Author : Deepshikha and Rahul Kumar

The conventional Z-source inverter can be used for boosting the output voltage for the various applications of dc–ac, ac–ac, dc–dc, and ac–dc power conversion. The main limitation of Z-source inverter is voltage stress across the switches because of high boosting feature. This paper presents the performance analysis of Z-source multilevel inverter using three level NPC inverter to overcome the limitation of conventional Z-source inverter. Multilevel converters gives a flexibility to choose voltage levels as a supplementary control element and allows more alternatives to generate the output waveform. For this reason, the power quality of multilevel inverters have inherently upgraded, distinguished by: lower voltage distortion (more sinusoidal waveforms), diminished dv/dt, and lesser common-mode voltages, that will decrease or even remove the necessity of output filters. The topology is implemented in MATLAB Simulink environment in order to evaluate the performance, the model is tested with different modulation indices. The simple boost pulse width modulation scheme is used along with In-phase level shift modulation in the present work.

Keywords: Z-source inverter; diode clamped multilevel inverter; shoot through duty ratio; modulation index; voltage stress; level shift modulation; neutral point clamped inverter

Article published in International Journal of Current Engineering and Technology, Vol.6, No.3 (June-2016)