Research On Marine Supercharged Boiler Combustion Control System

Supercharged boiler is a new stage of marine steam boiler development. It has many advantages, such as high reliability, economy, light weight, small size and big power. Supercharged boiler is the development direction of marine boiler.Supercharged boiler combustion control system is an important control system for steam power equipment. This system has large inertia and complex mathematical model, and has involute correlation between parameters and strong coupling relationship. Because of the complexity of the control system, it puts forward to higher requirement to control system, but also determines the complexity of the control system.Used supercharged boiler as the basis and combustion control system as research object, this paper mainly focuses on the following research work:First of all, comprehensively analyse supercharger boiler overall structure and combustion system constitute, and establish mathematic model for three big sub-system. Establish flue flow system model making use of flow characteristic equation; establish torque balance equation using Newton's second law, and then elicit mathematic model for air flow system; establish dynamic physical mechanism model for main steam pressure system using steam and water two-phase mass balance equation and energy balance equation and settle a certain of foundation for combustion control system research.Secondly, aming at the air flow system control difficulty of nonlinear, time-varying, design FUZZY-CMAC controller for air flow system and optimize FUZZY-CMAC control parameters using of time-varying genetic algorithm. This control strategy improves convergence speed of the algorithm and achieves good control effect. At the same time, design a PID controller for fuel flow system, which gains satisfied control result.Thirdly, put forwards to the combustion control system characterized by a variable offset and dual-crisscross amplitude limit based on FUZZY controller. The variable offset function plays an important role in amplitude limit process, the author optimizes and modifies the offset function making use of FUZZY controller. This method not only advances economical performance of control system, but also conquers the disadvantages of flue and air flow frequent change and making against of physical implementation in combustion control process.Finally, in view of the characteristics of large time delay, time-varying and nonlinear in main steam pressure control system, present y incremental stair-like generalized predictive control stategy based on CMAC neural network. This method combines CMAC andγincremental stair-like generalized predictive control commendably, and resolves well main steam pressure control difficulty of large time delay and possesses good robustness.