An assembly comprising: a synchronous machine including a stationary portion and a rotating portion, the stationary portion including a direct current armature winding, and the rotating portion including a rotating inverter coupled to an alternating current field winding 118); a controller; a current regulator coupled to the rotating inverter and the controller, wherein the current regulator is configured to adjust current output of the rotating inverter, and wherein the current regulator is coupled to one or more current sensors that determine a current output at each phase of the rotating inverter, and the current regulator is configured to selectively adjust the current supply from the rotating inverter to the AC field winding based on the current output at each phase of the rotating inverter and the relative position determined by the controller; the assembly is characterized by: a carrier generator configured to cause a carrier signal to be injected into a magnetic field between the AC field winding and the DC armature winding; and wherein the controller is configured to cause the rotating inverter to communicate alternating current to the AC field winding at a frequency that is based upon the carrier signal and is adjusted to synchronize with a relative position of the rotating portion; wherein the controller includes a rotor position estimator configured to determine the position of the rotating portion based on an electrical parameter at the other one of the AC field winding and the DC armature winding, the electrical parameter being at a frequency of the carrier signal, wherein the rotor position estimator is coupled to a voltage sensor Z to obtain a voltage signal at the stator armature winding, the electrical parameter being the obtained voltage signal, the obtained voltage signal including angular information about the rotating portion at the frequency of the carrier signal, and further wherein the carrier generator is configured to inject the carrier signal to the current regulator, and the current regulator is configured to communicate the carrier signal to the rotating inverter, such that the carrier signal is injected into the rotating magnetic field. a synchronous machine including a stationary portion and a rotating portion, the stationary portion including a direct current armature winding, and the rotating portion including a rotating inverter coupled to an alternating current field winding 118); a controller; a current regulator coupled to the rotating inverter and the controller, wherein the current regulator is configured to adjust current output of the rotating inverter, and wherein the current regulator is coupled to one or more current sensors that determine a current output at each phase of the rotating inverter, and the current regulator is configured to selectively adjust the current supply from the rotating inverter to the AC field winding based on the current output at each phase of the rotating inverter and the relative position determined by the controller; the assembly is characterized by: a carrier generator configured to cause a carrier signal to be injected into a magnetic field between the AC field winding and the DC armature winding; and wherein the controller is configured to cause the rotating inverter to communicate alternating current to the AC field winding at a frequency that is based upon the carrier signal and is adjusted to synchronize with a relative position of the rotating portion; wherein the controller includes a rotor position estimator configured to determine the position of the rotating portion based on an electrical parameter at the other one of the AC field winding and the DC armature winding, the electrical parameter being at a frequency of the carrier signal, wherein the rotor position estimator is coupled to a voltage sensor Z to obtain a voltage signal at the stator armature winding, the electrical parameter being the obtained voltage signal, the obtained voltage signal including angular information about the rotating portion at the frequency of the carrier signal, and further wherein the carrier generator is configured to inject the carrier signal to the current regulator, and the current regulator is configured to communicate the carrier signal to the rotating inverter, such that the carrier signal is injected into the rotating magnetic field.