Comparative Analysis of Symmetrical/Asymmetrical Quasi Z-Source Cascaded Multilevel Inverter with Alternative Phase Opposition Disposition Technique.

This paper presents a detailed comparative analysis between Symmetrical and Asymmetrical Quasi Z-Source Cascaded Multilevel Inverter (QZS-CMI). The comparative analysis investigates for boost operation in both Symmetrical and Asymmetrical System. Analysis is done based on the achieved input current, capacitor voltage of the upper capacitor and parallel capacitor and the two inductors current of DC link (Quasi Z-Source network) which is combined with H-bridge. In Asymmetrical QZS-CMI, the input voltage for three DC sources are given in the ratio of 1:3:9, i. e. the system is designed for 27 level. Asymmetrical QZS-CMI is new system and proposed in this paper for comparative analysis with Symmetrical QZS-CMI. An advanced optimal Alternative Phase Opposition Disposition (APOD) technique is developed and implemented. Symmetrical system has high boosting capability of output voltage, reducing the switching losses, high voltage gain and lower spikes in switching voltage. The comparative study is done and results are verified with Experimental 250 W prototype model and also verified by using MATLAB/ Simulink. [ABSTRACT FROM AUTHOR]