Comparison of Dual-Permanent-Magnet-Excited Machines and Surface-Mounted Permanent Magnet Machines in Terms of Force

In this paper, finite element analysis demonstrates the difference between dual-permanent-magnet-excited machines (DPMM) and surface-mounted permanent magnet machines (SPM) in terms of tangential force at the same air gap, diameter, stacking length, and input current. Different from most conventional machines, a novel DPMM has two sets of permanent magnets employed on both stator and rotor. To make a fair comparison, the novel DPMM, based on an original design, is specified to have the same dimensions as a conventional SPM. With the aid of 2D finite element analysis, tangential force generated from the novel DPMM is 167.65% higher than the conventional SPM. To verify the validity of the analyses, a prototype was fabricated and tested. Experiments showed that average deviation was only approximately 1.85%.