166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz Windings
The safe operation of high-power solid-state transformers (SSTs) in medium-voltage grid-connected applications relies on medium-frequency transformers (MFTs). In MFTs, hybrid foil-litz windings present a cost-effective alternative to litz wire, since foil is employed as the main conductor. This inno...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IEEE
2024-01-01
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| Series: | IEEE Open Journal of Power Electronics |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/10400858/ |
| _version_ | 1797304890776616960 |
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| author | Andrea Cremasco Daniel Rothmund Marco Milone Sudheer Mokkapaty Elena A. Lomonova |
| author_facet | Andrea Cremasco Daniel Rothmund Marco Milone Sudheer Mokkapaty Elena A. Lomonova |
| author_sort | Andrea Cremasco |
| collection | DOAJ |
| description | The safe operation of high-power solid-state transformers (SSTs) in medium-voltage grid-connected applications relies on medium-frequency transformers (MFTs). In MFTs, hybrid foil-litz windings present a cost-effective alternative to litz wire, since foil is employed as the main conductor. This innovative topology exhibits lower ohmic losses than conventional foil windings. Besides, the dielectric stress in the insulation is mitigated, facilitating a more compact design. This paper presents the experimental validation of a <inline-formula><tex-math notation="LaTeX">${166}\; \mathrm{k}\mathrm{W}$</tex-math></inline-formula> MFT prototype rated for the <inline-formula><tex-math notation="LaTeX">$ {17.5}\;\mathrm{k}\mathrm{V}$</tex-math></inline-formula> AC/<inline-formula><tex-math notation="LaTeX">$ {26.3}\; \mathrm{k}\mathrm{V}$</tex-math></inline-formula> DC insulation class. The MFT features hybrid foil-litz windings insulated with ester liquid. The design of the active parts, the insulation and the cooling system are described. The performances of alternative design concepts is evaluated. The power rating of the MFT prototype is verified experimentally by the temperature rise test at full load, operating the MFT within the cell of an SST. The insulation withstand is confirmed through dielectric tests, including AC and DC overvoltage tests up to <inline-formula><tex-math notation="LaTeX">$ {54}\; \mathrm{k}\mathrm{V}$</tex-math></inline-formula> peak, and the lightning impulse up to <inline-formula><tex-math notation="LaTeX">$ {95}\; \mathrm{k}\mathrm{V}$</tex-math></inline-formula>. |
| first_indexed | 2024-03-08T00:16:56Z |
| format | Article |
| id | doaj.art-45cff40d52eb4b488b69a9fa13662f2a |
| institution | Directory Open Access Journal |
| issn | 2644-1314 |
| language | English |
| last_indexed | 2024-03-08T00:16:56Z |
| publishDate | 2024-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Open Journal of Power Electronics |
| spelling | doaj.art-45cff40d52eb4b488b69a9fa13662f2a2024-02-17T00:02:56ZengIEEEIEEE Open Journal of Power Electronics2644-13142024-01-01520121310.1109/OJPEL.2024.335480710400858166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz WindingsAndrea Cremasco0https://orcid.org/0000-0001-9627-7853Daniel Rothmund1https://orcid.org/0000-0003-3373-8346Marco Milone2Sudheer Mokkapaty3Elena A. Lomonova4https://orcid.org/0000-0002-2515-1441Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The NetherlandsABB Research Center Switzerland, Department of Power Electronics, Baden, SwitzerlandSGB-SMIT Group, Regensburg, GermanySGB-SMIT Group, Regensburg, GermanyDepartment of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The NetherlandsThe safe operation of high-power solid-state transformers (SSTs) in medium-voltage grid-connected applications relies on medium-frequency transformers (MFTs). In MFTs, hybrid foil-litz windings present a cost-effective alternative to litz wire, since foil is employed as the main conductor. This innovative topology exhibits lower ohmic losses than conventional foil windings. Besides, the dielectric stress in the insulation is mitigated, facilitating a more compact design. This paper presents the experimental validation of a <inline-formula><tex-math notation="LaTeX">${166}\; \mathrm{k}\mathrm{W}$</tex-math></inline-formula> MFT prototype rated for the <inline-formula><tex-math notation="LaTeX">$ {17.5}\;\mathrm{k}\mathrm{V}$</tex-math></inline-formula> AC/<inline-formula><tex-math notation="LaTeX">$ {26.3}\; \mathrm{k}\mathrm{V}$</tex-math></inline-formula> DC insulation class. The MFT features hybrid foil-litz windings insulated with ester liquid. The design of the active parts, the insulation and the cooling system are described. The performances of alternative design concepts is evaluated. The power rating of the MFT prototype is verified experimentally by the temperature rise test at full load, operating the MFT within the cell of an SST. The insulation withstand is confirmed through dielectric tests, including AC and DC overvoltage tests up to <inline-formula><tex-math notation="LaTeX">$ {54}\; \mathrm{k}\mathrm{V}$</tex-math></inline-formula> peak, and the lightning impulse up to <inline-formula><tex-math notation="LaTeX">$ {95}\; \mathrm{k}\mathrm{V}$</tex-math></inline-formula>.https://ieeexplore.ieee.org/document/10400858/Medium-frequency transformersolid-state transformerfoil windingester liquid |
| spellingShingle | Andrea Cremasco Daniel Rothmund Marco Milone Sudheer Mokkapaty Elena A. Lomonova 166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz Windings IEEE Open Journal of Power Electronics Medium-frequency transformer solid-state transformer foil winding ester liquid |
| title | 166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz Windings |
| title_full | 166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz Windings |
| title_fullStr | 166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz Windings |
| title_full_unstemmed | 166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz Windings |
| title_short | 166 kW Liquid-Insulated Medium-Frequency Transformer With Hybrid Foil-Litz Windings |
| title_sort | 166 kw liquid insulated medium frequency transformer with hybrid foil litz windings |
| topic | Medium-frequency transformer solid-state transformer foil winding ester liquid |
| url | https://ieeexplore.ieee.org/document/10400858/ |
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