Induction motors are the most common type of AC motors (about 80% of all motors) used today in industrial applications due to their simplicity, rugged construction and relatively low manufacturing cost. However, fuel efficiency of this type of motor is still not sufficiently high. Scientists and experts are try for many years to improve the energy efficiency only finding that their efficiency has reached a point of diminishing return. Therefore, people are seeking alternative forms of motor, among which is the PM type.
Permanent motor materials can be any of the following:
Instead of applying a field winding on the stator frame, a permanent magnet motor relies on a permanent magnet to provide the magnetic field against which the rotor field interacts to produce torque.
To minimize overall weight and size while ensuring the energy efficiency, a permanent magnet motor can apply Neodymium or other strategic materials with high flux density and energy product. Electric machines with high-energy permanent magnets are at least competitive with all optimally designed singly fed synchronous and induction electric machines.
Permanent magnet motors have yielded multiple advantages over induction ones and are gaining everyday wider applications. You can have a better knowledge of this aspect at Permanent Magnetic Synchronous Motors-Development, Advantages and Challenges.