Abstract: An electrical motor or generator asymmetrical armature winding configuration generating a multi-phase balanced power output. Each winding group for each pole, and the conductors constituting each winding group, are chosen individually according to their magnetomotive force (MMF) vector relationship to provide a balanced power output even though the individual windings may not be balanced or symmetrical.

Abstract: A shear gear arrangement with gear teeth on the bearing liner positioned to engage complementary teeth on a shear gear main body. The bearing liner is static, while the shear gear main body mounts on the rotating drive shaft. If a failure occurs, the drive shaft displacement causes the shear gear main body gear teeth to engage the bearing liner teeth, instantaneously loading the shear section of the shaft with a sufficient torque load to shear the section as designed.

Abstract: A motor drive circuit has a converter for coupling to an AC voltage source and an inverter coupled to the converter for providing a drive current for a motor. A common mode circulation loop is coupled to the converter and to the inverter, and circulates common mode current from both the converter and the inverter.

Abstract: A synchronous electric machine operates as a starter-generator for an aircraft. When operating in a starting mode, a main stator of the machine is supplied with electrical power at a constant frequency. An exciter stator is supplied with variable frequency power. As rotational speed increases, the exciter variable frequency changes correspondingly to maintain synchronous operation of the machine and maximum torque. In a generator mode, variable frequency is applied to the exciter stator with the exciter frequency varying as a function of rotational speed of an engine driving the machine. This provides for a constant frequency output from the machine.

Abstract: An electrical power system architecture uses an auxiliary power unit as an electrical power source during taxi (ground idle) and approach idle (if required). Using the APU as a power source enables a low pressure spool driven electrical generator to be off-line when its speed is too low for it to operate effectively.

Abstract: A generator system is configured to supply two phase excitation current from an exciter rotor to a main generator rotor. When driven by a variable speed prime mover, the generator system provides relatively constant frequency AC power by independently controlling the main rotor flux rotational speed. The generator system includes an exciter stator that induces current in the exciter rotor windings at a desired frequency and phasing. The exciter rotor windings are electrically connected to the main rotor windings to provide two-phase excitation current to the main rotor windings. Excitation is supplied to the exciter stator from an exciter controller, which controls the frequency and phasing of the exciter excitation, based on the rotational speed of the generator, to maintain a constant output frequency.

Abstract: Methods for active power management, i.e., the power management method may be activated in response to changes in the supply and demand of power in a system, are disclosed. The power management method may use dynamically collected data reporting levels of electrical power utilized by systems while matching them to the available power. One embodiment of the present invention may be applied in smaller or medium sized systems. Another embodiment of the present invention may be implemented making use of additional aircraft resources, such as an integrated modular avionics (IMA) line replaceable unit (LRU) in larger sized systems. Both of these embodiments may make use of data collected from systems utilizing or generating electrical via the bus power control unit (BPCU) LRU, the data processing taking place either locally in the BPCU (small or medium sized systems) or in the IMA (larger systems).

Abstract: A disengagement/disconnect assembly for disengaging a generator from a gear box includes an inner ball screw having an angled threading on an outer surface thereof and surrounding and operatively engaged to a rotating generator drive shaft to cause rotation of the inner ball screw, the inner ball screw having axial dog teeth engaged to corresponding teeth of the gear box drive shaft, an outer ball screw surrounding and normally rotating with the inner ball screw and having a spherical ball and an angled ball track between the inner and outer ball screws, a lock, and a brake for slowing or stopping rotation of the outer ball screw so that the inner ball screw rotates relative to the outer ball screw along the ball track and slides axially toward the lock thereby disengaging the generator from the gear box drive shaft.

Abstract: A solid state power controller (SSPC) often contains electronic circuitry which could be damaged or upset by the excessive transient voltages induced by the lightning and SSPC could result in undesirable (or nuisance) trips due to lightning strikes. The present invention is intended to address the “nuisance trip” issue, by relying on the lightning indicative signals to distinguish between the transient current surge due to the lightning strike and that due to the circuit fault in the power distribution channel. The present invention utilizes either the break-down current in a transient voltage suppression (TVS) device, or a voltage signal at the output of the SSPC as the indication of lightning strike, to avoid nuisance trips.

Abstract: A generator control unit for fast field discharge of a field coil is disclosed. The generator control unit comprises a control domain for detecting an excessive generator output voltage, a buck regulator with a feedback pin fed from the control domain, and an over-voltage protection switch connected in a field coil return path which is bypassed by a voltage limiting device. The control domain receives a point of regulation voltage feedback and upon detection of an over-voltage, emits a disable signal to cause the buck switch shut off along with the over-voltage protection switch. Thus dual breaking points are created at two ends of the field coil to dissipate the field charge quickly through the voltage limiting device. When the buck switch experiences a shorting failure, the over-voltage protection switch provides a second breaking point to allow the field discharge through the voltage limiting device, thereby controlling the field discharge with directly controlled over-voltage protection switch.

Abstract: A control system for an electrical power generation system (EPGS) provides overload protection without disconnecting a generator of the EPGS from an excessive electrical load. Available engine power and current levels of the electrical load are continuously measured and computed. A command voltage is calculated in real time that corresponds to a voltage required to sustain with the maximum available power. Output voltage of a generator of the EPGS is controlled at the calculated command voltage so that a power limit of the engine is not exceeded during electrical overload conditions.

Abstract: A battery health or prognosis system may employ a ferrite disc embedded in a printed wiring board (PWB) to perform both a battery current sensing role and a temperature sensing role. The ferrite disc may be surrounded with a coil that may be comprised of surface conductors and electrically conductive vias of the PWB. Excursions of coil current may be produced to generate observable hysterisis loops in the ferrite disc. The generated hysterisis loops may be compared to a temperature-dependent family of hysterisis loops for the magnetic material from which the ferrite disc is constructed. A processor mounted on the PWB may collect and process outputs from a Hall-effect sensor to develop both temperature and battery current information to produce a prognosis for the battery.

Abstract: A ground fault interruption (GFI) system is incorporated onto a DSP based LRM of an aerospace vehicle. The GFI system operates with digital controls and, unlike the prior art, the system does not employ current transformers. Synchronization pulses are employed to coordinate instantaneous current measurement samplings in each phase of a multi-phase power system. Coordinated sampling may reduce phase angle current differential errors and improve operational precision of the GFI system.

Abstract: A power supply system allowing remote adjustments of the power output of the power supply unit without having to physically access the power supply unit itself is disclosed. A power supply system in accordance with the present invention utilizes a central processing unit (CPU) to provide a command that adjusts to the power output via a modified pulse width modulator (MPWM). Moreover, the central processing unit (CPU) may also be used to provide fine tune adjustments to the error signal of the power supply system, wherein the central processing unit (CPU) produces a command for the modified pulse width modulator to control the power output.

Abstract: A method is provided for selecting and optimizing an electric drive system by analyzing critical-to-quality subjects of the electric drive system according to Six Sigma theory. The critical-to-quality subjects include weight, volume, reliability, efficiency and cost. Various design approaches may be evaluated to select an optimal design. The design approaches may include electric machine type, cooling system, electrical integration and electrical-mechanical interface.

Abstract: An apparatus and method for allowing continuous operation of a generator control unit (GCU) despite a ground fault short circuit is disclosed. More specifically, a generator control unit (GCU) that maintains an isolated power pass domain in a completely floating set up with respect to the ground referenced control domain is used to allow continuous operation of a generator control unit (GCU) even when an internal wiring such as a permanent magnet generator wire or a generator field coil wire comes in contact with the chassis due to failure of the insulation. In addition, the apparatus and method also utilizes a high ohmic resistor as the only connection between the isolated power pass domain and the ground referenced control domain to control the voltage spike that occurs during a ground fault short circuit.

Abstract: Methods for detecting wet arc faults are based on the direct current (DC) signature analysis and pattern matching pertaining to wet arc characteristics. While magnifying some wet arc fault signatures, it may be found that the wet arc current signal itself resembles a normal current signal in both time and frequency domains. The change in magnitude or high frequency behavior found may not be enough to distinguish a wet arc fault signature from a normal signature. Embodiments of the present invention may look at the magnitude change in the DC content per cycle of the wet arc current signal, which may be more positive in one cycle while, in the next cycle, it may be negative in a relative manner. A particular number of these changes may be determinative of a wet arc fault.

Abstract: A high frequency starter-generator system uses an electric machine design that does not employ rotating rectifiers installed on the rotor. The output frequency of such a starter-generator is increased by about 200% as compared with a conventional starter-generator with the same number of poles operating in the same speed range. This design allows significant weight and volume reductions of the electric machine while its reliability is increased. The present invention may find application in any starter-generator application, including more electric architecture-type aircraft designs currently in development.

Abstract: A voltage regulator with an adaptive field discharge control system may use the rate of change of the POR voltage, the rate of change of the output current and rate of change of the field current, or any combination of these, as an input. The adaptive field discharge control system may process the inputs, identify an operating condition, such as unbalanced load, overcurrent and overload, and compare reference setpoints against that condition. Conventional field control circuits may be triggered by a fixed POR voltage setpoint for all operating conditions. In addition, conventional field control circuits may trigger field discharge to turn on and off continuously during systems oscillations. To avoid these issues, the adaptive field control circuit of the present invention may include a variable POR voltage setpoint, based upon one or more of the rate of change in the POR voltage, the DC bus voltage, or the percentage of unbalanced load.

Abstract: A control system for an electrical power generation system (EPGS) provides overload protection without disconnecting a generator of the EPGS from an excessive electrical load. Available engine power and current levels of the electrical load are continuously measured. A command voltage is calculated that corresponds to a voltage required to sustain with the maximum available power. Output voltage of a generator of the EPGS is controlled at the calculated command voltage so that a power limit of the engine is not exceeded during electrical overload conditions.