Performance Analysis of Three Phase On-Line UPS Using Single Stage Power Converter

Abstract

This paper proposes the performance improvement of the power converters in Uninterruptible Power Supply (UPS) based on size reduction, efficiency improvement and power quality. The traditional UPS consists of step up transformer or dc-dc chopper to boost the voltage which decreases the efficiency, reduces the power quality and leads to increase the cost of energy conversion. The proposed ZSI is a single stage power converter and it overcomes the limitations of traditional pwm inverter in UPS. In the three phase Z-source inverter a symmetrical LC network is employed to couple the main power circuit of an inverter to a battery bank. The ZSI having the advantages of operating at shoot through time period which is forbidden in the traditional VSI. By controlling the shoot through time the ZSI can operate in both buck and boost mode. The effectiveness of ZSI is greatly utilized in this research for UPS application. The analysis of proposed UPS system is based on cost effective, energy conversion efficiency and power quality. The proposed and conventional system of UPS is simulated in MATLAB/SIMULINK software and its results are validated with 2 kVA experimental setup in the laboratory.