Analysis And Research On Coordinated Control System Of Boiler-turbine Unit Based On Internal Model Adaptive Control Algorithm

The coordinated control system(CCS) has many characters such as nonlinear, strong coupling, significant delay and parameters time varying. It is also a complicated MIMO control plant. Traditional coordinated control algorithms can't respond to the requests of the power network, which can not only make pressure maintain nearby the rating, but also adapt to change of the load in the electric network quickly. Based on the analysises above, the internal model adaptive control algorithm is proposed in the paper. During research and application, the internal model adaptive control algorithm is found to be of many advantages, such as excellent high robustness, servo performance, overcoming model uncertainty and parameters time varying.By the way the non-linear space of CCS is divided into many sub-spaces. Every sub-space has a responding sub-model, and every sub-model has a internal model controller. Finally an effective switch scheme of multiple models is designed. The paper focuses on the application of CCS, and then a multivariable nonlinear model of the boiler-turbine units is analyzed. Because of decoupling design is used in the paper, synthetical design of the multi-variable system is changed into design of a few single-variable systems separately. So calculation becomes very easy, and the control algorithm is easy to widely apply. The basic thought of switch scheme of multiple models is: firstly design internal model controllers separately and calculate their outputs according to each mathematical model and the given performance index; then design a weight controller which can determine the output weight of each internal model controller by calculating the posterior probability; finally the output of each controller multiplies its weight to take the actual total control output.Finally the internal model adaptive control algorithm is successfully applied into a 600MW coordinated control system based on its mathematical model. The results of simulation show that the internal model adaptive control algorithm in the paper has sufficient capability for controling coordinated control system. So the new control algorithm supplies a new thought to research coordinated control system and has certain therory meaning and project using value.