Documents disponibles écrits par cet auteur

MATLAB-based modeling to study the effects of partial shading on PV array characteristics / Patel, H. in IEEE transactions on energy conversion, Vol. 23 N°1 (Mars 2008) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 23 N°1 (Mars 2008) . - pp. 302 - 310 Titre : MATLAB-based modeling to study the effects of partial shading on PV array characteristics Type de document : texte imprimé Auteurs : Patel, H., Auteur ; Agarwal, V., Auteur Année de publication : 2008 Article en page(s) : pp. 302 - 310 Note générale : Energy conversion Langues : Anglais (eng) Mots-clés : DC-DC  power  convertors;  distributed  power  generation;  mathematics  computing;  photovoltaic  power  systems;  solar  cell  arrays Résumé : The performance of a photovoltaic (PV) array is affected by temperature, solar insolation, shading, and array configuration. Often, the PV arrays get shadowed, completely or partially, by the passing clouds, neighboring buildings and towers, trees, and utility and telephone poles. The situation is of particular interest in case of large PV installations such as those used in distributed power generation schemes. Under partially shaded conditions, the PV characteristics get more complex with multiple peaks. Yet, it is very important to understand and predict them in order to extract the maximum possible power. This paper presents a MATLAB-based modeling and simulation scheme suitable for studying the I-V and P-V characteristics of a PV array under a nonuniform insolation due to partial shading. It can also be used for developing and evaluating new maximum power point tracking techniques, especially for partially shaded conditions. The proposed models conveniently interface with the models of power electronic converters, which is a very useful feature. It can also be used as a tool to study the effects of shading patterns on PV panels having different configurations. It is observed that, for a given number of PV modules, the array configuration (how many modules in series and how many in parallel) significantly affects the maximum available power under partially shaded conditions. This is another aspect to which the developed tool can be applied. The model has been experimentally validated and the usefulness of this research is highlighted with the help of several illustrations. The MATLAB code of the developed model is freely available for download. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4453994&sortType%3Das [...] [article] MATLAB-based modeling to study the effects of partial shading on PV array characteristics [texte imprimé] / Patel, H., Auteur ; Agarwal, V., Auteur . - 2008 . - pp. 302 - 310. Energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 23 N°1 (Mars 2008) . - pp. 302 - 310 Mots-clés : DC-DC  power  convertors;  distributed  power  generation;  mathematics  computing;  photovoltaic  power  systems;  solar  cell  arrays Résumé : The performance of a photovoltaic (PV) array is affected by temperature, solar insolation, shading, and array configuration. Often, the PV arrays get shadowed, completely or partially, by the passing clouds, neighboring buildings and towers, trees, and utility and telephone poles. The situation is of particular interest in case of large PV installations such as those used in distributed power generation schemes. Under partially shaded conditions, the PV characteristics get more complex with multiple peaks. Yet, it is very important to understand and predict them in order to extract the maximum possible power. This paper presents a MATLAB-based modeling and simulation scheme suitable for studying the I-V and P-V characteristics of a PV array under a nonuniform insolation due to partial shading. It can also be used for developing and evaluating new maximum power point tracking techniques, especially for partially shaded conditions. The proposed models conveniently interface with the models of power electronic converters, which is a very useful feature. It can also be used as a tool to study the effects of shading patterns on PV panels having different configurations. It is observed that, for a given number of PV modules, the array configuration (how many modules in series and how many in parallel) significantly affects the maximum available power under partially shaded conditions. This is another aspect to which the developed tool can be applied. The model has been experimentally validated and the usefulness of this research is highlighted with the help of several illustrations. The MATLAB code of the developed model is freely available for download. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4453994&sortType%3Das [...]

MPPT scheme for a PV-fed single-phase single-stage grid-connected inverter operating in CCM with only one current sensor / Patel, H. in IEEE transactions on energy conversion, Vol. 24 N°1 (Mars 2009) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 24 N°1 (Mars 2009) . - pp. 256 - 263 Titre : MPPT scheme for a PV-fed single-phase single-stage grid-connected inverter operating in CCM with only one current sensor Type de document : texte imprimé Auteurs : Patel, H., Auteur ; Agarwal, V., Auteur Année de publication : 2009 Article en page(s) : pp. 256 - 263 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : Electric  sensing  devices;  invertors;  photovoltaic  power  systems;  power  grids Résumé : The cost and efficiency of a photovoltaic (PV)-based grid-connected system depends upon the number of components and stages involved in the power conversion. This has led to the development of several single-stage configurations that can perform voltage transformation, maximum power point tracking (MPPT), inversion, and current shaping-all in one stage. Such configurations would usually require at least a couple of current and voltage sensors and a relatively complex control strategy. With a view to minimize the overall cost and control complexity, this paper presents a novel MPPT scheme with reduced number of sensors. The proposed scheme is applicable to any single-stage, single-phase grid-connected inverter operating in continuous conduction mode (CCM). The operation in CCM is desirable as it drastically reduces the stress on the components. Unlike other MPPT methods, which sense both PV array's output current and voltage, only PV array's output voltage is required to be sensed to implement MPPT. Only one current sensor is used for shaping the buck-boost inductor current as well as for MPPT. The information about power output of the array is obtained indirectly from array's voltage and the inductor current amplitude. Detailed analysis and the flowchart of the algorithm for the proposed scheme are included. Simulation and experimental results are also presented to highlight the usefulness of the scheme. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4783113&sortType%3Das [...] [article] MPPT scheme for a PV-fed single-phase single-stage grid-connected inverter operating in CCM with only one current sensor [texte imprimé] / Patel, H., Auteur ; Agarwal, V., Auteur . - 2009 . - pp. 256 - 263. energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 24 N°1 (Mars 2009) . - pp. 256 - 263 Mots-clés : Electric  sensing  devices;  invertors;  photovoltaic  power  systems;  power  grids Résumé : The cost and efficiency of a photovoltaic (PV)-based grid-connected system depends upon the number of components and stages involved in the power conversion. This has led to the development of several single-stage configurations that can perform voltage transformation, maximum power point tracking (MPPT), inversion, and current shaping-all in one stage. Such configurations would usually require at least a couple of current and voltage sensors and a relatively complex control strategy. With a view to minimize the overall cost and control complexity, this paper presents a novel MPPT scheme with reduced number of sensors. The proposed scheme is applicable to any single-stage, single-phase grid-connected inverter operating in continuous conduction mode (CCM). The operation in CCM is desirable as it drastically reduces the stress on the components. Unlike other MPPT methods, which sense both PV array's output current and voltage, only PV array's output voltage is required to be sensed to implement MPPT. Only one current sensor is used for shaping the buck-boost inductor current as well as for MPPT. The information about power output of the array is obtained indirectly from array's voltage and the inductor current amplitude. Detailed analysis and the flowchart of the algorithm for the proposed scheme are included. Simulation and experimental results are also presented to highlight the usefulness of the scheme. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4783113&sortType%3Das [...]

A single-stage single-phase transformer-less doubly grounded grid-connected PV interface / Patel, H. in IEEE transactions on energy conversion, Vol. 24 N°1 (Mars 2009) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 24 N°1 (Mars 2009) . - pp. 93 - 101 Titre : A single-stage single-phase transformer-less doubly grounded grid-connected PV interface Type de document : texte imprimé Auteurs : Patel, H., Auteur ; Agarwal, V., Auteur Année de publication : 2009 Article en page(s) : pp. 93 - 101 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : Earthing;  harmonic  distortion;  invertors;  photovoltaic  power  systems;  power  grids;  tracking Résumé : A transformer provides galvanic isolation and grounding of the photovoltaic (PV) array in a PV-fed grid-connected inverter. Inclusion of the transformer, however, may increase the cost and/or bulk of the system. To overcome this drawback, a single-phase, single-stage [no extra converter for voltage boost or maximum power point tracking (MPPT)], doubly grounded, transformer-less PV interface, based on the buck-boost principle, is presented. The configuration is compact and uses lesser components. Only one (undivided) PV source and one buck-boost inductor are used and shared between the two half cycles, which prevents asymmetrical operation and parameter mismatch problems. Total harmonic distortion and DC component of the current supplied to the grid is low, compared to existing topologies and conform to standards like IEEE 1547. A brief review of the existing, transformer-less, grid-connected inverter topologies is also included. It is demonstrated that, as compared to the split PV source topology, the proposed configuration is more effective in MPPT and array utilization. Design and analysis of the inverter in discontinuous conduction mode is carried out. Simulation and experimental results are presented. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4781557&sortType%3Das [...] [article] A single-stage single-phase transformer-less doubly grounded grid-connected PV interface [texte imprimé] / Patel, H., Auteur ; Agarwal, V., Auteur . - 2009 . - pp. 93 - 101. energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 24 N°1 (Mars 2009) . - pp. 93 - 101 Mots-clés : Earthing;  harmonic  distortion;  invertors;  photovoltaic  power  systems;  power  grids;  tracking Résumé : A transformer provides galvanic isolation and grounding of the photovoltaic (PV) array in a PV-fed grid-connected inverter. Inclusion of the transformer, however, may increase the cost and/or bulk of the system. To overcome this drawback, a single-phase, single-stage [no extra converter for voltage boost or maximum power point tracking (MPPT)], doubly grounded, transformer-less PV interface, based on the buck-boost principle, is presented. The configuration is compact and uses lesser components. Only one (undivided) PV source and one buck-boost inductor are used and shared between the two half cycles, which prevents asymmetrical operation and parameter mismatch problems. Total harmonic distortion and DC component of the current supplied to the grid is low, compared to existing topologies and conform to standards like IEEE 1547. A brief review of the existing, transformer-less, grid-connected inverter topologies is also included. It is demonstrated that, as compared to the split PV source topology, the proposed configuration is more effective in MPPT and array utilization. Design and analysis of the inverter in discontinuous conduction mode is carried out. Simulation and experimental results are presented. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4781557&sortType%3Das [...]