Controlling a DC-AC inverter of an electric machine, where the electric machine comprises a resonant main exciter having rotary transformer. A voltage level of DC power received at a DC-AC inverter is monitored and the frequency of AC power generated by the DC-AC inverter and supplied to the rotary transformer is controlled based at least in part on the voltage level of the DC power.

A system includes a generator control unit (GCU). The GCU includes a saturable reactor and a rectifier. Each of the saturable reactor and the rectifier has a separate input to receive AC power from a separate respective permanent magnet generator (PMG). A method includes supplying AC power from a first permanent magnet generator (PMG) of a generator to a saturable reactor of a generator control unit (GCU) that is operatively connected to control the generator. The method includes supplying AC power from a second PMG to a rectifier of the GCU, wherein the first PMG supplies a lower AC voltage to the saturable reactor than the second PMG supplies to the rectifier.

Described is a hybrid permanent magnet and wire wound starter generator system. The system includes a polyphase stator that converts a rotating magnetic field to electrical energy. The system also includes a rotor including a plurality of permanent magnets and a wound rotor section. The plurality of permanent magnets and the wound rotor section each generate a portion of the rotating magnetic field. Further, the system includes a controller that controls a polarity of the wound rotor section by transitioning the wound rotor section between a magnetic flux enhancement mode and a magnetic flux weakening mode.

A brushless DC motor system control method provided is based on a hybrid energy storage unit. The HESU topology is designed, and the output of the designed HESU is connected to the input of three-phase inverter, and the output of three-phase inverter is connected with the three-phase windings of the BLDCM. In braking operation, two kinds of braking vectors are constructed according to the HESU and three-phase inverter. Moreover, through the combined action of the two vectors, the braking torque control is achieved and meanwhile the braking energy is fed back to the supercapacitor. In electric operation, four kinds of electric vectors are constructed according to the HESU and three-phase inverter. Moreover, the power sharing control between battery and supercapacitor is realized by different vectors action during motor acceleration mode, and the torque ripple in commutation period is suppressed by different vectors action during motor constant speed mode.

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.

A motor is provided with stator windings arranged on a circumference of stator. Multiple-phase currents are supplied to the stator windings. A current is supplied to rotor windings. The multiple-phase currents include torque current components, which are arranged to be opposite in directions to torque current components of the current. By this mutually opposite-directional current arrangement, a sum of both torque current components results in a magnetomotive force of zero. It is also possible to reduce influence of the torque current components on the field magnetic fluxes of the motor. In the motor, circumferential magnetic flux components can be concentrated on an airgap and a portion near therearound, so that a larger amount of torque can be obtained, and constant output control can be performed more easily.

An electric generator assembly for an aircraft is provided. The electric generator assembly includes: a main generator having a main rotor and a main stator, the main stator comprising a first three-phase winding and a second three-phase winding, the first and second three-phase windings each configured to have a voltage induced therein by the main rotor, the first three-phase winding defining a phase shift from the second three-phase winding greater than zero degrees

The invention related to a control method for operating a synchronous machine, the machine comprising an exciter connected to a synchronous generator and a controller (40) for controlling the machine field excitation. The method comprises the steps of predefining a stable operation torque derivative range within which a stable operation of the machine occurs, performing a torque measuring or calculating for the machine, calculating the derivative of said torque, determining whether the calculated torque derivative is within the predefined stable operation torque derivative range for the machine, and, if the torque derivative is not within the predefined stable operation torque derivative range, modifying the machine field excitation to bring the torque derivative within the predefined stable operation torque derivative range.

A method of performing de-excitation of a brushless synchronous machine having a stator; and a rotor including: a field winding, an exciter armature, a rectifier having thyristors, the rectifier having input terminals connected to the exciter armature and output terminals connected to the field winding, a field discharge resistor connected in series with the field winding, and a bypass switch connected in parallel with the field discharge resistor, the bypass switch being operable between a closed state in which the field discharge resistor is bypassed, and an open state, wherein the method including: a) controlling the thyristors to fire only during a negative half-cycle of the armature voltage waveforms, and b) controlling the bypass switch to obtain the open state from the closed state to thereby discharge a field winding current through the field discharge resistor.

Also disclosed is a method for exciting a generator of a direct current power supply with a controller. The method includes receiving a phase voltages associated with multiphase output of the generator. The method includes determining a maximum line-to-line voltage based on the phase voltages. The method includes operating an exciter winding driver with an oscillating signal generated according to the maximum line-to-line voltage.