Analysis And Advanced Control Strategy Research Of Coordinated Control System In Power Unit

Coal-fired power generation is the main form in China. Facing the challenge of resource and environment, a kind of efficient and clean coal-fire technology is badly in need. Ultra supercritical unit combines high steam parameters and large capacity, which can not only improve the thermal efficiency but also reduce the coal consumption and pollutant emissions. Ultra supercritical unit is the future developing direction of the coal-fired power unit. As an important part of automatic generation control (AGC), coordinated control system (CCS) plays a vital role in safety and economical operation of power unit. The performance of CCS affects the operation of the whole unit, so CCS is the key to optimization for power unit.The thesis analyzes the dynamic performance of CCS and designs three different kinds of advanced control strategies for ultra supercritical unit. Ultra supercritical unit uses once-through boiler. By analyzing the dynamic performance of CCS, the characteristic of strong coupling and nonlinearity is summarized. Because of the control difficulty of CCS in ultra supercritical unit, the advanced control strategies are designed. Firstly, an improved predictive control algorithm is designed based on transfer function model. This method takes full advantage of predictive information. The simulation results show that the control algorithm can ensure the tracking speed and reduce the overshoot. In order to make state constraints and theoretical research easily, an extended state space predictive control is applied to ultra supercritical unit. It is easily to draw the conclusion that the control algorithm can track the set value and has the characteristic of anti-interference and robustness. Due to the strong nonlinearity of ultra supercritical unit, an internal model control based on feedback linearization is given. Through the feedback linearization, the nonlinear model is converted into a linear system. It comes to a result that the control strategy is effective for ultra supercritical unit.