ABSTRACT
The robustness of the AC machines compared with DC machines makes them attractive in various motor drive applications including those for electric and hybrid vehicles. The robustness advantages are of bene‹t only when AC motor controllers can deliver performance comparable to or better than that of DC machines. The control simplicity in DC machines is due to the mechanical arrangements of commutators and brushes that maintain the orthogonality between the stator and rotor ¨uxes without any controller involvement. Fast response is a critical requirement for traction applications; motor drives must respond instantaneously with torque changes following a command change. In DC machines, the torque is directly proportional to the armature current without any dynamics involved, which makes the response instantaneous. The AC motor drives can be designed with fast response characteristics, but at the expense of controller complexity.
