Design of robust controllers for HVDC links in AC-DC power systems

The paper presents the design of a very simple fuzzy logic controller for HVDC transmission links for fast stabilization of transient oscillations. The performance of this controller is compared with variable-structure and adaptive controllers for a variety of short-circuits and system operational changes. Unlike both adaptive and variable-structure controllers which require, at least functionally, an accurate model of the system dynamics, the fuzzy controller does not require a mathematical model of the system to estimate the control input under disturbances. The transient simulation studies presented in this paper reveal the superior performance of the simple fuzzy controller in damping out system transients.