Design and Analysis of Impedance Network-Based Cascaded Multilevel Inverter

This paper describes the design along with an analysis of a Z-Source or impedance-source-based cascaded MLI for adoption in online UPS applications. The motive of this study is to build a dc-to-ac converter that is utilized for UPS to the load side without stoppage of power and with a step-up output voltage. This is accomplished by feeding CHB-Multilevel circuits through a front-side Z-source unit. Z-source-based MLIs have boosting capabilities and achieve waveforms that are almost sinusoidal. The Z-source unit uses a distinctive impedance circuit to link the converter's main circuit to the power supply, thus the proposed converter provides properties, such as shoot-through state, that are unattainable in conventional inverters. In contrast to conventional inverters, Z-source-based MLIs are more reliable and credible for uninterruptible power supply (UPS) applications. The proposed converter's performance is assessed analytically by varying the shoot-through duty ratio, and MATLAB/SIMULINK is used to simulate and validate the results. The inverter switches are controlled by implementing shoot-through control along with Standard Phase Shifted Pulse Width Modulation (PS-SPWM). The simulation results demonstrate that the proposed converter control using PS-SPWM along with shoot-through exhibits higher voltage utilisation and a lower power squander compared to the conventional SPWM inverter. The simulation results have been discussed by employing Fast Fourier Transform (FFT) analysis shows higher gain and better performance compared to the conventional topologies.