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Open AccessFeature PaperArticle
Optimal Design Considering AC Copper Loss of Traction Motor Applied HSFF Coil for Improving Electric Bus Fuel Economy
1
Advanced Mobility System Group, Korea Institute of Industrial Technology, Daegu 42994, Republic of Korea
2
Department of Automotive Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
3
Department of Mechanical, Robotics, and Energy Engineering, Dongguk University, Seoul 04620, Republic of Korea
4
Department of Electrical Engineering, Soonchunhyang University, Asan 31538, Republic of Korea
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Mathematics 2025, 13(9), 1509; https://doi.org/10.3390/math13091509 (registering DOI)
Submission received: 7 April 2025
/
Revised: 28 April 2025
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Accepted: 30 April 2025
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Published: 3 May 2025
Abstract
Improving the fuel economy of electric buses requires traction motors that provide not only high-power density but also high efficiency under diverse driving conditions. While high slot fill factor (HSFF) coils such as the maximum slot occupation (MSO) coil improve motor torque and power density, they inevitably increase AC copper losses due to elevated AC resistance, especially at high speeds. Unlike conventional motor optimization studies that mainly focus on efficiency at specific operating points, this paper proposes a drive-cycle-aware design optimization method that minimizes AC copper loss to enhance real-world fuel economy. By combining 2D finite element analysis (FEA) with vehicle-level simulations under three representative driving cycles (Manhattan, HWFET, HDUDDS), an optimal motor design was derived. The optimized motor achieved improvements in fuel economy by 0.20%, 0.86%, and 0.36%, respectively, compared to the initial design. Experimental validation through prototype fabrication confirmed the effectiveness of the proposed method. These results demonstrate that the proposed design approach can contribute to improving energy efficiency and reducing operational costs in electric bus applications.
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MDPI and ACS Style
Cha, K.-S.; Jung, Y.-H.; Park, S.-H.; Park, M.-R.
Optimal Design Considering AC Copper Loss of Traction Motor Applied HSFF Coil for Improving Electric Bus Fuel Economy. Mathematics 2025, 13, 1509.
https://doi.org/10.3390/math13091509
AMA Style
Cha K-S, Jung Y-H, Park S-H, Park M-R.
Optimal Design Considering AC Copper Loss of Traction Motor Applied HSFF Coil for Improving Electric Bus Fuel Economy. Mathematics. 2025; 13(9):1509.
https://doi.org/10.3390/math13091509
Chicago/Turabian Style
Cha, Kyoung-Soo, Young-Hoon Jung, Soo-Hwan Park, and Min-Ro Park.
2025. "Optimal Design Considering AC Copper Loss of Traction Motor Applied HSFF Coil for Improving Electric Bus Fuel Economy" Mathematics 13, no. 9: 1509.
https://doi.org/10.3390/math13091509
APA Style
Cha, K.-S., Jung, Y.-H., Park, S.-H., & Park, M.-R.
(2025). Optimal Design Considering AC Copper Loss of Traction Motor Applied HSFF Coil for Improving Electric Bus Fuel Economy. Mathematics, 13(9), 1509.
https://doi.org/10.3390/math13091509
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