• Journal of IKEEE
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• v.23 no.3
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• pp.826-831
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• 2019

The stand-alone photovoltaic power systems are widely used for lighting equipment and CCTV. In order for these devices to be competitive, the life of power storage devices such as batteries is very important. The characteristic Hybrid supercapacitor is the high power density and long life. We have proposed a stand-alone photovoltaic power system that uses hybrid supercapacitor. The charge and discharge characteristics and the internal resistance of the hybrid capacitor were measured to configure the power converter. A stable maximum output point tracking control algorithm is proposed even with the change in solar radiation. In order to verify the validity of the proposed system, a prototype was fabricated and tested using a 18W hybrid capacitor and a 10W solar cell.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.20-28
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• 2008

It is prevalent to research on the energy saving systems using daylight. Daylight responsive dimming systems are to automatically control lighting output by available daylight for maintaining target illuminance on the workplane. The system application is not popular because of blocked daylight by shading systems. Automated roller shading systems automatically control shade height by sun position and sky conditions. Both daylight responsive dimming systems and automated roller shading systems should be integrated for energy savings and visual luminous environment. In this research, software are developed and integrated for control of integrated systems.

• Journal of IKEEE
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• v.23 no.4
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• pp.1448-1456
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• 2019

In this study, when applying LED light sources within a single-span glass greenhouse for growing crops, the illumination simulation was performed on the ceiling and side of the glass greenhouse to determine the selective placement and effective light transmission of Si series solar cells and dye-sensitive solar cells (DSSC) for supplying LED power source. In addition, energy saving effects of glass greenhouses were analyzed for optimum lighting control when both daylight and LED light sources are considered in glass greenhouses.

• Journal of Korea Multimedia Society
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• v.14 no.9
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• pp.1125-1137
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• 2011

Recently, there have been previous research about the iris recognition in mobile device to increase portability, whose accuracy is affected by the quality of iris image. Iris image is affected by illumination environment during the image acquisition. The existing system has high accuracy in indoor environment. However the accuracy is degraded in outdoor environment, because the gray levels of iris patterns in image are changed, and ghost and eyelash shading regions are produced by the sunlight of various wavelengths into iris region. To overcome these problems, we propose new mobile iris camera system which uses the near-infrared (NIR) light illuminator of 850 nm and band pass filter (BPF) of 850 nm. To measure the performance of the proposed system, we compared it to the existing one with the iris images captured in indoor and outdoor sunlight environments in terms of the equal error rates (EER) based on false acceptance rate (FAR) and false rejection rate (FRR). The experimental result showed that the proposed system had the lower EERs than those of previous system by 0.96% (with frontal light in indoors), 4.94% (with frontal light in outdoor), 9.24% (with side light in outdoor), and 7% (with back light in outdoor), respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.36-42
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• 2003

This paper presents a new current-source PWM inverter based on Buck-boost configuration to interface between photovoltaic system and utility line. Proposed inverter is consisted by two set of buck-boost topology, and the input inductor is designed to be operated on the discontinuous current conduction mode. So high power factor can be achieved without additional input CtUTent controller. As a result, overall system has simple structure, and it can obtain higher ac output rms voltage than the terminal voltage of the photovoltaic system without additional boosting procedure. The operational modes are theoretically analyzed, and then the validity of the proposed system was verified through simulation and experimental results using a prototype.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.608-614
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• 2018

In addition to the diffusion of ICT technology, various protocols of short range wireless communication technology are being applied for efficient information operation. However, due to limitations of short-range wireless communication, communication is not smooth in places where frequency environment is poor, such as frequency confusion and warehouse type factory. When an alternative is needed. The development of LED technology and expansion of infrastructure through LED based visible light communication is attracting attention as an alternative and spreading the usage in wide range now a days. In addition, the infrastructure has been expanded with solar panels in response to the development of smarthome built-in with renewable energy. In this situation, visible light communication using PD has been limitedly applied in a near environment where the receiving angle of the PD and the ambient light ensure the LoS and the influence of the ambient light is small. In order to solve this problem, we have implemented visible light communication using LED lighting with large current infrastructure and solar panel with large receiving area, and proposed a circuit for restoring accurate data even in ambient light. Through this study results, it is expected that visible light communication can be more widely used and this result used as the base data for visible light communication research using the solar panel as the receiver.

• Journal of Broadcast Engineering
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• v.22 no.2
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• pp.207-213
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• 2017

In order to accurately perform multispectral imaging using a multiplexed illumination, intensity of illumination in a scene must be uniform. For image acquisition that requires accurate color information, even if not multispectral imaging, the illumination information must be accurate, and a flat light source or illumination calibration is performed for accurate illumination characteristics. In this paper, we propose a method of color correction to uniformly illuminate an image with non-uniform illumination intensity. The proposed method uses multispectral imaging instead of illumination calibration for color correction. First of all, we perform multispectral imaging with two images obtained from non-uniformity illumination to acquire spectral reflectance. The obtained reflection spectrum is relit as the illumination characteristic of the image obtained from general planar light such as fluorescent light or sunlight. By comparing the image obtained by relighting with the uniformly illuminated image, the non-uniformity of the illumination is confirmed, and the color correction is performed as the image obtained from the uniform image. It is expected that the experimental results will confirm whether the non-uniformity of the illumination is uniformly corrected and reduce the restriction of illumination in obtaining the color information of the image.

• Transactions of the KSME C: Technology and Education
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• v.2 no.1
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• pp.57-63
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• 2014

In this paper new air-cooling system utilizing Stirling engine was proposed for improving efficiency in solar photovoltaic power generation. The solar cell plate was equipped with semi-circular channel for air flow on the backside. Beta-type Stirling engine was installed on the plate and its flywheel was connected to a motor fan by a transmission belt. A forced convective air flow for heat radiation was generated by the operation of the self-starting Stirling engine. The performance tests for power generation of solar cell with or without the proposed air-cooling system were conducted under halogen lamp. From the experimental results, it was found that decline in output voltage of the solar cell with proposed cooling system was 25% less than that of the solar cell without cooling system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.137-142
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• 2021

A Photovoltaic power streetlight is a system that uses solar energy to charge a secondary battery and then uses it for night lighting through a lamp, and can be configured as a standalone or grid-connected type by installing an LED streetlight at the load end. The energy generated through the solar cell module can be charged to the secondary battery through the charge/discharge control device, and then the LED street light can be turned on and off by comparing the power generation voltage and the charging voltage according to the monitoring of solar radiation, or by setting a specific time after sunset or sunrise. Based on these contents, this paper designed and manufactured a simulated solar power streetlight for education using new and renewable energy utilization and storage functions. Using these educational equipment, students can 1) understand the flow of energy change using renewable energy including sunlight as electric energy, 2) understand new and renewable energy, and cultivate basic design and manufacturing application power of related products, 3) The use of new and renewable energy through power conversion and strengthening of practical training and analysis through hardware production can be instilled.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.4
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• pp.166-176
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• 2010

The output characteristics of photovoltaic(PV) arrays are nonlinear and are affected by the temperature and solar insolation of cells. Maximum power point tracking(MPPT) methods are used to maximize PV array output power by tracking maximum power point(MPP) continuously. To increase the output efficiency of PV system, it is important to have more efficient MPPT. This paper proposes a novel maximum power point tracking(MPPT) control algorithm considering insolation to improve efficiency of PV system. The proposed algorithm is composed perturb and observe(P&O) method and constant voltage(CV) method. The proposed method is simulated under varying operating conditions. The effectiveness of these different MPPT methods is investigated thoroughly by PSIM simulation. The simulation results show that this proposed method provides better performance than conventional methods at a variable insolation without self-excited vibration of the power. By the simulation results, the validity of the proposed HB method is proved.