• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.2
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• pp.99-104
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• 2019

Solar power generation systems require maximum power point tracking (MPPT) control to acquire maximum power using inefficient and high-cost PV modules. Most conventional MPPT algorithms are based on the slope-tracking concept. The perturb and observe (P&O) algorithm is a typical slope-tracking method. The two factors that determine the MPPT performance of P&O algorithm are the MPPT control period and the magnitude of the perturbation voltage. The MPPT controller quickly moves to the new maximum power point at insolation change when the perturbation voltage is set to large, and the error of output power will be huge in the steady state even when insolation is not changing. The dynamics of the MPPT controller can be accelerated even though the perturbation voltage is set to small when the MPPT control period is set to short. However, too short MPPT control period does not improve MPPT performance but consumes the MPPT controller resources. Therefore, analyzing the performance of the MPPT controller is necessary for actual insolation conditions in real weather environment to determine the optimum MPPT control period and the magnitude of the perturbation voltage. This study proposes an optimum MPPT control period that maximizes MPPT efficiency by measuring and analyzing actual insolation profiles in typical clear and cloudy weather in central Korea.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.3
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• pp.205-212
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• 2012

This paper proposes the fuzzy logic based variable step-size MPPT (Maximum Power Point Tracking) method for the stability at the steady state and the improvement of the transient response in the wind power system. If the change value of duty ratio is set on stability of the steady state, MPPT control traces to maximum power point slowly. And if the change value is set on improvement of the transient response, the system output oscillates at the maximum power point. By adjusting the step size with fuzzy logic, it can be improved the MPPT response speed and stability at steady state when MPPT control is performed to track the maximum power point. The effectiveness of the proposed method has been verified by simulations and experimental results.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.503-506
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• 2003

The photovoltaic generators have a nonlinear V-I characteristics and maximum power points which vary with the illumination levels and temperatures. Using maximum power point tracker with the intermediate converter can increase the system efficiency by matching the PV systems to the load. A novel MPPT control for photovoltaic system is proposed. The system input parameters are (dP, dI, and last incremental of duty ratio $L\deltaD$)and the output is the new incremental value (new ${\deltaD}$) according to the maximum power point under various illumination levels. Using fuzzy logic controller allows extracting the maximum power rapidly and without significant oscillations. Also FLC provides excellent features such as fast response, good performance and the ability to change the fuzzy parameters to improve control system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.9-18
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• 2014

This paper proposes the fuzzy PI controller for maximum power point tracking(MPPT) control of photovoltaic system. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation. The MPPT control is a very important technique in order to increase an output and efficiency of the photovoltaic system. The conventional perturbation and observation(PO) and incremental conductance(IC) are the method which finding maximum power point(MPP) by the continued self-excitation vibration, and uses the fixed step size. If the fixed step size is a large, the tracking speed of maximum power point is faster, but the tracking accuracy in the steady state is decreased. On the contrary, when the fixed step size is a small, the tracking accuracy is increased and the tracking speed is slower. Therefore, this paper proposes the MPPT control using the fuzzy PI controller that can be improve a MPPT control performance. The fuzzy PI controller is adjusted a input of PI controller by fuzzy control and compensated a cumulative error of fuzzy control by PI controller. The fuzzy PI MPPT control is compared to conventional PO and IC MPPT method for various temperature and radiation condition. This paper proves the validity of the fuzzy PI controller using these results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.27-34
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• 2012

This paper proposes variable incremental conductance(IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. The conventional perturbation & observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small step size reduces a tracking error in the steady state but slows a tracking speed in the transient state. Also, a large step size is fast a tracking speed but increases a tracking error. Therefore, this paper proposes variable IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve a tracking speed and accuracy, when operating point is far from the maximum power point(MPP), the step size uses maximum value and when a operating point is near from the MPP, the step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional PO and IC MPPT algorithm.

• 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 Korean Institute of Fire Investigation
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• v.10 no.1
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• pp.87-95
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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 same 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 Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.33-38
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• 2010

Recently, photovoltaic generator system is widely extended by energy policy of the government. Add to this, high efficiency of photocell power generation is steady needed to sun tracking method. However sun tracking method is not widely extended by insufficiency of tracking technology. As method of solving this problem, this paper applied sunlight sensor and neural network control algorithm for maximum power tracking of sun photocell. Sun tracking sensor consists of one upright square pole and form light sensor of east, west, south, north on flat board. Sun tracking dual axes control is operated respectively by two motor. Motor control input is calculated by neural network control algorithm. The function of proposed control method is verified by sun tracking experiment of photocell generation. The sun tracking method of this paper is increased 32[%] efficiency more than fixed method.

• Journal of Power Electronics
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• v.17 no.5
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• pp.1308-1316
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• 2017

The distributed maximum power point tracking (DMPPT) concept is widely adopted in photovoltaic systems to avoid mismatch loss. However, the high cost and complexity of DMPPT hinder its further promotion in practice. Based on the concept of DMPPT, this paper presents an integrated submodule level half-bridge stack structure along with an optimal current point tracking (OCPT) control algorithm. In this full power processing integrated solution, the number of power switches and passive components is greatly reduced. On the other hand, only one current sensor and its related AD unit are needed to perform the ideal maximum power generation for all of the PV submodules in any irradiance case. The proposal can totally eliminate different small-scaled mismatch effects in real-word condition and the true maximum power point of each PV submodule can be achieved. As a result, the ideal maximum power output of the whole PV system can be achieved. Compared with current solutions, the proposal further develops the integration level of submodule DMPPT solutions with a lower cost and a smaller size. Moreover, the individual MPPT tracking for all of the submodules are guaranteed.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.4
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• pp.376-386
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• 2013

This paper proposes an improved Maximum Power Point Tracking method and design methods of unmanned solar vehicle system by parts of hardware, unmanned driving control and power conversion. The hardware design is offered on the weight reduction and structural reliability by using structural analysis software. The technique of curve fitting is applied to unmanned control system due to minimizing the vehicle's behavior. Furthermore, lateral controller applying actuator dynamics is robust enough to prevent performance degradation by measurement noise regarding position and heading angle. The power conversion system contains battery charger system and tapped-inductor boost converter. In the battery charger system, variable step-size MPPT is conducted for quick response of maximum power point tracking. The validity of the proposed algorithm are verified by simulations and experiments.