Affiliations: [a] Univ. Artois, ER4025, LSEE, Béthune, France | [b] Univ. Artois, ER4025, LSEE, Béthune, France | [c] Institute of Mechatronics and Information Systems, University of Technology, Lodz, Poland | [d] Univ. Artois, ER4025, LSEE, Béthune, France | [e] Securelec-Socem, Courrières, France
Correspondence:
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Corresponding author: Daniel Roger, Univ. Artois, ER4025, LSEE, 62400 Béthune, France. E-mail: daniel.roger@univ-artois.fr
Abstract: This article proposes a design of windings for medium-frequency transformers (MFTs) at the heart of high-power Solid-State Transformers (SSTs). With aluminum interleaved foils of the correct thicknesses, it is possible to obtain low winding losses and a very low leakage inductance well adapted to high-power SSTs able to operate in the medium-voltage grid (5–20 kV). The MFT equivalent resistance and leakage inductance are determined using an analytical model based on Dowell’s hypotheses. Several interleaved winding configurations are analyzed and compared to the standard structure made of two concentric foil coils. The experimental validation is made with short-circuit tests of an MFT fed by a low-level square voltage source at several kHz, which can provide the necessary high current.
Keywords: Solid-State Transformer (SST), medium frequency transformer (MFT), aluminum-foil winding, grain oriented electrical steel (GOES) wound core
