PROJECT TITLE :

A New Three-Phase AC-DC-AC Multilevel Converter Based on Cascaded Three-Leg Converters - 2017

ABSTRACT:

This paper proposes and investigates a replacement three-part ac–dc–ac multilevel conversion system obtained from cascaded three-leg converters. Such configuration presents blessings in terms of reduced switch blocking voltages and consequently lower dc-link voltage rating. Operating principles, a pulse-width modulation (PWM) technique primarily based on vector approach, and a control strategy are presented. The operation with completely different dc-link voltage values and a balancing technique are mentioned, and is supported by simulation and experimental results. The PWM technique is in a position to get multilevel voltage waveforms, that permits reducing the switching frequency stress leading to reduced semiconductor losses. Simulation results are used to compare the proposed configuration with a conventional resolution in terms of harmonic distortion and semiconductor losses. Experimental results demonstrate the feasibility of the studied converter, and were obtained by using a downscaled prototype with insulated gate bipolar transistors with dedicated drives and a digital signal processor with appropriated plug-in boards and sensors.