Analytical modeling of permanent magnet excited brushed DC motor for low-cost applications

In this paper, we present an analytical modelling of permanent magnet excited brushed dc motor for cost sensitive applications. General solutions to the Laplacian/quasi-Poissonian magnetic field equations are first derived in the motor airgap. Applying the specified boundary conditions, normal and tangential components of flux density in the airgap can be analytically predicted. With distributed windings employed in the armature slots, their flux linkage, induced voltage and motor performance can also be calculated. The proposed analytical model can also be used to parameterize the brushed dc motor for optimal performance such as minimum torque ripple. The proposed model shows very good agreement with the results obtained from FEM. Furthermore, the analytical model compares the calculated results between the 12-slot armature dc motor and 10-slot armature dc motor.