• Journal of IKEEE
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• v.19 no.1
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• pp.118-123
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• 2015

According to the recent report, solar street lamp connected to a non Maximum Power Point Tracking(MPPT) charger, can lead to a system-wide decline in power output with as much as 30%. This paper proposes the charge controller with direct duty ration control for 250W solar street lamp in order to improve the efficiency of photovoltaic from these output power reduction. This paper covers the Pulse Width Modulation(PWM) controller and power conversion topology and analyze the MPPT method for charge controller. The power conversion part consists of push pull converter based on PWM controller using 8bit MCU in order to have lower manufacturing cost. The PWM controller with direct duty ratio control algorithm is constantly tracking the maximum power point of photovoltaic module and increases energy output power. The test results shows 97.1~97.4% MPPT efficiency and the experimental hardware is implemented based on the solar simulator condition for 241W. Thus, the implemented charge controller shows its feasibility for the real application, especially under solar street lamp.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.27-32
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• 2015

A maximum power point tracking (MPPT) algorithm using fuzzy controller was considered. MPPT method was implemented based on the voltage and reference PV voltage value was obtained from Artificial Neural Network (ANN)-model of PV modules. Therefore, measuring only the PV module voltage is adequate for MPPT operation. Fuzzy controller is used to directly control dc-dc buck converter. The simulation results have been used to verify the effectiveness of the algorithm. The proposed method is compared with conventional PO(perturbation & observation), IC(Incremental Conductance) method. The nonlinearity and adaptiveness of fuzzy controller provided good performance under parameter variations such as solar irradiation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.675-676
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• 2014

Photovoltaic (PV) systems bosed on solar energy offer an environmentally friendly source of electricity. A key feature of such PV sysem is the efficiency of conversion at which the power converter stage can extract the energy from the PV arrays and deliver to the load. The Maximum power point tracking (MPPT) of the PV output for all sunshine conditions allows reduction of the cost installation and maximizes the power output from the PV panel. The proposed algorithm is to control the width of the pulse for battery charging based on the open voltage of the PV panel. As a lab results, the proposed system was implemented functions to adapt to the changes of the PV open voltage, and improved the charging efficiency.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.9
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• pp.779-788
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• 2014

The satellite should generate electric power efficiently to perform the mission successfully within limited power. For this reason, the electrical power system of LEO satellites usually regulates the power which is generated from the solar cells using MPPT (Maximum Power Point Tracking) method. This paper proposes advanced MPPT algorithm based on the fuzzy logic applied to small CubeSat satellite. The simulation has been performed to confirm the validity of the proposed method by interlocking between MATLAB/Simulink and STK (Systems Tool Kit). The EBA(Energy Balance Analysis) has also been performed at two different pointing modes of KAUSAT-5 for solar irradiation according to the satellite orbit and attitude, and load capacity varied with operation modes by Simulink and STK. The performance of fuzzy logic-based MPPT algorithm was verified through the EBA. The validity of the proposed MPPT algorithm based on the fuzzy logic was also confirmed by comparing with P&O (Perturbation & Observation) algorithm that is general in the MPPT.

• Advances in Energy Research
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• v.1 no.2
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• pp.97-106
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• 2013

This study designs and tests a photovoltaic system with distributed maximum power point tracking (DMPPT) methodology using a field programmable gate array (FPGA) controller. Each solar panel in the distributed PV system is equipped with a newly designed DC/DC converter and the panel's voltage output is regulated by a FPGA controller using PI control. Power from each solar panel on the system is optimized by another controller where the quadratic maximization MPPT algorithm is used to ensure the panel's output power is always maximized. Experiments are carried out at atmospheric insolation with partial shading conditions using 4 amorphous silicon thin film solar panels of 2 different grades fabricated by Chi-Mei Energy. It is found that distributed MPPT requires only 100ms to find the maximum power point of the system. Compared with the traditional centralized PV (CPV) system, the distributed PV (DPV) system harvests more than 4% of solar energy in atmospheric weather condition, and 22% in average under 19% partial shading of one solar panel in the system. Test results for a 1.84 kW rated system composed by 8 poly-Si PV panels using another DC/DC converter design also confirm that the proposed system can be easily implemented into a larger PV power system. Additionally, the use of NI sbRIO-9642 FPGA-based controller is capable of controlling over 16 sets of PV modules, and a number of controllers can cooperate via the network if needed.

• 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.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.114-118
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• 2022

The photovoltaic system is affected by various conditions such as temperature and irradiance. Because non-uniform irradiation and partial shading conditions affect the entire string of cells connected in series, a bypass diode is used to bypass the current flow normally. In order to find the maximum power point in partial shade conditions, it is necessary to estimate various methods of maximum power point tracking. In this paper, the hybrid method of MPPT using Lambert W function and perturbation & observation algorithm is proposed under partial shading conditions. The simulation results are obtained using MATLAB/Simulink and shows the improvement of the accuracy of MPPT.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.316-321
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• 2007

This paper is proposed a novel method to approximate the maximum power for a photovoltaic inverter system and tracking method. It is designed for power systems application and utilities. The proposed Maximum Power Point Tracking(MPPT) control has the advantage to provide a new simple way to approximate the optimal or rated voltage, the optimal or rated current and maximum power rating produced by a solar panel and the photovoltaic inverter. And this straightforward method will be named linear reoriented coordinates method(LRCM) with the advantage that Pmax and $V_{op}$ can be approximated using the satre variable as the dynamic model without using complicate approximations or Taylor series. Furthermore tracking method is improved over 50% photovoltaic efficiency. This paper is proposed MPPT using LRMC and tracking method using weather condition of domestic moderate program technique. This paper is proposed the experimental results to verify the effectiveness of the new methods.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.2
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• pp.141-151
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• 2020

Since it was first studied in 1980, solar energy analysis model for geographic information systems has been used to determine the approximate spatial distribution of terrain. However, the spatial pattern was not able to be grasped in 3D (three-dimensional) space with low accuracy due to the limitation of input data. Because of computational efficiency, using a constant value for the brightness of the sky caused the simulation results to be less reliable especially when the slope is high or buildings are crowded around. For the above reasons, this study proposed a model that predicts solar energy of vertical surfaces of buildings with four stages below. Firstly, CIE (Commission Internationale de l'Eclairage) luminance distribution model was used to calculate the brightness distribution of the sky using NREL (National Renewable Energy Laboratory) solar tracking algorithm. Secondly, we suggested a method of calculating the shadow effect using ray tracing. Thirdly, LOD (Level of Detail) 3 of 3D spatial data was used as input data for analysis. Lastly, the accuracy was evaluated based on the atmospheric radiation data collected through the ground observation equipment in Daejeon, South Korea. As a result of evaluating the accuracy, NMBE was 5.14%, RMSE 11.12, and CVRMSE 7.09%.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.925-928
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• 2003

As the maximum power operating point(MPOP) of photovoltaic(PV) power generation systems changes with changing atmospheric conditions such as solar radiation and temperature, an important consideration in the design of efficient PV system is to track the MPOP correctly. Many maximum power point tracking(MPPT) techniques have been considered in the past, however, techniques using microprocessors with appropriate MPPT algorithms are favored because of their flexibility and compatibility with different PV arrays. Although the efficiency of these MPPT algorithms is usually high, it drops noticeably in case of rapidly changing atmospheric conditions. This paper proposed a new MPPT algorithm based on perturb & observe(P&O) algorithm with experiment. The results shows that the new P&O algorithm has successfully tracked the MPOP, even in case of rapidly changing atmospheric conditions, and has higher efficiency than ordinary algorithms.