A Series VSI Based Voltage Sag Correcting Device with Additional VAR Compensation for Sensitive Loads

Abstract

A series Voltage Source Inverter based voltage sag correcting device has been developed and tested in this paper. A control system is designed using the derived mathematical model of the sag correcting device. Voltage tracking capabilities for inner controllers and good performance characteristics for load voltage regulation and reactive power loops are demonstrated for steady state and transient conditions.
Also, additional loops for unbalanced sag conditions are designed decomposing the voltages and currents into positive and negative sequence components. Verification of the designed system has done by both simulation and experimental studies.