Many power plants of big factories apply mother-tube units of parallel running steam boilers. These units have different operation form and control way with Unit generating units. Moreover, the automation control level of these generating units also is lower than Unit generating units. As a matter of fact, except drum water level, many other important parameters such as main steam temperature, main steam tube pressure and so on, can not be controlled automatically for a long time because of some reasons. All these problems are disadvantage of secure, steady and economical operation of generating units. This dissertation was finished based on the project "Computer control system of thermal process of boiler of mother-tube units ". As to typical thermal process of boiler of mother-tube units, problems appearing in implementation of automation control are illustrated. In order to solve these problems, according to characteristic of control, advanced control strategies are introduced and applied to the locale .The contents of the paper include two parts: (1) Automation control system of combustion process in mother-tube units boiler. Analysis of the reasons causing inside and outside disturbances of the combustion process, for counteracting the disturbances, cascade control method with feedforward and parameters of load assignment is applied to fuel control, and thermal energy signal substitute for fuel signal to counteract the inside disturbance; Smith predictor control strategy can counteract the problem of time delay of mother-tube pressure; A identification method called First Order Plus Dead Time can identify the model of mother-tube pressure and make the parameters of the Smith predictor more precise. (2) Automation control of super-heated steam temperature. Through discriminating differences among various kinds of control strategies and being acquaint with the development status of automation control about super-heated steam temperature, problems in realizing control of super-heated steam temperature are analyzed. For solving the problems, integrating fuzzy controller with cascade control method, cascade control method with Fuzyy-PI combined control structure is proposed and implemented. The dissertation, which is finished on the basis of practical project, means to solve the difficulties confronted in mother-tube set thermal process control and improve automation level. Control strategies mentioned above are all applied in real control system and testified in practical locale, and the quality is appreciated by customers.
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