Common mode voltage feed fault protection

Patent metadata

Field	Value
Publication number	US-2023400530-A1
Application number	US-202217986293-A
Country	US
Kind code	A1
Filing date	Nov 14, 2022
Priority date	Jun 9, 2022
Publication date	Dec 14, 2023
Grant date	—

Abstract

A system includes a generator. Three AC feeders are connected for feeding AC output from the generator. A rectifier is electrically connected to the three AC feeders and to a load via a first DC feeder and a second DC feeder. A first resistor connects between a first one of the DC feeders and ground. A first voltage sensor is operatively connected to detect voltage across the first resistor. A second resistor connects between the second DC feeder and ground. A second voltage sensor is operatively connected to detect voltage across the second resistor. A controller is configured to monitor for changes in common mode voltage based on the input from the first sensor and from the second sensor, and to determine presence of a fault if change in the common mode voltage exceeds a predetermined threshold.

First claim

What is claimed is:

1 . A system comprising:
a generator; three AC feeders connected for feeding AC output from the generator; a rectifier electrically connected to the three AC feeders, the rectifier being configured to convert three phase AC from the three AC feeders of the generator into DC output to a load via a first DC feeder and a second DC feeder; a first resistor connecting between a the first DC feeder and ground; a first voltage sensor operatively connected to detect voltage across the first resistor; a second resistor connecting between the second DC feeder and ground; a second voltage sensor operatively connected to detect voltage across the second resistor; and a controller operatively connected to receive input from the first voltage sensor and from the second voltage sensor, wherein the controller is configured to monitor for changes in common mode voltage based on the input from the first sensor and from the second sensor, and to determine presence of a fault if change in the common mode voltage exceeds a predetermined threshold.

2 . The system as recited in claim 1 , wherein the controller is part of a generator control unit (GCU) or rectifier operatively connected to control the generator, part of a motor control unit (MCU) connected to control a motor connected to be powered as a load by the first and second DC feeders, part of a solid state power controller (SSPC) device, or a separate controller from the GCU, rectifier, SSPC device, and MCU.

3 . The system as recited in claim 2 , wherein the controller is configured to take corrective action upon detection of a fault.

4 . The system as recited in claim 1 , wherein the first voltage sensor and the second voltage sensor are hosted in a DC load.

5 . The system as recited in claim 4 , wherein the DC load is operatively connected to be powered by the first and second DC feeders.

6 . The system as recited in claim 1 , wherein the first voltage sensor and the second voltage sensor are integrated in a solid state power controller that is operatively connected to be powered by the first and second DC feeders.

7 . The system as recited in claim 1 , wherein the first voltage sensor and the second voltage sensor are integrated in a motor controller that is operatively connected to be powered by the first and second DC feeders.

8 . The system as recited in claim 7 , wherein the motor controller is connected by three motor feeders to provide three-phase alternating current to power a motor.

9 . A method comprising:
detecting a first voltage across a first resistor between a first DC feeder from a rectifier and ground; detecting a second voltage across a second resistor between a second DC feeder from the rectifier and ground; using the first and second voltages to calculate a common mode voltage; determining the common mode voltage; and determining a fault has occurred base on a change in the common mode voltage that exceeds a predetermined threshold.

10 . The method as recited in claim 9 , further comprising:
determining the fault is located in one of the DC feeders if the common mode voltage is constant, and if the fault is located in one of the DC feeders:
isolating the fault to a positive DC feeder if the common mode voltage is negative; and
isolating the fault to a negative DC feeder if the common mode voltage is positive; and
determining the fault is located in one of the AC feeders if the common mode voltage follows an AC waveform, and if the fault is located in one of the AC feeders:
determining which one of the AC feeders has the fault wherein phase angle of the common mode voltage matches phase angle sensed in one of the AC feeder that has the fault.

11 . The method as recited in claim 9 , wherein determining a fault has occurred includes using common mode current input as an additional logic qualifier.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Ives Kyle Stephen
• Harke Michael C
• Utecht Tom A

Classifications

• G01R31/52 Primary

  Testing for short-circuits, leakage current or ground faults · CPC title

• H02M1/123

  Suppression of common mode voltage or current · CPC title

• H02M1/325

  with means for allowing continuous operation despite a fault, i.e. fault tolerant converters · CPC title

• H02M1/4216

  operating from a three-phase input voltage (H02M1/4233 takes precedence) · CPC title

• H02H3/165 Primary

  for three-phase systems · CPC title