Design Analysis of High-Frequency, High Power 3-Phase DAB Transformer for Electric Vehicle Charger Applications

Mustafa, Uvais; Kougioulis, Ioannis; Watson, Alan J.; Wheeler, Patrick; Ahmed, Md. Rishad

Abstract

The power requirements for onboard chargers in Electric Vehicles are increasing due to the need for increased charging speeds. The 3-Phase Dual Active Bridge (DAB) DC-DC converter is an enabling topology for high-power onboard chargers (22kW). However, the design of a 3-phase high-power, high-frequency transformer (3P-HPFT) for the 3-phase DAB poses several challenges. To understand those challenges, two design approaches are considered in this paper: a single-core based design referred to as integrated transformer design, and a three-core based design referred to as 3CT. The results are compared to understand the design challenges. Ansys and PLECS magnetic simulation tools are utilized to validate the design. For a 22kW converter, the integrated 3-phase DAB Transformer has a 19% higher power density (88 mW/mm3), 50% lower core losses (133 W) and is 25% lighter (1.5 kg) in comparison to 3CT which has a power-density of 74 mW/mm3, core losses of 262 W and a weight of 2 kg. Leakage inductance can be utilised as the energy-storing element during the phase shift operation of the DAB thus, the range of achievable leakage inductance in both the designs is explored. The integrated transformer design can achieve a leakage inductance range of 0.5 μH - 9.6 μH. Whereas, the 3CT transformer offers a leakage inductance range of 1.5 μH - 9 μH. To operate at nominal power, apart from the leakage inductance, both designs will require an additional inductance of 5 μH. Soft switching conditions for the nominal power operation are also derived and it was found that both the bridges operate within the soft switching boundaries.

Citation

Mustafa, U., Kougioulis, I., Watson, A. J., Wheeler, P., & Ahmed, M. R. (2024, June). Design Analysis of High-Frequency, High Power 3-Phase DAB Transformer for Electric Vehicle Charger Applications. Presented at 2024 IEEE Transportation Electrification Conference and Expo (ITEC), Chicago, IL, USA

• Presentation Conference Type: Edited Proceedings
• Conference Name: 2024 IEEE Transportation Electrification Conference and Expo (ITEC)
• Start Date: Jun 19, 2024
• End Date: Jun 21, 2024
• Acceptance Date: Jun 19, 2024
• Online Publication Date: Jul 24, 2024
• Publication Date: Jun 19, 2024
• Deposit Date: Sep 16, 2024
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Series ISSN: 2473-7631
• Book Title: 2024 IEEE Transportation Electrification Conference and Expo (ITEC)
• ISBN: 979-8-3503-1767-1
• DOI: https://doi.org/10.1109/ITEC60657.2024.10598844
• Public URL: https://nottingham-repository.worktribe.com/output/38100669
• Publisher URL: https://ieeexplore.ieee.org/document/10598844