• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.218-219
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• 2007

Silicon feed stock shortage have acted as major restraints for growth of photovoltaic industry. Concentrating photovoltaic (CPV) system will reduce the use of silicon PV materials. This paper presents the application possibility of mono-crystalline silicon solar cell, which has increased in market share, for PV concentrator. We measured the power of solar cell using sun simulator and I-V curve tracer and compared the results. The comparison of results showed that the concentrated solar cell generated the power more approximately 7 times than without concentration in spite of non-heat sink. If CPV technology included heat sink combines already developed PV tracking system, it will have a merit economically.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.9-10
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• 2007

In this paper, we investigated the effect of solar cell breakage on maximum output power of PV module. The test result using artificial light source didn't give any change in output power in case of crack near electrical ribbon. Also, there was a reduction in output power in case of increasing of crack area far from electrical ribbon. But, this experiment is under artificial light source test method. So, when such a PV module is outdoor for a long time, there would be problems on electrical output power and durability because of thermal aging phenomenon of solar cell breakage.

• Journal of Power Electronics
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• 제17권5호
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• pp.1327-1337
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• 2017

Photovoltaic (PV) systems are influenced by disproportionate impacts on energy production caused by frequent mismatch cases. The occurrence of multiple maximum power points (MPPs) adds complexity to the tracking process in various PV systems. However, current maximum-power point tracking (MPPT) techniques exhibit limited performance. This paper introduces an enhanced simulated annealing (ESA)-based GMPPT technique against multiple MPP issues in P-V curve with different PV system structures. The proposed technique not only distinguishes global and local MPPs but also performs rapid convergence speed and high tracking accuracy of irradiance changing and restart capability detection. Moreover, the proposed global maximum power tracking algorithm can be applied in the central converter of DMPPT and hybrid PV system to meet various application scenarios. Its effectiveness is verified by simulation and test results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.13-14
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• 2008

In this paper, we analyze the electrical characteristics of PV depending on distance among solar cells before and after lamination process. From the result, the PV module's maximum power increases about 3.37% when solar cells's distance is 10mm. And the maximum power increases up to 8.42% when solar cells's maximum distance is 50mm. It is assumed that PV module's surface temperature decreases because of increasing distance between solar cells that would give high power generation. Also, short distance between solar cell and frame result in contamination on glass. When considering reduced maximum power caused by contaminant, from that, we can fabricated PV module of lower cost with high performance.

• 전기학회논문지
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• 제61권3호
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• pp.407-412
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• 2012

This study investigated the process of thermal-induced growth of micro-crack developed at the crystalline solar cell using EL image, determined the output characteristic according to the pattern of micro-crack, analyzed the I-V characteristic according to the pattern of crack growth, and predicted the output value using simulation. The purpose of this study was, therefore, to investigate the process of thermal-induced growth of micro-crack developed at the early stage of PV module completion using EL image, to analyze the resulting decrement of output and predict the output value using simulation. It was observed that the crack grew increasingly by the thermal condition, and accordingly the lowering of output was accelerated. The output values of crack patterns with various direction were predicted using simulation, resulting in close I-V curve with only around 4% of error rate. It is considered that it is possible to predict the electric characteristic of solar cell module using only pattern of micro-crack occurred at solar cell based on our results.

• 전력전자학회논문지
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• 제17권5호
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• pp.423-430
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• 2012

An adaptive maximum power point tracking (MPPT) scheme employing a variable scaling factor is presented. A MPPT control loop was constructed analytically and the magnitude variation in the MPPT loop gain according to the operating point of the PV array was identified due to the nonlinear characteristics of the PV array output. To make the crossover frequency of the MPPT loop gain consistent, the variable scaling factor was determined using an approximate curve-fitted polynomial equation about linear expression of the error. Therefore, a desirable dynamic response and the stability of the MPPT scheme were maintained across the entire MPPT voltage range. The simulation and experimental results obtained from a 3 KW rated prototype demonstrated the effectiveness of the proposed MPPT scheme.

• 대한전기학회논문지:전력기술부문A
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• 제50권7호
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• pp.340-347
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• 2001

In this Paper, we proposed a new voltage stability analysis algorithm. Using $ $ calculated by the optimal load How method(OLF), it rapidly and correctly calculates a PV curve with voltage collapse point in the stable region. OLF can calculates voltage collapse point as well as the operating point in the stable region. Specially, $ $ indicates the relative distance between voltage collapse point and the solution in the unstable region. In the study of a sample system, we verified the superiority of proposed algorithm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.126-128
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• 2018

Solar array simulator (SAS) is a special DC power supply that regulates the output voltage or current to emulate characteristics of photovoltaic (PV) panels. Especially, the control of SAS is a challenging task due to the nonlinearity in the output curve, which is dependent on irradiance as well as temperature and is determined by panel materials. Conventionally, both current-mode control and voltage-mode control should be alternated by partitioning the operating curve into multiple sections, which is not only for the measurement noise problem with the feedback sensing but also for the control stability issue near the maximum power point. However, the occurrence of transition among different controllers may deteriorate the overall performance. To eliminate the mode transitions, a novel single controller scheme has been introduced in this paper, where the reference operating projection technique enables simple, smooth and numerically stable control. Theoretical consideration on the loop stability issue is discussed and the performance is verified experimentally for the emulation of a PV panel data in view of stability and response speed.

• 대한간호학회지
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• 제35권1호
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• pp.47-55
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• 2005

Purpose: This study was to evaluate the validity of the Pediatric Index of Mortality Ⅱ(PIM Ⅱ). Method: The first values on PIM Ⅱ variables following ICU admission were collected from the patient's charts of 548 admissions retrospectively in three ICUs(medical, surgical, and neurosurgical) at P University Hospital and a cardiac ICU at D University Hospital in Busan from January 1, 2002 to December 31, 2003. Data was analyzed with the SPSSWIN 10.0 program for the descriptive statistics, correlation coefficient, standardized mortality ratio(SMR), validity index(sensitivity, specificity, positive predictive value, negative predictive value), and AUC of ROC curve. Result: The mortality rate was 10.9% (60 cases) and the predicted death rate was 9.5%. The correlation coefficient(r) between observed and expected death rates was .929(p<.01) and SMR was 1.15. Se, Sp, pPv, nPv, and the correct classification rate were .80, .96, .70, .98, and 94.0% respectively. In addition, areas under the curve (AUC) of the receiver operating characteristic(ROC) was 0.954 (95% CI=0.919～0.989). According to demographic characteristics, mortality was underestimated in the medical group and overestimated in the surgical group. In addition, the AUCs of ROC curve were generally high in all subgroups. Conclusion: The PIM Ⅱ showed a good, so it can be utilized for the subject hospital. better.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1966-1967
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• 2007

Photovoltaic(PV) power generation system [1-2] has been extensively studied and watched with keen interest as a clean and renewable power source. So hardware and software studies strongly indicate the feasibility of commercially producing a low cost, user-friendly solar cell curve tracer. Generally, V-I curve tracer indicates only the commonly used solar cell parameters. However, with the conventional V-I curve tracer it is almost impossible to abstract the more detail parameters of solar cell ; A, Rs, and Rsh, which satisfies the user, who aims at the analysis of the development PV power generation system; advanced simulation. In this paper, the proposed method gives us the satisfactory results to abstract the detail parameters of solar cell ; A, Rs, and Rsh