Researchers at Oxford University say they have developed a lightweight electric motor that offers increased efficiencies for high-torque, low-weight applications such as hybrid electric vehicles and renewable energy applications. They claim that their “segmented armature torus motor” operates with efficiencies of up to 97% and that its multi-phase winding results in low torque ripple.

The motor, developed by the Electronic Power Group in the University’s Department of Engineering, uses novel combinations of materials that reduce the need for iron and copper. This results in a lightweight machine with a good power-to-weight performance. The segmented design is said to improve cooling.

A 13kg version of the motor can deliver a peak output of about 50kW and a peak torque of 130Nm. Simulations show that the same motor could achieve a peak torque of more than 200Nm and a peak power of at least 150kW.

The motor can also operate as a generator and potential applications include regenerative braking systems in hybrid vehicles, and wind turbines without gearboxes.

Oxford University’s technology transfer business, Isis Innovation, is looking for licensees for the motor technology.