PROJECT TITLE :

Control and Experiment of an H-Bridge-Based Three-Phase Three-Stage Modular Power Electronic Transformer

ABSTRACT:

Compared with conventional power transformer, the facility electronic transformer (PET) or solid-state transformer has several enticing additional features. This paper focuses on an H-bridge-based 3-phase 3-stage modular PET, that consists of an input stage with series-connected H-bridge converters, an isolation stage with many independent twin-active-bridge converters, and an output stage with parallel-connected H-bridge converters. This PET suffers dc-link capacitor voltage unbalancing issue, and also the parallel-connected module current unbalancing sharing issue. During this paper, a system management structure is proposed for the PET to house these issues. Totally different input-stage individual module dc-link voltage balancing control ways are analyzed and compared. It's found that the one implemented by directly trimming module output voltage amplitude is most appropriate for PET. Moreover, a downscaled laboratory prototype is meant, built, and tested to verify the management strategy.