Electrical system

Patent metadata

Field	Value
Publication number	US-11175349-B2
Application number	US-201916437569-A
Country	US
Kind code	B2
Filing date	Jun 11, 2019
Priority date	Jun 12, 2018
Publication date	Nov 16, 2021
Grant date	Nov 16, 2021

Abstract

An electrical system includes a ground fault detection unit including a low frequency ground fault detection circuit and a high frequency ground fault detection circuit, and/or a ground fault control unit connected to the low frequency ground fault detection circuit and the high frequency ground fault detection circuit. The ground fault unit may be configured to detect a ground fault according to an output of the low frequency ground fault detection circuit and/or an output of the high frequency ground fault detection circuit. The electrical system may include a first current sensor connected to the low frequency ground fault detection circuit and/or a second current sensor connected to the high frequency ground fault detection circuit.

First claim

What is claimed is:

1. An electrical system, comprising:
a ground fault detection unit, including:
a low frequency ground fault detection circuit; and
a high frequency ground fault detection circuit, including a signal conditioner, a filter, an inverting amplifier, a demodulator, and a comparator; and
a ground fault control unit connected to the low frequency ground fault detection circuit and the high frequency ground fault detection circuit, the ground fault control unit configured to detect a ground fault according to an output of the low frequency ground fault detection circuit and/or an output of the high frequency ground fault detection circuit;
wherein the high frequency ground fault detection circuit is configured to detect ground faults in a high frequency range that includes frequencies of at least 25 kHz.

2. The electrical system of claim 1 , including a first current sensor connected to the low frequency ground fault detection circuit and a second current sensor connected to the high frequency ground fault detection circuit.

3. The electrical system of claim 2 , wherein the first current sensor and the second current sensor are both configured to sense ground current at an output of an AC power source.

4. The electrical system of claim 3 , wherein the second current sensor is configured for use with frequencies of at least 30 kHz.

5. The electrical system of claim 3 , wherein said AC power source includes a generator connected to an aircraft engine.

6. The electrical system of claim 1 , wherein the ground fault control unit is configured to detect the ground fault if a ground current exceeds a threshold.

7. An electrical system, comprising:
a ground fault detection unit, including:
a low frequency ground fault detection circuit; and
a high frequency ground fault detection circuit, including a signal conditioner, a filter, an inverting amplifier, a demodulator, and a comparator; and
a ground fault control unit connected to the low frequency ground fault detection circuit and the high frequency ground fault detection circuit, the ground fault control unit configured to detect a ground fault according to an output of the low frequency ground fault detection circuit and/or an output of the high frequency ground fault detection circuit;
wherein the ground fault control unit is configured to detect the ground fault if a ground current exceeds a threshold; and
the threshold is about 500 mA or less.

8. The electrical system of claim 7 , wherein the high frequency ground fault detection circuit is configured to detect ground faults at or above about 25 kHz.

9. The electrical system of claim 1 , including a low frequency current sensor connected to the low frequency ground fault detection circuit and a high frequency current sensor connected to the high frequency ground fault detection circuit.

10. The electrical system of claim 9 , wherein the high frequency current sensor is not a Hall-effect sensor.

11. An electrical system, comprising:
a ground fault detection unit, including:
a low frequency ground fault detection circuit; and
a high frequency ground fault detection circuit; and
a ground fault control unit connected to the low frequency ground fault detection circuit and the high frequency ground fault detection circuit, the ground fault control unit configured to detect a ground fault according to an output of the low frequency ground fault detection circuit and/or an output of the high frequency ground fault detection circuit;
wherein the high frequency ground fault detection circuit includes:
a signal conditioner;
a filter;
an inverting amplifier;
a demodulator; and
a comparator.

12. The electrical system of claim 11 , wherein the high frequency ground fault detection circuit is connected to an input of the ground fault control unit.

13. The electrical system of claim 12 , wherein the high frequency ground fault detection circuit includes a timer circuit connected to the comparator.

14. The electrical system of claim 11 , wherein the demodulator includes a radio frequency demodulator and the comparator includes a threshold comparator.

15. The electrical system of claim 11 , wherein the filter is a bandpass filter having a passband including 150 kHz or 300 kHz.

16. The electrical system of claim 11 , wherein the signal conditioner is connected to the filter, the filter is connected to the inverting amplifier; and the inverting amplifier is connected to the comparator.

17. An electrical system, comprising:
a ground fault detection unit, including:
a low frequency ground fault detection circuit; and
a high frequency ground fault detection circuit; and
a ground fault control unit connected to the low frequency ground fault detection circuit and the high frequency ground fault detection circuit, the ground fault control unit configured to detect a ground fault according to an output of the low frequency ground fault detection circuit and/or an output of the high frequency ground fault detection circuit;
wherein the high frequency ground fault detection circuit is configured to detect ground faults in a high frequency range that includes frequencies of at least 25 kHz; and the high frequency ground fault detection circuit includes a first portion and a second portion; the first portion includes a first signal conditioner, a first filter, a first inverting amplifier, a first demodulator, and a first comparator; and the second portion includes a second signal conditioner, a second filter, a second inverting amplifier, a second demodulator, and a second comparator.

18. The electrical system of claim 17 , wherein the first filter has a first passband including 150 kHz and the second filter has a second passband including 350 kHz.

19. The electrical system of claim 18 , wherein the high frequency ground fault detection circuit includes a third portion including a third signal conditioner, a third filter, a third inverting amplifier, a third demodulator, and a third comparator; and the third filter has a third passband including 20 kHz.

20. An aircraft, comprising:
the electrical system of claim 11 ; and
an AC power source;
wherein the ground fault detection unit is connected to an output of the AC power source.

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Bhalwankar Chaitanya
• Pahl Birger
• Schmalz Steve
• Chui Galen

Classifications

• G01R31/52 Primary

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

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• H02H3/16

  responsive to fault current to earth, frame or mass (with balanced or differential arrangement H02H3/26 {; monitoring earth connection H02H5/105}) · CPC title

• G01R15/202

  using Hall-effect devices (Hall elements in arrangements for measuring electrical power G01R21/08) · CPC title

• H02H7/1216

  for AC-AC converters · CPC title