Comparative Investigation of SPM and IPM Synchronous Electric Machine

This paper compares SPM(Surface-mounted Permanent Magnet) and IPM(Interior Permanent Magnet) machine in various aspects: differences in rotor machining and assembly;different performances under power generating state.Investigation shows that the voltage regulation rate and harmonic distortion rate of SPM are less than those of IPM.Comparing with IPM,the operation stability is larger,the flux leakage is less and rotor assembly is easier.