Damping improvement of an AC-DC interconnected system using a fuzzy logic coordinated modulation controller

Design of a fuzzy logic controller does not need an accurate model of the system. Qualitative knowledge about the system behaviour is adequate for designing the controller. This paper presents a fuzzy logic coordinated modulation controller for improving the damping of electromechanical oscillations of an AC-DC power system that consists of an HVDC scheme embedded in an interconnected four-area AC power system. The proposed controller coordinates the modulation of current in the DC link and generator excitation in the rectifier side AC system, in response to the frequency difference between the two ends of the DC line and DC current deviation. Simulation results revealed that a fuzzy logic coordinated modulation controller can be successfully implemented to improve the damping of electromechanical oscillations in an interconnected power system.