T. Das

Rochester Institute of Technology, Rochester, NY, United States

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Publications (6)2 Total impact

  • Source
    T. Allag, T. Das
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    ABSTRACT: Mitigating fuel starvation and improving load-following capability of solid oxide fuel cells (SOFC) are conflicting control objectives. In this paper, we address this issue using a hybrid SOFC ultracapacitor configuration. Fuel starvation is prevented by regulating the fuel cell current using a steady-state invariant relationship involving fuel utilization, fuel flow, and current. Two comprehensive control strategies are developed. The first is a Lyapunov-based nonlinear control and the second is a standard H <sub>∞</sub> robust control. Both strategies additionally control the state of charge of the ultracapacitor that provides transient power compensation. A hardware-in-the-loop test stand is developed where the proposed control strategies are verified.
    IEEE Transactions on Control Systems Technology 02/2012; · 2.00 Impact Factor
  • Source
    Tahar Allag, Tuhin Das
    IEEE Trans. Contr. Sys. Techn. 01/2012; 20:1-10.
  • Source
    T. Das, S. Snyder
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    ABSTRACT: Solid oxide fuel cells (SOFCs) offer a number of advantages beyond those of most other fuel cells. However, like other fuel cells, rapid load following is difficult, and can lead to fuel starvation and consequently fuel cell damage. Mitigating fuel starvation and improving load following capabilities are conflicting control objectives. However, the issue can be addressed by the hybridization of the system with an energy storage device. A steady-state utilization property, combined with a current regulation strategy, is used to manage transient fuel utilization. Meanwhile, an overall system strategy is employed to manage energy sharing in the hybrid system for load following as well as for maintaining the state-of-charge of the energy storage device. This work presents an adaptive strategy which updates the controller based on current parameter estimates. The control design is validated on a hardware-in the-loop setup and experimental results are provided.
    American Control Conference (ACC), 2011; 08/2011
  • Source
    T. Allag, T. Das
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    ABSTRACT: In this paper we design robust control strategies for a hybrid solid oxide fuel cell ultra-capacitor system. Fuel cell control is established by using an invariant property of fuel utilization within an input-shaping framework. Two control strategies are developed. The first design uses a nonlinear control approach for which we prove the stability of the closed-loop system in presence of system uncertainties. The second uses a standard H<sub>∞</sub> robust control approach. Both strategies enforce the control of State of Charge (SOC) of the ultra-capacitor to a desired level. A hardware-in-the-loop test-stand is developed and experimental results are provided.
    American Control Conference (ACC), 2010; 08/2010
  • Source
    T. Das
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    ABSTRACT: In this paper we present an observer design for species concentration estimation in recirculation based solid oxide fuel cell systems. The proposed strategy is useful for sensor reduction and control. In designing the observer, we attempt to reduce the number of required concentration sensors, that are often less reliable and also expensive, and instead use readily available voltage. We design a nonlinear adaptive observer based on voltage measurement that is an improvement upon our prior results. For this observer, we prove ultimate boundedness of state and parameter estimation errors with arbitrarily small error bounds.
    American Control Conference, 2009. ACC '09.; 07/2009
  • Source
    T. Das, R. Weisman
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    ABSTRACT: Solid oxide fuel cells are attractive energy conversion devices due to their fuel flexibility and high efficiency. Fuel utilization is a critical variable in SOFC systems that directly impacts efficiency and longevity. In this paper we propose a control strategy for mitigating drastic fluctuations in fuel utilization that arise during load transients. The strategy uses a feedback based dynamic input shaping approach. A preliminary control law derived from a model-based analysis forms the basis of this design. The strategy requires one fuel flow sensor upstream of the integrated fuel processor and admits convenient integration into a comprehensive hybrid fuel cell control algorithm.
    American Control Conference, 2009. ACC '09.; 07/2009

Publication Stats

8 Citations
5 Downloads
413 Views
2.00 Total Impact Points

Institutions

  • 2009–2012
    • Rochester Institute of Technology
      • • Department of Electrical and Microelectronic Engineering
      • • Department of Mechanical Engineering
      Rochester, NY, United States
  • 2011
    • University of Central Florida
      • Department of Mechanical and Aerospace Engineering
      Orlando, Florida, United States