Novel approach to control of active rectifier during voltage dips

Abstract

The paper is about voltage oriented control (VOC) of an active rectifier during short periods of voltage dips. Most of voltage dips are caused by short circuits in one line or between two lines. This leads to the three phase voltages unbalance. While power grid is unbalanced, the voltage vector is rotating, but its hodograph of the generalized voltage vector is not a circle. The control system of an active rectifier is orienting the current vector in the direction of the voltage vector. Because of the specifity of the control system, these conditions lead to the harmonic distortion of rectifier's currents. In the article, the mechanism of forming the currents is circumstantially described. A MATLAB Simulink model of an active rectifier and simulation results are presented. The solution of the described problem is to improve the control system to achieve sine wave currents. The novel approach to the active rectifier control is proposed and the efficiency is confirmed by simulation results.