Documents disponibles écrits par cet auteur

Highly efficient high step-up converter for fuel-cell power processing based on three-state commutation cell / Araujo, Samuel Vasconcelos in IEEE transactions on industrial electronics, Vol. 57 N° 6 (Juin 2010) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 57 N° 6 (Juin 2010) . - pp. 1987 - 1997 Titre : Highly efficient high step-up converter for fuel-cell power processing based on three-state commutation cell Type de document : texte imprimé Auteurs : Araujo, Samuel Vasconcelos, Auteur ; Torrico-Bascope, René P., Auteur ; Torrico-Bascope, Grover V., Auteur Article en page(s) : pp. 1987 - 1997 Note générale : Génie électrique Langues : Anglais (eng) Mots-clés : DC-DC  Power  conversion  Fuel  cells Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : The interest toward the application of fuel cells is increasing in the last years mainly due to the possibility of highly efficient decentralized clean energy generation. The output voltage of fuel-cell stacks is generally below 50 V. Consequently, low-power applications with high output voltage require a high gain for proper operation. Several solutions were so far proposed in the literature, ranging from the use of high-frequency transformers to capacitive multipliers. This paper proposes the modification of a boost converter operating with a three-state commutation cell that is already well suited for high current stress in the input due to the current sharing between the active switches. Here, an additional winding is added to the autotransformer to provide not only the required high gain but also to significantly reduce the voltage stress across the active switches. Moreover, by employing the three-state switching cell, the size of the inductor is reduced because the operating frequency is double of the switching frequency. A prototype for the verification of the circuit was built for a 30-45-V input-voltage range, 400-V output voltage, and 250-W output power. The operation is evaluated, and the experimental waveforms and efficiency curves are presented. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5208314 [article] Highly efficient high step-up converter for fuel-cell power processing based on three-state commutation cell [texte imprimé] / Araujo, Samuel Vasconcelos, Auteur ; Torrico-Bascope, René P., Auteur ; Torrico-Bascope, Grover V., Auteur . - pp. 1987 - 1997. Génie électrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 57 N° 6 (Juin 2010) . - pp. 1987 - 1997 Mots-clés : DC-DC  Power  conversion  Fuel  cells Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : The interest toward the application of fuel cells is increasing in the last years mainly due to the possibility of highly efficient decentralized clean energy generation. The output voltage of fuel-cell stacks is generally below 50 V. Consequently, low-power applications with high output voltage require a high gain for proper operation. Several solutions were so far proposed in the literature, ranging from the use of high-frequency transformers to capacitive multipliers. This paper proposes the modification of a boost converter operating with a three-state commutation cell that is already well suited for high current stress in the input due to the current sharing between the active switches. Here, an additional winding is added to the autotransformer to provide not only the required high gain but also to significantly reduce the voltage stress across the active switches. Moreover, by employing the three-state switching cell, the size of the inductor is reduced because the operating frequency is double of the switching frequency. A prototype for the verification of the circuit was built for a 30-45-V input-voltage range, 400-V output voltage, and 250-W output power. The operation is evaluated, and the experimental waveforms and efficiency curves are presented. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5208314

Highly efficient single-phase transformerless inverters for grid-connected photovoltaic systems / Araujo, Samuel Vasconcelos in IEEE transactions on industrial electronics, Vol. 57 N° 9 (Septembre 2010) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 57 N° 9 (Septembre 2010) . - pp. 3118 - 3128 Titre : Highly efficient single-phase transformerless inverters for grid-connected photovoltaic systems Type de document : texte imprimé Auteurs : Araujo, Samuel Vasconcelos, Auteur ; Zacharias, Peter, Auteur ; Mallwitz, Regine, Auteur Année de publication : 2011 Article en page(s) : pp. 3118 - 3128 Note générale : Génie électrique Langues : Anglais (eng) Mots-clés : Photovoltaic  (PV)  power  systems  Pulsewidth-modulated  (PWM)  inverters Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : Driven by worldwide demand for renewable sources, the photovoltaic market saw in the last years a considerable amount of innovations regarding the construction and operation of inverters connected to the grid. One significant advance, among some that will be here discussed is, for example, the abolition of the galvanic isolation in inverters installed in Germany. There, transformerless topologies, like the H5 and Heric, can reach very high levels of efficiency and allow the best cost-benefit ratio for low-power grid-tied systems. This paper will follow this direction and propose a single-phase transformerless inverter circuit being composed of the association of two step-down converters. Each one modulates a half-wave of the output current, as the correct polarity of the connection to the grid is provided by low-frequency switches. Due to its straightforward design, reduced amount of semiconductors, and simple operation, it is possible to achieve a high level of efficiency and reliability. These and some other characteristics will be benchmarked against other existing circuits, being followed by a theoretical analysis on the properties of the proposed solution. The project of a laboratory prototype will be presented, along with a discussion about the obtained experimental results. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5345742 [article] Highly efficient single-phase transformerless inverters for grid-connected photovoltaic systems [texte imprimé] / Araujo, Samuel Vasconcelos, Auteur ; Zacharias, Peter, Auteur ; Mallwitz, Regine, Auteur . - 2011 . - pp. 3118 - 3128. Génie électrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 57 N° 9 (Septembre 2010) . - pp. 3118 - 3128 Mots-clés : Photovoltaic  (PV)  power  systems  Pulsewidth-modulated  (PWM)  inverters Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : Driven by worldwide demand for renewable sources, the photovoltaic market saw in the last years a considerable amount of innovations regarding the construction and operation of inverters connected to the grid. One significant advance, among some that will be here discussed is, for example, the abolition of the galvanic isolation in inverters installed in Germany. There, transformerless topologies, like the H5 and Heric, can reach very high levels of efficiency and allow the best cost-benefit ratio for low-power grid-tied systems. This paper will follow this direction and propose a single-phase transformerless inverter circuit being composed of the association of two step-down converters. Each one modulates a half-wave of the output current, as the correct polarity of the connection to the grid is provided by low-frequency switches. Due to its straightforward design, reduced amount of semiconductors, and simple operation, it is possible to achieve a high level of efficiency and reliability. These and some other characteristics will be benchmarked against other existing circuits, being followed by a theoretical analysis on the properties of the proposed solution. The project of a laboratory prototype will be presented, along with a discussion about the obtained experimental results. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5345742