Soft Switched Four Wire Inverter for UPS Applications

This paper presents a method for controlling the output voltage of a three phase four leg inverter based Uninterrupted Power Supply (UPS) The use of a four wire inverter increases the quality of the output whereas the soft switching technique employed helps to increases the overall efficiency of the inverter Furthermore, in order to improve the system response to load variations, a PI control strategy is proposed The 4 leg three phase inverters handles the neutral current caused by non-linear loads in a better manner The main feature of a 4 leg inverter is its ability to deal with load unbalance in a system The additional leg maintains a desired sinusoidal output voltage waveform for all loading conditions and transients The neutral connection is present to handle the ground current due to unbalanced loads The feasibility of the proposed modulation technique is verified by MATLAB simulation It also discusses the experimental analysis of the 4 wire inverter. Copyright (C) 2010 Praise Worthy Prize S.r.l - All rights reserved.