1. PERMANENT MAGNET SYNCHRONOUS MOTOR DRIVES (PMSM)
The notation for PMSM is PMAC
In PMSM the D.C field winding of the rotor is replaced by Permanent Magnets
Permanent Magnet Materials: Alnico, Cobalt-Samarium, Ferrite.
Advantages:
Elimination of field copper loss.
Higher power density.
Lower rotor inertia.
More robust construction of motor.
Higher efficiency.
Disadvantages :
Loss of flexibility of field flux control.
Remagnetization effect.
Higher costs.
Application:
Low power range motors are widely used in industries.

2. Types Permanent Magnet Synchronous motors
1.Surface Mounted-PMSM
Projecting type
Inset type
2.Interioror Buried-PMSM

3. Types of Permanent Magnet Synchronous motors
1.Surface Mounted-PMSM
Projecting type
Inset type
2.Interioror Buried-PMSM

4. Types of Permanent Magnet Synchronous motors
Based on nature of voltage induced in the stator
classified as
Sinusoid ally excited PMAC:
Stator has distributed winding.
Stator induced voltage has sinusoidal waveform.
Trapezoid ally excited PMAC:
Stator has concentrated winding.
Stator induced voltage has trapezoidal waveform.

5. Speed control of sinusoidal PMAC
The speed of the PMAC motor is controlled by feeding them from variable frequency ,voltage and current.
They are operated in self controlled mode.
In closed loop control ,current regulated VSI is used.
The inverter is operated to supply motor three phase currents of the magnitude and phase commanded by reference currents isa,isb and isc which generated by a reference current generator.
The stator current templates for the three phases are generated by the rotor position sensors in such a way that δ = π/2

6. Speed control of sinusoidal PMAC

7. Sinusoidally excited PMAC

8. Trapezoid ally excited PMAC

9. Speed control of Trapezoidal PMAC
According to the torque equation torque is proportional to Id.
Regenerative braking mode operation is obtained by reversing phase currents.
This will also reverse the source current Id.
Now power flow from the machine to inverter and from inverter to dc source.

10. Speed control of Trapezoidal PMAC

11. Trapezoidally excited PMAC