A novel hybrid excited synchronous machine for (H)EV applications

Numerous different motor types have been examined recently to be used as main traction drives for EV applications. The aims are typically to increase power density and efficiency, fulfill safety requirements and to save costs. Due to price fluctuations of rare earth magnets in the past, such magnets are identified as unpredictable future costs and their content in a motor should be minimized. In contrast, traction motor concepts without rare earth magnets typically cannot achieve a comparable power and torque density. In this paper, a new hybrid excited synchronous motor concept is presented, combining aspects of permanent magnet (PM) machines and electrically excited synchronous motors. The benefits of each concept are combined while overcoming the individual drawbacks. After a presentation of the concept, the prototype design and manufacturing are explained. Test bench results proof the functionality of the concept. The highlights and benefits of this concept are summarized.