A rotating field machine (200) including a stator (140) and a rotor (150) are provided. In particular, a dual-winding rotating field machine (200) in which the stator (140) includes two separate windings can be provided. In one example implementation, the stator (140) can include an excitation winding (220) configured to control an excitation current and a power winding (230) configured to control power flow to an electrical system. The dual-winding rotating field machine (200) can further include a starting mode and a generating mode. During the starting mode, both the excitation winding (220) and the power winding (230) can be coupled to one or more switching power converters (170). During the generating mode, the power winding (230) can be coupled to a variable frequency bus and the power converter (170) can be used to manage excitation power only.

A electromagnetic machine system includes a rotor and a stator positioned about the rotor. A current injection mechanism is coupled with windings of the stator and structured to inject electrical currents therein so as to change a flux distribution of a magnetic field produced by the stator. The injected currents may be harmonic currents. The rotor further includes an inductor positioned to interact with the magnetic field when the flux distribution is changed, to produce an electrical excitation current for exciting windings in the rotor. The machine system may be a synchronous motor or generator, and may be brushless. Applications of the current injection strategy to direct torque control and vector control are also disclosed.

A electromagnetic machine system includes a rotor and a stator positioned about the rotor. A current injection mechanism is coupled with windings of the stator and structured to inject electrical currents therein so as to change a flux distribution of a magnetic field produced by the stator. The injected currents may be harmonic currents. The rotor further includes an inductor positioned to interact with the magnetic field when the flux distribution is changed, to produce an electrical excitation current for exciting windings in the rotor. The machine system may be a synchronous motor or generator, and may be brushless. Applications of the current injection strategy to direct torque control and vector control are also disclosed.

Unique systems, methods, techniques and apparatuses of a rotating DC power supply are disclosed. One exemplary embodiment includes a first and second DC bus rail, a first and second leg, and a discharge resistor. The first leg includes a first semiconductor device and a second semiconductor device coupled in series at a first midpoint connection, the first semiconductor device being coupled to a first point on the first DC bus rail and the first midpoint connection being coupled to a field winding. The second leg includes a third semiconductor device and a fourth semiconductor device coupled in series at a second midpoint connection, the third semiconductor device being coupled to a second point on the first DC bus rail and the second midpoint connection being coupled to the field winding. The discharge resistor is operatively coupled to the first DC bus rail between the first point and the second point.

Unique systems, methods, techniques and apparatuses of a rotating DC power supply are disclosed. One exemplary embodiment includes a first and second DC bus rail, a first and second leg, and a discharge resistor. The first leg includes a first semiconductor device and a second semiconductor device coupled in series at a first midpoint connection, the first semiconductor device being coupled to a first point on the first DC bus rail and the first midpoint connection being coupled to a field winding. The second leg includes a third semiconductor device and a fourth semiconductor device coupled in series at a second midpoint connection, the third semiconductor device being coupled to a second point on the first DC bus rail and the second midpoint connection being coupled to the field winding. The discharge resistor is operatively coupled to the first DC bus rail between the first point and the second point.

A rotary electric machine is equipped with a stator and a rotor. The rotor has a d-axis magnetic circuit that is produced by a magnetomotive force of a field winding, and magnet magnetic circuits that are produced by a magnetic force of permanent magnets. The d-axis magnetic circuit and a q-axis magnetic circuit have at least a part thereof that is common to both. The permeance of the d-axis magnetic circuit is smaller than the permeance of the q-axis magnetic circuit, when a load is being applied to the rotor. A control apparatus of the rotary electric machine has a switching circuit that controls the field current in the field winding, and a control section that makes the switching frequency of the switching circuit become higher when the field current is above a threshold value than when the field current is less than or equal to the threshold value.

A brushless winding field rotational electric machine positioned between a starting device and a case enclosing the starting device includes: a stator, which is held to the case, including an alternating-current coil configured to generate a rotation magnetic field by alternating current; a field core, which is held to the case, including a field coil to be excited by direct current; and a rotor disposed on an outer periphery of the starting device and rotatably held about a rotational axis relative to the stator and the field coil. The rotor includes a connection portion to be connected to a synchronized rotation member configured to rotate in synchronization with an engine along the rotational axis, on a facing surface to the synchronized rotation member.

A brushless winding field rotational electric machine includes: a stator, held to a case, including an alternating-current coil configured to generate a rotation magnetic field by alternating current; a field core, held to the case, including a field coil to be excited by direct current; and a rotor on an outer periphery of a rotation member and rotatably held about a rotational axis relative to the stator and field coil. The field coil includes a plurality of coil winding layers stacked in a radial direction of the rotational axis. A cross-sectional area along an axial direction of the rotational axis, of a coil winding layer closest to the rotational axis in the radial direction of the rotational axis is smaller than a cross-sectional area along the axial direction of the rotational axis, of a coil winding layer farthest from the rotational axis in the radial direction of the rotational axis.

A rotating electrical machine of a brushless wound field type disposed between a stationary case and rotating member that rotates inside the case includes a stator held by the case, including an AC coil that generates a rotating magnetic field with an alternating current, a field core held by the case, the field core including a field coil that generates a magnetic flux with a direct current, a rotor fixed in contact with an outer circumferential surface of the rotating member and held rotatably relative to the stator and field coil, a rotor side core portion that is a part of the rotating member. The magnetic flux of the field coil passes from the field core through the rotor via the second air gap, the stator and rotor via the first air gap, the rotor side core portion, and the field core via the third air gap.

A doubly fed brushless induction starter generator includes a stator and a rotor, which are separated by an air gap. The stator includes stator winding slots, each of which includes a first layer of power windings, a second layer of power windings, and a third layer of control windings, which include 2-pole single-phase windings. The control windings are arranged in the stator winding slots between the air gap and the first and second layers of power windings. Direct current is delivered to control windings in the generator as an excitation current to thereby produce a magnetic flux, through which the stator is moved to produce and alternating current in the power windings as an output current. The output current can be delivered to an electrical load, such as an electrical component on an aircraft.