Analysis and design of a robust coordinated AVR/PSS

A robust coordinated AVR/PSS, called the "desensitized four loops regulator" (DFLR) has been recently designed using the "desensitized control" theory. Its synthesis method (which can be applied to problems other than excitation control) and its structure are detailed in this paper. It is a state feedback controller including an integrator on the regulation error. This structure, although well known in the control community, is not usual for the excitation control of generators (except in France). Hence, in order to make this approach more widely applicable in an industrial point of view, this controller is placed, using approximations, in the standard AVR+PSS structure IEEE ST1A+PSS1A. The resulting AVR+PSS is proven to have good performance, in particular for damping inter-area oscillations.