Single-Stage Matrix-Type Power Electronic Transformer With Reduced Switches

In this article, a single-stage matrix-type power electronic transformer (PET) with reduced switches is proposed, which has the advantages of fewer components and compact structure. The presented PET consists of a two-phase interleaved totem-pole converter on the grid side, and a dual active bridge (DAB) and a full bridge on the load side commutate at line frequency. The interleaved totem-pole converter converts the sinusoidal input voltage to the half sine voltage on primary side of dc link, and the high-frequency switched bridge arms of the interleaved totem-pole converter also act as the primary-side bridge of the DAB converter. The DAB adopts single-phase-shift control for active power regulation. As a result, the required power switches and power losses are reduced, and the double line-frequency power pulsation in the conventional single-phase converters is avoided. Besides, the omission of the dc electrolytic capacitor significantly improves the reliability and power density of the converter. By merging the active bridges of the totem pole and the primary-side bridges of the DAB, the number of switches is lower than the separate solution and the total conduction losses do not increase. Finally, a 2-kW prototype is built and tested, and the correctness and feasibility of the presented methods are verified by experimental results.