This paper aims to study the modeling and controller of an electrically driven tractor optimized for energy efficiency under off-road conditions and when subjected to loads such as plowing. The dynamic model design is aimed at a 30kW electric tractor. The vehicle model consists of a 30kW motor, transmission, wheels, and a controller, designed using the commercial software Matlab/Simulink. In order to optimize energy efficiency under load conditions, this paper designs and implements a PID controller focusing on the vehicle's speed and wheel slip. The newly proposed electric tractor modeling and PID controller aim to demonstrate improved energy efficiency through simulation.

최근 대기오염으로 인한 환경오염을 줄이고자 국제 산업계의 노력의 일환으로 국제해사기구(IMO)의 규제 발효등으로 이어지 고 있다. IMO는 EEXI,EEDI,CII 등 선박에서 나오는 대기오염을 줄이기 위해 각종 규제를 발효시키고 선박에서 소모되는 전력을 줄여 에너 지를 절약하는 방안을 추진하고 있다. 선박에서 사용되는 전력의 대부분은 전동기가 차지한다. 선박에 설치된 전동기 중 큰 부하를 차지 하는 기관실 송풍기는 수요와 관계없이 정속운전으로 운전하기 때문에 주파수제어를 통한 에너지절감을 기대할 수 있다. 본 연구에서는 발전기의 과급기에 연소공기를 공급하는 발전기 송풍기의 전동기 주파수를 제어하여 에너지 절감에 대한 실효성을 입증하였다. 송풍기 주파수 입력에 따른 과급기출구 온도의 출력 데이터를 기반으로 시스템을 모델링하고, 과급기 출구온도를 목표값으로 하여 주파수를 제 어하는 PI 제어계를 형성하여 과급기 설계기준 출구온도를 유지하면서 송풍기의 주파수 제어를 통해 연간 15,552kW 전력소모량을 절감하 였다. 송풍기 팬 주파수 제어를 통한 에너지절감액의 유효성은 하계(4월~9월) 및 동계(3월~10월) 기간동안 검증하였으며 이를 토대로 실습 선의 연간 6,091천원의 유류비 절약과 이산화탄소 8.5Ton, SOx 2.4kg, NOx 7.8kg의 대기오염물질 저감을 달성하였다.

The Calorifier is a device that supplies hot water to the crew for showering and cooking. In particular, problems such as hot water not coming out when a trainee and a crew member take a shower at the same time may occur due to a malfunction of the temperature control valve that controls the temperature. In particular, when the hot water usage time is almost constant, such as a training ship, a high calorific value is required. When there is no dissatisfaction with the use of hot water, satisfaction with the educational environment is improved. Therefore, in this study, a solenoid temperature control valve is applied to increase satisfaction with hot water use, and a mechanical time switch is applied to the hot water circulating water pump to save energy.

This study is about the control method of smart skin applying SPD(Suspended Particles Display). Smart skin is a self-developed composite window system for the purpose of reducing the cooling load and lighting load. The simulation by TRNSYS18 was modeled in detail based on an actual office located in Jeonju. The previously studied smart skin control method (case1) is a time-dependent control method, and a new control method (case2) was devised based on the data that consideration of daily insolation is important in an actual environment. As a result of simulation by case1, it was found that the amount of cooling energy and lighting energy saved was reduced by 15.1% and 39.2%, respectively, compared to the general model. As a result of the simulation by case2, it was found that the amount of cooling energy and lighting energy saved was reduced to 17.6% and 57.5%, respectively, compared to the general model. Therefore, the newly proposed control method considering the amount of insolation and time was found to be effective in reducing cooling energy and lighting energy.

In this study, a smart skin system that combines SPD (suspended particle display) and LGG (Lighting Guide Glass) and its optimal control method was developed for the purpose of simultaneously reducing the lighting load and cooling load in office buildings. And a demonstration site was built to test the results. The demonstration site was constructed as an experimental group with a smart skin system installed and a control group with a general window system installed. When the cooling energy consumption of the experimental group to which the smart skin system was applied was reduced by about 36.9% compared to the control group, the lighting energy was also reduced by 54.4%.

In this study, an algorithm for control of SPD(Suspended Particles Display) on Smart Skin was proposed. The office with SPD located in Jeonju, Jeollabuk-do was modeled and simulated using TRNSYS18. Through simulation, the energy and lighting consumption of building were analyzed The two kinds of control algorithm(SPD and dimming control method for cool energy and lighting energy saving(CASE 1) and improved control method(CASE 2)) were compared. For this research, Two models(with and without SPD and dimming control) were analyzed by comparing the cooling energy and the light energy consumption was reduced 15.1%, and the lightind energy consumption was reduced by 39.2% more than the model without SPD and dimming control. But, at the improved control method(CASE 2) the cooling energy consumption was reduced of more 2.5% and lighting energy consumptions was reduced of more 18.3% than CASE 1. When using SPD and dimming control, lighting energy consumptions showed more sensitive to solar radiation than cooling energy consumptions. As the improved control method(CASE 2) showed more advantageous saving tate than SPD and dimming control metrhod for cool energy and lighting energy saving(CASE 1), it was found that the improved control method (CASE 2) must be utilized in practice for SPD and dimming control.

A new design concept for integrated thermal energy storage system is suggested to increase energy saving rate for heating and cooling system of the closed glass greenhouse. Heat pump of air source is installed in the mechanical room and air flows then controlled by damper system located between the greenhouse and outdoor environments. A damper control algorithm is designed to enhance the usage of excessive energy in the glass greenhouse. Since the proposed system is installed at the actual glass greenhouse site for experimental verification of energy savings, the proposed system with damper control is compared with conventional greenhouse heating and cooling system. From results, it is found that more than 10% increase of energy saving rate is achieved.

The area of greenhouse heating is 21,202 ha which becomes 42% among the total greenhouse area. As heating fuel, diesel or oil is usually used by 60%, and the heating cost takes 30 to 40% percentage at the greenhouse running. In this study, the pellet fuel heater was developed to replace oil for reducing the burden of greenhouse heating cost. The pellet fuel heater was composed of a conveying grate stoker, which could control temperature precisely like the diesel heater. Diesel and pellet were used for the greenhouse heating, whose calorific values are 9,200 and 3,898 kcal/kg, respectively. As the heating cost due to the saving effect of pellet fuel heater compared with diesel, greenhouse heating cost was reduced by 44% with pellet

Heating and air conditioning system is changing rapidly from the traditional HVAC central supply system to the individual supply system with electrical heat pump system (EHP) in Korean school buildings. The individual supply system has advantages to turn on and off individually and to adjust the thermal comfort separately, but energy is wasted in the unoccupied classroom when the last leaving occupant does not turn off the controller. If the controller is to be off automatically while the classroom is not in use, energy consumption would decrease dramatically. This project aims to cease the unnecessary EHP supply in vacant classroom by inputting the class schedule from the central control room to reduce the energy-spending. Experimental measurements were carried out between the controlled classroom that is turned off when not in use and the uncontrolled room that is turned on continually. Occupant's comfort and energy consumption were measured and compared between the controlled case and the uncontrolled case. The energy consumption of controlled classroom case is 30-60% less than that of the uncontrolled classroom case. This result shows that controlling the cooling supply for the unoccupied classroom using the class schedule can decrease the energy consumption remarkably. This supply control system can be used to conserve energy in school structures like universities.

Most of steam power plant in Korea are heating the feed water system to prevent freezing water flowing in the pipe in winter time. The heating system is operated whenever the ambient temperature around the power plant area below 5 degree Centigrade. But this kind of heat supplying system cause a lot of energy consuming. If we think about the method that the temperature of the each pipe is controled by attaching the temperature measuring sensor like RTD sensor and heat is supplied only when the outer surface temperature of the pipe is under 5 degree Centigrade, then we can save a plenty of energy. In this study, the computer program package for simulation is used to compare the energy consumption load of both systems. Energy saving rate is calculated for the location of Youngweol area using the data of weather station in winter season, especially the January' severe weather data is analyzed for comparison. Various convection heat transfer coefficients for the ambient air and the flowing water inside the pipe was used for the accurate calculation. And also the various initial flowing water temperature was used for the system. Steady state analysis is done previously to approximate the result before the simulation. The result shows that the temperature control system using RTD sensor represents the high energy saving effect which is more than 90% of energy saving rate. Even in the severe January weather condition, the energy saving rate is almost 60%.

In the present study, we developed optimal heat supply algorithm which minimizes the heat loss through the distribution pipe line in group energy apartment. Heating load variation of group energy apartment building in accordance with outdoor air temperature was predicted by the correlation obtained from calorimeter measurements of whole households of apartment building. Supply water temperature and mass flow rate were conjugately controlled to minimize the heat loss rate through distribution pipe line. Group heating apartment located in Hwaseong city, Korea, which has 1,473 households divided in 4 regions, was selected as the object apartment for verifying the present heat supply control algorithm. Compared to the original heat supply system, 10.4% heat loss rate reduction can be accomplished by employing the present control algorithm.

이전 실험에서 결정된 생육 단계별 최적 환경조건을 평가하기 위한 4가지 처리는 다음과 같았다: 생육 단계별 최적 환경 조건을 사용한 광독립 영양배양(photoautotrophic optimum condition with growth stage (POG)), 생육 단계별 평균 광합성 광량자속 밀도(photosynthetic photon flux density(PPFD))와 CO2 농도를 사용한 광독립 영양배양(photoautotrophic constant condition with average PPFD and CO2 of POG(PCA)), 생육 단계별 최대 PPFD와 CO2농도를 사용한 광독립 영양배양(photoautotrophic constant condition with maximum PPFD and CO2 of POG(PCM)) 그리고 대조군으로 3%의 당을 포함한 광혼합 영양배양(photomixotrophic conventional condition with 3% sucrose(PMC)). 실험 결과 각 생육 단계별 환경제어(POG)는 기내에서 배양된 감자 소식물체의 모든 생육 관련 항목에서 유의적 증진을 유도하였다. 또한 단위 건물중 당 소비된 전력과 CO2는 모든 처리 중 POG에서 가장 낮았다. 기외 이식 이후에도 POG에서 생산된 감자 묘는 PMC에서 자란 감자 묘와 전체적으로 큰 차이 없이 왕성한 생육을 유지하였다. 특히 POC는 기존 광혼합 영양방식(PCM)과 비교했을 때 기외 이식전과 이식 후 20일째 각각 4.7배와 3.8배 높은 건물중을 기록하였다. 따라서 POG와 같은 생육 단계별 환경 조절을 통한 광독립 영양 미세 증식 방법은 에너지 절감 효과와 함께 무균의 건강한 감자 묘의 생산에 효과적이었다.

본 논문은 Z-형 컨버터와 수정된 공간벡터 PWM인버터로 구성된 분산전원시스템의 회로모델과 제어 알고리즘을 보여주고 있다. Z-형 컨버터는 수동소자인 L과 C로 간단히 구성되어 있으며 인버터의 상하 양 소자가가 동시에 도통되도록 하는 구간을 이용해 승압을 함으로써 기존의 DC/DC 변환기와는 다른 형태를 취하고 있다. 점근 관측기를 이용한 이산시간 슬라이딩모드제어를 통해 전류제어를 함으로써 센서수를 줄이고 제어성능을 개선하였다. 대체에너지로 관심이 많은 태양광이나, 연료전지 그리고 소형 풍력발전으로부터 생산된 직류 에너지를 상용으로 사용할 수 있도록 하는 전력변환기로써 유용하게 사용될 수 있을 것이다.

본 논문은 에너지소산 제어알고리듬의 제어이득 산정에 관하여 연구하였다. Lyapunov안정성이론에 기초하여 속도 되먹임 포화제어알고리듬, 뱅뱅제어 알고리듬 그리고 에너지게인 제어알고리듬을 제안하였고, 이 알고리듬의 성능을 평가하고 비교하였다. 속도 되먹임 포화제어알고리듬과 에너지게인 제어알고리듬에서는 포화현상을 고려하였고, 뱅뱅제어에서는 경계층을 이용하여 채터링현상을 고려하였다. 수치적인 해석을 통해서 제안된 제어알고리듬이 바람하중에 의해 야기되어지는 구조물의 에너지를 효과적으로 소산시킬 수 있음을 보여주었다.

A temperature control system was developed to save energy in freeze dryer. The objective part in the freeze dryer was a shelf with an electrical heater and cooling compressor. The shelf was a fluid circulation heat exchanger. The temperature control of the shelf is generally a feedback control by present and set values of the shelf temperature only, whereas in new control algorithm the circulating fluid temperature and fluid circulating speed were included as well. The control algorithm was based on a concept of refraining the heater and cooler from being in operation if unnecessary. Actuators in use were mainly thyristor for heater, relay for cooling compressor, inverter for fluid circulating pump, etc. Type of Interfaces were RS232C, and digital-analog converter and digital-output converter. Program language was Visual Basic 6.0. Finally, control performance by the new algorithm could be improved in terms of energy saving and accuracy.

This study is on the development of energy dissipation control algorithms for vibration control of a 76 -story building under wind excitation. Velocity feedback, bang-bang, and energy gain control algorithms are proposed based on the Lyapunov stability theory and the performance of them are evaluated and compared. Saturation problem is considered in the design of velocity feedback and energy gain control algorithms, and chattering problem in bang-bang control is solved by using boundary layer. Numerical results show that the proposed control algorithms can dissipate the structural energy induced by wind loads, and thus they provide good control performance.

구조물이 가지는 에너지의 확률밀도함수를 이용한 능도제어 알고리듬을 제안한다. 구조물의 에너지는 Rayleigh 확률분포를 가지는 것으로 가정된다. 이것은 에너지가 항상 양의 값을 가지고 최소에너지가 발생할 확률은 1이라는 조건을 Rayleigh 확률분포가 만족시킨다는 사실에 근거한다. 제어력의 크기는 가정된 확률밀도함수에 따라 구조물의 에너지가 설계자에 의해 설정된 에너지 임계값을 넘을 확률의 크기에 비례하도록 산정되며, 제어력의 방향은 Lyapunov 제어기 설계기법에 따라 결정된다. 제시된 알고리듬은 LQR 제어기와 비교하여 최대응답을 줄이는 효과를 가지며, 제어력의 임계를 고려할 수 있는 장점을 가진다. 또한 Lyapunov 제어기에서 발생가능한 채터링(chattering)현상을 피할 수 있다.