• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.424.2-424.2
• /
• 2016

Solar cell converts light energy to electric energy. But a solar cell generates low power, PV module is fabricated by connected in series with dozens of solar cell. Owing to solar cell connected in series, power of PV module is influenced by shading or mismatch power of solar cells. To prevent power loss of PV module by shading or mismatch current, Bypass diodes are installed in PV module. Bypass diode operating reverse voltage by shading or mismatch power of solar cells bypass mismatch current. However, bypass diode in module exposed outdoor is easily damaged by surge voltage. In this paper, we confirm characteristics variation of PV module with damaged bypass diode. As a result, power of PV module with damaged bypass diode is reduced and Temperature of that is increased.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.12 no.1
• /
• pp.59-65
• /
• 2012

A study on the electrical characteristic analysis of solar cell diodes under experimental conditions of varying temperature and frequency has been conducted. From the current-voltage (I-V) measurements, at the room temperature, we obtained the ideality factor (n) for Space Charge Region (SCR) and Quasi-Neutral Region (QNR) of 3.02 and 1.76, respectively. Characteristics showed that the value of n (at SCR) decreases with rising temperature and n (at QNR) increases with the same conditions. These are due to not only the sharply increased SCR current flow but the activated carrier recombination in the bulk region caused by defects such as contamination, dangling bonds. In addition, from the I-V measurements implemented to confirm the junction uniformity of cells, the average current dispersion was 40.87% and 10.59% at the region of SCR and QNR, respectively. These phenomena were caused by the pyramidal textured junction structure formed to improve the light absorption on the device's front surface, and these affect to the total diode current flow. These defect and textured junction structure will be causes that solar cell diodes have non-ideal electrical characteristics compared with general p-n junction diodes. Also, through the capacitance-voltage (C-V) measurements under the frequency of 180 kHz, we confirmed that the value of built-in potential is 0.63 V.

• Journal of the Semiconductor & Display Technology
• /
• v.21 no.1
• /
• pp.127-131
• /
• 2022

The effect of bypass diodes on the output energy of solar cells was investigated under the condition of partial shading. The maximum power point was estimated using the perturbation & observation algorithm, taking into account the correlation effect between the arrangement and number of bypass diodes. The performance of the bypass diode was tested under the consideration of the partial shading effect and simulated using a Matlab/Simulink.

• Journal of the Korean Solar Energy Society
• /
• v.37 no.4
• /
• 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.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.04a
• /
• pp.356-357
• /
• 2003

Organic materials are suitable for use in photoelectric conversion devices. Thus, Organic semiconductors are promising materials for photovoltaic devices and other optoelectronic applications such as light emitting diodes(LED). The organic solar cell seems to be the usefulness in comparison with the inorganic solar cell in terms of workability, ease of processing, low cost, flexibility and area expansion. (omitted)

• Journal of the Korean Solar Energy Society
• /
• v.35 no.4
• /
• pp.67-75
• /
• 2015

PV module is conventionally connected in series with some solar cell to adjust the output of module. Some bypass diodes in module are installed to prevent module from hot spot and mismatch power loss. However, bypass diode in module exposed outdoor is easily damaged by surge voltage. In this paper, we study the thermal and electrical characteristics change of module with damaged bypass diode to easily find module with damaged bypass diode in photovoltaic system consisting of many modules. Firstly, the temperature change of bypass diode is measured according to forward and reverse bias current flowing through bypass diode. The maximum surface temperature of damaged bypass diode applied reverse bias is higher than that of normal bypass diode despite flowing equal current. Also, the output change of module with and without damaged bypass diode is observed. The output of module with damaged bypass diode is proportionally reduced by the total number of connected solar cells per one bypass diode. Lastly, the distribution temperature of module with damaged bypass diode is confirmed by IR camera. Temperature of all solar cells connected with damaged bypass diode rises and even hot spot of some solar cells is observed. We confirm that damaged bypass diodes in module lead to power drop of module, temperature rise of module and temperature rise of bypass diode. Those results are used to find module with a damaged bypass diode in system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2019.05a
• /
• pp.137-138
• /
• 2019

The photovoltaic module connects the voltage generated by the solar cell to the inverter. In the photovoltaic module, a diode is used to block the reverse voltage from the inverter to the solar cell. The heat generation of this diode is the main cause of the solar connection fire. In this paper, we propose a method to monitor the heat generation of diodes and prevent fire by using IoT devices.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.3
• /
• pp.549-557
• /
• 2012

In this paper an on-chip photo energy harvesting system with MPPT(Maximum Power Point Tracking) control is proposed. The ISC(Integrated Solar Cell) is implemented using p-diff/n-well diodes available in CMOS processes. MPPT control is implemented using the linear relationship between the open-circuit voltage of a PV(Photovoltaic) cell and its MPP(Maximum Power Point) voltage such that a small pilot PV cell can track the MPP of a main PV cell in real time. Simulation results show that the designed circuit with the MPPT control delivers the MPP voltage to load even though the load is heavy such that the load circuit can operate properly. The proposed circuit is designed in 0.18um CMOS process. The designed main PV cell and pilot PV cell occupy $8mm^2$ and $0.4mm^2$ respectively.

• Solar Energy
• /
• v.18 no.2
• /
• pp.105-113
• /
• 1998

In general, the thermo-diode is a device designed to allow heat to be transferred only in one direction. However, the bidirectional thermo-diode devised to change the heat flow in the desired direction can be used for the reduction of the heating load in winter as well as the cooling load in summer. In this study, a solar heating system using loop-type bidirectional thermo-diodes is designed and set up, also it is successfully applied to an outdoor test cell for the verification of its usefulness.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.2
• /
• pp.39-43
• /
• 2017

It was confirmed that the silicon thin films fabricated on the p-Si (100) substrates by using DIPAS (DiIsoPropylAminoSilane) and TDMA-Sb (Tris-DiMethylAminoAntimony) sources by RPCVD method were amorphous and n-type silicon. The fabricated amorphous n-type silicon films had electron carrier concentrations and electron mobilities ranged from $6.83{\times}10^{18}cm^{-3}$ to $1.27{\times}10^{19}cm^{-3}$ and from 62 to $89cm^2/V{\cdot}s$, respectively. The ideality factor of the pn junction diode fabricated on the p-Si (100) substrate was about 1.19 and the efficiency of the fabricated pn solar cell was 10.87%.