| The super-heated steam temperature is the maximum temperature in the whole steam channels in the process of thermodynamic engineering in power plant. If the steam temperature is too high or too low, it will bring on dangerous factors. We must control the super-heated steam temperature of the output of the super-heated implement to some required range. The steam temperature object is a multi-container element. Its dead time and time constant is relatively big. It has many disturbances. Its object model is not confirmable. It is not easy to measure steam temperature in the super-heated implement. It is the most difficult control system in the thermodynamic automatic control systems.According to the above features of super-heated temperature, there are two aspects study in this dissertation. On the one hand, system dynamic characteristics will be changed by state feedback. But it is difficult to take the state variable of the super heated implement. A design method of state observer with the dead time delay is studied in the dissertation. On the other hand, the application of Fuzzy-PI composite control in the super-heated steam temperature system of power plant is primarily studied by the fully use of both the good dynamic characteristics of fuzzy control and eliminating static deviation of PI control. In order to adapting the change of work condition and disturbances, an adjusting mothod of scale factor of fuzzy controller is studied. Simulation is done by application of MATLAB software. The results of simulation indicate that while the quantizing factor and the scale factor of fuzzy controller vary with real condition, the control system will have powerful anti-disturbance capacity and adaptability. |
PDF Full Text Request