The Efficiency Enhancement of a Single-phase Single-stage Buck-boost type Manitoba Inverter Using SiC MOSFETs for Residential PV Applications

摘要

One of the advantages of Silicon Carbide (SiC) MOSFET is high breakdown voltage with low switching losses, this leads single-stage buck-boost type converters using SiC devices becoming attractive for industrial applications. This paper presents a mixed combination of SiC MOSFETs, Si-IGBTs, and Si-MOSFETs in a single-stage buck-boost type grid-connected inverter for Photovoltaic (PV) applications to achieve low power losses and high efficiency. In order to identify the most suitable semiconductor combination for the required power rating and switching frequency in this inverter, a comparative research on the static characteristic of SiC MOSFETs and Si-based devices is conducted. Moreover, the power losses of various devices are further estimated by mathematical power loss model. Finally, an experimental evaluation is carried out in a 1.2kW inverter prototype. The results indicate that the use of the proposed mixed combination can benefit PV inverter with up to 4% higher system efficiency comparing with all-Si-based system and the advantages of various devices can be fully utilized.