Analytical prediction of stator flux density waveforms and iron losses in brushless DC machines, accounting for load condition

An analytically based technique for predicting on-load flux density waveforms in different regions of the stator core and the associated iron loss density of permanent magnet brushless DC motors is described. It combines an analytical model for predicting the instantaneous airgap field distribution with a nonlinear lumped reluctance model of the motor, accounting for time and spatial harmonics. Predicted flux density waveforms and iron loss under various load conditions are compared with those derived from finite element analysis and measurements.