Advanced Electric Machines for Electric and Hybrid Vehicles

In this chapter, more advanced electric machines for electric and hybrid vehicles are introduced. Even though not all the performance metrics of these advanced electric machines are as good as conventional electric machines, they have some distinct advantages surpassing the conventional counterparts. Hence, these advanced electric machines have been gaining attention. As the rotor permeant magnet (PM) machines suffer from the risk of irreversible demagnetization due to poor thermal dissipation and/or faulty conditions as well as demanding magnet retention, several stator PM machines are introduced including doubly-salient PM machines, flux-switching PM machines, and flux-reversal PM machines. In order to improve the torque density, magnetic gear-based machines are introduced including vernier PM machines and magnetically-geared PM machines. Both the stator PM machines and the magnetic gear-based machines belong to the family of flux-modulated machines, since their original PM flux is modulated by the flux modulator in principle. Furthermore, in order to achieve both high torque density and wide speed range, the concept of flux-controllable/variable-flux machines is introduced including hybrid-excited machines and memory PM machines. The principle, development, and novel topologies of all these aforementioned advanced electric machines will be demonstrated in detail in this chapter. The trends and tradeoffs of these machines for electric and hybrid vehicle applications are highlighted.