| Hydraulic turbine governing system is an important part of hydropower plants. Generally speaking, a typical hydropower plant is made up of the reservoir, water tunnel, surge tank, penstock, hydraulic turbine, speed governor, generator, and grid. Due to the water inertia, column compressibility and penstock-wall elasticity, the hydro-turbine governing system has a series of significant nonlinear characteristics. For the hydropower plant with long conduits, the elastic water hammer occurrence in penstock can cause major problems to hydraulic turbine. In this dissertation, the sliding mode control for hydraulic turbine governing system based on elastic water hammer is studied. The content of the research includes the following five parts:1. A detailed comment on the present development of hydraulic turbine governing system is given, and the problems of hydraulic turbine governing system are analyzed. Then, the objective of this dissertation is proposed.2. Under the assumption of elastic water hammer, a nonlinear mathematical model of hydraulic turbine governing system is built, and hydraulic turbine governing system of non-linear characteristics is analyzed in detailed.3. A sliding mode control approach is proposed based on the hydraulic turbine governing system. The design steps and the principle of choosing parameters are given. Also theoretically analyses are presented to prove all the sliding mode surfaces are asymptotically stable.4. In view of the uncertainty problem, based on neural network compensation fuzzy sliding mode control and integral sliding mode control are proposed. The structure of controller and selection principles of parameters are introduced in detail, and stability of the system is analyzed, the simulation results show that this method can effectively improve the dynamic characteristics of the system;5. The main conclusions are summarized and the possible avenues of further issues about the control methods for hydro-turbine governing systems are addressed. |
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