• 한국태양에너지학회 논문집
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• 제39권4호
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• pp.69-77
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• 2019

Among the main functions of the grid-connected photovoltaic (PV) system, the anti-islanding operation function is a very important problem. Recently, due to the improvement in power generation efficiency and the maintenance advantages in PV system, the use of string inverter has increased so that the possibility of islanding operation has been raised. Generally, when a power system faults, the PV inverter must be disconnected from power system within 10 cycles by the anti-islanding operation function. However, in the real-time of power system, the output power of the PV system within 10cycles is effected. In this paper, we analyzed the effect of grid-connected PV system on power quality in a short time within 10 cycles on fault case of power system using the Matlab Simulink program.

• Journal of Electrical Engineering and Technology
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• 제6권6호
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• pp.731-741
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• 2011

Conventional methodologies (empirical, analytical, numerical, hybrid, etc.) for sizing photovoltaic (PV) systems cannot be used when the relevant meteorological data are not available. To overcome this situation, modern methods based on artificial intelligence techniques have been developed for sizing the PV systems. In the present study, the optimum PV/inverter sizing ratio for grid-connected PV systems with orientation due south and inclination angles of $45^{\circ}$ and $60^{\circ}$ in selected Algerian locations was determined in terms of total system output using type-2 fuzzy logic. Because measured data for the locations chosen were not available, a year of synthetic hourly meteorological data for each location generated by the PVSYST software was used in the simulation.

• Journal of Power Electronics
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• 제17권5호
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• pp.1338-1348
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• 2017

In this study, a modified ripple correlation control (RCC) maximum-power point-tracking (MPPT) algorithm is proposed for a single-stage single-phase voltage source inverter (VSI) on a grid-connected photovoltaic system (GCPVS). Unlike classic RCC methods, the proposed algorithm does not require high-pass and low-pass filters or the increment of the AC component filter function in the voltage control loop. A simple arithmetic mean function is used to calculate the average value of the photovoltaic (PV) voltage, PV power, and PV voltage ripples for the MPPT of the RCC method. Furthermore, a high-accuracy and high-precision MPPT is achieved. The performance of the proposed algorithm for the single-stage single-phase VSI GCPVS is investigated through simulation and experimental results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.707-710
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• 2003

3kW grid-connected photovoltaic (PV) system and data acquisition system are constructed for performance analysis of PV system at field demonstration test center of Gwang-Ju in Korea. As climatic and irradiation conditions are varied, operation characteristics of the PV system are collected and analyzed in data acquisition system. From these results, the performances of PV system have simulated and evaluated using simulation tool in comparison with actual value of data acquisition system of field demonstration test center. Furthermore, performance of total PV system e.g. electric power and loss factor at the site are reviewed.

• Journal of Power Electronics
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• 제17권5호
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• pp.1317-1326
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• 2017

The cascaded H-bridge (CHB) multilevel converter is a promising topology for large-scale photovoltaic (PV) systems. The output voltage over-modulation derived by the inter-module active power imbalance is one of the key issues for CHB PV systems. This paper proposed a dynamic power distribution strategy to eliminate the over-modulation in a CHB PV system by suitably redistributing the reactive power among the inverter modules of the CHB PV system. The proposed strategy can effectively extend the operating region of the CHB PV system with a simple control algorithm and easy implementation. Simulation and experimental results carried out on a seven-level CHB grid-connected PV system are shown to validate the proposed strategy.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1211-1212
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• 2007

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 and experiment. As a result, we may obtain the high performance of the proposed control strategy.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
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• pp.524-527
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• 2003

This paper describes control of the grid connected transformer-less type photovoltaic(PV) power conditioning system. which is simpler and more efficient than conventional transformer type systems. With modeling and analysis of PV system, the validity of the control strategy was verified by simulations and experimental results.

• 전력전자학회논문지
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• 제13권5호
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• pp.369-375
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• 2008

본 논문에서는 Z-소스 인버터를 사용하여 단상 계통 연계형 태양광 시스템을 제어하는 기법을 제시하였다. 인버터 스위칭소자의 전압 스트레스를 고려하여 광전지 출력전압에 대한 계통 연계형 Z-소스 인버터의 동작영역을 분석하였다. 스위칭 손실을 감소시키면서 shoot-through 시간을 효율적으로 제어하는 스위칭 패턴을 사용하였다. 시뮬레이션 및 32-비트 DSP를 사용한 실험을 통하여 계통연계형 Z-소스 인버터의 제어 시스템의 성능을 평가하였다.

• 전력전자학회논문지
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• 제25권6호
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• pp.433-441
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• 2020

This study proposes a constant power tracking algorithm to compensate for the intermittent characteristics of Photovoltaic connected to a DC micro grid. A PV-ESS integrated module in which distributed ESS is additionally connected is utilized for the proposed algorithm. PV performs P&O MPPT control at all times. To supplement the intermittent characteristics of PV, the proposed constant power tracking algorithm maintains constant power by operating the distributed ESS of the PV-ESS integrated module in accordance with the output state of the PV. By performing PSIM simulation and an experiment, this study verifies the performance of the integrated module of PV-ESS for DC micro grids applying the constant power tracking algorithm.

• 전력전자학회논문지
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• 제17권5호
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• pp.377-387
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• 2012

A single-phase grid-connected PV system is known as suitable for housing of less than 3 kW. The DC link voltage in a single-phase PV system has necessarily twice component of fundamental wave. It makes high THD in the grid current. According to the problem, power quality is lower. Many engineers have studied about this problem. The most simple method is to use low pass filter on DC link voltage control. However it is affected by DC link voltage control bandwidth. If cutoff frequency is reduced to increase the performance of low pass filter, it also lowers DC link voltage control bandwidth. Second method is using band stop filter, it works good on steady state but not good on transient state. This paper proposes the new method for removing ripple voltage to get an exact current reference. It improves the responses on steady state and transient state. The performance was verified through computer simulation using MATLAB and actual experiments.