• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.271-274
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• 2003

In this paper, compare and analyze existent MPPT algorithms. Existent algorithms have defects which don't generate it in a partial shade or low insolation. Therefore, to supplement it, we design improved IncCond algorithm consisted of a Aux. switch and capacitor with Generation Control circuit which can always obtain maximum generation power at the factor which is reduced generational efficiency by partial shade. Generation Control circuit is method which can always get maximum output power as it regularly controls each voltage of serial connected solar cell. Accordingly, it can improve efficiency and confidence of utility interaction inverter. Construction of system use a low price PIC16F87X. We analyze special character according to system operation through simulation and prove the validity through experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.1
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• pp.54-62
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• 2013

This paper proposes a high-efficiency DC-DC converter with improved dynamic response characteristics for modular photovoltaic power conversion. High power efficiency is achieved by reducing switching power losses of the DC-DC converter. The voltage stress of power switches is reduced at primary side. Zero-current switching of output diodes is achieved at secondary side. A modified proportional and integral controller is suggested to improve the dynamic responses of the DC-DC converter. The performance of the proposed converter is verified based on a 200 [W] modular power conversion system including the grid-tied DC-AC inverter. The proposed DC-DC converter achieves the efficiency of 97.9 % at 60 [V] input voltage for a 200 [W] output power. The overall system including DC-DC converter and DC-AC inverter achieves the efficiency of 93.0 % when 200 [W] power is supplied into the grid.

• Current Photovoltaic Research
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• v.6 no.1
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• pp.17-20
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• 2018

The dependency of the photovoltaic performance of p-/n-type silicon solar-cells on the metallic contaminant type (Fe, Cu, and Ni) and concentration was investigated. The minority-carrier recombination lifetime was degraded with increasing metallic contaminant concentration, however, the degradation sensitivity of recombination lifetime was lower at n-type than p-type silicon wafer, which means n-type silicon wafer have an immunity to the effect of metallic contamination. This is because heavy metal ions with positive charge have a much larger capture cross section of electron than hole, so that reaction with electrons occurs much more easily. The power conversion efficiency of n-type solar-cells was degraded by 9.73% when metallic impurities were introduced in the silicon bulk, which is lower degradation compared to p-type solar-cells (15.61% of efficiency degradation). Therefore, n-type silicon solar-cells have a potential to achieve high efficiency of the solar-cell in the future with a merit of immunity against metal contamination.

• Current Photovoltaic Research
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• v.6 no.1
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• pp.27-30
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• 2018

The dependency of the electrical characteristics of silicon solar-cells on the depth of damaged layer induced by wire-sawing process was investigated. To compare cell efficiency with residual sawing damage, silicon solar-cells were fabricated by using as-sawn wafers having different depth of saw damage without any damaged etching process. The damaged layer induced by wire-sawing process in silicon bulk intensely influenced the value of fill factor on solar cells, degrading fill factor to 57.20%. In addition, the photovoltaic characteristics of solar cells applying texturing process shows that although the initial depth of saw-damage induced by wire-sawing process was different, the value of short-circuit current, fill-factor, and power-conversion-efficiency have an almost same, showing ~17.4% of cell efficiency. It indicated that the degradation of solar-cell efficiency induced by wire-sawing process could be prevented by eliminating all damaged layer through sufficient pyramid-surface texturing process.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.29-34
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• 2018

The systems associated with the ESS never stop. It runs 24 hours everyday. The system must be managed to run. The ESS system should perform normally even if the power IT equipment fails or communication failure occurs. Therefore, there is a need for a system that actively addresses, manages and controls the high precision power data of the ESS, even if a variety of failures occur. I would like to propose a power management communication unit to cope with the occurrence of communication failure. This paper also includes an integrated management system that can perform micro grid site management, maintenance and monitoring for the ESS system connected with the solar power generation facility.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.370-375
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• 2011

BIPV시스템 분야는 다른 PV 적용 기술 분야에 비해 빠르게 성장하고 있으나 소형 건축물 위주로 적용되었으며, 초고층 건축물과 같이 수직적으로 높은 건축물의 외부환경조건에 대응하기 위한 BIPV의 적용 방안은 현재까지 연구되어지지 않았다. 국내의 경우 선진국에 비해 초고층 건축물에 대한 BIPV시스템 적용기술은 아직 초기 연구단계에 불과하다. 초고층 건축물의 고유의 특징을 고려하여 초고층 건축물 파사드에 입사하는 일사량의 분포가 균일하지 않을 것이라고 예측하고 실측을 진행하였으며, 실측 결과의 분석을 통하여 초고층 건축물에서의 BIPV시스템 최적 설계방안을 제시하였다. 결론적으로 본 연구에서는 초고층 건축물의 외벽에 입사하는 일사량을 고려한 Unit형 BIPV설계 방안을 제시하였으며, 특히, 측정된 일사량 데이터를 활용하여 초고층 건축물에 적합한 인버터의 선정의 대안을 제시하였다.

• Current Photovoltaic Research
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• v.1 no.1
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• pp.11-16
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• 2013

The current solar cell industry is experiencing a temporary plateau due to a sluggish economy and oversupply. It is expected that the solar industry can see similar growth to that of the recent past by overcoming the current situation, as there is growing demand globally for solar energy. The current situation led to restructuring of the world's solar industry, and domestic firms will need to have competitiveness through strategic approaches and proprietary technology to survive in the global solar market. Crystalline and amorphous silicon based solar cells have led the solar industry and occupied half or more of the market thus far. They will do so in the future PV market as well by playing a pivotal role in the solar industry. In this paper, the current status and prospects of silicon based solar cells, from materials to comprehensive and high efficiency technology that can emerge in the future, are discussed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.393-398
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• 2015

City or Community-scale Energy Management System(CEMS) is used to reduce the total energy consumed in the city by arranging the energy resources efficiently at the planning stage and controlling them economically at the operating stage. Of the operational functions of the CEMS, generation forecasting of renewable energy resources is an essential feature for the effective supply scheduling. This is because it can develop daily operating schedules of controllable generators in the city (e.g. diesel turbine, micro-gas turbine, ESS, CHP and so on) in order to minimize the inflow of the external power supply system, considering the amount of power generated by the uncontrollable renewable energy resources. This paper is written to introduce numerical models for photo-voltaic power generation prediction based on the weather forecasting information. Unlike the conventional methods using the average radiation or average utilization rate, the proposed models are developed for CEMS applications using the realtime weather forecast information provided by the National Weather Service.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.3
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• pp.179-187
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• 2010

This paper proposes a new anti-islanding method for single-phase grid-connected photovoltaic (PV) systems using Goertzel algorithm. The proposed scheme is based on inducing increases or decreases of frequencies of load voltage and current that is in the form of existences or periodical variations of the reactive power components. The frequency detection is needed to apply this power variation method to the grid-connected power converter. The proposed method is able to get a fast detection for anti-islanding without the effect of harmonics and noises. The simulation and experiment results validate the effectiveness of the proposed method.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.236-238
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• 2019

국내 마이크로그리드는 실증단지, 도서지역, 캠퍼스, 산업단지등에 구축되고 있다. 특히 산업단지는 수용가의 전기에너지 이용 효율화와 신재생에너지 전원을 활용한 전력거래를 위해 마이크로그리드를 구축하는 추세이다. 본 논문에서는 ESS(Energy Storage System) 복합운영을 통한 비용절감과 전력거래 수익창출 실증을 위하여 나주혁신도시 동수산업단지 내계통과 연계된 제조업체(태산, 범한, 하이옥스)에 구축되는 마이크로그리드 경제성을 분석한다. 경제성 분석 툴인 HOMER를 이용하여 각 업체별 PV(PhotoVoltaic) 및 ESS용량에 따른 순 현재비용과 1[kWh]당 발전단가를 산출한다. 경제성 분석을 위해 각 제조업체의 최근 1년간 부하량과 산업용 전기요금기준, 기업체 소재지의 기후조건에 따른 태양광발전량, 각 기업체 마이크로그리드 실제구축비용을 입력하고, 공인할인율 5.5[%]와 유류비 1500[원/ℓ]를 기준으로 경제성을 분석한다. 분석을 바탕으로 개별 제조업체 부하 특성에 부합한 마이크로그리드 분산전원 및 설비 용량 선정과 운영방안을 제안한다.