Reducing Rotor Temperature Rise in Concentrated Winding Motor by Using Magnetic Powder Mixed Resin Ring

Mitsuhide Sato, Keigo Takazawa, Manabu Horiuchi, Ryoken Masuda, Ryo Yoshida, Masami Nirei, Yinggang Bu and Tsutomu Mizuno
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Mitsuhide Sato: Faculty of Engineering, Shinshu University, Matsumoto 380-8553, Japan
Keigo Takazawa: Faculty of Engineering, Shinshu University, Matsumoto 380-8553, Japan
Manabu Horiuchi: Faculty of Engineering, Shinshu University, Matsumoto 380-8553, Japan
Ryoken Masuda: Faculty of Engineering, Shinshu University, Matsumoto 380-8553, Japan
Ryo Yoshida: Faculty of Engineering, Shinshu University, Matsumoto 380-8553, Japan
Masami Nirei: National Institute of Technology, Nagano College, Nagano 381-8550, Japan
Yinggang Bu: Faculty of Engineering, Shinshu University, Matsumoto 380-8553, Japan
Tsutomu Mizuno: Faculty of Engineering, Shinshu University, Matsumoto 380-8553, Japan

Energies, 2020, vol. 13, issue 24, 1-15

Abstract: The demand for high-speed servomotors is increasing, and minimal losses in both high-speed and high-torque regions are required. Copper loss reduction in permanent magnet motors can be achieved by configuring concentrated winding, but there are more spatial harmonics compared with distributed winding. At high-speed rotation, the eddy current loss of the rotor increases, and efficiency tends to decrease. Therefore, we propose a motor in which a composite ring made from resin material mixed with magnetic powder is mounted on the stator to suppress spatial harmonics. This paper describes three characteristic motor types, namely, open-slot motors, composite-ring motors, and closed-slot motors. Spatial harmonics are reduced significantly in composite-ring motors, and rotor eddy current loss is reduced by more than 50% compared with open-slot motors. Thermal analysis suggests that the saturation temperature rise value is reduced by more than 30 K. The use of a composite ring is effective in reducing magnet eddy current loss during high-speed rotation. Conversely, the torque characteristics in the closed-slot motor are greatly reduced as well as the efficiency. Magnetic circuits and simulations show that on electrical steel sheets with high relative permeability, the ring significantly reduces the torque flux passing through the stator, thus reducing the torque constant. To achieve reduced eddy current loss during high-speed rotation while ensuring torque characteristics with the composite ring, it is necessary to set the relative permeability and thickness of the composite ring according to motor specifications.

Keywords: eddy current loss; heat generation; magnetic circuit; magnetic composite material; spatial harmonics; concentrated winding motor (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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