Constrained Optimization Based Robust PID Controller Design for Hydraulic Turbine Governing System

The characteristics of hydraulic turbine governing system change with operating conditions, therefore the governor must be capable of providing satisfactory control under different operating points. For this reason a design method of robust PID controller is proposed. The effects of the characteristic variations are defined as uncertainties in the system model, and based on this model, the requirements for fast dynamic response, strong robust stability and good disturbance rejection are analyzed. The PID gains are selected by optimization of the transient behaviors with constraints on the robustness to model uncertainties and the sensitivity to disturbances. In this way, the design problem is formulated into a constrained optimization problem. The performances of robust PID controller are evaluated by simulating the operation of a generating unit supplying an isolated load. The results show that, compared with traditional optimal PID controller, the robust PID controller produces better dynamic performance under the promise of ensuring system stability over the entire operating range.