Comparative Study of High-Speed PM Motors with Laminated Steel and Soft Magnetic Composite Cores

Soft magnetic composite (SMC) material is formed by surface-insulated iron powder particles, and has very low eddy current. To explore the application of SMC materials, two types of high-speed (20 krpm) permanent magnet (PM) motor have been designed and constructed. One employs radial flux type with laminated steel core, and the other employs transverse flux type with SMC core. Considering the importance of core loss in high speed motors, laminated steel and SMC material are tested by 2-D magnetic tester, and rotational core loss model is employed in the core loss calculation. Details of machine geometry and design procedure are described and some features of the machines are compared.