Dynamic study of an electronically brushless DC machine via computer simulations

The authors analyze a machine with a conventional DC armature winding on the stator which does not have a field winding connected with slip rings. At positions where the winding would have been attached to a commutator segment, a transistor switch is attached instead. The rotor contains a permanent magnet field. The lap wound stator winding is sequentially commutated by a system consisting of a position sensor and logic circuitry. Analytical expressions for a full pitch lap wound machine are given. A computer simulation of the machine was implemented. The results serve to illustrate the considerations which must be made in the design of this type of machine, in particular the effects of the winding design on commutation and cost efficiency