• Proceedings of the KIEE Conference
• /
• 2004.04a
• /
• pp.208-211
• /
• 2004

Photovoltaic(PV) array, which is generally installed outside, has the possibility to be damaged by high voltage due to lightning. Because the electrical characteristics of PV array have not been fully identified by lightning yet, there is a very important issue whether PV array should be connected with ground or not. In this paper, a basic model of PV array is provided considering the PV cell's barrier capacitance and ground capacitance for analysis of electrical characteristics by lightning using PSCAD/EMTDC.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.121-123
• /
• 2008

The PV modules are affected by heat. The hotter the PV module, the lower the power output, then the life time will be short. If the cell temperature rises above a certain limit the encapsulating materials can be damaged, and this will degrade the performance of the PV module. This is called the ‘hot spot’ formation. This paper presents that the PV module temperature can be estimated by using a thermal analysis program, and demonstrates the thermal characteristics of the PV module.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.314-319
• /
• 2009

The photovoltaic(PV) industry has been growing worldwide. Recently, the PV industries not also in the traditional PV advanced countries but also in other countries are rapidly growing. Especially, China has become the largest supplier in the world PV supply side since 2007. Both the world PV supply and demand rose steadily in 2008 like recent bumper years. In 2008, the world solar cell production reached 6.85GW~7.91GW presenting growth of 85% over the previous year. On the demand side, 81 countries contributed to the 5.95GW presenting growth of 110% over the previous year.

• Journal of Power Electronics
• /
• v.11 no.2
• /
• pp.179-187
• /
• 2011

This paper proposes a MATLAB Simulink simulator for photovoltaic (PV) systems. The main contribution of this work is the utilization of a two-diode model to represent a PV cell. This model is known to have better accuracy at low irradiance levels which allows for a more accurate prediction of PV system performance. To reduce computational time, the input parameters are reduced to four and the values of $R_p$ and $R_s$ are estimated by an efficient iteration method. Furthermore, all of the inputs to the simulator are information available on a standard PV module datasheet. The simulator supports large array simulations that can be interfaced with MPPT algorithms and power electronic converters. The accuracy of the simulator is verified by applying the model to five PV modules of different types (multi-crystalline, mono-crystalline, and thin-film) from various manufacturers. It is envisaged that the proposed work can be very useful for PV professionals who require a simple, fast and accurate PV simulator to design their systems.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.5
• /
• pp.577-584
• /
• 2015

A photovoltaic (PV) system generates electricity by installing a solar energy array; therefore, the photovoltaic system can be easily exposed to external factors, which include environmental factors such as temperature, humidity, and radiation. These factors-as well as shading, in particular-lead to power degradation. When there is an output loss in the solar cell of a PV module package, the output loss is partly controlled by the bypass diode. As solar cells become highly efficient, the characteristics of series resistance and parallel resistance improve, and the characteristics of reverse voltage change. A bypass diode is connected in parallel to the string that is connected in series to the PV module. Ideally, the bypass diode operates when the voltage is -0.6[V] around. This study examines the bypass diode operating time for different types of crystalline solar cells. It compares the reverse voltage characteristics between the single solar cell and polycrystalline solar cell. Special modules were produced for the experiment. The shading rate of the solar cell in the specially made solar energy module was raised by 5% each time to confirm that the bypass diode was operating. The operation of the bypass diode is affected not only by the reverse voltage but also by the forward bias. This tendency was verified as the number of strings increased.

• Journal of the Korean Solar Energy Society
• /
• v.40 no.4
• /
• pp.13-22
• /
• 2020

As the supply of photovoltaic (PV) increases worldwide, the cumulative installations in 2018 were 7.9 and 560 GW in Korea and the world, respectively. Typically, when the ground on commercial PV modules is installed, the area is limited; hence, new designs of PV modules are required to install additional PVs. Among the new design of PV modules, lightweight PV modules can be utilized in PV systems, such as buildings, farmlands, and floating PV. Concerning the investigation of lightweight PV modules, several studies on materials for replacing low-iron tempered glass, which comprises approximately 65% of the PV module weight, have been conducted. However, materials that are used as substitutes for glass should possess similar lightweight properties and reliability as glass. In this study, experimental tests were performed to evaluate the applicability of ethylene tetrafluoroethylene (ETFE) film with excellent resistance to water and aging as a front material of PV modules. The transmittance and ultraviolet properties of the ETFE film were determined and compared with those of glass. A 1-cell module and laboratory-scale 24-cell module were manufactured using the ETFE film and glass, and the electrical output was measured and analyzed. Furthermore, damp heat and thermal cycle tests were conducted to evaluate the reliability of the ETFE film module. Based on the experimental results, the electrical output and reliability of the ETFE film module were similar to those of the glass module, and the ETFE film could be used as the front material of PV modules.

• Journal of IKEEE
• /
• v.24 no.1
• /
• pp.364-367
• /
• 2020

This paper presents the off-grid PV-ESS system of sequential voltage control method applied to OR logic gate. The conventional off-grid PV-ESS system with the low-voltage series connection has problems due to capacity expansion. To solve these problems, this paper proposes a noble PV-ESS system with high efficiency and low cost by applying sequential voltage control technique of the high-voltage series connection of analog circuit type. The input voltage of DC to AC inverter can be converted from the low-voltage by the combinations of series connection of the conventional cascaded 24V solar cell unit modules to the high-voltage of 384V in battery. The output voltage of the battery was 384V as the each input voltage of three phase DC to AC inverter, and the each output voltage of three phase 10kW DC to AC inverter is designed to be AC380V@60Hz as the line to line rms voltage value. To prove the validity of the theoretical analysis by PSIM simulation, the operating characteristics of sequential voltage control system with OR logic gate were confirmed through experiment results.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.3
• /
• pp.407-412
• /
• 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.

• 한국태양에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.239-244
• /
• 2011

In this paper, we analyzed the electrical characteristics with crack pattern in crystalline solar cell. crystalline solar cells with a thin substrate, even small shocks can be easily damaged. Before the module goes through many processes, because the solar cells are at risk of a crack. That occurred early in the PV module micro-crack is not easily detection by eye test or output test. Because the EL (Electroluminescence) device has been detected using. PV module is made by laminated of a variety of materials. By different properties of each material will affect the crack. For this reason, the crack will grow and affect the output. And We analyzed the three crack patterns in crystalline solar cell. A growth of cracks on crystalline solar cell was interpreted by analysing generated cracks on the PV modules. Based on this interpretation, an electrical output value was calculated by mathematical modeling on electrical output characteristic with each crack patterns.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.6
• /
• pp.359-362
• /
• 2016

In the PV (Photovoltaic) power system, a junction box collects the DC voltage generated from the PV module and transfers it to the PCS (power conditioning system). The junction box prevents damage caused by the voltage difference between the serially connected PV modules and provides convenience while repairing or inspecting the PV array. In addition, the junction box uses the diode to protect modules from the inverse current when the PV power system and electric power system are connected for use. However, by using the reverse blocking diode, heat is generated within the junction box while generating electric power, which decreases the generating efficiency, and causes short circuit and electric leakage. In this research, based on the purpose of improving the performance of the PV module by decreasing the heat generation within the junction box, a junction box with a built-in bypass circuit was designed/manufactured so that a certain capacity of current generated from the PV module does not run through the reverse blocking diode. The manufactured junction box was used to compare the electric power and heating power generated when the circuit was in the bypass/non-bypass modes. It was confirmed that the electric power loss and heat generation indicated a decrease when the circuit was in the bypass mode.