Modeling of a Brushless DC Motor with Solid Parts Involving Eddy Currents

A study method is presented for solid salient pole permanent magnet machines fed by voltage inverter. The study of the machine converter set is performed by modeling the machine in a d, q axis system for each voltage harmonic delivered by the inverter. The elements of the d, q axis system are determined by numerical field calculation taking into account the eddy currents through the pole pieces. The knowledge of a model which represents the machine for each harmonic delivered by the inverter leads to the calculation of the feeding current, the eddy current losses, and the electromagnetic torque. The influence of the eddy current flow in the salient poles is studied when the machine speed increases and when a modulation of the feeding voltage is performed. To show the importance of the eddy current effects, the behavior of a machine with laminated poles is considered.