Similar to BLDC motors, PMSMs have a three-phase stator and
a rotor with surface/interior-mounted permanent magnets.
A PMSM provides rotation at a fixed speed in synchronization
with the frequency of the power source. PMSMs are therefore ideal for
high-accuracy fixed-speed drives. Boasting very highpower density, very high
efficiency and high response, the motor is suitable for most sophisticated
applications in the industrial segment. It also has a high overload capability.
A PMSM is largely maintenance free, which ensures the most efficient operation.
Synchronous motors operate at an improved power factor, thereby improving the overall system power factor and eliminating or reducing utility power factor penalties. An improved power factor also reduces the system’s voltage drop and the voltage drop at the motor terminals.
ADVANTAGES OF PERMANENT MAGNET SYNCHRONOUS MOTOR:
• Heat generated in stator is easy to remove.
• High torque per frame size.
• Reliability due to absence of brushes and commutator.
• Highest efficiency.
• Synchronous operation makes field orientation easy.
• Good high-speed performance.
• Precise speed monitoring and regulation possible.
• Smooth torque.
DRAWBACKS OF PERMANENT MAGNET SYNCHRONOUS MOTOR:
• Rotor position sensing required.
• Position sensor or sensorless technique is required for motor operation.
• Difficult to startup the motor using sensorless technique.