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A review of solid oxide fuel cell (SOFC) dynamic models / Debangsu Bhattacharyya in Industrial & engineering chemistry research, Vol. 48 N° 13 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6068–6086 Titre : A review of solid oxide fuel cell (SOFC) dynamic models Type de document : texte imprimé Auteurs : Debangsu Bhattacharyya, Auteur ; Raghunathan Rengaswamy, Auteur Année de publication : 2009 Article en page(s) : pp. 6068–6086 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : State-of-the-art  dynamic  models  Solid  oxide  fuel  cells  Dynamic  modeling Résumé : In this paper, state-of-the-art dynamic models for solid oxide fuel cells (SOFCs) in the open literature are reviewed. The review also includes the transient modeling of SOFC systems with reformers. In the transients of a SOFC, three characteristic time constants are observed. One of the challenges in transient modeling is to capture these characteristic times. The first characteristic time is on the order of milliseconds and is mostly neglected, because it is too small, from the viewpoint of practical applications. The second time constant is on the order of seconds and arises mainly because of the mass-transport dynamics. The third characteristic time is on the order of minutes or hours and is dependent on the energy transport characteristics of the system. These characteristic times are extremely system-specific and, therefore, must be identified on a case-to-case basis. In this paper, the existing literature on dynamic studies are reviewed, focusing mainly on the fidelity of the model that is required to capture these time constants. The dynamic modeling of SOFC is still not as rich as the steady-state modeling. Therefore, steady-state models are also reviewed, whenever required. The utility of the dynamic models in design, control, and operation is discussed. A dynamic model from the literature is chosen for this purpose. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801664j [article] A review of solid oxide fuel cell (SOFC) dynamic models [texte imprimé] / Debangsu Bhattacharyya, Auteur ; Raghunathan Rengaswamy, Auteur . - 2009 . - pp. 6068–6086. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 13 (Juillet 2009) . - pp. 6068–6086 Mots-clés : State-of-the-art  dynamic  models  Solid  oxide  fuel  cells  Dynamic  modeling Résumé : In this paper, state-of-the-art dynamic models for solid oxide fuel cells (SOFCs) in the open literature are reviewed. The review also includes the transient modeling of SOFC systems with reformers. In the transients of a SOFC, three characteristic time constants are observed. One of the challenges in transient modeling is to capture these characteristic times. The first characteristic time is on the order of milliseconds and is mostly neglected, because it is too small, from the viewpoint of practical applications. The second time constant is on the order of seconds and arises mainly because of the mass-transport dynamics. The third characteristic time is on the order of minutes or hours and is dependent on the energy transport characteristics of the system. These characteristic times are extremely system-specific and, therefore, must be identified on a case-to-case basis. In this paper, the existing literature on dynamic studies are reviewed, focusing mainly on the fidelity of the model that is required to capture these time constants. The dynamic modeling of SOFC is still not as rich as the steady-state modeling. Therefore, steady-state models are also reviewed, whenever required. The utility of the dynamic models in design, control, and operation is discussed. A dynamic model from the literature is chosen for this purpose. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801664j

System identification and nonlinear model predictive control of a solid oxide fuel cell / Debangsu Bhattacharyya in Industrial & engineering chemistry research, Vol. 49 N° 10 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4800–4808 Titre : System identification and nonlinear model predictive control of a solid oxide fuel cell Type de document : texte imprimé Auteurs : Debangsu Bhattacharyya, Auteur ; Raghunathan Rengaswamy, Auteur Année de publication : 2010 Article en page(s) : pp. 4800–4808 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nonlinear  system  Oxide  fuel  cell Résumé : Solid oxide fuel cells (SOFCs) are high temperature fuel cells with a strong potential for stationary power house applications. However, considerable challenges need to be overcome to connect these cells to the power grid. The fluctuating grid demand has to be met without sacrificing the cell efficiency and causing structural/material damage to the system. This requirement coupled with fast and highly nonlinear transients of the transport variables results in a challenging control problem. This paper is on synthesizing a controller that can address some of these challenges. For using in the model predictive controller (MPC), input−output models are identified from the data generated by a detailed dynamic model. A traditional SISO control and a novel MIMO control are considered here. In the SISO control problem, power is the controlled variable (CV) and H2 flow is the manipulated variable (MV). In the MIMO control problem, power and the utilization factor (UF) of the fuel are the CVs while voltage and the flow of H2 are the MVs. The identification study shows that the nonlinear NAARX models with properly chosen cross terms can improve the model performance significantly in a MIMO problem. The results from the control study indicate that a well-tuned proportional−integral−derivative (PID) controller is sufficient for the single input single output (SISO) power control of a tubular SOFC. It also shows that the mutiple input multiple output (MIMO) control of power and the UF is highly interactive and necessitates a nonlinear model predictive controller (NMPC). Without using any additional hardware such as an ultracapacitor or battery pack, the designed NMPC could satisfy a step change in load with acceptable overshoot in power and the UF. A well-tuned PID controller is found to perform poorly for the MIMO problem. On the basis of these findings, future work will focus on the development of nonlinear predictive control approaches for stack-level control of tubular solid oxide fuel cells. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020254 [article] System identification and nonlinear model predictive control of a solid oxide fuel cell [texte imprimé] / Debangsu Bhattacharyya, Auteur ; Raghunathan Rengaswamy, Auteur . - 2010 . - pp. 4800–4808. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 10 (Mai 2010) . - pp. 4800–4808 Mots-clés : Nonlinear  system  Oxide  fuel  cell Résumé : Solid oxide fuel cells (SOFCs) are high temperature fuel cells with a strong potential for stationary power house applications. However, considerable challenges need to be overcome to connect these cells to the power grid. The fluctuating grid demand has to be met without sacrificing the cell efficiency and causing structural/material damage to the system. This requirement coupled with fast and highly nonlinear transients of the transport variables results in a challenging control problem. This paper is on synthesizing a controller that can address some of these challenges. For using in the model predictive controller (MPC), input−output models are identified from the data generated by a detailed dynamic model. A traditional SISO control and a novel MIMO control are considered here. In the SISO control problem, power is the controlled variable (CV) and H2 flow is the manipulated variable (MV). In the MIMO control problem, power and the utilization factor (UF) of the fuel are the CVs while voltage and the flow of H2 are the MVs. The identification study shows that the nonlinear NAARX models with properly chosen cross terms can improve the model performance significantly in a MIMO problem. The results from the control study indicate that a well-tuned proportional−integral−derivative (PID) controller is sufficient for the single input single output (SISO) power control of a tubular SOFC. It also shows that the mutiple input multiple output (MIMO) control of power and the UF is highly interactive and necessitates a nonlinear model predictive controller (NMPC). Without using any additional hardware such as an ultracapacitor or battery pack, the designed NMPC could satisfy a step change in load with acceptable overshoot in power and the UF. A well-tuned PID controller is found to perform poorly for the MIMO problem. On the basis of these findings, future work will focus on the development of nonlinear predictive control approaches for stack-level control of tubular solid oxide fuel cells. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9020254