PERMANENT MAGNET SYNCHRONOUS MOTOR DRIVES PMSM PERMANENT MAGNET

Types Permanent Magnet Synchronous motors 1. Surface Mounted-PMSM § Projecting type § Inset type

Types of Permanent Magnet Synchronous motors 1. Surface Mounted-PMSM § Projecting type § Inset

Types of Permanent Magnet Synchronous motors Based on nature of voltage induced in the

Speed control of sinusoidal PMAC • The speed of the PMAC motor is controlled

Speed control of Trapezoidal PMAC • According to the torque equation torque is proportional

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PERMANENT MAGNET SYNCHRONOUS MOTOR DRIVES (PMSM) PERMANENT MAGNET SYNCHRONOUS MOTOR • 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.

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

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

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.

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

Speed control of sinusoidal PMAC

Sinusoidally excited PMAC

Trapezoid ally excited PMAC

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.

Speed control of Trapezoidal PMAC

Trapezoidally excited PMAC