Hybrid wound-rotor motor and generator with induction feed and persistent current

A method for operation of a device in a motor mode, the method comprising:

• cooling, with a cryocooler, a superconducting coil of a rotor until a temperature of windings of the superconducting coil is at a superconducting operating temperature;
• providing, by a flux pump, flux to the superconducting coil until a persistent current flowing through the windings of the superconducting coil is at a persistent operating current;
• receiving, by a main stator coil, an alternating current input from a power distribution bus;
• receiving, by a control stator coil, a control current from a controller;
• generating, by an alternating current within the main stator coil, a rotating magnetic field;
• electrically interacting, by the rotating magnetic field, with the persistent current of the superconducting coil;
• generating, by the rotating magnetic field interacting with the persistent current, an electromagnetic torque to rotate the rotor;
• generating, by the control stator coil, a current at a non-superconducting coil of the rotor;
• modulating, by a magnetic field produced by the current of the non-superconducting coil, a magnetic field produced by the alternating current of the main stator coil;
• and
• varying at least one of magnitude, phase, or frequency of a combination of the rotating magnetic field of the main stator coil and the magnetic field of the non-superconducting coil in comparison to at least one of a magnitude, phase, or frequency of the rotating magnetic field produced by the main stator coil alone to control a speed of the rotor.