Tuning a PID controller for a digital excitation control system

Some of the modern voltage regulator systems are utilizing the proportional, integral and derivative (PID) control for stabilization. Two PID tuning approaches, pole placement and pole-zero cancellation, are commonly utilized for commissioning a digital excitation system. Each approach is discussed including its performance with three excitation parameter variations. The parameters considered include system loop gain, uncertain exciter time constants, and forcing limits. This paper is intended for various engineers, and technicians to provide a better understanding of how the digital controller is tuned with the pros and cons for each method.