Controller for motor

A controller for a motor that has a first rotor and a second rotor, each of which produces a field by a permanent magnet, and an output shaft capable of rotating integrally with the first rotor of the rotors, which are coaxially disposed, said second rotor being capable of relatively rotating with respect to said first rotor, and the strength of a composite field of the fields of the permanent magnets of the rotors being capable of being changed by changing the phase difference between the rotors by the relative rotation of the second rotor, the controller comprising:

• a phase difference changing driving means that has an actuator that produces a driving force to make said second rotor relatively rotate with respect to said first rotor;
• and
• a phase difference controlling means for controlling the phase difference between the rotors to a predetermined phase difference for which the strength of said composite field is lower than a maximum strength thereof via said phase difference changing driving means in the case where the absolute value of the value of the torque produced on said output shaft is equal to or less than a predetermined set torque, and the value of the rotational velocity of said output shaft is equal to or less than a predetermined set velocity.

A controller for a motor mounted on a vehicle as a propulsion force generating source, the motor having a first rotor and a second rotor, each of which produces a field by a permanent magnet, and an output shaft capable of rotating integrally with the first rotor of the rotors, which are coaxially disposed, said second rotor being capable of relatively rotating with respect to said first rotor, and the strength of a composite field of the fields of the permanent magnets of the rotors being capable of being changed by changing the phase difference between the rotors by the relative rotation of the second rotor, the controller comprising:

• a phase difference changing driving means for making said second rotor relatively rotate with respect to said first rotor;
• and
• a phase difference controlling means for controlling the phase difference between the rotors of said motor to a predetermined phase difference for which the strength of said composite field is lower than a maximum strength thereof via said phase difference changing driving means at least in the case where the vehicle is creeping by the action of a torque produced by said motor.