The Effect of the Ratio of Remanent Flux Density to Coercivity of Magnet on Spoke-Type Permanent Magnet Synchronous Motor (PMSM) Performance

Spoke-type PMSMs were designed with commercial permanent magnets and theoretically designed hexaferrite: Nd-Fe-B (NdFe35, G1NH), Alnico (8B, 8H, 9), and La-CoSrM hexaferrite (NMF-15G). It was found that coercivity (H
c
) plays a crucial role in determining motor performance. The ANSYS Maxwell software was used to characterize the designed motor performance. Commercial RE-free Alnico 9 holds a 10.5 MGOe of (BH)
max
, much higher than a 5.5 MGOe of RE-free Alnico 8B/8H and SrM (SrFe
12
O
19
) hexaferrite magnets. However, the Alnico 9 motor performance is not better than the other Alnico 8B/8H and hexaferrite motors. The spoke-type PMSM with our theoretically designed SrM hexaferrite simulated motor performance. A motor performs best when the H
c
/B
r
ratio equals one with a high H
c
. For instance, the motor torque and peak power increase to 189 Nm and 178 kW, respectively, as the H
c
increases to 4.86 kOe from 2.43 kOe. However, the motor performance is not significantly changed with a fixed H
c
and various B
r
. It was found that regardless of (BH)
max
, coercivity (H
c
) plays a dominant role in motor performance.