity might be expressed as a function of cumulative rainfall energy and average capillary pressure head might be expressed as a function of porosity of a tilled soil. The model was calibrated by an optimization technique, Hooke and Jeeves method using hourly surface runoff data. With the calibrated parameters, the model was verified satisfactorily.

• 대한교통학회지
• /
• 제30권2호
• /
• pp.117-126
• /
• 2012

교통부문에서 발생되는 $CO_2$ 배출량이 전체 $CO_2$ 배출 총량의 33%를 차지하고 있는 상황에서 지구 온난화를 방지할 수 있도록 교통부문 온실가스 저감 대책을 마련하는 것은 매우 중요하다. 효과적인 교통부문 온실가스 저감대책을 수립하기 위하여 자동차의 오염물질 배출량을 객관적이고 정확하게 산출할 수 있는 방법론 개발이 선행되어야 하지만, 현재까지 표준화된 교통부문 오염물질 배출량 산출 방법론이 정립되어 있지 못한 실정이다. 세계적으로 가장 널리 사용되고 있는 평균 차속 모형은 빠르고 간편하게 대기오염 영향을 산출할 수 있다는 장점을 갖지만, 다양한 도로조건과 교통조건을 반영하지 못하는 한계가 있다. 본 논문에서는 현행 평균 차속 모형을 통하여 산출된 배출량이 주행 여건에 따라 현실에서 발생하는 배출량과 많은 차이가 있음을 실제 데이터 분석을 통하여 확인하였으며, 향후에는 평균 차속 모형의 배출계수가 도로 유형과 교통 상황에 따라 구분될 필요가 있음을 제기하였다.