成果報告書詳細
管理番号20110000000034
タイトル*平成21年度中間年報 次世代自動車用高性能蓄電システム技術開発/要素技術開発/脱レアアース次世代モータの研究開発(2)
公開日2012/6/29
報告書年度2009 - 2009
委託先名学校法人東京理科大学
プロジェクト番号P07001
部署名スマートコミュニティ部
和文要約1. 研究開発の内容及び成果等
(1)本研究開発の目標(設定理由含む)および達成度
本研究では、脱レアアース次世代モータの開発を行う。主として2つの大学で異なったアプローチを取りながら研究開発を進める。いずれもレアアース使用量をゼロとする方式であり、目標としては従来のトヨタプリウス搭載のIPMモータと等しい大きさ、効率を実現するものである。すなわち、目標:直径269 mm、軸長156 mm(コイルエンドを含む)の寸法で軸出力50 kW、運転効率同等(負荷点により85-95%)を実現する。
英文要約Project title: Rare Earth Free Motor Development( high speed SR motor and 3D motor)

To protect environments, there are demands for developing electronic motors with high torque density, high efficiency and low cost for Hybrid Electric Vehicles (HEV). Interior Permanent Magnet Synchronous Motor (IPMSM) is the most popular electric motors for HEVs. However, an IPMSM contains permanent magnets with rare earth material such as Neodymium and Dysprosium. The price of rare earth material has been increased by few times for last several years. Therefore, the demands of rare-earth-free-motor for the next generation HEV are high. Switched reluctance motor is one of the possible solutions. There are several advantages in SRM such as simple structure, low cost, rotor robustness and possible operation in high temperatures or high rotational speeds. SRMs have neither a permanent magnet nor a second winding in the rotor. Cooling is easy because most of the heat generation occurs in the stator. Only silicon steel and stator winding are used in SRM, thus recycling is easy. However, torque density and efficiency of SRM are low with respect to these of IPMSM in general. A 3kW SRM is reputed to be achieved 95% efficiency what is competitive to IPMSM. In SRMs for HEVs, torque density of SRM is reported to be one third of a IPMSM. This paper reports the design and analysis of a SRM which is in equal dimensions, power, torque and efficiency to the compared IPMSM.
Fig.1 shows the structures of calculated 4 types of SRMs. There are 6/4, 8/6, 12/8 and 18/12 (stator poles/ rotor poles). The motor efficiency is also important for HEV. Iron loss is the dominant loss at high speed operation. Fig.2 shows efficiency comparison of 18/12 SRM with 35A300 and 10JNEX900. The efficiency of 35A300 is a range of 91.5% to 93.5%. The efficiency of 10JNEX900 is in a range of 94.5% to 96%. To achieve target torque 400Nm with 10JNEX900, an expansion of stator taper angle is proposed. Fig.3 shows the structure of 18/12 SRM with stator taper. The taper angle of stator pole is increased from 3 degree to 10 degree. Also, the stator slot area is decreased, so rotor diameter is increased from 200mm to 180mm.The SRM achieves 400Nm with 10JNEX900, while slot fill is decreased from 57% to 49%. The current density is decreased from around 30 A/mm2 to 25.8 A/mm2. Then, to reduce current density, winding turns per pole is increased and slot fill is set to 57%. Finally, current density is decreased to 21.7 A/mm2.Table.1 shows comparison of IPMSM and SRM motors. Maximum torque density of SRM is equal to IPMSM. While SRM has about 20% higher rms current and current density, copper loss of SRM is lower than that in the IPMSM, then efficiency of SRM at 1,200r/min is better than that in the IPMSM.
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