Multivariable robust regulation of an industrial boiler-turbine with model uncertainties

Efficient robust control methods are required to keep the boiler-turbine unit performance appropriately. In this paper, a hybrid multivariable robust control strategy including the regulator and observer is designed to improve the performance of an industrial boiler-turbine unit. In the nonlinear model of the process, output variables including the drum pressure, electric power and water level of the drum are controlled at the desired set-points by manipulation of the fuel, steam, and feed-water flow rates. Due to economic and technical reasons and for the estimation of process states, the full-order observer is designed. For disturbance rejection and process stability, a regulator system is used. The performance of the hybrid control system is investigated in the presence of model uncertainties for two cases. For the regulation purpose, the dynamic system of Case I shows a more smooth variation of drum water level. Finally, it is observed that in the presence of model uncertainties, the hybrid control system guarantees the robust stability and performance of the process in estimation and regulation objectives. Implementation of the above proposed control law in its related electronic circuit of the boiler-turbine will be considered as the future stage of the current research.

[1]  Hamed Moradi,et al.  Design & application of adaptive variable structure & H∞ robust optimal schemes in nonlinear control of boiler-turbine unit in the presence of various uncertainties , 2018 .

[2]  Pang-Chia Chen.  Multi-objective control of nonlinear boiler-turbine dynamics with actuator magnitude and rate constraints. , 2013, ISA transactions.

[3]  Chunjiang Qian,et al.  Model development, state estimation, and controller design of a nonlinear utility boiler system , 2008, 2008 IEEE International Conference on Industrial Technology.

[4]  Sabrina Eberhart.  Linear Control System Analysis And Design Conventional And Modern , 2016 .

[5]  V. I. Kouprianov,et al.  Modeling the effects of operating conditions on fuel and environmental costs for a 310 MW boiler firing fuel oil , 2004 .

[6]  Rahmat-Allah Hooshmand,et al.  A coordinated MIMO control design for a power plant using improved sliding mode controller. , 2014, ISA transactions.

[7]  Karl Johan Åström,et al.  Dynamic Models for Boiler-Turbine Alternator Units : Data Logs and Parameter Estimation for a 160 MW Unit , 1987 .

[8]  Jeff S. Shamma,et al.  Gain-scheduled ℓ1-optimal control for boiler-turbine dynamics with actuator saturation , 2004 .

[9]  Benito R. Fernandez,et al.  Boiler system identification using sparse neural networks , 1993 .

[10]  Xiao Wu,et al.  Hierarchical optimization of boiler–turbine unit using fuzzy stable model predictive control , 2014 .

[11]  Jiong Shen,et al.  GA-based nonlinear predictive switching control for a boiler-turbine system , 2012 .

[12]  Firooz Bakhtiari-Nejad,et al.  Robust control of an industrial boiler system; a comparison between two approaches: Sliding mode control & H∞ technique , 2009 .

[13]  Xiaobing Kong,et al.  Nonlinear fuzzy model predictive iterative learning control for drum-type boiler–turbine system , 2013 .

[14]  Aaron Hussey,et al.  Simultaneous gains tuning in boiler/turbine PID-based controller clusters using iterative feedback tuning methodology. , 2012, ISA transactions.

[15]  Jorge L. Moiola,et al.  Model of a once - through boiler for dynamic studies , 1994 .

[16]  Chunjiang Qian,et al.  Real-time optimal control of a boiler-turbine system using pseudospectral methods , 2009 .

[17]  Gholamreza Vossoughi,et al.  Multivariable robust adaptive sliding mode control of an industrial boiler-turbine in the presence of modeling imprecisions and external disturbances: A comparison with type-I servo controller. , 2015, ISA transactions.

[18]  K. L. Lo,et al.  Modelling and state estimation of power plant steam turbines , 1990 .

[19]  Stefano Bracco,et al.  A simple dynamic model and stability analysis of a steam boiler drum , 2009 .

[20]  Ali Ghaffari,et al.  Thermodynamic modeling based optimization for thermal systems in heat recovery steam generator during cold start-up operation , 2014 .

[21]  John D'Azzo,et al.  Linear Control System Analysis and Design: Conventional and Modern , 1977 .

[22]  Xiao Wu,et al.  Data-Driven Modeling and Predictive Control for Boiler–Turbine Unit , 2013, IEEE Transactions on Energy Conversion.