Cost effective PM rotor design for servo motor applications

The recently developed harmonic-utilization permanent magnet (HUPM) rotor shows to be a promising candidate for electric machines with less rare-earth materials in various applications. In this paper two different HU rotor topologies have been considered and investigated for low costs servomotor solution. The first motor is a six pole PM machine with a HU rotor having only four magnets, while the second motor is an eight pole machine with a HU rotor having six magnets. Using these new rotor topologies, the magnet amount compared to the well know standard PM rotors can be reduced up to 30%. To prove their properties, various results based on the analytical approach, finite element analysis, and experimental measurements were presented and discussed.