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 example method includes receiving, from one or more sensors of a battery module, sensor information indicative of a health status of the battery module; determining, based on sensor information, battery health parameters of the battery module; determining, based on the battery health parameters, a target state-of-charge (SoC) indicating a target battery capacity to which the battery module is to be charged; determining an end-of-charge voltage (EOCV) to be attained at an end of charging the battery module to achieve the target SoC; and commanding a battery charger to charge the battery module until the EOCV is achieved.

Abstract: An electric propulsion unit comprising a housing, an AC motor, a beta rod, a propeller, a governor, an inverter, and a controller. The AC motor is disposed within the housing and includes bearings supported inside the housing, a hollow motor shaft rotatably coupled to the housing by the bearings, a stator which is supported by the housing, and a rotor which is mounted to the hollow motor shaft. The beta rod is axially translatable inside the hollow motor shaft. The propeller is mechanically coupled to the hollow motor shaft. The propeller includes propeller blades having an adjustable pitch angle which depends on an axial position of the beta rod. The governor is configured to adjust a pitch angle of the propeller blades by actuating axial translation of the beta rod. The controller is disposed inside the housing and configured to control the pitch angle of the propeller blades.

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: 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: 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: An inductive filtering device includes a plurality of grouped electrical conductors and at least two toric magnetic cores, each formed around a central void, the two magnetic cores having different magnetic lengths, the electrical conductor being wound together around both magnetic cores by passing through the central voids of both magnetic cores.

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: An architecture for an aircraft comprises two air-conditioning systems, two converters, each intended to supply one of the air-conditioning systems, and at least one first electric machine which starts up a first main engine of the aircraft. The electrical architecture is configured such that the two converters can together supply the first electric machine. A method of operating the architecture is also provided.

Abstract: Systems for suppressing adverse exothermic reactions in an energy storage container. One energy storage system includes a container configured to support a plurality of battery cells; a plurality of battery cells disposed inside and supported by the container; an agent supply port attached to the container; and a tube disposed inside the container and having a closed end and an open end. The open end of the tube is in fluid communication with the agent supply port. The tube comprises fusible portions which are designed to melt or soften at a temperature which is lower than the melting or softening temperature of another portion of the tube. In response to melting or softening of the fusible portions of the tube, pressurized exothermic reaction-suppressing agent is distributed inside the container via the tube.

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: An electric propulsion unit comprising a housing, an AC motor, a beta rod, a propeller, a governor, an inverter, and a controller. The AC motor is disposed within the housing and includes a plurality of bearings supported inside the housing, a hollow motor shaft rotatably coupled to the housing by the plurality of bearings, a stator which is supported by the housing, and a rotor which is mounted to the hollow motor shaft. The beta rod is axially translatable inside the hollow motor shaft. The propeller is mechanically coupled to the hollow motor shaft. The propeller includes propeller blades having an adjustable pitch angle which depends on an axial position of the beta rod. The governor is configured to adjust a pitch angle of the propeller blades by actuating axial translation of the beta rod. The inverter is disposed within the housing and connected to receive DC power for conversion into AC power.

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: A fault-tolerant power system architecture for aircraft electric propulsion. The fault-tolerant systems continue to operate in the event of the failure of (or one or more faults within) some component. The fault-tolerant design enables the system to continue its intended operation, possibly at a reduced level, rather than failing completely, when some part of the system fails. When a turn-to-turn fault in an AC motor is detected, a motor controller will short three top or three bottom switches in the inverter together (effectively shorting the associated stator windings) to divert fault current from the motor windings to the motor controller, where cooling is available. Also, when a fault in or at the input to a motor controller is detected, the motor controller cuts off power to the motor by issuing a command that causes an upstream contactor with high-voltage DC bus input to open.

Abstract: Systems and methods for current ripple reduction for a direct current (DC) source powering an alternating current (AC) load. In accordance with one embodiment, the system and method involve interleaved operation of a 3×3-phase AC motor having multiple groups of windings. In accordance with another embodiment, the system and method involve interleaved operation of multiple co-shafted 3-phase AC motors. In accordance with a further embodiment, the system and method involve interleaved operation multiple 3-phase AC motors (not co-shafted) of the same level of power. The interleaved operation entails interleaved switching inside a set of inverters which are connected in parallel between a DC bus and the windings of the AC motor (motors).

Abstract: Systems and methods for current ripple reduction for a direct current (DC) source powering an alternating current (AC) load. In accordance with one embodiment, the system and method involve interleaved operation of a 3×3-phase AC motor having multiple groups of windings. In accordance with another embodiment, the system and method involve interleaved operation of multiple co-shafted 3-phase AC motors. In accordance with a further embodiment, the system and method involve interleaved operation multiple 3-phase AC motors (not co-shafted) of the same level of power. The interleaved operation entails interleaved switching inside a set of inverters which are connected in parallel between a DC bus and the windings of the AC motor (motors).

Abstract: An electrical transformer includes a first winding, called primary, at least one second winding, called secondary, switches, and a current detection system, wherein it comprises at least one metal screen having a connection point linked to a neutral potential of the primary winding or intended to be linked to an electrical ground and placed between the primary winding and the at least one secondary winding, the screen being made of an electrically conductive material having a melting point higher than that of the materials constituting the windings; in that the primary winding comprises an input intended to be linked to an external energy source, the switches are placed at the input of the primary winding so as to be able to isolate the primary winding from the external energy source and in that the current detection system is configured to detect a current at the input of the primary winding or a current at the connection point and to close or open the switches based on the detection of the current, the dete