Method and system for brushless wound field synchronous machines

A method of generating torque utilizing an electric machine, the method comprising:

• applying a voltage to a stator winding;
• producing, via the stator winding, a first rotating magnetic field;
• producing, via the stator winding, a second rotating magnetic field that has a different spatial frequency than the first rotating magnetic field;
• inducing an alternating current in an induction winding in a rotor through asynchronous interaction of the induction winding with the first rotating magnetic field;
• rectifying the alternating current to a direct current;
• supplying the direct current to a field winding on the rotor;
• and
• producing torque through synchronous interaction of the field winding with the second rotating magnetic field.

An electric powertrain comprising:

• a multiphase inverter;
• an electric machine electrically coupled to the multiphase inverter, the electric machine comprising:
• a stator having a stator winding disposed thereon;
• a rotor;
• a field winding disposed on the rotor;
• an induction winding disposed on the rotor;
• a rectifier electrically coupled to the induction winding and the field winding;
• wherein, upon application of a voltage to the stator winding, the stator winding produces a first rotating magnetic field and an independently controlled second rotating magnetic field that has a different spatial frequency than the first rotating magnetic field;
• wherein, the first rotating magnetic field interacts asynchronously with the induction winding to produce an alternating current in the induction winding;
• wherein, the rectifier changes the alternating current to a direct current that is supplied to the field winding;
• and
• wherein the field winding interacts synchronously with the second rotating magnetic field.