A Power Flow Controller Design for Phase Shifter Used in Parallel AC/DC Links

A Circuit Theory Based Approach

Abstract

The paper presents an effective power flow controller design for a phase shifter used in parallel AC/DC links which interconnect power systems both by the phase shifter as an AC link and a BTB (back-to-back) as a DC link in parallel. An equivalent DC power flow model of the interconnected power systems is first introduced. Then, based on circuit theory, approximate equations are formulated to quantify the relation among phase-shifting angles of the phase shifter and power flows and impedances of the power systems. The validity of these equations are demonstrated through power flow studies and digital simulations. Finally, using the approximate equations, a power flow controller with feedback and feedforward structure is designed for the phase shifter. The effective control performance of the designed controller is also demonstrated through digital simulations.