Methods for optimal control of unified power flow controllers

Recent advances in the power electronics have made the use of the voltage source inverter (VSI) feasible at both transmission and distribution levels. This paper demonstrates a new optimal control scheme for the Unified Power Flow Controller (UPFC) to control power flow as well to improve the system stability and to eliminate current harmonics and voltage flickers in the system. In this paper optimal control with two tracking strategies have been tested: tracking according to steady state behavior and tracking with PI controller. The shunt converter only and the series converter only have been demonstrated too.