Current transformer sensing with saturation protection

Patent metadata

Field	Value
Publication number	US-2025385510-A1
Application number	US-202418746745-A
Country	US
Kind code	A1
Filing date	Jun 18, 2024
Priority date	Jun 18, 2024
Publication date	Dec 18, 2025
Grant date	—

Abstract

An apparatus includes a transient voltage suppression (TVS) device configured to be coupled in parallel with a burden resistor. The apparatus also includes a switch configured to couple the TVS device across the burden resistor. The apparatus further includes a comparator configured to detect a peak output voltage provided by a circuit, determine whether the peak output voltage meets or exceeds a threshold, and control the switch based on whether the peak output voltage meets or exceeds the threshold.

First claim

What is claimed is:

1 . An apparatus comprising:
a transient voltage suppression (TVS) device configured to be coupled in parallel with a burden resistor; a switch configured to couple the TVS device across the burden resistor; and a comparator configured to:
detect a peak output voltage provided by a circuit;
determine whether the peak output voltage meets or exceeds a threshold; and
control the switch based on whether the peak output voltage meets or exceeds the threshold.

2 . The apparatus of claim 1 , wherein the switch is configured to disconnect the TVS device from the burden resistor in response to the peak output voltage being less than the threshold, thereby preventing the TVS device from affecting a measurement accuracy of the burden resistor.

3 . The apparatus of claim 1 , further comprising:
a differential sense circuit coupled across the burden resistor and configured to provide the peak output voltage to the comparator.

4 . The apparatus of claim 3 , wherein the differential sense circuit comprises:
a voltage source; a first operational amplifier coupled in parallel with the voltage source, a first resistor, and a first capacitor; and a second operational amplifier coupled in parallel with the voltage source, a second resistor, a second capacitor, and a third capacitor.

5 . The apparatus of claim 1 , wherein the TVS device is configured to limit voltage across the burden resistor in response to the switch being closed.

6 . The apparatus of claim 1 , wherein the switch has a lower leakage current than the TVS device.

7 . The apparatus of claim 1 , wherein the threshold is based on a reference voltage.

8 . A system comprising:
a current transformer; a burden resistor coupled to the current transformer; a transient voltage suppression (TVS) device configured to be coupled in parallel with the burden resistor; a switch configured to couple the TVS device across the burden resistor; and a comparator configured to:
detect a peak output voltage provided by the current transformer;
determine whether the peak output voltage meets or exceeds a threshold; and
control the switch based on whether the peak output voltage meets or exceeds the threshold.

9 . The system of claim 8 , wherein the switch is configured to disconnect the TVS device from the burden resistor in response to the peak output voltage being less than the threshold, thereby preventing the TVS device from affecting a measurement accuracy of the burden resistor.

10 . The system of claim 8 , further comprising:
a differential sense circuit coupled across the burden resistor and configured to provide the peak output voltage to the comparator.

11 . The system of claim 10 , wherein the differential sense circuit comprises:
a voltage source; a first operational amplifier coupled in parallel with the voltage source, a first resistor, and a first capacitor; and a second operational amplifier coupled in parallel with the voltage source, a second resistor, a second capacitor, and a third capacitor.

12 . The system of claim 8 , wherein the TVS device is configured to limit voltage across the burden resistor in response to the switch being closed.

13 . The system of claim 8 , wherein the switch has a lower leakage current than the TVS device.

14 . The system of claim 8 , wherein the threshold is based on a reference voltage.

15 . A method comprising:
detecting a peak output voltage provided by a circuit; determining whether the peak output voltage meets or exceeds a threshold using a comparator; and controlling a switch that selectively couples a transient voltage suppression (TVS) device across a burden resistor based on whether the peak output voltage meets or exceeds the threshold.

16 . The method of claim 15 , wherein the switch disconnects the TVS device from the burden resistor in response to the peak output voltage being less than the threshold, thereby preventing the TVS device from affecting a measurement accuracy of the burden resistor.

17 . The method of claim 15 , further comprising:
providing, by a differential sense circuit coupled across the burden resistor, the peak output voltage to the comparator.

18 . The method of claim 17 , wherein the differential sense circuit comprises:
a voltage source; a first operational amplifier coupled in parallel with the voltage source, a first resistor and a first capacitor; and a second operational amplifier coupled in parallel with the voltage source, a second resistor, a second capacitor, and a third capacitor.

19 . The method of claim 15 , wherein the TVS device limits voltage across the burden resistor in response to the switch being closed.

20 . The method of claim 15 , wherein the switch has a lower leakage current than the TVS device.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Blazer Christopher
• Ross Brian

Classifications

• H02H9/042

  comprising means to limit the absorbed power or indicate damaged over-voltage protection device · CPC title

• H02H9/005

  avoiding undesired transient conditions · CPC title

• H02H3/283 Primary

  and taking into account saturation of current transformers · CPC title

• G01R19/04

  Measuring peak values {or amplitude or envelope} of AC or of pulses · CPC title