BASIC CONTROL OF UNIFIED POWER FLOW CONTROLLER

This paper presents a mathematical model of unified power flow controller based on switch function; Based on park transformation, it designs a decoupled control scheme of UPFC in d and q-axis with the utilization of predictive current. It deduces the state of each power electronics device in UPFC by means of the voltage space vector pulse width modulation method. Considering the importance of capacitor voltage control of UPFC, it puts forward a fuzzy self-adaptive PID control strategy comparing with the traditional PID control method. MATLAB simulation program indicates that it can enhance the stability of the capacitor voltage and power flow. It is similar to enlarge the capacity of the capacitor. The whole control scheme can be referred by other similar control system.