This paper presents an overview of development trends of interior permanent magnet (IPM) motors in the automotive industry from the perspective of rotor design and the quantity of permanent magnets. The emphasis is on rotor geometry and different approaches to increasing the reluctance component of the torque, thereby reducing the magnet mass. Specific quantities are calculated and compared, namely specific torque and specific power per magnet mass, together with power density of the active volume, which serve as the key indicators of magnet utilization. Finally, the paper also addresses the current shift toward heavy rare-earth-free and magnet-free machines among European manufacturers.
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