Airgap Length Analysis of a 350kW PM-Assisted Syn-Rel Machine for Heavy Duty EV Traction

Zou, Tianjie; Gerada, David; La Rocca, Salvatore; La Rocca, Antonio; Walker, Adam; Vakil, Gaurang; Arevalo, Saúl López; Xu, Zeyuan; Cui, Mengmeng; Bardalai, Anuvav; Wang, Meiqi; Kumar, R. M. Ram; Marfoli, Alessandro; Paciura, Krzysztof; Barden, Richard; Ernest, Emil; Zhu, Shaohong; Qayyum, Naila; McQueen, Alastair; Zhang, Fengyu; Gerada, Chris

Abstract

Synchronous reluctance (Syn-Rel) machines with embedded permanent magnets (PMs) are research hotspots in variable speed motor drives due to their robust rotor structure and wide constant power speed range (CPSR). In this paper, the potential of PM-assisted Syn-Rel machine to be next generation heavy duty traction motor solution has been investigated, with special attention put on one key geometric parameter, i.e., airgap length. Careful machine design and optimization has been conducted based on geometric parametrization including airgap length variation, for 15000rpm peak speed and 350kW peak power output. In low speed operations, the influence of airgap length on different torque components has been analyzed in detail based on the frozen permeability method. In field weakening region, the variation trend of several key parameters such as output power, torque ripple, and power losses have been investigated along with airgap length. It is found that with high electric and magnetic loading, reducing the electromagnetic airgap length is not always beneficial. There exists a suitable airgap length value to comprehensively balance torque/power density, cooling capability, efficiency and reliability. Numerical FEA and experimental tests of the prototype are combined to verify the conclusions.

Citation

Zou, T., Gerada, D., La Rocca, S., La Rocca, A., Walker, A., Vakil, G., Arevalo, . S. L., Xu, Z., Cui, M., Bardalai, A., Wang, M., Kumar, R. M. R., Marfoli, A., Paciura, . K., Barden, R., Ernest, E., Zhu, . S., Qayyum, N., McQueen, A., Zhang, F., & Gerada, C. (2023). Airgap Length Analysis of a 350kW PM-Assisted Syn-Rel Machine for Heavy Duty EV Traction. IEEE Transactions on Industry Applications, 59(2), 1557-1570. https://doi.org/10.1109/TIA.2022.3225255

• Journal Article Type: Article
• Acceptance Date: Nov 18, 2022
• Online Publication Date: Nov 28, 2022
• Publication Date: 2023
• Deposit Date: Mar 29, 2023
• Publicly Available Date: Apr 18, 2023
• Journal: IEEE Transactions on Industry Applications
• Print ISSN: 0093-9994
• Electronic ISSN: 1939-9367
• Publisher: Institute of Electrical and Electronics Engineers
• Peer Reviewed: Peer Reviewed
• Volume: 59
• Issue: 2
• Pages: 1557-1570
• DOI: https://doi.org/10.1109/TIA.2022.3225255
• Keywords: Electrical and Electronic Engineering; Industrial and Manufacturing Engineering; Control and Systems Engineering
• Public URL: https://nottingham-repository.worktribe.com/output/14322424
• Publisher URL: https://ieeexplore.ieee.org/document/9964435