• Journal of Energy Engineering
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• v.26 no.1
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• pp.34-44
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• 2017

This paper deals with the effectiveness of a fiber optic solar lighting system that uses a Fresnel lens mounted on a two-axis solar tracker. A series of comparative analyses were made concerning its performance as compared to fluorescent lighting by using a simulation model based on ECOTECT and RADIANCE as well as referring to actual data. ECOTECT was used to model the test room (space) while RADIANCE was used for its indoor lighting conditions (environment). It was found that the average indoor light levels of fluorescent lighting fully satisfy the KS standard (KS A 3011, general office, class [G]: 300-400-600lux) whereas those of the solar lighting with light diffusers depends on the occlusion factor of roller shades installed on the south window.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.89-101
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• 2006

This paper addresses Electrical Power Subsystem(EPS) design and verification of HAUSAT-2 small satellite through energy balance analysis(EBA) depending on individual operation modes. GaAs solar cells are used for satellite power generation and digital peak power tracking is implemented for EPS architecture. One battery pack is consisted of 4 Li-Ion cells. Battery charge is accomplished by peak power tracker and battery charge regulator. Power conditioning assembly uses three DC-DC converters, and power distribution assembly which consists of commercial IC and MOSFET switch distributes power to subsystems and payloads. The altitude of 650km and sun-synchronous LEO with various local time ascending node(LTAN) are considered in EBA.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.5
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• pp.583-591
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• 2007

This paper reports the performance of a 150W PV-wave hybrid system with battery storage in buoy. This system was originally designed to meet a new hybrid ower system for buoy in Korea. In the case or lighted buoys and lighthouses, a light failure alarm system of wireless radio is attached so that light failures are immediately notified to the office. At lighthouse offshore fixed lights and light buoys where commercial electricity is not available, the power source depends on solar system and batteries. This power system has a various problems. Therefore energy derived from the sunshine, wind and waves has been used as the energy source lot aids to navigation. Recently a hybrid system of combining the solar, wind and the wave generator is a favorable system lot the ocean facilities like lighthouse and buoy. The hybrid system in this paper is intended for variable DC load like light, communication system in the buoy and includes a PV-wane generation system and battery. This is composed a high efficiency charging algorithm, switching converter and controller. This paper includes discussion on system reliability, power quality, and effects of hybrid system in the buoy. Simulation and experimental results show excellent performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1913-1920
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• 2009

An intelligent accurate sun tracking controller for solar lighting system was developed. This controller can detect the faulty sensor and correct the error signal based on Principle Component Analysis theory. A fuzzy controller was developed to control the tracker by using the collected sensor signal for precise position control. Also a multiple range searching sensor module for sun tracking was designed. To show the validity of the developed system, some experiments in the field were illustrated.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.6
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• pp.916-921
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• 2004

This paper describes microprocessor-based control of photovoltaic power conditioning system. where the microprocessor is responsible for control of output power in accordance with the generated array DC power. The microprocessor includes the control algorithm of maximum power point tracking and converter control algorithm. In this power, we have designed a MPPT(Maximum Power Point Tracker) algorithm with environment factors and a PWM(Pulse Width Modulation) algorithm for high efficiency. The controller has been tested in the laboratory with the power conditioner and shows excellent performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.311-314
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• 2003

This paper describes a virtual instrument system with faulty sensor reconstruction mechanism based on personal computer. This system consists of sensor control board using 16bit RISC machine, error signal reconstruction algorithm based on principal component analysis and auto tunned GUI interface according to the attached sensors. USB module is used for fast communication between PC and sensor controller. To show the veridity of the proposed system, the proposed system was applied to the developed sun tracker with 8 solar sensors.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.966-971
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• 1998

The studies on the photovoltaic system are extensively exhaustible and broadly available resourse as a future energy supply. In this paper, a new maximum power point tracker(MPPT) using neural network theory is proposed to improve energy conversion efficiency. The boost converter and neural network controller(NNC) were employed so that the operating point of solar cell was located at the Maximum Power Point. And the back propagation algorithm with one input layer of two inputs(E, CE) and output layer(cnntrol value) was applied to train a neural network. Simulation and experimental results show that the performance of NNC in MPPT of photovoltaic array is better than that of controller based upon the Hill Climbing Method.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.340-342
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• 2005

A sliding mode controller for the grid-connected photovoltaic system has been presented. This controller is constructed from the time-varying sliding surface In order to control the sinusoidal inductor current and solar array power simultaneously. The proposed controller can achieve the tight regulation of current and power under the parameter variation environment.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.369-371
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• 2007

Due to the measurement noise or system noise, the performance of photovoltaic power generation system can be degraded. If this noise is contained in the solar array voltage measurement signal, the correct operation of the maximum power point tracker can not be guaranteed. The application of the extended Kalman filter to the photovoltaic system can obtain enhanced states estimation result. The Kalman filter provides a recursive solution to optimally estimate from random noise signals. Additionally, as a consequence of Kalman filter, the unmeasurable state such as inductor current can be estimated without current sensor. The methods for system modeling and extended Kalman filter design are presented and the experimental results verify the validity of the proposed system.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1544-1553
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• 2019

The efficiency of photovoltaic generation systems depends on the maximum power point tracking (MPPT) technique. Among the various schemes presented in the literature, the incremental conductance (INC) method is one of the most frequently used due to its superb tracking ability under changes in insolation and temperature. Generally, conventional INC algorithms implement a simple duty-cycle updating rule that is mainly found on the polarity of the peak-power evaluation function. However, this fails to maximize the performance in both steady-state and transient conditions. In order to overcome this limitation, a novel regulated INC (r-INC) method is proposed in this paper. Like the compensators in automatic control systems, this method applies a digital compensator to evaluate the INC function and improve the capability of power tracking. Precise modeling of a new MPPT system is also presented in the optimized design process. A 120W boost peak power tracker is utilized to obtain comparative test results and to confirm the superiority of the proposed method over existing techniques.