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Multivariable control of an industrial boiler-turbine unit with nonlinear model: A comparison between gain scheduling and feedback linearization approaches

Moradi, H ; Sharif University of Technology | 2013

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  1. Type of Document: Article
  2. Publisher: Sharif University of Technology , 2013
  3. Abstract:
  4. Due to demands for the economical operations of power plants and environmental awareness, performance control of a boiler-turbine unit is of great importance. In this paper, a nonlinear Multi Input-Multi Output model (MIMO) of a utility boilerturbine unit is considered. Drum pressure, generator electric output and drum water level (as the output variables) are controlled by manipulation of valves position for fuel, feedwater and steam flows. After state space representation of the problem, two controllers, based on gain scheduling and feedback linearization, are designed. Tracking performance of the system is investigated and discussed for three cases of 'near', 'far' and 'so far' setpoints. According to the results obtained, using feedback linearization approach leads to more quick time responses with a bit more overshoots (in comparison with the gain scheduling method). In addition, in feedback linearization strategy, input control signals (valves position) are actuated in less time with less oscillations. It is observed that in the presence of an arbitrary random uncertainty in model parameters, the controller designed based on feedback linearization is more robust. Finally, according to the phase portraits of the problem, as the desired speed of tracking process is increased, dynamic system tends to demonstrate a chaotic behaviour
  5. Keywords:
  6. Boiler-turbine ; Nonlinear model ; Boilers ; Controllers ; Electric machine control ; Feedback ; Linearization ; MIMO systems ; Multivariable control systems ; Nonlinear feedback ; Nonlinear systems ; Scheduling ; State space methods ; Turbines ; Water levels ; Boiler turbines ; Environmental awareness ; Feedback linearization approaches ; Gain Scheduling ; Multi-input-multi-output models ; Multivariable control ; State space representation ; Feedback linearization ; Comparative study ; Control system ; Nonlinearity ; performance assessment ; power plant ; pressure gradient ; Tracking ; Turbine ; Uncertainty analysis ; Water level
  7. Source: Scientia Iranica ; Volume 20, Issue 5 , 2013 , Pages 1485-1498 ; 10263098 (ISSN)
  8. URL: http://www.scientiairanica.com/fa/ManuscriptDetail?mid=46