Theoretic and Experimental Approach to the Adoption of Bonded Magnets in Fractional Machines for Automotive Applications

This paper aims to tackle the general problem of increasing the performances of small permanent-magnet (PM) machines, through the use of bonded magnets instead of the more diffused ferrite magnets. In particular, the study is developed for a fractional-slot concentrated winding PM machines for automotive applications. Neodymium bonded magnets with different and unconventional resins are realized in the internal laboratories. The rotors with the different magnet technologies are experimentally characterized, and the experimental values are compared with the simulation ones. The obtained results allow to define the possible performance increment. Finally, this paper analyzes the possible improvement of the rotor magnetic circuit for a better exploitation of the bonded magnets, without altering the stator structure and the motor housing.