• Fire Science and Engineering
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• v.30 no.6
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• pp.71-77
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• 2016

The electrolyte of the capacitor in mobile phone chargers leaks to the power input terminal resulting in tracking on the PCB board to form a carbonized conductive path. As a result of structural analysis of the cause of the tracking, It occurred when the power input terminal and the PCB board were connected directly using the connector. The larger the amount of electrolyte leaked from the capacitor into the power input terminal, or the lower the height of the partition provided between the plug pins of the power input terminal, the higher the tracking occurrence rate. Accordingly, to lower the occurrence rate of tracking in the charger, it is necessary to provide a partition on the capacitor or increase the height of the partition provided on the power input terminal so that the leaked electrolyte does not flow to the power input terminal. In addition, the tracking occurrence rate will be reduced further if the shape of the PCB board touching ther power connection terminal is changed to ${\Pi}$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.466-474
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• 2014

According to wireless network technology and mobile processors performance were improved, the small wireless mobile device such as smart phones has been widely utilized. The mobile devices can be used GPS information, thereby the services based on location information was increased. GPS was impossible to provide location information in indoor and signal shading environment, and the tracking systems based on short distance wireless communication are required infrastructure. The IEEE 802.11 based tracking system is possible estimation using APs, however the tracking device is exhausted battery power seriously. In this paper, we propose IEEE 802.11 based low-power tracking system. We reduced power consumption from channel scanning and network connection. For performance evaluation, we designed and implemented the tracking tag device, and measured power consumption of the device. As the simulation result, we confirmed that the power consumption was reduced 46% compare to the standard execution.

• Journal of Power Electronics
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• v.17 no.5
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• pp.1327-1337
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• 2017

Photovoltaic (PV) systems are influenced by disproportionate impacts on energy production caused by frequent mismatch cases. The occurrence of multiple maximum power points (MPPs) adds complexity to the tracking process in various PV systems. However, current maximum-power point tracking (MPPT) techniques exhibit limited performance. This paper introduces an enhanced simulated annealing (ESA)-based GMPPT technique against multiple MPP issues in P-V curve with different PV system structures. The proposed technique not only distinguishes global and local MPPs but also performs rapid convergence speed and high tracking accuracy of irradiance changing and restart capability detection. Moreover, the proposed global maximum power tracking algorithm can be applied in the central converter of DMPPT and hybrid PV system to meet various application scenarios. Its effectiveness is verified by simulation and test results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.74-82
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• 2013

This paper presents a novel maximum power point tracking for a photovoltaic power (PV) system with a direct control plan. Maximum power point tracking (MPPT) must usually be integrated with photovoltaic (PV) power systems so that the photovoltaic arrays are able to deliver maximum available power. The maximum available power is tracked using specialized algorithms such as Perturb and Observe (P&O) and incremental Conductance (indCond) methods. The proposed method has the direct control of the MPPT algorithm to change the duty cycle of a dc-dc converter. The main difference of the proposed system to existing MPPT systems includes elimination of the proportional-integral control loop and investigation of the effect of simplifying the control circuit. The proposed method thus has not only faster dynamic performance but also high tracking accuracy. Without a conventional controller, this method can control the dc-dc converter. A simulation model and the direct control of MPPT algorithm for the PV power system are developed by Matlab/Simulink, SimPowerSystems and Matlab/Stateflow.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1075-1082
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• 2010

This paper analyzes a operating characteristic for maximum power point tracking (MPPT) of photovoltaic generation system. 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. MPPT algorithm is widely used the control method such as the perturbation and observation(PO) method, incremental conductance(IC) method and constant voltage(CV) method. In case of the radiation is changed, this paper proposes a response characteristic with MPPT control algorithms. Also, it proposes the direct for a novel MPPT control algorithm development through the analyzed data, hereby proves the effectiveness of this paper.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1290-1292
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• 2001

Photovoltaic(PV) power generation system has been extensively studied and watched with keen interest as a clean and renewable power source. On the other hand, because the output power of solar cell is not only unstable but uncontrollable, the maximum power point tracking(MPPT) control is still hot issue with the tracking failure left unsolved under the sudden fluctuation of irradiance. Hence, in this paper, we introduce the mechanism of the tracking failure under the fluctuation of irradiance, and show the simulation results using SPRW(simulation method for PV power generation system using real weather conditions).

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.111-117
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• 2020

The photovoltaic module has the characteristic that the output power varies according to the amount of insolation. If partial shading occurs in an environment composed of an array, a number of local maximum power points (LMPPs) may be generated according to the shading state. Photovoltaic arrays require global maximum power point tracking due to variations in output characteristics caused by solar radiation and temperature. Conventional algorithms, such as P&O and Incond, do not follow the global maximum power point in a partial shaded solar array. In this study, we propose a technique to follow the global maximum power point by using the correlation of voltage, current, and power in solar arrays. The proposed control technique 2qw validated through simulation and experiments by constructing a 2-kW solar system.

• Journal of IKEEE
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• v.22 no.2
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• pp.460-475
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• 2018

In the variable-speed wind energy system, to achieve maximum power point tracking (MPPT), the wind turbine should run close to its optimal angular speed according to the wind speed. Non-linear control methods that consider the dynamic behavior of wind speed are generally used to provide maximum power and improved efficiency. In this perspective, the mechanical power is estimated using Kalman filter. And then, from the estimated mechanical power, the wind speed is estimated with Newton-Raphson method to achieve maximum power without anemometer. However, the blade shape and air density get changed with time and the generator efficiency is also degraded. This results in incorrect estimation of wind speed and MPPT. It causes not only the power loss but also incorrect wind resource assessment of site. In this paper, the adaptive maximum power point tracking control algorithm for wind turbine system based on the estimation of wind speed is proposed. The proposed method applies correction factor to wind turbine system to have accurate wind speed estimation for exact MPPT. The proposed method is validated with numerical simulations and the results show an improved performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.342-348
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• 2013

It proposes an efficient control algorithm to increase electric power transmission efficiency between photovoltaic power generating system and the grid. The main controller finds a maximum efficiency condition by considering the quantity of power generated from PV arrays, the number of inverters, and efficiency of PV inverter. According to the condition, a relay board arranges a point of contract of PV arrays. By the disposition of PV arrays, it assigns the optimized power on each PV inverter. Operational principle of the proposed maximum efficiency point tracking algorithm is given in detail. To verify the validity of the proposed approach, computer-aided simulation and experiment carried out.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.5
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• pp.502-508
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• 2012

Heliostat, as a concentrator to reflect the incident solar energy to the receiver, is the most important system in the tower-type solar thermal power plant since it determines the efficiency and ultimately the overall performance of solar thermal power plant. Thus, a good sun tracking ability as well as a good optical property of it are required. Heliostat sun tracking system uses usually an open loop control system. Thus the sun tracking error caused by heliostat's geometrical error, optical error and computational error cannot be compensated. Recently use of sun tracking error model to compensate the sun tracking error has been proposed, where the error model is obtained from the measured ones. This work is a development of heliostat sun tracking error measurement and compensation method using BCS (Beam Characterization System). We first developed an image processing system to measure the sun tracking error optically. Then the measured error is modeled in linear polynomial form and neural network form trained by the extended Kalman filter respectively. Finally error models are used to compensate the sun tracking error. We also developed the necessary image processing algorithms so that the heliostat optical properties such as maximum heat flux intensity, heat flux distribution and total reflected heat energy could be analyzed. Experimentally obtained data shows that the heliostat sun tracking accuracy could be dramatically improved using either linear polynomial type error model or neural network type error model. Neural network type error model is somewhat better in improving the sun tracking performance. Nevertheless, since the difference between two error models in compensation of sun tracking error is small, a linear error model is preferred in actual implementation due to its simplicity.