Doubly Excitated Synchronous Machines for Traction Applications

Electrical motor is the crucial component in the drivetrain of hybrid and electric vehicles. Over the last decades, most traction drive systems have been mainly equipped with induction machines, wound field synchronous machines, and permanent magnet machines. Among these three alternatives, permanent magnet is currently the most used topology for traction applications. This paper discusses alternative machine solutions reported in literature that combines advantages of both permanent magnet machines and wound field synchronous machines. These machine topologies, usually referred in literature as doubly excited synchronous machines, are classified on the basis of three criteria: excitation paths, excitation sources location, field direction. The paper reports feature and drawbacks for the considered machine structures and compares both performance and constructive complexity in the light of their perspective use in traction applications.