Magnetic field and operating performance analysis of conical-rotor permanent magnet synchronous motor

In order to accurately analyze the magnetic field of conical-rotor permanent magnet synchronous motor (CR-PMSM), the effectiveness of two methods was studied on handling of problems concerned with non-uniform distribution of magnetic field along axial direction in CR-PMSM, which were sectional calculation (SC) method and three-dimensional finite element (3-D FE) method. On this basis, the influence of the axial displacement and dq-axis currents on the operating characteristics of axial magnetic force and torque is analyzed by using the 3-D FE model. Analysis results show that the axial magnetic force and torque decrease with the increase of axial displacement of the rotor, and the amplitude regularity of the axial magnetic force is affected by the d-axis current. A prototype machine is fabricated and tested, in order to validate the design theory.