Boiler DrumWater Level Control Based on Nonlinear Valve Characteristic Compensation

Maintaining the normal boiler drum water level is a necessary condition for stable operation of the unit. General boiler drum water level fluctuations do not exceed 30mm similar to 50mm range. Valve flow characteristics refers to the relationship between the valve flow and the valve opening. When the drum opening is controlled by adjusting the opening of the control valve, the non-linearity of the valve can affect the control quality of the control system. In this paper, by using matlab2013a to build a simulation model, the control of boiler drum water level based on nonlinear valve characteristics compensation is studied. According to the flow characteristics of non-linear valve, the compensator based on polynomial curve fitting method is designed to compensate the valve opening command. Simulation results verify the feasibility of this method.