Medium Frequency Transformer Optimization and Insulation Testing for Solid State Transformer Applications

L. Bolzonella; R. Mirzadarani; M. G. Niasar

doi:10.1109/IECON58223.2025.11221021

Medium Frequency Transformer Optimization and Insulation Testing for Solid State Transformer Applications

L. Bolzonella, R. Mirzadarani, M. G. Niasar

High Voltage Technology Group

Research output: Chapter in Book/Conference proceedings/Edited volume › Conference contribution › Scientific › peer-review

Abstract

This paper presents the design and optimization of a Medium Frequency Transformer (MFT) for use in Solid State Transformer (SST) systems supporting green hydrogen production. Operating at 1 kHz and integrated within an LLC resonant converter, the transformer is optimized for minimal weight and high efficiency while ensuring adequate leakage inductance and insulation performance. A core-type configuration with cylindrical windings was selected based on FEM simulations and mass-efficiency trade-offs. The final prototype, using copper conductors, achieves 97.8% efficiency with a mass below 50 kg and meets the required 7 mH leakage inductance. High-voltage testing, including partial discharge and breakdown tests, confirmed the insulation coordination of the design. The results demonstrate a practical and scalable approach for high-performance SST integration in renewable energy applications.

Original language	English
Title of host publication	Proceedings of the IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society
Publisher	IEEE
Number of pages	6
ISBN (Electronic)	979-8-3315-9681-1
ISBN (Print)	979-8-3315-9682-8
DOIs	https://doi.org/10.1109/IECON58223.2025.11221021
Publication status	Published - 2025
Event	IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society - Madrid, Spain Duration: 14 Oct 2025 → 17 Oct 2025

Publication series

Name	IECON Proceedings (Industrial Electronics Conference)
ISSN (Print)	2162-4704
ISSN (Electronic)	2577-1647

Conference

Conference	IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society
Country/Territory	Spain
City	Madrid
Period	14/10/25 → 17/10/25

Bibliographical note

Green Open Access added to TU Delft Institutional Repository as part of the Taverne amendment. More information about this copyright law amendment can be found at https://www.openaccess.nl. Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Keywords

dry-type transformer
green hydrogen
high voltage
insulation breakdown
insulation coordination
partial discharge
solid state transformer

Access to Document

10.1109/IECON58223.2025.11221021

Cite this

Bolzonella, L., Mirzadarani, R., & Niasar, M. G. (2025). Medium Frequency Transformer Optimization and Insulation Testing for Solid State Transformer Applications. In Proceedings of the IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society (IECON Proceedings (Industrial Electronics Conference)). IEEE. https://doi.org/10.1109/IECON58223.2025.11221021

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title = "Medium Frequency Transformer Optimization and Insulation Testing for Solid State Transformer Applications",

abstract = "This paper presents the design and optimization of a Medium Frequency Transformer (MFT) for use in Solid State Transformer (SST) systems supporting green hydrogen production. Operating at 1 kHz and integrated within an LLC resonant converter, the transformer is optimized for minimal weight and high efficiency while ensuring adequate leakage inductance and insulation performance. A core-type configuration with cylindrical windings was selected based on FEM simulations and mass-efficiency trade-offs. The final prototype, using copper conductors, achieves 97.8% efficiency with a mass below 50 kg and meets the required 7 mH leakage inductance. High-voltage testing, including partial discharge and breakdown tests, confirmed the insulation coordination of the design. The results demonstrate a practical and scalable approach for high-performance SST integration in renewable energy applications.",

keywords = "dry-type transformer, green hydrogen, high voltage, insulation breakdown, insulation coordination, partial discharge, solid state transformer",

author = "L. Bolzonella and R. Mirzadarani and Niasar, {M. G.}",

note = "Green Open Access added to TU Delft Institutional Repository as part of the Taverne amendment. More information about this copyright law amendment can be found at https://www.openaccess.nl. Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.; IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society ; Conference date: 14-10-2025 Through 17-10-2025",

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doi = "10.1109/IECON58223.2025.11221021",

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address = "United States",

}

Bolzonella, L , Mirzadarani, R & Niasar, MG 2025, Medium Frequency Transformer Optimization and Insulation Testing for Solid State Transformer Applications. in Proceedings of the IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society. IECON Proceedings (Industrial Electronics Conference), IEEE, IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society, Madrid, Spain, 14/10/25. https://doi.org/10.1109/IECON58223.2025.11221021

Medium Frequency Transformer Optimization and Insulation Testing for Solid State Transformer Applications. / Bolzonella, L.; Mirzadarani, R.; Niasar, M. G.
Proceedings of the IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society. IEEE, 2025. (IECON Proceedings (Industrial Electronics Conference)).

Research output: Chapter in Book/Conference proceedings/Edited volume › Conference contribution › Scientific › peer-review

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AU - Bolzonella, L.

AU - Mirzadarani, R.

AU - Niasar, M. G.

N1 - Green Open Access added to TU Delft Institutional Repository as part of the Taverne amendment. More information about this copyright law amendment can be found at https://www.openaccess.nl. Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

PY - 2025

Y1 - 2025

N2 - This paper presents the design and optimization of a Medium Frequency Transformer (MFT) for use in Solid State Transformer (SST) systems supporting green hydrogen production. Operating at 1 kHz and integrated within an LLC resonant converter, the transformer is optimized for minimal weight and high efficiency while ensuring adequate leakage inductance and insulation performance. A core-type configuration with cylindrical windings was selected based on FEM simulations and mass-efficiency trade-offs. The final prototype, using copper conductors, achieves 97.8% efficiency with a mass below 50 kg and meets the required 7 mH leakage inductance. High-voltage testing, including partial discharge and breakdown tests, confirmed the insulation coordination of the design. The results demonstrate a practical and scalable approach for high-performance SST integration in renewable energy applications.

AB - This paper presents the design and optimization of a Medium Frequency Transformer (MFT) for use in Solid State Transformer (SST) systems supporting green hydrogen production. Operating at 1 kHz and integrated within an LLC resonant converter, the transformer is optimized for minimal weight and high efficiency while ensuring adequate leakage inductance and insulation performance. A core-type configuration with cylindrical windings was selected based on FEM simulations and mass-efficiency trade-offs. The final prototype, using copper conductors, achieves 97.8% efficiency with a mass below 50 kg and meets the required 7 mH leakage inductance. High-voltage testing, including partial discharge and breakdown tests, confirmed the insulation coordination of the design. The results demonstrate a practical and scalable approach for high-performance SST integration in renewable energy applications.

KW - dry-type transformer

KW - green hydrogen

KW - high voltage

KW - insulation breakdown

KW - insulation coordination

KW - partial discharge

KW - solid state transformer

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T3 - IECON Proceedings (Industrial Electronics Conference)

BT - Proceedings of the IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society

PB - IEEE

T2 - IECON 2025 – 51st Annual Conference of the IEEE Industrial Electronics Society

Y2 - 14 October 2025 through 17 October 2025

ER -

Medium Frequency Transformer Optimization and Insulation Testing for Solid State Transformer Applications

Abstract

Publication series

Conference

Bibliographical note

UN SDGs

Keywords

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