• 한국조경학회지
• /
• 제23권4호
• /
• pp.20-27
• /
• 1996

The main purpose of this research is to develop a program supporting landscape planting design on AutoCAD basis using AutoLISP and DCL language. Current CAD use in landscape architecture field is mainly focused on customizing plant symbols for supporting two dimensional drafting rather than three dimensional consideration. This program is composed of eight module a such as PLANT module for inserting plant symbols, LABEL module for labeling task, SIMULATION module for simulating plant growth and seasonal color variation, TABLE module for generating plant table automatically, BUILDING module, BLOCK module, UTILITY module for deleting, transforming, shading symbols and DB MANAGER module for manipulating data. Design automation ability using automatic object recognition technique in this program allows AutoCAD to be used as a design tool in addition to its main role as a drafting tool through supporting landscape designers to generate many alternatives in the early phase of design.

• 전력전자학회논문지
• /
• 제16권2호
• /
• pp.105-113
• /
• 2011

태양광 발전 시스템이 대용량화됨에 따라 태양전지 어레이 구성 시 부정합(mismatch) 문제가 대두되는 가운데, 태양전지 모듈을 직접 계통에 연계하는 AC 모듈형 태양광 모듈 집적형 전력변환장치(PV-MIC)에 관한 연구가 지속되고 있다. PV-MIC는 수명 및 고효율이 가장 큰 문제이며 이 문제를 해결하기 위해서 본 논문에서는 ZVS 동작을 통하여 스위칭 손실을 저감시키고 입력전류 리플감소를 통하여 입력 커패시턴스를 저감할 수 있는 능동 클램프 전류원 하프 브릿지 컨버터를 적용한 PV-MIC를 제안하고, 이에 관한 제어분담 및 설계에 대하여 고찰한다.

• 멤브레인
• /
• 제4권3호
• /
• pp.142-151
• /
• 1994

역삼투 공정을 농축공정에 이용하기 위해 향류식 역삼투 나권형 모듈을 고안, 제작하여 염수의 농축실험을 수행하였다. 역삼투 분리의 배제도와 농축도의 관계를 고찰한 결과, 배제유량에 대한 투과유량의 비가 양쪽 관계의 중요한 매개 변수이며, 반사계수 값에 따라, 역삼투막의 배제도와 농축도가 Spiegler-Kedem 식의 경향을 따른다. 향류식 역삼투 공정은 일반 역삼투 농축 공정에 비해 농축의 장애 요소인 삼투압차를 효과적으로 저하시키는 효과가 있으며 농축도가 상대적으로 우수하였다. 향류식 나권형 모듈의 수치모사 결과 농축공정의 농축도 증가를 위해서는 모듈의 지름보다 모듈의 길이를 늘리는 것이 유리함을 알 수 있었다.

• Current Photovoltaic Research
• /
• 제9권3호
• /
• pp.106-109
• /
• 2021

In order to perform photovoltaic (PV) operation and management (O&M) efficiently, individual PV module monitoring is becoming more important. In this research, we developed wireless IoT sensor which can monitor individual photovoltaic modules. This IoT sensor can detect the output voltage, current and module temperature of individual modules and provide monitored data by wireless communication. Measured voltage error was 1.23%, and it shows 16.6 dBM, 0.42sec and 7.1 mA for voltage, transmittance output, response time and mean power consumption, respectively. IoT sensors were demonstrated in the test field with real climate environment condition and each of 5 sensors showed precise results of voltage, current and temperature. Also, sensors were compared with commercial power-optimizers and showed result difference within 5%.

• Progress in Superconductivity
• /
• 제7권2호
• /
• pp.114-119
• /
• 2006

High critical current density, high n value, multiple faults endurances, and fast recovery characteristics of YBCO thin films are very attractive characteristics for developing resistive type superconducting fault current limiters. But due to the limited current and voltage ratings of one YBCO module, it is needed to construct series and parallel module connections for high capacity electric networks. Especially for distribution network, more than 30 units should be connected in series to meet voltage level. So in order to construct distribution-level superconducting fault current limiter, simultaneous quench in one YBCO thin films should be realized, and furthermore, quench should be occurred in all fault current limiting units equally to avoid local heating and failures. In this paper, we proposed optimum design of YBCO thin films for fault current limiting module and technical method using shunt resistor to achieve simultaneous quench between multi current limiting units. From the analytical and the experimental results, optimal current path and thickness of shunt material was determined for YBCO thin films and shunt resistor between modules was developed. Finally, 14 kV one phase resistive fault current limiter using multi YBCO thin films was constructed and it was possible to get satisfactory test results.

• Journal of Electrical Engineering and Technology
• /
• 제8권5호
• /
• pp.1212-1220
• /
• 2013

In general, for a large power system like DC distribution system for buildings, several power converters are modularized for parallel operation. However, in parallel operation, inconsistency of parameters in each module causes circulating current in the whole system. Circulating current is directly related to loss, and, therefore, it is most important for the safety of the power system to supply the suitable current to each module. This paper proposes a control method to reduce circulating current caused during parallel operation. Accordingly, the validity of parallel operation system including response characteristics and normal state was verified by simulation and experiment result.

• 전기학회논문지
• /
• 제66권7호
• /
• pp.1155-1161
• /
• 2017

This study examines environmental performance of the arcing measurement module according to international standards. The module assesses the collected current performance using a computer system. The module is required to assess environmental impact resulting from electromagnetic waves, shock and temperature change during train operation. The test includes testing EMI/EMC, vibration, shock and temperature cycling for interface between trains and the arcing measurement module. The module test items were determined in compliance with the standards suggested by the International Electrotechnical Commission (IEC) and Europaische Norm (EN). This study describes the method of test, test equipment operation and how to choose relevant performance standards. The analysis and test results of environmental performance for the module based on computer system are described in this study.

• 한국태양에너지학회 논문집
• /
• 제37권4호
• /
• pp.1-11
• /
• 2017

Most PV modules are fabricated by 6 cell-strings with solar cells connected in series. Moreover, bypass diodes are generally installed every 2 cell-strings to prevent PV modules from a damage induced by current mismatch or partial shading. But, in the case of special purpose PV module, like as BIPV (Building Integrated Photovoltaic), the number of cell-strings per module varies according to its size. Differ from a module employing even cell-strings, the configuration of bypass diode should be optimized in the PV module with odd strings because of oppositely facing electrodes. Hence, in this study, electrical characteristics of special purposed PV module with odd string was empirically and theoretically studied depending on arrangement of bypass diode. Here, we assumed that PV module has 3 strings and the number of bypass diodes in the system varies from 2 to 6. In case of 2 bypass diodes, shading on a center string increases short circuit current of the module, because of a parallel circuit induced by 2 bypass diodes connected to center string. Also, the loss is larger, as the shading area in the center string is enlarged. Thus, maximum power of the PV module with 2 bypass diode decreases by up to 59 (%) when shading area varies from 50 to 90 (%). On the other hand, In case of 3 and 6 bypass diodes, the maximum power reduction was within about 3 (W), even the shading area changes from 50 to 90 (%). As a result, It is an alternative to arrange the bypass diode by each string or one bypass diode in the PV module in order to completely bypass current in case of shading, when PV module with odd string are fabricated.

• 한국태양에너지학회 논문집
• /
• 제29권6호
• /
• pp.88-93
• /
• 2009

This study was conducted to improve the power of PV module using a surface cooling system One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1 V and O.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
• /
• pp.309-313
• /
• 2009

This study was conducted to improve the power of PV module using a surface cooling system. One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1V and 0.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.