Systems for parallel excitation for a synchronous machine are provided. Aspects include a rectification circuit coupled to an output of a permanent magnet generator, and an excitation winding connected to an output of the rectification circuit, a direct current (DC) power source connected between an output of the rectification circuit and the excitation winding, wherein the excitation winding supplies an excitation voltage to an excitation armature in a main generator during a during a plurality of operational modes, wherein the plurality of operational modes comprise a startup mode and a generator mode, wherein a DC excitation voltage is provided to the excitation windings by the DC power source during the startup mode, and wherein the DC excitation voltage is provided to the excitation windings by the rectification circuit during the generator mode.

A stator defines multiple stator poles with associated stator windings. A rotor defines multiple fixed rotor poles with associated teeth with a ferromagnetic material. The fixed rotor poles have associated rotor windings configured to be energized substantially by the stator. Each of the rotor windings is associated with the tooth. Each of the rotor windings includes an alternating current (AC) coil (or auxiliary coil) configured to carry an AC current induced by an AC current flowing in the stator. A direct current (DC) coil (or primary coil) defines a rotor field energizable by magnetic fields produced by the stator windings to produce relative forces between the rotor and the stator. The DC coil is at least partially powered or controlled by the AC coil.

An independent speed variable frequency alternating current (AC) generator apparatus may include a rotor and a stator, the rotor configured to rotate relative to the stator. The apparatus may further include a magnetic field source attached to the rotor and configured to generate a first rotating magnetic field upon rotation of the rotor, where a rotational frequency of the first rotating magnetic field is dependent on a rotational frequency of the rotor. The apparatus may also include a main rotor winding attached to the rotor and configured to generate a second rotating magnetic field upon the rotation of the rotor, where a rotational frequency of the second rotating magnetic field is independent of the rotational frequency of the rotor.

An alternator includes an exciter field device generating an exciter magnetic field in a first air gap, an exciter armature device configured to rotate with respect to the exciter magnetic field and impart a first voltage in a first set of coils at the first air gap, a main stator device including a second set of coils, and a rotor field device configured to be energized by the first current in the first set of coils and generate a main magnetic field that imparts a second voltage on the main stator device at a second air gap. The main stator device and the exciter field device lie in on a common plane normal to an axis of rotation, and the exciter armature device is inwardly spaced from the exciter field device, main stator device, and the rotor field device.

An aircraft main power generation system includes a rotor shaft, a main power generator a permanent magnet, an exciter, an aircraft power bus, and a generator control unit. The generator control unit is configured to provide a control current to the exciter in response to a speed of the main power generator reaching a threshold speed and electrically couple the main power generator to the aircraft power bus in response to the speed of the main power generator reaching a minimum operating speed, the threshold speed being lower than the minimum operating speed; or provide a control current to the exciter in response to the speed of the main power generator reaching a predetermined speed and electrically coupling the main power generator to the aircraft power bus in response to a time period elapsing after the speed of the main power generator has reached the predetermined speed.

In one embodiment, a generator includes a rotor configured to rotate in cooperation with a stator to generate electrical power. An exciter of the generator includes at least one circuit board, a stationary exciter stator, and a control circuit. The circuit board is mechanically coupled to a rotor of the generator and includes at least one coil of an electrical conductor. The stationary exciter stator is configured to induce a current in the at least one coil of the at least one circuit board. The control circuit is configured to modify the current from the at least one coil and provide the modified current to a field of the generator.

The present disclosure relates to motor vehicles. The teachings thereof may be embodied in the operation and control of an externally excited electrical generator in an on-board electrical system of a motor vehicle. An example method may include: setting the excitation voltage within the scope of regulating an actual output voltage of the generator at a predetermined setpoint output voltage of the generator; evaluating load requirements of at least one peak load consumer supplied from the on-board electrical system; identifying exceptional situations based on the load requirements; and in the event of an exceptional situation, setting an associated temporary excitation output voltage of the generator.

A variable frequency starter generator (VFSG) system includes a VFSG having a start mode and a generate mode, a permanent magnet generator (PMG) and a main generator section and an exciter section. The system also includes a controller electrically connected to the VFSG. The controller flow start mode three phase electrical power from aircraft power to the exciter of the VFSG in the start mode and flows single phase electrical power to the exciter of the VFSG in the generate mode. The controller includes: an input active rectifier that receives input AC power and converts it to DC power and provides it to across a positive rail and negative rail; an output inverter coupled to an output of the input active rectifier; and one or more line inductors connected along one or both of the positive rail and negative rail between the input active rectifier and the output inverter.

An assembly according to an embodiment of the present disclosure includes, among other things, a synchronous machine including a rotating portion and a stationary portion, the rotating portion including at least one rotating diode coupled to a field winding, and the stationary portion including a stator winding and an exciter winding. A control unit includes a first gate and a second gate. The exciter winding is connected in series to the first gate and the second gate during a first operating mode to energize the exciter winding. The exciter winding is electrically connected in series to a first gate but is electrically disconnected from the second gate in a second, different operating mode to electrically disconnect the exciter winding from an exciter energy source. A method of operating a synchronous machine is also disclosed.

A vehicle includes an engine and alternator having a field coil and a plurality of output windings, a field current controller configured to receive an AC input and convert the AC input into a regulated DC output that is supplied to the field coil of the alternator, and a controller configured to monitor at least one operating parameter of the field current controller and to compare a monitored value of the at least one operating parameter to a threshold range.