A FRESH STRUCTURE FOR A 7-LEVEL BUCK BOOST CASCADE MULTILEVEL INVERTER UTILIZED IN RENEWABLE ENERGY APPLICATIONS

Abstract

This document unveils a cutting-edge, high-efficiency single-phase dual-mode cascaded Buck-Boost multilevel transformer-less PV inverter tailored for home use. This innovative inverter architecture fuses a regulated cascaded H-bridge multilevel inverter stage with an unregulated GaN-driven AC Boost converter. The shared inductor serves both the cascaded H-bridge inverter and the AC Boost. In contrast to conventional cascaded H-bridge PV inverters, this design markedly broadens the input voltage spectrum thanks to the supplementary AC Boost. Additionally, it accommodates a versatile array of PV panels. To regulate the various DC link PV voltages and minimize AC Boost switching losses, this initiative further incorporates a dual-mode operation. The operational modes include Buck mode and Buck-Boost mode. To optimize the use of DC link voltages, this project introduces a streamlined AC Boost duty-cycle generation strategy featuring feedforward. Subsequently, a dual-mode modulation scheme based on the Boost feedforward duty-cycle generation is presented.