
5-1
Power electronics has emerged as the key enabling technology for all aspects of modern electric
machines. Broadly speaking, rotating electric machines are of two types: dc and ac machines. In each
category, permanent magnet (PM) materials are widely employed to achieve ecient performances.
e basic principle of electromagnetic energy conversion is well known. e electromotive force
(EMF), simply called voltage (V) is generated in a rotating machine by the Blv principle involving the
cross product of the magnetic eld vector (B) and the velocity vector lv, where l is the rotor length and
v is the velocity of the prime mover coupled wit