Modified fuzzy adaptive PID algorithm and its application in power plant

The characteristics of thermal plant are nonlinearity, time variation and uncertainty during variable condition. It is difficult to obtain the satisfying control effect with traditional PID controller. In order to solve this problem, a modified fuzzy adaptive PID control algorithm is proposed in the paper. The method is attained by optimizing the traditional fuzzy PID control algorithm based on analysis of the thought of changing universe and online self-tuning. Under the premise of unchanging rules number, make whole universe changes in synchronization with error change, and online adjust the fuzzy PID parameters. So the fuzzy rules of proposed controller are online dynamic adjustment. A series of simulation are tested. The simulation results indicate that, compared with conventional PID control method, the proposed method can not only shorten the step input response time, but also have stronger adaptive capability to the unknown disturbance, parameter time variable character and nonlinear of the system. The proposed algorithm can obtain satisfactory dynamic and stationary performances.