Fuzzy Logic Controller Based on Voltage Source Converter-Hvdc System

264  Abstract— This paper suggests a Shrinking Span Membership function to be utilized in very fact changing system like VSC-HVDC system. The fast control capability of the VSC-HVDC and process of area mode oscillations are analyzed. An auxiliary Fuzzy Logic Controller designed in MATLAB/SIMULINK for the Voltage Source Converter based HVDC transmission system, to improve the stability by decreasing the deceleration energy of oscillation. VSC applications are not only used in HVDC but also includes in FACTS and Wind generators and Active filters. The VSC based HVDC system is very attractive an option for bulk power transmission over long or short distances and the grid integration of renewable energy sources in existing transmission and distribution systems. The precise control of active and reactive power flow to maintain the system voltage stability is the main requirement in a power transmission system. Here both active and reactive power can be controlled independently of one another. In the case of power reversal, there is no change in the DC voltage polarity for VSC based transmission system and it depends only on the direction of DC current. Furthermore, the reactive power flow can also be bi-directional depending on the AC network operating conditions. In this work, a3-phase, 2-level, 6-switch VSC connected to an active but weak AC system at both ends of HVDC link is developed using MATLAB/SIMULINK.