Comparison of tuning methods for design of PID controller as an A VR

The primary means of generator reactive power control is the generator-excitation Control, using Automatic Voltage Regulator (A VR). The role of A VR is to hold the terminal voltage magnitude of Synchronous generator at a specified level. This paper presents the design of a proportional integral-derivative (PID) controller as an A VR. The PID controller has been tuned by various tuning methods. From all methods, PID parameters are computed through various techniques i.e. Process-reaction curve, Closed-loop system, open-loop system gain margin and phase-margin specifications. From these methods, it has been found that Zhaung- Atherton method and Ho, Hang and Cao method are much superior to the conventional Ziegler-Nichols rules. The performance of the controller has been evaluated through Simulation Studies in MATLAB environment. It has been demonstrated that the PID controller, tuned with the said methods, yields highly satisfactory closed-loop performance. (author)