Modeling and Analysis of Permanent Magnet Synchronous Machines With Axial Magnetization Rotor by Air Gap Field Modulation Theory

The permanent magnet synchronous machine with axial magnetization rotor (AMR-PMSM), which is capable of low noise, low vibration, and high reliability, has a wide application prospect in wind power generation, industrial automation, robotics, etc. In this article, the novel analytical models (AMs) originating from the air gap field modulation theory (AFMT) are proposed and constructed to quickly predict and analyze the performance of the AMR-PMSM. First, the radial and tangential modulation functions of the stator and rotor cores are deduced. Second, combined with the primitive magnetomotive force (MMF) of the permanent magnets (PMs) and armature windings (AWs), the air gap radial PM and AW magnetic fields are modeled, as well as the tangential PM and AW magnetic fields. Furthermore, the AMs for the back-EMF, cogging torque, and electromagnetic torque of the AMR-PMSM are derived based on the radial and tangential magnetic fields. Then, taking a 12-slot/50-pole(12s/50p) AMR-PMSM, for example, its performance predicted by AMs is obtained and compared with that calculated by the 3-D finite element model (3D-FEM). Finally, experiments concerning a 12s/50p AMR-PMSM prototype are conducted to verify the effectiveness of the proposed AMs and 3D-FEM.