IMC-PID controller design for power control loop based on closed-loop identification in the frequency domain

This paper proposes a closed-loop identification method for the design of a robust PID controller of the power control loop in the coordinated control system. The process model is firstly identified. In the identification procedure, set-point change tests are adopted to calculate the model based on process inputs and outputs in control loops. On the basis of process input and output data in the loop, the process frequency-response matrix is estimated, and then a transform function matrix is obtained by least square method. The robust PID controller of the power control loop is designed by using the internal model control (IMC) method based on the obtained model. It is shown that the IMC-PID controller maintains the robust performance and minimizes the effects of the external disturbance in power system or the internal disturbances in the power plant.