In applications requiring low acoustic noise, smooth torque and high
efficiency, Technelec has designed permanent magnet AC synchronous
motors.  The permanent magnets are buried within the rotor to deliver a
combination of reluctance torque and permanent magnet torque.  This
delivers field weakening and a wide constant power region.

Technelec's sensorless vector controlled inverters operate with
sinusoidal phase currents while maintaining synchronism with the rotor
position and delivering the most efficient excitation for the torque on
the shaft.

The sensorless inverters offer four quadrant operation, allowing the
permanent magnet machine to operate as a motor or generator.