Analytical model of a permanent magnet brushless DC motor with non-linear ferromagnetic material

This paper presents an analytical model for determining air-gap radial and tangential magnetic field in permanent magnet brushless dc (PMBLDC) motor. The solution is based on two-dimensional analysis in polar coordinates for radially magnetized magnet. Effects caused due to non-linear behavior of the stator ferromagnetic yoke are mainly considered. Radial and tangential magnetic field, back emf and cogging torque are calculated and are validated with finite element results. The finite element analysis demonstrates the accuracy of the developed analytical model of PMBLDC motor for no load magnetic field calculation.