Five-Level SPWM converter based UPFC

Abstract

The unified power flow controller (UPFC) based on the flying capacitor FC multilevel voltage-source converter (VSC) topology with phase-shifted sinusoidal pulse width modulation (PWM) control is proposed. This converter allows higher power handling, potentially lower power loss, lower harmonic distortion and hence less Filtering requirements when compared with the three-level converter. The series converter injects a voltage with controlled magnitude and phase to control the active/reactive power flow in a transmission line. The shunt converter absorbs/supplies active power demanded by the series converter to maintain a constant DC link voltage also providing independent reactive support to the network. A complete model of the proposed UPFC system is shown and control circuits are described in the synchronous d-q frame. Finally simulation results are provided to confirm the robustness of the proposed system.