Traction motor could improve efficiency of electric vehicles

GE researchers have developed a traction motor for hybrid and electric vehicles (EVs) that they claim delivers higher power density and better efficiency at a lower cost.

The company recently tested a prototype of its interior permanent magnet traction motor, developed as part of a $5.6m (£3.5m) US Department of Energy project to extend the range of EVs and hybrids.

According to a statement, the motor operates at a peak power output of 55kW, delivering nearly twice the power density, and thus acceleration, of existing EV motors.

It is also around three to five per cent more efficient since the required torque is achieved using much lower DC bus voltage — as low as 200V versus 650V in existing motors.

Most significantly, GE claims the motor operates continuously at 105ºC over a wide speed range (2,800–14,000rev/min at 30kW) and can be cooled with engine coolant.

The elimination of a separate cooling system, which most EVs rely on, allows the vehicle to be lighter, which directly translates into greater range.

‘This is a significant accomplishment. We at GE are pushing the boundaries to build more robust, yet more efficient, motors for hybrid and fully electric platforms,’ said Ayman El-Refaie, electrical engineer in GE Global Research’s Electrical Machines Lab. ‘We have built a motor that is substantially more powerful than what’s commercially available now, all while improving efficiency by up to five per cent.’