Development of Permanent-Reluctance-Magnet Motor for EV and HEV motor

Structure of PRM

Fig.1 Structure of PRM

Motor efficiency in various speeds

Fig.2 Motor efficiency in various speeds

Motor efficiency in various speeds of PRM for a hybrid truck

Photo.1 Motor efficiency in various speeds of PRM for a hybrid truck

Hybrid vehicle (HEV) and electric vehicles (EV), the motor driving performance as the sole driving source or engine together, it determins the fuel economy and it is the most important part for practical use. Newly developed mass-production motor, permanent magnet is arranged to offset the invalid flux due to the armature current on the highest magneto-resistance of the rotor structure with a strong magnetic anisotropy, gets high magnetic flux by increasing the effective. The possible output is increasing and high efficiency is achieved. Consequently, as a vehicle driving performance, fuel efficiency that are both improved, it has become reluctance torque adopted new motors suitable for EV and HEV use. High output and small size (about 1.5 times the previous one), high efficiency (maximum efficiency 97%, 2 to 5% better than before), a wide range of variable speed operation (previously 1.5 times) are achieved.
This motor is applied to the world's first hybrid SUV (sport-utility vehicle multi-purpose). From 2004, the million units product for a year have started (output 65kW-maximum speed of 13500rpm). In 2007, the motor for a small HEV truck has started in production. The new motor has become the world's highest levels of performance for HEV, EV, FCEV.
Practical Application of motor to vehicles, the performance improvement of the motor and power supply, inverter and the manufacturing technology are both necessary. Mass production of this motor, for improvement of motor characteristics in addition to the items mentioned above, noise and vibration of K = 4 (wave number) mode arrised in trial machine , the inverter control technology in high speed and sudden change of torque at idling wheel of the bound body which is specific for automotive, manufacturing technology for further increases the space factor of copper in slot from industrial motors, the technology of the motor insulation with direct cooling oil have to be established. Developers established the avoidance and suppression techniques of noise and vibration that resonate with the electromagnetic force and the stator natural frequency. The inverter control technology with high-speed and high-precision for this motor which direct pole direction are changing significantly according to vehicle condition is also developed. They also carried endurance tests and developed insulation technology, manufacturing technology for a single digit as large amount as industrial motors. They contributed greatly to development and mass production for this new motor.

The Institute of Electrical Engineers, in honor of this achievement, Mr. Masanori Arata, Mr. Motoyasu Mochizuki (Toshiba Co.), Mr. Takashi Hanai (Toshiba industrial products manufacturing co ), presented the 2009 IEE Prize promotion (Progress Award) with.


[1] M. Arata and K. Sakai, “Development of a permanent magnet reluctance motor for automobile use”, Journa of IEEJ, vol. 128, No.4, pp.231-234, 2008
[2] M.Arata,N.Takahashi,K.Sasaki,K.Hagiwara, and T.Araki, “Large Torque and High Efficiency Permanent Magnet Reluctance Motor for A Hybrid Truck”, Proc.EVS22,D5,2006
[3] K.Sakai, N.Takahashi, E.Shimomura, M.Arata, Y.Nakazawa, and T. Tajima, “Development of Permanent Magnet Reluctance Motor Suitable for Variable-Speed Drive for Electric Vehicle”,IEEJ Transactions on Electronics, Industry Applications, Vol.123,No.6,pp.681-688,2003
[4]K.Sakai,T.Hattori,N.Takahashi,M.Arata, and T. Tajima, “High efficiency and high performance motor for energy saving in systems”, IEEE Proc.PES.Winter Meeting,Vol.3,pp.1413 - 1418,2001

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