i-Motor Co., Ltd. of Kyoto, Japan has developed a new variable flux brushless permanent magnet (PM) motor currently undergoing testing at the nationally recognized test laboratories Advanced Energy’s test facilities. i-Motor is a subsidiary of T.N.G. Technologies, a research and development company working on products that enhance energy efficiency.

The new Type 5 variable flux motor can electronically adjust the motor’s back EMF over a wide range of speeds from 750 rpm to 8,500 rpm and beyond. The initial prototype motor can develop over 9,000 W output at power efficiencies above 90% over a wide speed range. The technology is scalable to larger and higher power sizes.

i-Motor has developed a number of patented PM motors that use both electro-magnetic and mechanical means of field weakening while maintaining high power efficiency. The company has developed these high-efficiency PM motors for traction applications that include hybrid and electric vehicles.

Two key challenges in boosting performance in existing motors for electric and hybrid-electric vehicles are field control and energy efficiency, especially during regenerative braking. This new motor uses variable permanent magnets for field control which can be added to existing motor structures and which accomplishes field strengthening and weakening control independent of drive current.

As this article comparing an AC induction motor with a PM AC motor explained, the PM AC motor outperforms the induction motor in applications with significant speed changes, such as in drivetrain applications. The new i-Motor Type 5 motors should be an improvement on these standard PM AC motors. One thing is for sure; as electric and hybrid vehicle design continues to evolve, new motor and drive technologies will continue to vie for shares of this growing application space.

Visit www.i-motor.jp/en/works.html to find out more.