Patent ID: 11878594
Assignee: THE BOEING COMPANY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC B  H  G  Y | IPC B  G

Claim 14:
15. An electric propulsion system comprising:
a battery pack comprising parallel strings of battery modules;
a busbar connected to receive DC power from the battery pack;
a power line connected to receive DC power from the busbar;
a motor controller comprising power switches which are connected to receive DC power from the power line and configured to convert the DC power to AC power;
an AC motor connected to receive AC power from the motor controller;
a first current sensor connected to sense a first current supplied by the battery pack to a first end of a protection zone that includes at least a portion of the power line and configured to output first sensor data representing a magnitude of the first current;
a first voltage sensor connected to sense a first voltage at the first end of the protection zone current and configured to output second sensor data representing a magnitude of the first voltage;
a second current sensor connected to sense a second current supplied to the motor controller at a second end of the protection zone and configured to output third sensor data representing a magnitude of the second current;
a second voltage sensor connected to sense a second voltage at the second end of the protection zone current and configured to output fourth sensor data representing a magnitude of the second voltage; and
a differential protection control module connected to receive the first through fourth sensor data, wherein the differential protection control module is configured to perform operations comprising:
(a) calculating an integrated power difference based on the first through fourth sensor data received at a succession of instants during a window of time, wherein the integrated power difference is derived by integrating a difference between a first power at the first end of the protection zone and a second power at the second end of the protection zone;
(b) determining that the integrated power difference exceeds an integrated difference threshold indicating a fault in the protection zone; and
(c) commanding the electric propulsion system to operate in a mode that isolates the fault in response to operation (b) by changing states of the power switches in the motor controller to short the AC motor, thereby blocking current regenerated by the AC motor from reaching the power line.