• 한국철도학회논문집
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• 제18권4호
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• pp.325-334
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• 2015

본 논문에서는 하이브리드 에너지 저장장치의 계통연계 제어에 대하여 기술 하였다. 배터리는 큰 에너지 밀도를 가지지만 순간 전력밀도는 낮아 급격한 전류변동이 일어날 경우 수명이 저하된다. 이러한 단점을 보완하기 위해 수퍼커패시터를 함께 사용하는 하이브리드 에너지 저장장치를 구성하였고 이에 대한 제어방법을 제안하였다. 배터리와 수퍼커패시터의 제어를 위해서는 예측형 전류제어기를 가지는 p-q 제어방법을 적용하였다. 제안된 제어기의 효용성을 검증하기 위해 실제 계통모델에 대한 PSIM과 RTDS를 이용한 시뮬레이션을 수행하였다.

• 조명전기설비학회논문지
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• 제21권1호
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• pp.91-97
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• 2007

This paper presents a pitch angle controller of a grid-connected wind turbine system for extracting maximum power from wind and implements a modeling and simulation of the wind turbine system on MATLAB/Simulink. It discusses the maximum power control algorithm for the wind turbine and presents, in a graphical form, the relationship of wind turbine output, rotor speed, and power coefficient with wind speed when the wind turbine is operated under the maximum power control algorithm. The objective of pitch angle control is to extract maximum power from wind and is achieved by regulating the blade pitch angle during above-rated wind speeds in order to bypass excessive energy in the wind. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction during above-rated wind speeds and effectiveness of the proposed controller would be satisfactory.

• 대한전기학회논문지:전력기술부문A
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• 제51권8호
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• pp.391-397
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• 2002

This paper presents a modeling and simulation of a PI controller for maximum power extraction of a grid-connected wind energy conversion system with a link of a rectifier and an inverter. It discusses the maximum power control algorithm fnr a wind turbine and proposes, in a graphical form, the relationships of wind turbine output, rotor speed, power coefficient, tip-speed ratio with wind speed when the wind turbine is operated under the maximum power control. The control objective is to always extract maximum power from wind and transfer the power to the utility by controlling both the Pitch angle of the wind turbine blades and the inverter firing angle. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation method. The simulation results performed on MATLAB will show the variation of generator's rotor angle and rotor speed, pitch angle, and generator output.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.202-205
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• 2006

In the PV power system, output of the PV array must contain inherent ripples due to the single-phase inverter. So the function of maximum power point tracking to increase the output efficiency of PV system is degraded. Therefore, to overcome this problem, this paper presents a control strategy for the reducing ripples of the PV array output in grid-connected photovoltaic power system. The proposed control system consists of two loops the maximum power point tracking loop using the perturbation and observation method is used to calculate the reference solar array terminal voltage(Vref) for reducing ripples of the PV array output and the PI control loop is used to regulate the solar array output voltage according to the Vref. The performance of proposing control strategy is analyzed by means of the PSCAD/EMTDC simulation. As a result, we may obtain the high performance of the proposed control strategy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.1945-1947
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• 1997

In this paper, a characteristics analysis of the grid-connected photovoltaic power generation system which uses the simulation method of PV array is reported. The control method of DC/AC power conversion were suggested to establish the basic application technology of photovoltaic systems. The results of the demonstration test of a 3kW grid-connected PV system show that the system utilization rate is 17.6% and the system efficiency is 8.9%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.519-520
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• 2006

In this paper, to evaluate the grid-connected 120kW class Photovoltaic(PV) system performance, as a consisted of solar cells, PCS, 150kVA transformer station. The paper address modeling and analysis of a grid-connected 120kW class photovoltaic generation system(PV system) PSCAD/EMTD and Psim. A PWM voltage source inverter(VIS) and its current control scheme have been implemented. A P&O(Perturbation and Observation) MPPT algorithms technique modeling has been simulated and analysed.

• Journal of Power Electronics
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• 제13권1호
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• pp.94-103
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• 2013

A capacitor deterioration of LCL-filter grid-connected PWM converters is progressed by the self-healing mechanism. It leads to the degradation of the filter performance and drop of power factor. Thus, it is required to diagnose fault-point of capacitors and determine the replacement time. Typically, the fault of capacitors is determined when the capacitance is reduced up to 80% from initial value. This paper proposes algorithm to the determine capacitor replacement time of an LCL filter. The algorithm takes the advantage of change of the response on the injected resonant frequency corresponding to 80% value from the initial capacitance. The results of the algorithm are demonstrated through simulations and experiments.

• 전기학회논문지
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• 제60권3호
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• pp.471-478
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• 2011

This paper proposes a method of maximum power point tracking (MPPT) using fuzzy logic control for grid-connected photovoltaic systems (PV). First, for the purpose of comparison, because of its proven and good performances, the incremental conductance (IncCond) technique is briefly introduced. A double fuzzy logic controller (DFLC) based MPPT is then proposed which has shown better performances compared to the IncCond MPPT based approach. Modeling and Simulation in grid-connected PV system results are provided for both controllers under same atmospheric condition based PSCAD/EMTDC. The double fuzzy logic MPPT controller is then simulated and evaluated, which has shown better performances.

• 전기학회논문지
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• 제66권1호
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• pp.40-47
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• 2017

In this paper, a small signal model for grid-connected inverter with unipolar pulse width modulation method is presented. Small-signal analysis allows to predict the stability and dynamics of the inverter. To regulate output voltage and to achieve power factor correction, inverter has two control loops. Loop gains are useful to identify the stability for multi-loop controlled system. Based on small-signal model, controllers are designed to improve audio susceptibility and output impedance characteristics. Proposed small-signal model and controllers are verified by PSIM simulation and experiments.

• 대한전기학회논문지:전력기술부문A
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• 제53권11호
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• pp.589-595
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• 2004

This paper presents a modeling and simulation of a grid-connected wind turbine generation system with respect to wind variations, starting of large induction motor and three-phase fault in the system, and investigates voltage variations of the system for disturbances. It describes the modeling of the wind turbine system including the drive train model, induction generator model, and grid-interface model on MATLAB/Simulink. The simulation results show the variation of the generator torque, the generator rotor speed, the pitch angle, terminal voltage, system voltage, fault current, and real/reactive power output, etc. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction for wind speed variations, starting of a large induction motor causes a voltage sag due to a large starting current, and a fault on the system influences on the output of the wind turbine generator.