• Journal of Power Electronics
• /
• 제16권6호
• /
• pp.2306-2314
• /
• 2016

Design and implementation of a low cost grid-connected 5kVA solar photovoltaic (PV) system is proposed in this paper. Since the inverter is a major component of the PV system, the B4 inverter used in this paper reduces the total cost of the PV system. In order to eliminate the massive transformer, the PV system is connected to the grid through IGBT switches. In addition to injection of active power into the grid, the B4 inverter can compensate reactive power and reduce harmonics of the nonlinear loads. A TMS320F28335 DSP processor is used for effective control of the B4 inverter. Various features of this processor enable the implementation of the necessary control algorithms. As a first step, the PV system is simulated and evaluated in Matlab/Simulink. In the second step, hardware circuits are designed and implemented based on the simulation results. The operation of the PV system has been evaluated under balanced, unbalanced, linear and nonlinear loads which proves its accuracy and efficiency.

• Journal of Power Electronics
• /
• 제17권6호
• /
• pp.1600-1610
• /
• 2017

We propose maximum power extraction from a rooftop solar photovoltaic (PV) array during partial shading conditions. Partial shading is unavoidable during power extraction from rooftop PV systems due to nearby tall buildings (construction of additional floors) and trees (growth of trees). Many reconfiguration techniques can be used to extract maximum power in partial shading conditions, but in several cases, the real maximum power output is not achieved. In this study, a new switched PV technique is proposed to enhance the power output. The proposed technique is simple to use and more cost effective than other reconfiguration techniques. Therefore, it is suitable for rooftop applications. The power output of the proposed technique is compared with that of existing techniques with similar shading patterns. Eight panels with ratings of 250 watts (2 kW) each are used for testing. MATLAB simulation and hardware verification are done for the proposed and existing techniques. The proposed technique is implemented on a $4{\times}2$ PV array, although it can be extended to a number of arrays.

• 전기학회논문지
• /
• 제64권7호
• /
• pp.1012-1018
• /
• 2015

The studies on the operating performance analysis or design about the fixed tilt angle flat-plate photovoltaic (PV) system are still lively going off. However the operating property analysis about the arch type PV system which means PV array were designed as round type is dissatisfied. In this paper, we theoretically established the factors which are cause of the deterioration in performance of arch type PV system. In addition, we use the Solar Pro simulation tools to design both flat-plate type and arch type 30kW PV systems. The simulations about arch type PV system applied two ways such as central inverter and string inverter were conducted. The performance ratio (PR) of the PV system with flat-plate type shows the highest value 74[%] when the tilt angle is 30°. In case of arch type, when applying central inverter method, PR value shows approximately 73[%] and no more difference with arch type of the PV array. This value shows 1[%] decrease compare with the flat-plate type. However when applying string inverter methods, the average PR value shows 80 % and 6% improved than the central inverter method.

• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
• /
• pp.303-308
• /
• 2009

In 2008, the global photovoltaic(PV) market reached 5.6GW and the cumulative PV power installed totalled almost 15GW compared to 9GW in 2007. Due to a favourable feed-in-tariff, Korea emerged in 2008 as the 4th largest PV market worldwide. PV power installation rose 495.5 percent to 268MW in 2008 compare to 45MW in 2007. However many PV systems are not installed in suitable part which is concerned about geometrical factor. It is generally recognized that the actual output of PV system in field is a function of orientation, tilt angle, irradiance, temperature, soiling and various system-related losses. Thus this paper shows that a experimental result of PV modules(A group) with uniform azimuth angle and PV modules(B group) with non-uniform azimuth angle. As a result, the electrical output of B group is decreased 48.8% as compared with electrical output of A group.

• KIEAE Journal
• /
• 제7권6호
• /
• pp.17-22
• /
• 2007

The integration of PV modules into building facades or roof could raise their temperature that results in the reduction of PV system's electrical power generation. Hot air can be extracted from the space between PV modules and building envelope, and used for heating in buildings. The extraction of hot air from the space will enhance the performance of BIPV systems. The solar collector utilizing these two aspects is called PV/T(photovoltaic/thermal) solar collector. This paper compares the experimental performance of two different types of air type PV/T collector units: the base case of a collector unit with 10cm gap for forced ventilation and the other unit with copper pin attached to PV module to enhance its thermal performance. The experimental results shows that the base case unit had the overall efficiency of 41.9% and the improved unit with copper pin attached to PV module had 50.1% efficiency. For these air type PV/T units, the forced ventilation of the air space improved the electrical performance as well as the thermal performance.

• Journal of Power Electronics
• /
• 제14권6호
• /
• pp.1281-1292
• /
• 2014

Photovoltaic (PV) solar systems with series-connected module integrated converters (MICs) are receiving increased attention because of their ability to create high output voltage while performing local maximum power point tracking (MPPT) control for individual solar panels, which is a solution for partial shading effects in PV systems at panel level. To eliminate the partial shading effects in PV system more effectively, sub-MICs are utilized at the cell level or grouped cell level within a PV solar panel. This study presents the results of a series-output-connection MPPT (SOC-MPPT) controller for sub-MIC architecture using a single sensor at the output and a single digital MPPT controller (sub-MIC SOC-MPPT controller and architecture). The sub-MIC SOC-MPPT controller and architecture are investigated based on boost type sub-MICs. Experimental results under steady-state and transient conditions are presented to verify the performance of the controller and the effectiveness of the architecture.

• 전력전자학회논문지
• /
• 제17권6호
• /
• pp.539-545
• /
• 2012

Due to merits cost and efficiency, the transformer-less type photovoltaic (PV) inverters have been popularized in the solar market. However, the leakage current flowing through a parasitic capacitor between PV array and ground can cause adverse effect in the transformer-less PV system. In this paper, a bi-directional PV inverter with high efficiency and low noise is proposed for the PV system with an energy storage device. The proposed inverter is a transformer-less type and performs the bi-directional power control between dc sources and grid with high efficiency. In addition, the proposed inverter can suppress the leakage current and obtain low noise characteristic. Finally, 3-kW prototype was implemented to confirm validity of the proposed inverter.

• 한국기후변화학회지
• /
• 제6권2호
• /
• pp.105-111
• /
• 2015

With PV market extension, Operation & Maintenance (O&M) went on the floor as an effective method so solve the reduction phenomenon of Performance Ratio (PR) of PV power plant and as a new business model of photovoltaic industry. This study chose institutionalization of O&M to vitalize domestic photovoltaic industry improving level of photovoltaic technology and dominate the market in advance. The result of analyzing advanced researches and domestic cases indicates that O&M is essential of operating PV power plant, therefore, now is the time for a systematic approach to establish O&M policy.

• 한국환경농학회지
• /
• 제24권4호
• /
• pp.350-357
• /
• 2005

농약별 수직이동 양상을 파악하고, 흡착계수와 토양관련 매개변수를 이용하여 대류이동성 모형(Convective mobility test model)으로 예측한 용탈 속도와 비교 평가하기 위하여 강서통(논), 중동통(밭), 예산통(산림토양) 및 신엄통(화산회토)을 사용하여 카바메이트계 농약 metolcarb, molinate, fenobucarb 및 dimepiperate와 유기인계 농약 isazofos, diazinon, fenitrothion, parathion 및 chlorpyrifos-methyl의 도주용탈실험을 수행하였다. 각 농약을 $50{\mu}g/cm^2$ 수준으로 토주 상단에 처리하였을 때 토심 10 cm 이동 후 용탈되는 농약별 최대용탈(peak) 농도는 화산회토를 제외한 3종 토양의 경우 metolcarb $6.5{\sim}12.6mg/L$, molinate $2.6{\sim}5.0mg/L$, fenobucarb $4.5{\sim}7.8mg/L$, dimepiperate $0.39{\sim}1.36mg/L$ isazofos $1.1{\sim}4.6mg/L$, diazinon $0.01{\sim}0.14mg/L$, fenitrothion 0.01 mg/L 미만${\sim}0.70mg/L$ 및 parathion 0.01 mg/L 미만${\sim}0.44mg/L$ 수준이었고 chloipyrifos-methyl은 네 토양 모두에서 용탈되지 않았다. Peak 농도 출현까지 소요된 용탈수량은 metolcarb $1.1{\sim}2.1$ pore volume(PV), molinate $1.6{\sim}3.3$ PV, fenobucarb $1.6{\sim}3.3$ PV, isazofos $2.1{\sim}4.4$ PV, diazinon $6{\sim}15$ PV 및 dimepiperate $8{\sim}21$ PV 수준이었다. 대류이동성 모형에 의한 예측결과는 대부분의 토양-농약 조합에서 토주용탈 양상과 일치하였고 표준조건(water flux 1 cm/일)에서 예측된 이동소요시간에 따라 metolcarb는 most mobile, molinate와 fenobucarb, isazofos는 mobile내지 most mobile, dimepiperate는 moderately mobile이나 mobile, diazinon은 mobile, fenitrothion과 parathion은 slightly mobile 또는 mobile, chloipyrifos-methyl은 immobile이나 slightly mobile 등급에 속하는 것으로 나타났다.

• 한국식물병리학회지
• /
• 제12권2호
• /
• pp.169-175
• /
• 1996

콩 불마름병균 Xanthomonas campestris pv. glycines 8ra는 X. c. pv. vesicatoria에 길항력이 있는 bacteriocin인 glycinecin을 생성 분비한다. Bacteriocin 생성 분비 능력이 있는 콩 불마름병균을 효과적인 생물학적 방제원으로 활용하기 위해서는 좀더 체계적인 연구가 필요하여, bacteriocin 생성에 관계되는 유전자의 분리를 시도하였다. 약 2,000개의 Xanthomonas campestris pv. glycines 8ra cosmid library에서 bacteriocin의 생성 분비 능력을 조사하여 다섯 개의 clone을, pG011, pG0113, pG33과 pG35, 선발하였다. 그중 한 clone pG08을 임의로 선택하여 plasmid DNA를 분리하였다. Plasmid pG08에서 약 6.0 kb의 DNA를 떼어내어 다른 plasmid vector에 넣은 subclone pBL5는 bacteriocin의 생성 분비 능력이 있었다. Plasmid pG08을 제한효소 처리후 다시 접함시켜 만든 몇 개의 subclone과 pBL5의 제한효소 지도를 비교 분석한 결과 약 3.0 kb의 BamHI-HindIII 부분의 DNA가 bacteriocin의 생성에 관계함을 알았다.