Ali Ghasemi - Electrical and Electronic Engineering Department Shahed University Tehran, Iran
Koosha Choobdari Omran - Faculty of Electrical Engineering tarbiat modares university Tehran, Iran
Mahdi Akhbari - Electrical and Electronic Engineering Department Shahed University Tehran, Iran

This paper proposes a unified power flow controller (UPFC) with a DC-link module composed of a DC-link capacitor and a full bridge converter as a series voltage compensator. The voltage compensator is connected in series with the DC bus line and generates a voltage to eliminate the voltage ripples on the DC-link capacitor. By applying this voltage source converter, the overall required capacitance is reduced allowing the replacement of electrolytic capacitors by alternatives with longer lifetime and reduced volume and cost. The simulation study of the proposed topology is carried out and investigated the effects of DC-link capacitance reduction on output parameters of UPFC by using a series voltage compensator. The complete simulation of model voltage compensator is implemented in MATLAB/Simulink and the results realize that proposed series voltage compensator reduced the DC-link voltage ripples and improved the active and reactive power injection and also reduced the harmonic effects on system.

Unified power flow controller (UPFC); voltage regulation; DC-link capacitor; Full bridge converter; series voltage compensator