Integrated motor drive and battery charger

Researchers at Chalmers University of Technology in Sweden have developed a new integrated motor drive and battery charger for electric vehicles (EVs) to facilitate cheaper and faster charging.

The new charger will reduce charging times from eight to two hours, as well as reducing costs by around $2,000.

Developed by Saeid Haghbin, a doctor of electric power engineering, the high-power integrated motor drive and battery charger for vehicle applications uses a new power transfer technique that involves a rotating transformer.

According to researchers, the ideal situation is to have a charger powerful enough to charge a car in five to ten minutes, although this would cost more than $100,000.

For the study, which was funded by The Swedish Hybrid Vehicle Centre (SHC), researchers aim to reduce the size, weight and price of the on-board charger.

"The ideal situation is to have a charger powerful enough to charge a car in five to ten minutes, although this would cost more than $100,000."

Since the electric motor and the inverter are not used during battery charging, researchers have evaluated if it would be possible to use the motor and inverter in the charger circuit to increase the charging power at a lower cost.

Haghbin said: "Instead of having a separate isolated battery charger, we introduced a new concept for the power transfer, the rotating transformer, which was developed to transfer electric power while rotating."

"The battery is charged through the transformer and a split-phase electric motor that was especially designed for this purpose."

According to the university, the new integrated charger, which has a Swedish and an international patent, is still at laboratory level, and requires further investigations and experimentation in order to achieve a more optimal system.

Chalmers is currently seeking a potential industrial user, while Volvo is currently working on the concept for additional enhancement to be used in its system.

Image: Model of the integrated motor drive and battery charger. Photo: Chalmers University of Technology.