Systems and methods for measuring electrical power usage in a structure and systems and methods of calibrating the same

• US 9,594,098 B2
• Filed: 08/11/2014
• Issued: 03/14/2017
• Est. Priority Date: 09/25/2009
• Status: Active Grant

• Current Assignee: Belkin International Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Belkin International Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Patel, Shwetak N., Gupta, Sidhant, Reynolds, Matthew S., Yogeeswaran, Karthik
• Primary Examiner(s): Laballe, Clayton E
• Assistant Examiner(s): SANGHERA, JAS A
• Application Number:
  US14/457,032
• Publication Number:
  US 20140347039A1
• Time in Patent Office: 946 Days
• US Class Current: 1/1
• CPC Class Codes: G01R 1/20 Modifications of basic electric elements for use in electric measuring instruments; Structural combinations of such elements with such instruments
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 21/001 Measuring real or reactive component; Measuring apparent energy G01R21/01, G01R21/02, G01R21/08, G01R21/10 and G01R21/127 take precedence
• CPC Class Codes: G01R 21/06 by measuring current and voltage G01R21/08 - G01R21/133 take precedence
• CPC Class Codes: G01R 22/06 by electronic methods
• CPC Class Codes: G01R 22/063 related to remote communication
• CPC Class Codes: G01R 31/327 Testing of circuit interrupters, switches or circuit-breakers
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/09 Magnetoresistive devices
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence
• CPC Class Codes: G01R 35/007 Standards or reference devices, e.g. voltage or resistance standards, "golden references"
• CPC Class Codes: G01R 35/04 of instruments for measuring time integral of power or current

Abstract

A magnetic field sensing device can include two or more magnetic field sensors configured to detect a magnetic field in a current carrying conductor. The magnetic field sensing device also can include a phase detector electrically coupled to outputs of the two or more magnetic field sensors. The magnetic field sensing device further can include a phase indicator electrically coupled to the phase detector. The phase indictor can include a display that indicates when the two or more magnetic field sensors are in a position in relation to the current carrying conductor. Other embodiments are provided.

Claims

1. A method of calibrating a magnetic field sensor device, the magnetic field sensor device coupled to a first surface of a circuit breaker box, the circuit breaker box overlying at least part of an electrical power infrastructure of a building, the electrical power infrastructure having one or more main electrical supply conductors, a first phase branch, and a second phase branch, the magnetic field sensor device comprising two or more magnetic field sensors, the method comprising:

determining via the magnetic field sensor device a first amplitude and a first phase angle of a first magnetic field in the two or more magnetic field sensors of the magnetic field sensor device while the magnetic field sensor device is coupled to the first surface of the circuit breaker box;

after a first load has been coupled to the first phase branch of the electrical power infrastructure, determining via the magnetic field sensor device, a second amplitude and a second phase angle of a second magnetic field in the two or more magnetic field sensors of the magnetic field sensor device while the magnetic field sensor device is coupled to the first surface of the circuit breaker box and while the first load is coupled to the first phase branch;

after the first load has been uncoupled from the first phase branch of the electrical power infrastructure and a second load has been coupled to the second phase branch of the electrical power infrastructure, determining via the magnetic field sensor device, a third amplitude and a third phase angle of a third magnetic field in the two or more magnetic field sensors of the magnetic field sensor device while the magnetic field sensor device is coupled to the first surface of the circuit breaker box and while the second load is coupled to the second phase branch; and

determining via a computer processor one or more calibration coefficients for the magnetic field sensor device at least in part using the first amplitude and the first phase angle of the first magnetic field in the two or more magnetic field sensors, the second amplitude and the second phase angle of the second magnetic field in the two or more magnetic field sensors, and the third amplitude and the third phase angle of the third magnetic field in the two or more magnetic field sensors,

wherein;

the magnetic field sensor device is not electrically coupled in series with or physically coupled directly to the one or more main electrical supply conductors at the circuit breaker box when the magnetic field sensor device is coupled to the first surface of the circuit breaker box.

2. The method of claim 1 further comprising:

after the first load has been uncoupled from the first phase branch of the electrical power infrastructure and a second load has been uncoupled to the second phase branch of the electrical power infrastructure, determining via the magnetic field sensor device a fourth amplitude and a fourth phase angle of a fourth magnetic field in the two or more magnetic field sensors of the magnetic field sensor device while the magnetic field sensor device is coupled to the first surface of the circuit breaker box; and

determining if the fourth amplitude and the fourth phase angle of the fourth magnetic field in the two or more magnetic field sensors is within a predetermined amount of the first amplitude and the first phase angle of the first magnetic field in the two or more magnetic field sensors.

3. The method of claim 1, wherein determining via the computer processor the one or more calibration coefficients for the magnetic field sensor device comprises:

determining, for each of the two or more magnetic field sensors, first branch calibration coefficients for the first phase branch;

determining, for each of the two or more magnetic field sensors, second branch calibration coefficients for the second phase branch;

determining, for each of the two or more magnetic field sensors, a comparison of at least a portion of the first branch calibration coefficients and at least a portion of the second branch calibration coefficients;

determining a statistical mode for remaining sensors each selected from the two or more magnetic field sensors in which, for each of the remaining sensors, the comparison of at least a portion of the first branch calibration coefficient and at least a portion of the second branch calibration coefficient is within a predetermined tolerance; and

determining a first part of the one or more calibration coefficients, a second part of the one or more calibration coefficients, and a third part of the one or more calibration coefficients based at least in part on the first branch calibration coefficients and the second branch calibration coefficients of the remaining sensors.

4. The method claim 1, wherein:

the magnetic field sensor device further comprises a phase detector electrically coupled to outputs of the two or more magnetic field sensors; and

the phase detector is configured to determine when a first signal phase angle of a first signal in a first magnetic field sensor of the two or more magnetic field sensors is approximately 180 degrees out of phase with a second signal phase angle of a second signal in a second magnetic field sensor of the two or more magnetic field sensors.

5. A magnetic field sensing device comprising:

two or more magnetic field sensors configured to detect a magnetic field produced by an alternating current power signal in a current carrying conductor, each of the two or more magnetic field sensors being configured to output a different signal detected from the magnetic field produced by the alternating current power signal in the current carrying conductor due to different positions of each of the two or more magnetic field sensors relative to the current carrying conductor;

a phase detector electrically coupled to outputs of the two or more magnetic field sensors; and

a phase indicator electrically coupled to the phase detector,

wherein;

the phase indicator comprises a display that indicates, based on phase angles of the different signals detected by the two or more magnetic field sensors from the magnetic field produced by the alternating current power signal in the current carrying conductor, when the two or more magnetic field sensors are in a predefined position in relation to the current carrying conductor.

6. The magnetic field sensing device of claim 5, wherein:

a first magnetic field sensor of the two or more magnetic field sensors is configured to output a first signal detected by from the magnetic field at the position of the first magnetic field sensor produced by the alternating current power signal in the current carrying conductor;

a second magnetic field sensor of the two or more magnetic field sensors is configured to output a second signal detected by from the magnetic field at the position of the second magnetic field sensor produced by the alternating current power signal in the current carrying conductor; and

the phase detector is configured to determine when a first signal phase angle of the first signal output by the first magnetic field sensor of the two or more magnetic field sensors is approximately 180 degrees out of phase with a second signal phase angle of the second signal output by the second magnetic field sensor of the two or more magnetic field sensors.

7. The magnetic field sensing device of claim 5, wherein:

the two or more magnetic field sensors comprise;

a linear array of magnetic field sensors;

one or more multiplexers electrically coupled to the linear array of magnetic field sensors; and

a processor electrically coupled to the one or more multiplexers and configured to control the one or more multiplexers.

8. The magnetic field sensing device of claim 5, wherein:

the two or more magnetic field sensors comprise at least one of an inductive pickup sensor, a Hall effect sensor, or a magnetoresistive sensor.

9. The magnetic field sensing device of claim 5 further comprising:

one or more amplifiers electrically coupled to the two or more magnetic field sensors.

10. The magnetic field sensing device of claim 5 further comprising:

one or more filters electrically coupled to the two or more magnetic field sensors.

11. The magnetic field sensing device of claim 5 further comprising:

a wireless transmitter configured to transmit information regarding one or more magnetic field measurements from the two or more magnetic field sensors to a remote indicating device.

12. The magnetic field sensing device of claim 5, wherein:

each of the two or more magnetic field sensors comprises a ferromagnetic core and a sensing coil wrapped around the ferromagnetic core.

13. A method of providing a magnetic field sensing device, the method comprising:

providing two or more magnetic field sensors configured to detect a magnetic field produced by an alternating current power signal in a current carrying conductor, each of the two or more magnetic field sensors being configured to output a different signal detected from the magnetic field produced by the alternating current power signal in the current carrying conductor due to different positions of each of the two or more magnetic field sensors relative to the current carrying conductor;

providing a phase detector electrically coupled to outputs of the two or more magnetic field sensors; and

providing a phase indicator electrically coupled to the phase detector,

wherein;

the phase indicator comprises a display that indicates, based on phase angles of the different signals detected by the two or more magnetic field sensors from the magnetic field produced by the alternating current power signal in the current carrying conductor, when the two or more magnetic field sensors are in a predefined position in relation to the current carrying conductor.

14. The method of claim 13, wherein:

providing two or more magnetic field sensors comprises;

providing a first magnetic field sensor of the two or more magnetic field sensors that is configured to output a first signal detected by from the magnetic field at the position of the first magnetic field sensor produced by the alternating current power signal in the current carrying conductor;

providing a second magnetic field sensor of the two or more magnetic field sensors that is configured to output a second signal detected by from the magnetic field at the position of the second magnetic field sensor produced by the alternating current power signal in the current carrying conductor; and

providing the phase detector comprises providing the phase detector configured to determine when a first signal phase angle of the first signal output by the first magnetic field sensor of the two or more magnetic field sensors is approximately 180 degrees out of phase with a second signal phase angle of the second signal output by the second magnetic field sensor of the two or more magnetic field sensors.

15. The method of claim 13, wherein:

providing the two or more magnetic field sensors comprises providing the two or more magnetic field sensors to comprise;

a linear array of magnetic field sensors;

one or more multiplexers electrically coupled to the linear array of magnetic field sensors; and

a processor electrically coupled to the one or more multiplexers and configured to control the one or more multiplexers.

16. The method of claim 13, wherein:

providing the two or more magnetic field sensors comprises providing the two or more magnetic field sensors to comprise at least one of an inductive pickup sensor, a Hall effect sensor, or a magnetoresistive sensor.

17. The method of claim 13 further comprising:

providing one or more amplifiers electrically coupled to the two or more magnetic field sensors.

18. The method of claim 13 further comprising:

providing one or more filters electrically coupled to the two or more magnetic field sensors.

19. The method of claim 13 further comprising:

providing a wireless transmitter configured to transmit information regarding one or more magnetic field measurements from the two or more magnetic field sensors to a remote indicating device.

20. The method of claim 13, wherein:

providing the two or more magnetic field sensors comprises providing each of the two or more magnetic field sensors to comprise a ferromagnetic core and a sensing coil wrapped around the ferromagnetic core.