Comparison of two different structure of permanent magnet dual mechanical port machine

There are two types of permanent magnet dual mechanical port electrical machine (DMPM), namely, non-uniform magnetic-field DMPM and uniform magnetic-field DMPM. In this paper, both the equivalent-magnetic-circuit method and FEM are adopted to compare the characteristics of the uniform field DMPM to the non-uniform field DMPM such as electromagnetic coupling etc. The analysis indicates that both outer and inner air gap flux density of uniform field DMPM are higher even with the same volume of magnets; the electromagnetic coupling between stator and inner rotor is stronger. Because the non-magnetic material is used in the outer rotor of uniform field DMPM, Ld, Lq decrease, the torque coupling between the stator and the inner rotor of uniform field DMPM is not significant. One uniform field and one non-uniform field DMPM prototypes are manufactured. The simulation results are verified by experiments.