Brushless permanent magnet motor/generator with axial rotor decoupling to eliminate magnet induced torque losses

A method of method of operating a permanent magnet motor/generator so as to eliminate magnet induced torque drag which method comprises:

• providing permanent magnet motor/generator that includes:
• i) a housing;
• ii) a stator located in the housing in a fixed position with respect to the housing, the stator having a plurality of stator magnetic poles and windings for generating a rotating filed in the stator magnetic poles, said stator having a central axis;
• iii) a rotatable shaft extending through the housing and having a central axis which coincides with the central axis of the stator;
• and
• iv) a rotor located in the housing and movably positioned on the rotatable shaft, the rotor provided with a plurality of permanent magnets at a peripheral surface thereof and having a central axis which coincides with the central axis of the stator;
• and
• b) moving the rotor axially along the rotatable shaft within the housing so as to move the rotor while the stator is maintained in a fixed position with respect to the housing, the rotor being moved a sufficient distance relative to the stator to completely decouple the rotor from the stator so as to eliminate magnet induced torque drag.

A parallel hybrid vehicle which comprises:

• an internal combustion engine and
• a permanent magnetic motor/generator, wherein the permanent magnet motor/generator includes:
• a housing;
• a stator located in the housing in a fixed position with respect to the housing, the stator having a plurality of stator magnetic poles and windings for generating a rotating filed in the stator magnetic poles, said stator having a central axis;
• a rotatable shaft extending through the housing and having a central axis which coincides with the central axis of the stator;
• a rotor located in the housing and movably positioned on the rotatable shaft, the rotor provided with a plurality of permanent magnets at a peripheral surface thereof and having a central axis which coincides with the central axis of the stator;
• and
• an actuator for moving the rotor axially along the rotatable shaft within the housing so as to move the rotor while the stator is maintained in a fixed position with respect to the housing, the rotor being moved a sufficient distance relative to the stator to completely decouple the rotor from the stator so as to eliminate magnet induced torque drag.