Transformerless Single-Phase Buck-Boost Inverter Decoupled From the Midpoint of the Input Dc Capacitors

Abstract

A transformerless, single-phase, buck-boost inverter is proposed in this study. Unlike similar topologies, the proposed inverter does not need to have a mid-point of dc sources or dc-bus capacitors at the input side of the inverter. The proposed inverter can suppress the leakage current drawn from the input power source and provide a long-lasting solution for applications with a wide input voltage range and/or unregulated input voltage. This article presents the controller and modulation design details, and a comparative evaluation conducted for the proposed inverter. A single-phase, buck-boost inverter for realizing the power stage with 110 V-rms output ac voltage and a range of 100-200 V input dc voltage is investigated in this study. The proposed inverter has been proven through theory, computer simulations, and experimental studies with SiC MOSFETS-based prototype of a 300 VA power supply. Theory, computer simulation, and experimental results are all correlated.