Abstract: Methods and systems for protection/disconnect of airborne high-power/energy high-voltage modular multi-string battery packs (such as battery packs for airborne electric propulsion systems). The methods and systems are based on a dissimilar/redundant distributed battery pack protection architecture and use a smart mid-point battery disconnect in conjunction with centralized battery management system. The resulting battery disconnect/protection system is configured to detect bus faults, load faults and string faults and then take appropriate action to isolate the detected fault. For example, in response to a short circuit in one battery string, the faulty battery string may be disconnected from the positive and negative busbars while the remaining battery strings continue to provide power.

Abstract: Methods and apparatus for detecting and characterizing arc faults in an aerospace electric propulsion system and then coordinating the operation of various elements of the protection system to execute a fault-clearing sequence. In a current-based method, the arc is detected and characterized based on differential readouts from current sensors. The difference between currents measured at two ends of a protection zone are compared to a difference threshold. In a power-based method, the arc is detected and characterized based on differential readouts from voltage and current sensors. The differential voltage and current readouts are used to compute the respective powers at two ends of a protection zone. The difference between the respective powers is integrated over a period of time and then the integrated difference is compared to a difference threshold. A differential protection trip mode is invoked when the difference threshold is exceeded.

Abstract: An electrical system for an aircraft includes an AC electric power source electrically connected to a rotary electric motor via a plurality of AC contactors. An AC/DC inverter is electrically connected to the rotary electric motor, a DC power bus is electrically connected to the AC/DC inverter, and a plurality of sensors are arranged to monitor electric currents between the AC electric power source and the rotary electric motor. A first controller is arranged to control the AC/DC inverter; and a second controller is arranged to monitor the sensors and are operatively connected to the AC contactors. The second controller is operable to monitor, via the sensors, the electric currents between the AC electric power source and the rotary electric motor, and detect a fault based upon the electric currents, and deactivate the AC contactors in response to the fault.

Abstract: An aircraft adaptive battery charging system is provided. The adaptive battery charging system comprises: a battery system; a bidirectional converter, wherein the bidirectional converter is capable of an inverter mode and a rectifier mode; an alternating current (AC) motor; a number of controllable contactors that control electrical current between the battery system, bidirectional converter, AC motor, and a power source wherein the controllable contactors can be switched between a closed position to allow electrical current flow and an open position to prevent electrical current flow; a motor controller; a battery charging system controller configured to send control signals to the battery system, motor controller, and controllable contactors in response to system command signals; and a vehicle system controller that sends system command signals to the motor controller and battery charging system controller.

Abstract: A discrete signal interlock system for activating an electric machine in an aircraft includes a first controller, a second controller, and a power source coupled via a single wiring harness bundle to a motor controller that is operatively connected to the electric machine. The motor controller includes a first circuit that is electrically coupled to a driver enabler of the motor controller, and a second circuit that is electrically coupled to a driver of the motor controller. The single wiring harness bundle encloses a first signal cable electrically coupling the first controller to the first circuit, a second signal cable electrically coupling the second controller to the second circuit, a first power cable electrically coupled to the first circuit, and a second power cable electrically coupled to the second circuit. Activation of the motor controller requires activation of the driver in concert with activation of the driver enabler.

Abstract: Apparatus and methods for mitigating abrupt release of energy due to a short circuit or other fault external to battery modules in a battery pack. Each battery module includes a plurality of weakened fusible links, which may connect an associated cell to a virtual cell busbar or connect dedicated busbars. After the fault has been cleared and faulted battery modules have been bypassed, the battery pack is ready for reconnection to the electrical network to provide power for the load(s). The battery management includes detection and isolation of a fault followed by execution of an algorithm for reconnection of the battery pack to the power distribution system after burnout of the fusible links. In addition, the respective activation times for reconnecting operative (not faulty) modules in a faulty battery string versus reconnecting other operative battery strings in the battery pack are coordinated.

Abstract: Methods and apparatus for detecting and characterizing arc faults in an aerospace electric propulsion system and then coordinating the operation of various elements of the protection system to execute a fault-clearing sequence. In a current-based method, the arc is detected and characterized based on differential readouts from current sensors. The difference between currents measured at two ends of a protection zone are compared to a difference threshold. In a power-based method, the arc is detected and characterized based on differential readouts from voltage and current sensors. The differential voltage and current readouts are used to compute the respective powers at two ends of a protection zone. The difference between the respective powers is integrated over a period of time and then the integrated difference is compared to a difference threshold. A differential protection trip mode is invoked when the difference threshold is exceeded.

Abstract: Methods and systems for charging a battery string while protecting against overcharging. One system includes: a pair of disconnect devices; a power distribution bus which is electrically connected to a battery string via the disconnect devices; a battery charger connected to supply battery power to the power distribution bus for charging the battery string; a module monitoring unit configured to sense individual battery cell voltages during charging; a first processor configured to activate one disconnect device to open when the sensed individual battery cell voltages indicate overcharging; a plurality of sensors connected to sense a full-string voltage measured across the battery string and first and second half-string voltages measured across first and second half-strings of the battery string; and a second processor connected to receive sensor data during charging.

Abstract: Methods and systems for protection/disconnect of airborne high-power/energy high-voltage modular multi-string battery packs (such as battery packs for airborne electric propulsion systems). The methods and systems are based on a dissimilar/redundant distributed battery pack protection architecture and use a smart mid-point battery disconnect in conjunction with centralized battery management system. The resulting battery disconnect/protection system is configured to detect bus faults, load faults and string faults and then take appropriate action to isolate the detected fault. For example, in response to a short circuit in one battery string, the faulty battery string may be disconnected from the positive and negative busbars while the remaining battery strings continue to provide power.

Abstract: A method for protecting an electric propulsion system in response to occurrence of a fault. The method includes the step of activating short circuits in power switches of inverters in a motor controller to redirect current regenerated by a motor which is electrically coupled to the motor controller and mechanically coupled to a propeller. The method further includes feathering the propeller while the motor is regenerating current. The protection logic is designed to address different types of faults, including faults in the high-voltage direct-current bus, faults in the motor controller, and faults in the motor.

Abstract: An electrical system is provided. The electrical system includes an insulated electrical conductor installed in an aircraft and configured to conduct a current over a length of the insulated electrical conductor. The electrical system includes an optical fiber includes a jacket surrounding an optical core, the optical fiber installed adjacent to the insulated electrical conductor. The electrical system includes a photo detector coupled to the optical fiber and configured to detect an electromagnetic signal carried by the optical fiber and at least partially generated as a function of an electrical fault that occurs at a point along the length of the insulated electrical conductor.

Abstract: An electrical system is provided. The electrical system includes an insulated electrical conductor installed in an aircraft and configured to conduct a current over a length of the insulated electrical conductor. The electrical system includes an optical fiber includes a jacket surrounding an optical core, the optical fiber installed adjacent to the insulated electrical conductor. The electrical system includes a photo detector coupled to the optical fiber and configured to detect an electromagnetic signal carried by the optical fiber and at least partially generated as a function of an electrical fault that occurs at a point along the length of the insulated electrical conductor.

Abstract: Provided is a low-weight, high-efficiency inductor design for use with or in electrical power equipment, such as inverters. A toroidal power inductor includes a support structure comprising an outer shell, an inner shell, and one or more coolant channels formed therebetween, a plurality of conductors wrapped around and supported by an exterior surface of the outer shell, and an interior cavity substantially enclosed by the inner shell of the toroidal support structure. The plurality of conductors are configured to provide an inductance for the toroidal power inductor, and the one or more coolant channels are distributed beneath the exterior surface of the outer shell to cool the plurality of conductors. An air-core power inductor may implement the conductors using high-temperature superconducting (HTS) tapes cooled by cryogenic fluid flowing within the coolant channels.

Abstract: Systems and methods are provided for an inductive coil anti-icing and noise absorption system. In certain versions, the inductive coil anti-icing and noise absorption system may include an inductive coil and a skin. The inductive coil may generate electromagnetic fields and may electromagnetically couple with the skin. The skin, upon electromagnetically coupling with the inductive coil, may increase in temperature and the increase in temperature may melt or prevent the formation of ice on the skin. The skin or a portion of the skin may be porous and may allow incorporation of a sound absorbing liner. The sound absorbing liner may attenuate noise generated by the aircraft (e.g., noise generated by the aircraft engine). Certain versions may include a plurality of inductive coils and a plurality of skins.

Abstract: An induction heating system employs a ferromagnetic susceptor mounted proximate an exterior of flight surface of an aircraft. At least one electrically conductive coil is mounted proximate the ferromagnetic susceptor. The at least one electrically conductive coil is powered by a first power source with a first frequency. At least one compensating coil is mounted proximate the ferromagnetic susceptor having a geometry determined to provide substantially net-zero flux with respect to the at least one electrically conductive coil and positioned to induce induction heating where the first plurality of electrically conductive coils lacks induced inductive heating coverage. The at least one compensating coils is powered by a second AC power source with a second frequency.

Abstract: In general, certain embodiments of the present disclosure provide methods and systems for determination and assessment of arc flash hazards at an equipment in an electrical power system operative at 400-Hz. According to various embodiments, a method is provided comprising determining an arc current at the equipment and generating an arc flash model based on the determined arc current. The method further comprises determining a value of arc flash incident energy by use of the arc flash model. In some embodiments, an arc flash protection boundary distance and/or a level of Prosomal Protection Equipment (PPE) are further determined by use of the value of arc flash incident energy for the equipment in the 400-Hz electrical power system.

Abstract: Systems and methods are provided for an inductive coil anti-icing and noise absorption system. In certain versions, the inductive coil anti-icing and noise absorption system may include an inductive coil and a skin. The inductive coil may generate electromagnetic fields and may electromagnetically couple with the skin. The skin, upon electromagnetically coupling with the inductive coil, may increase in temperature and the increase in temperature may melt or prevent the formation of ice on the skin. The skin or a portion of the skin may be porous and may allow incorporation of a sound absorbing liner. The sound absorbing liner may attenuate noise generated by the aircraft (e.g., noise generated by the aircraft engine). Certain versions may include a plurality of inductive coils and a plurality of skins.

Abstract: A de-icing system is provided that includes a member, a coil, and a power supply. The member includes an anti-icing portion. The coil is inductively coupled to the anti-icing portion of the member. The power supply is coupled to the coil, and is configured to provide voltage to the coil. The coil emits electromagnetic energy responsive to power supplied by the power supply. Responsive to the electromagnetic energy, eddy currents are generated in the anti-icing portion that provide heating of the anti-icing portion.

Abstract: In general, certain embodiments of the present disclosure provide methods and systems for determination and assessment of arc flash hazards at an equipment in an electrical power system operative at 400-Hz. According to various embodiments, a method is provided comprising determining an arc current at the equipment and generating an arc flash model based on the determined arc current. The method further comprises determining a value of arc flash incident energy by use of the arc flash model. In some embodiments, an arc flash protection boundary distance and/or a level of Prosomal Protection Equipment (PPE) are further determined by use of the value of arc flash incident energy for the equipment in the 400-Hz electrical power system.

Abstract: Provided is a low-weight, high-efficiency inductor design for use with or in electrical power equipment, such as inverters. A toroidal power inductor includes a support structure comprising an outer shell, an inner shell, and one or more coolant channels formed therebetween, a plurality of conductors wrapped around and supported by an exterior surface of the outer shell, and an interior cavity substantially enclosed by the inner shell of the toroidal support structure. The plurality of conductors are configured to provide an inductance for the toroidal power inductor, and the one or more coolant channels are distributed beneath the exterior surface of the outer shell to cool the plurality of conductors. An air-core power inductor may implement the conductors using high-temperature superconducting (HTS) tapes cooled by cryogenic fluid flowing within the coolant channels.