Design of Coal Quality Disturbance Free System for Coordinated Control System Based on Gain Scheduling
The economic and stable operation was affected seriously by coal quality disturbance for power plants. Based on model analysis, influence of the disturbance can be considered as gain change of control system. Power capability coefficient of coal was constructed to inhibit it. Accuracy of the coefficient was verified by operating data. Then coal quality disturbance free system based on gain scheduling was designed for coordinated control system. Simulation showed that, the strategy improved control quality obviously, and inhibited the coal quality disturbance. Keywords—coordinate control system, coal quality disturbance, energy coefficient of coal quality, gain scheduling
GAIN SCHEDULED SERVO SYSTEM FOR BOILER-TURBINE UNIT
In this paper, a gain scheduled servo system is designed for a MIMO nonlinear boiler-turbine system whose parameters vary over a wide range. This gain scheduled control method linearizes the nonlinear system at several operating points. A servo system is designed for each operating point. These servo systems can guarantee good performance and stability at local operating points. A stability preserving interpolation method is deduced between operating points to guarantee the global stability. The condition for this interpolation and global stability is guaranteed by pole placement. This control system has good tracking property with zero steady-state error and can reject input disturbances. The controller works well even if some parameters change. The nonlinear simulation results show that this control system can work effectively over a wide region of operation.
Exponential stabilization of an axially moving string with geometrical nonlinearity by linear boundary feedback
This paper addresses the vibration suppression problem of an axially moving string using boundary control. Taking into account large transverse motion of the string via the second-order component of Lagrangian strain, a nonlinear oscillation equation is derived for the problem by employing the Hamilton's Principle. Direct Lyapunov method is then adopted to demonstrate that a linear boundary control of negative speed feedback ensures the vibration response of the moving string exponentially stable. The main contributions are a new stability condition in terms of controller gain parameter, and a detailed demonstration on the equilibrium condition at the boundary where the control is applied.