Influence Investigation of Multiphase Multipulse Converter and Floating Voltage Source Inverter-Based Motor Drive System

This article deals with a hybrid technique (phase conversion and phase displacement) to design a multipulse rectifier so that a medium voltage drive system annihilates an impact of harmonic components not only in a steady state but also in that state when it is not operating at rated conditions. A three-phase rectification faces power quality challenges when it is designed to supply power for a low-count dc source inverter. Hence, a set of transformers is designed with a three-phase to five-phase conversion, which makes an individual unit of rectifiers as a 10-pulse converter, and through a phase displacement, an overall converter converts into a 30-pulse converter. Moreover, a floating voltage source inverter-based four-level multilevel inverter is used to attain excellence in response at motor end. Hence, the proposed converter is capable of efficient utilization of electricity with high power quality, which is a main objective at global level. A hardware prototype of a drive system is developed for a 7.5 kW, 415 V, cage induction motor. Experimental results have demonstrated that power converters are effective in improving power quality at grid and motor. Operability and performance of the proposed power converter are experimentally validated at different loads and speeds.