REGULATED MAGNETIC FLUX DENSITY FOR EXTENDED CURRENT MEASUREMENT

• US 20140333300A1
• Filed: 05/09/2013
• Published: 11/13/2014
• Est. Priority Date: 05/09/2013
• Status: Abandoned Application

• Current Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Hamilton Sundstrand Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Rozman, Gregory I., Gieras, Jacek F., Moss, Steven J.
• Application Number:
  US13/890,388
• Publication Number:
  US 20140333300A1
• Time in Patent Office: Days
• US Class Current: 324/251
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: G01R 33/07 Hall effect devices

Abstract

A current sensor senses a primary current in a conductor. The current sensor includes a core, a sensing device, and a magnetizing coil. The core is configured so that the primary current generates a first magnetic field concentrated in the core. A magnetic flux density of the core is established based upon the first magnetic field and a magnetic permeability of the core. The sensing device senses the magnetic flux density of the core and provides a voltage representative of the primary current. The magnetizing coil receives a magnetizing current when the primary current is greater than a threshold value. The magnetizing coil generates a coil magnetic field in response to the magnetizing current to decrease the magnetic permeability of the core.

Claims

1. A current sensor for sensing a first current in a first conductor, the current sensor comprising:

a core configured so that the first current generates a first magnetic field concentrated in the core, wherein a magnetic flux density of the core is established based upon the first magnetic field and a magnetic permeability of the core;

a first sensing device that senses the magnetic flux density of the core and provides a first voltage representative of the first current; and

a magnetizing coil that receives a magnetizing current when the first current is greater than a threshold value, wherein the magnetizing coil generates a coil magnetic field in response to the magnetizing current to decrease the magnetic permeability of the core.

2. The current sensor of claim 1, wherein the current sensor senses a second current in a second conductor, and wherein the second current generates a second magnetic field concentrated in the core, and wherein the magnetic flux density of the core is further established based upon the second magnetic field.

3. The current sensor of claim 2, further comprising:

a second sensing device that senses the magnetic flux density of the core and provides a second voltage representative of the second current; and

wherein the magnetizing coil receives the magnetizing current when either the first current or the second current is greater than the threshold value.

4. The current sensor of claim 3, wherein the first and second sensing devices are Hall effect devices.

5. The current sensor of claim 1, wherein the magnetizing current is received from a current source, and wherein the current source is controlled by a control circuit based upon the voltage representative of the first current.

6. A method comprising:

concentrating in a core of a current sensor a first magnetic field generated by a first primary current, wherein a magnetic flux density of the core is established based upon the first magnetic field and a permeability of the core;

sensing the first primary current using a first sensing device of the current sensor based upon a first coefficient of proportionality between an output voltage of the first sensing device and the first primary current;

providing a magnetizing current to a magnetizing coil if the first primary current is greater than a threshold value, wherein the magnetizing coil produces a coil magnetic field in response to the magnetizing current that lowers the permeability of the core; and

sensing the first primary current using the first sensing device of the current sensor based upon a second coefficient of proportionality between the output voltage of the first sensing device and the first primary current when the first primary current is greater than the threshold value.

7. The method of claim 6, further comprising concentrating in the core of the current sensor a second magnetic field generated by a second primary current, wherein the magnetic flux density of the core is further established based upon the second magnetic field.

8. The method of claim 7, further comprising sensing the second primary current using a second sensing device of the current sensor based upon the first coefficient of proportionality.

9. The method of claim 8, wherein providing the magnetizing current further comprises providing the magnetizing current to the magnetizing coil if the second primary current is greater than the threshold value.

10. The method of claim 9, further comprising sensing the second primary current using the second sensing device of the current sensor based upon the second coefficient of proportionality when either the first primary current or the second primary current is greater than the threshold value.

11. The method of claim 10, wherein the first and second sensing devices are Hall effect devices.

12. A system comprising:

a current sensor that senses a first current, the current sensor comprising;

a core configured so that the first current generates a first magnetic field concentrated in the core, wherein a magnetic flux density of the core is established based upon the first magnetic field and a magnetic permeability of the core;

a first sensing device that senses the magnetic flux density of the core and provides a first voltage representative of the first current; and

a magnetizing coil that receives a magnetizing current when the first current is greater than a threshold value, wherein the magnetizing coil generates a coil magnetic field in response to the magnetizing current to decrease the magnetic permeability of the core; and

a control circuit that determines the first current based upon the output voltage of the first current sensor and provides the magnetizing current to the magnetizing coil when the primary current is greater than a threshold value.

13. The system of claim 12, wherein the current sensor senses a second current in a second conductor, and wherein the second current generates a second magnetic field concentrated in the core, and wherein the magnetic flux density of the core is further established based upon the second magnetic field.

14. The system of claim 13, wherein the current sensor further comprises:

a second sensing device that senses the magnetic flux density of the core and provides a second voltage representative of the second current; and

wherein the magnetizing coil receives the magnetizing current when either the first current or the second current is greater than the threshold value.

15. The system of claim 14, wherein the first and second sensing devices are Hall effect devices.

16. The system of claim 12, wherein the control circuit provides the magnetizing current to the magnetizing coil from a current source.