Comparative Performance Analysis of VSI and ZSI based DVRs in a Distribution Network with Welding Load

Abstract

Power quality is the most distressed areas in electrical power system. It has become important especially with the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply Power quality is signalized by parameters that reveal harmonic pollution, load disturbance and reactive power. One of the major problems which we deal here is power sag. To improve the power quality issues, custom power devices are used. The device considered here is DYNAMIC VOLTAGE RESTORER (DVR). DVR is the one who restore the voltage timely and provides best solution to power quality problems. DVR has very effective solution for mitigation of voltage sag and voltage swell in the distribution network. Here, the comparative study of Voltage Source Inverter (VSI) and Z-Source Inverter (ZSI) topologies based DVR to mitigate the power quality problems introduced into distribution network by welding power supply are introduced using MATLAB/SIMULINK. ZSI has both buck and boost capabilities as they allow inverters to be operated through shoot through state. This will provide ride through during voltage sag without any additional circuit and improve the power factor by reducing the harmonic current and common-mode voltage which will finally increase the reliability and extends the output voltage range. For unity power factor, pulse width modulation technique is developed.