Novel Three-Phase Electronic Transformer

• Published in: IEEE transactions on power electronics Vol. 39; no. 5; pp. 5027 - 5033
• Main Authors: Menzi, David, Yang, Aobo, Chhawchharia, Saransh, Coday, Samantha, Kolar, Johann W.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: AC–AC; bidirectional; converter; dual active bridge (DAB); Electric bridges; Electric converters; Electric potential; electronic transformer; high-frequency isolated; Magnetic cores; Modulation; Power flow; Power semiconductor devices; Power transistors; solid-state transformer (SST); Switches; Switching circuits; three-phase; Transformers; Transistors; Voltage; Voltage control; Waveforms; Weight reduction
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2024.3366752

Electronic transformers enable galvanic isolation and voltage level adaption at high frequency, and thus the magnetic core volume and weight can be reduced substantially compared to traditional transformers operating at the grid frequency. This article introduces a novel phase-modular single-stage three-phase electronic transformer (<inline-formula><tex-math notation="LaTeX">\mathbf {3\Phi }</tex-math></inline-formula>-ET) which advantageously enables the use of standard power transistors with unipolar voltage blocking capability. The output frequency is identical to the grid input frequency and the bidirectional power flow can be adjusted by means of a simple dual active bridge (DAB)-type modulation which results in inherently sinusoidal grid currents. The <inline-formula><tex-math notation="LaTeX">\mathbf {3\Phi }</tex-math></inline-formula>-ET is thoroughly described and experimental waveforms with a 6 kW prototype system operated in a 400 V (rms, line-line) three-phase grid provide a proof of concept and verify the theoretical considerations.