1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.... more 1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.tr 2Energy Research and Application Center, Pamukkale University, Denizli-Turkey mhekim@pau.edu.tr 3Energy Research and Application Center, ...
Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as win... more Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as wind, hydrogen, solar, etc. have been utilized simultaneously. In order to avoid global warming caused by greenhouse gases, special legislation on energy use came into effect in 2003, ...
1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.... more 1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.tr 2Energy Research and Application Center, Pamukkale University, Denizli-Turkey mhekim@pau.edu.tr 3Energy Research and Application Center, ...
The aim of this study is to investigate the effects of non-uniform solar irradiation distribution... more The aim of this study is to investigate the effects of non-uniform solar irradiation distribution on energy output of different interconnected configurations in photovoltaic (PV) arrays. In order to find which configuration is less susceptible to mismatch effects, a PV module model is developed. This model can take into consideration the effects of bypass diodes and the variation of the equivalent circuit parameters with respect to operating conditions. The proposed model can provide sufficient degree of precision as well as solar cell-based analysis in analyzing large scale PV arrays without increasing the computational effort. In order to produce more reliable and robust simulations, improved and extended algorithms are presented. Some results are discussed in detail and some recommendations are extracted by testing several shading scenarios.
In this paper, it is aimed to deal with the interactions of harmonic currents produced by differe... more In this paper, it is aimed to deal with the interactions of harmonic currents produced by different single phase loads. For this purpose, compact fluorescent lamps, incandescent lamps, and electric heaters were chosen as single phase loads. The study was performed by adopting a full range of response surface methodology using Box-Behnken experimental design to express the net harmonic current (3rd and 5th) as an empirical model. The model provided an excellent explanation of the relationship among the number of loads and the net harmonic currents. Contour graphs of some of the harmonic currents was plotted to show the interactions clearly and to discuss the results of model in the graphic detail. The results of experiments showed that the harmonic interaction between the loads can be defined as a regression model which is statistically significant.
2007 International Conference on Intelligent Systems Applications to Power Systems, 2007
Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking ... more Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking maximum power point (MPP), since their power-voltage (P-V) characteristics are complex and may have multiple local maxima. For this reason, conventional techniques fail to track MPP effectively, if the PV array is partially shaded. This paper presents a novel power compensation and control system for PV arrays under complicated non-uniform insolation conditions. The proposed system is based on forward biasing bypass diode of shaded modules by monitoring dynamic resistance and voltage of PV modules. For this purpose, the proposed system is used DC/DC converter equipped with each PV string in PV array. The proposed system can identify which modules are shaded. The effectiveness of the proposed system is investigated and confirmed for complicated partially shaded PV array.
The aim of this study is to investigate the effects of non-uniform solar irradiation distribution... more The aim of this study is to investigate the effects of non-uniform solar irradiation distribution on energy output of different interconnected configurations in photovoltaic (PV) arrays. In order to find which configuration is less susceptible to mismatch effects, a PV module model is developed. This model can take into consideration the effects of bypass diodes and the variation of the equivalent circuit parameters with respect to operating conditions. The proposed model can provide sufficient degree of precision as well as solar cell-based analysis in analyzing large scale PV arrays without increasing the computational effort. In order to produce more reliable and robust simulations, improved and extended algorithms are presented. Some results are discussed in detail and some recommendations are extracted by testing several shading scenarios.
International Journal of Smart Grid and Clean Energy, 2013
This paper presents the practical implementation of the real-time Estimate-Perturb-Perturb (EPP) ... more This paper presents the practical implementation of the real-time Estimate-Perturb-Perturb (EPP) algorithm for maximum power point tracking (MPPT) control in a photovoltaic (PV) system. The PV system usually consists of: a PV array that converts solar energy to electrical energy, a DC/DC converter that converters low dc voltages produced by the PV array to a high dc voltage, an inverter that converts the high dc voltage to a single or three-phase ac voltage and a digital controller that controls the system and implement the MPPT algorithm by controlling the current and voltage of the PV array. The MPPT algorithm is vital in increasing the efficiency of the system. A 1KW prototyping PV system was implemented with a boost dc-dc converter using a DSP controller to execute the proposed MPPT algorithm. Different hill-climbing MPPT algorithms were tested for fast changing environmental conditions, and the test results are analyzed and compared. It is demonstrated that the EPP method is a promising MPPT control scheme for residential PV systems.
Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking ... more Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking the maximum power point since their power-voltage characteristics are complex and may have multiple local maxima. For this reason, conventional techniques fail to track the maximum power point effectively if the PV array is partially shaded or some of its cells are damaged. This paper presents a novel power compensation system for PV arrays for complicated non-uniform insolation conditions. The proposed system is based on recovering the power of non-shaded PV modules into the system again completely by forward biasing a bypass diode of the shaded PV modules. For this purpose, the proposed system uses dc-dc converters equipped with each PV string in the PV array. For identifying which shaded PV modules should be deactivated, the operating voltage of the PV modules are monitored and compared. The proposed system enables the non-shaded PV modules to operate effectively at their normal maximum power point. The effectiveness of the proposed system is investigated and confirmed for complicated partially shaded PV arrays.
This paper presents a neural network based approach for improving the accuracy of the electrical ... more This paper presents a neural network based approach for improving the accuracy of the electrical equivalent circuit of a photovoltaic module. The equivalent circuit parameters of a PV module mainly depend on solar irradiation and temperature. The dependence on environmental factors of the circuit parameters is investigated by using a set of current-voltage curves. It is shown that the relationship between them is nonlinear and cannot be easily expressed by any analytical equation. Therefore, the neural network is utilized to overcome these difficulties. The neural network is trained once by using some measured current-voltage curves, and the equivalent circuit parameters are estimated by only reading the samples of solar irradiation and temperature very quickly without solving any nonlinear implicit equations that is necessary in conventional methods. To verify the proposed model, an experimental set up is installed. The comparison between the measured values and the proposed model results shows higher accuracy than the conventional model for all operating conditions.
Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as win... more Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as wind, hydrogen, solar, etc. have been utilized simultaneously. In order to avoid global warming caused by greenhouse gases, special legislation on energy use came into effect in 2003, ...
1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.... more 1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.tr 2Energy Research and Application Center, Pamukkale University, Denizli-Turkey mhekim@pau.edu.tr 3Energy Research and Application Center, ...
Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as win... more Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as wind, hydrogen, solar, etc. have been utilized simultaneously. In order to avoid global warming caused by greenhouse gases, special legislation on energy use came into effect in 2003, ...
1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.... more 1Energy Research and Application Center, Pamukkale University, Denizli-Turkey engincetin@pau.edu.tr 2Energy Research and Application Center, Pamukkale University, Denizli-Turkey mhekim@pau.edu.tr 3Energy Research and Application Center, ...
The aim of this study is to investigate the effects of non-uniform solar irradiation distribution... more The aim of this study is to investigate the effects of non-uniform solar irradiation distribution on energy output of different interconnected configurations in photovoltaic (PV) arrays. In order to find which configuration is less susceptible to mismatch effects, a PV module model is developed. This model can take into consideration the effects of bypass diodes and the variation of the equivalent circuit parameters with respect to operating conditions. The proposed model can provide sufficient degree of precision as well as solar cell-based analysis in analyzing large scale PV arrays without increasing the computational effort. In order to produce more reliable and robust simulations, improved and extended algorithms are presented. Some results are discussed in detail and some recommendations are extracted by testing several shading scenarios.
In this paper, it is aimed to deal with the interactions of harmonic currents produced by differe... more In this paper, it is aimed to deal with the interactions of harmonic currents produced by different single phase loads. For this purpose, compact fluorescent lamps, incandescent lamps, and electric heaters were chosen as single phase loads. The study was performed by adopting a full range of response surface methodology using Box-Behnken experimental design to express the net harmonic current (3rd and 5th) as an empirical model. The model provided an excellent explanation of the relationship among the number of loads and the net harmonic currents. Contour graphs of some of the harmonic currents was plotted to show the interactions clearly and to discuss the results of model in the graphic detail. The results of experiments showed that the harmonic interaction between the loads can be defined as a regression model which is statistically significant.
2007 International Conference on Intelligent Systems Applications to Power Systems, 2007
Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking ... more Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking maximum power point (MPP), since their power-voltage (P-V) characteristics are complex and may have multiple local maxima. For this reason, conventional techniques fail to track MPP effectively, if the PV array is partially shaded. This paper presents a novel power compensation and control system for PV arrays under complicated non-uniform insolation conditions. The proposed system is based on forward biasing bypass diode of shaded modules by monitoring dynamic resistance and voltage of PV modules. For this purpose, the proposed system is used DC/DC converter equipped with each PV string in PV array. The proposed system can identify which modules are shaded. The effectiveness of the proposed system is investigated and confirmed for complicated partially shaded PV array.
The aim of this study is to investigate the effects of non-uniform solar irradiation distribution... more The aim of this study is to investigate the effects of non-uniform solar irradiation distribution on energy output of different interconnected configurations in photovoltaic (PV) arrays. In order to find which configuration is less susceptible to mismatch effects, a PV module model is developed. This model can take into consideration the effects of bypass diodes and the variation of the equivalent circuit parameters with respect to operating conditions. The proposed model can provide sufficient degree of precision as well as solar cell-based analysis in analyzing large scale PV arrays without increasing the computational effort. In order to produce more reliable and robust simulations, improved and extended algorithms are presented. Some results are discussed in detail and some recommendations are extracted by testing several shading scenarios.
International Journal of Smart Grid and Clean Energy, 2013
This paper presents the practical implementation of the real-time Estimate-Perturb-Perturb (EPP) ... more This paper presents the practical implementation of the real-time Estimate-Perturb-Perturb (EPP) algorithm for maximum power point tracking (MPPT) control in a photovoltaic (PV) system. The PV system usually consists of: a PV array that converts solar energy to electrical energy, a DC/DC converter that converters low dc voltages produced by the PV array to a high dc voltage, an inverter that converts the high dc voltage to a single or three-phase ac voltage and a digital controller that controls the system and implement the MPPT algorithm by controlling the current and voltage of the PV array. The MPPT algorithm is vital in increasing the efficiency of the system. A 1KW prototyping PV system was implemented with a boost dc-dc converter using a DSP controller to execute the proposed MPPT algorithm. Different hill-climbing MPPT algorithms were tested for fast changing environmental conditions, and the test results are analyzed and compared. It is demonstrated that the EPP method is a promising MPPT control scheme for residential PV systems.
Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking ... more Partially shaded photovoltaic (PV) modules typically exhibit additional difficulties in tracking the maximum power point since their power-voltage characteristics are complex and may have multiple local maxima. For this reason, conventional techniques fail to track the maximum power point effectively if the PV array is partially shaded or some of its cells are damaged. This paper presents a novel power compensation system for PV arrays for complicated non-uniform insolation conditions. The proposed system is based on recovering the power of non-shaded PV modules into the system again completely by forward biasing a bypass diode of the shaded PV modules. For this purpose, the proposed system uses dc-dc converters equipped with each PV string in the PV array. For identifying which shaded PV modules should be deactivated, the operating voltage of the PV modules are monitored and compared. The proposed system enables the non-shaded PV modules to operate effectively at their normal maximum power point. The effectiveness of the proposed system is investigated and confirmed for complicated partially shaded PV arrays.
This paper presents a neural network based approach for improving the accuracy of the electrical ... more This paper presents a neural network based approach for improving the accuracy of the electrical equivalent circuit of a photovoltaic module. The equivalent circuit parameters of a PV module mainly depend on solar irradiation and temperature. The dependence on environmental factors of the circuit parameters is investigated by using a set of current-voltage curves. It is shown that the relationship between them is nonlinear and cannot be easily expressed by any analytical equation. Therefore, the neural network is utilized to overcome these difficulties. The neural network is trained once by using some measured current-voltage curves, and the equivalent circuit parameters are estimated by only reading the samples of solar irradiation and temperature very quickly without solving any nonlinear implicit equations that is necessary in conventional methods. To verify the proposed model, an experimental set up is installed. The comparison between the measured values and the proposed model results shows higher accuracy than the conventional model for all operating conditions.
Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as win... more Renewable hybrid energy systems (RHESs) are the systems where the renewable energy sources as wind, hydrogen, solar, etc. have been utilized simultaneously. In order to avoid global warming caused by greenhouse gases, special legislation on energy use came into effect in 2003, ...
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