Backstepping Control Design For Turbine Steam Valve With Multiple State Constraints

With the rapid development of economy in our country, the power industry, as thefoundation of industries, has also developed dramatically. Power systems have becomemultidimensional, strongly nonlinear, high complecity and large scale system. Thereby somedynamic problems which could threaten the operation of power systems in safe and stablemode are increased. If power systems don’t work properly, national economy and people’slife will suffer a great loss. Therefore, The design of efficient and advanced control system toimprove the power systems security and economy has become one of the important problemsin the study of power systems.In this thesis, the transient stability control of the turbine speed control system areaddressed with an approach based on the Lyapunov theory and backstrpping method. First ofall, considerding that rotor speed ω and mechanical power of high pressure cylinder PHof theturbine speed control system are with restrictions in the actual operation, the backsteppingmethod and barrier Lyapunov function are used to design the nonlinear controller of mainsteam valve. The controller can guarantee the stability of the closed-loop system, and as longas the initial value of the state satisfies certain condition, the change value of the state will notgo beyond its restriction. On secondly, with the uncertain damping coefficient D caused by inaccurate measurement is very difficult, a nonlinear adaptive controller was designed based onadaptive backstepping method. Thirdly, on the basis of previous achievements, a modifiedadaptive backstepping method was proposed based on the controller gain and transientresponse. The two important performance indicators of the controller gain and response speedare improved by using K-class function. At last, the results of the theoretical design areverified by simulation.