A comparison between AC side excited heteropolar and homopolar synchronous machines

Two forms of stator-side excited synchronous machines are considered in the paper, homopolar and heteropolar. They are compared by the use of 3D magnetostatic finite element modelling. The results from a prototype homopolar machine are also presented to validate the modelling method. It is found that the homopolar machine has some advantages over the heteropolar in weight and volume but there are some penalties in efficiency.