Stability analysis and reliability evaluation of a Z-source inverter

This paper presents stability analysis and reliability evaluation of three-phase Z-source inverter including load parameters. The impedance network of ZSI is operated for the shoot through period in order to achieve a desired voltage boost at DC link. Therefore, incremental change at DC link voltage of ZSI is a function of incremental change in shoot through ratio. However, impedance network parameters limit the safe range of shoot through ratio. So a novel method has been proposed for selection of inductor and capacitor values of impedance network based on the stability analysis. This method has been used for calculation of impedance network parameters and a ZSI has been designed using these values. The designed inverter is tested on AC drives to control the speed of three phase induction motor of power rating 1 HP. After testing, it has been observed that the reliability measured in terms of mean time between failures (MTBF) achieves 99.62%. © Copyright 2015 Inderscience Enterprises Ltd.