Method and device for measuring currents or magnetic fields using hall sensors and their offset-corrected measurement values

Patent metadata

Field	Value
Publication number	US-9983235-B2
Application number	US-201314380388-A
Country	US
Kind code	B2
Filing date	Feb 26, 2013
Priority date	Feb 28, 2012
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

The present invention relates to a method and a device for measuring currents or magnetic fields using at least one Hall sensor, which is operated with spinning current technology. In addition to first sample values for calculating a spinning current measurement value ( 6 ), second sample values are formed from the digitally converted sensor signals ( 1 ) of the Hall sensor in the method. The second sample values are formed over shorter periods of time ( 9 ) and are corrected with an offset, which is calculated from the spinning current measurement value ( 6 ) and the first sample values. In addition to the precise spinning current measurement value ( 6 ), fast offset-corrected measurement values ( 10 ) of the magnetic field or current are obtained using the method and the associated device, without elaborate calibration or additional analog circuitry expenses.

First claim

The invention claimed is:

1. A method for measuring a current or a magnetic field with at least one Hall sensor which is operated with N≥2 spinning current phases per a spinning current cycle, comprising:
converting sensor signals generated by the Hall sensor with an analogue-to-digital converter into digital signals,
reading and combining the digital signals of the analogue-to-digital converter over a first time period within each spinning current phase to obtain a first sample for each of the spinning current phases, each first sample obtained from switching between the spinning current phases of the at least one Hall sensor
summing the first samples of the spinning current phases of the spinning current cycle to form a spinning current measurement value of the current or the magnetic field,
combining the digital signals of the analogue-to-digital converter a plurality of times over a respective second time period within each spinning current phase, wherein the second time period is smaller than the first time period, in order to obtain a plurality of second samples in chronological sequence for each of the spinning current phases, each plurality of second samples obtained from the switching between the spinning current phases of the at least one Hall sensor,
calculating an offset for each spinning current phase of the first samples from the spinning current measurement value, and
correcting the second samples based on the offset, in order to obtain offset-corrected fast measurement values of the current or the magnetic field.

2. The method according to claim 1 , further comprising
inserting after each switching between the spinning current phases a first wait time between the switching and a beginning of the first time period.

3. The method according to claim 2 , further comprising
inserting after each switching between the spinning current phases a second wait time between the switching and a beginning of the second time period, which is equal to the first wait time or shorter than the first wait time.

4. The method according to claim 1 ,
wherein the analogue-to-digital converter is a delta-sigma converter of the first order.

5. The method according to claim 1 ,
further comprising
amplifying the sensor signals from the Hall sensor prior to the analogue-to-digital conversion.

6. The method according to claim 1 ,
further comprising
combining the digital signals over the first time period by means of a first decimator, and combining the digital signals over the second time period by a second decimator.

7. A device for measuring a current or a magnetic field with at least one Hall sensor that is operated in spinning current with N≥2 spinning current phases per a spinning current cycle, wherein the device comprises switches for switching between the spinning current phases,
an analogue-to-digital converter, with which sensor signals from the Hall sensor are converted into digital signals,
a first combiner, which reads out the digital signals from the analogue-to-digital converter and combines them over a first time period within each spinning current phase in order to obtain a first sample for each of the spinning current phases, and
an adder, which sums the first samples of the spinning current phases of the spinning current cycle to form a spinning current measurement value of the current or the magnetic field,
characterized by
a second combiner, which combines the digital signals from the analogue-to-digital converter a plurality of times over a respective second time period within each spinning current phase, which is smaller than the first time period, in order to obtain a plurality of second samples in chronological sequence, and
a correction unit, which calculates from the spinning current measurement value, for each spinning current phase, an offset of the first samples and corrects the second samples on the basis of this offset, in order to obtain offset-corrected fast measurement values of the the current or the magnetic field.

8. The device according to claim 7 ,
characterized in that
the analogue-to-digital converter is a delta-sigma converter of the first order.

9. The device according to claim 7 ,
characterized in that
each of the first combiner and the second combiner is a decimator.

10. The method according to claim 3 ,
comprising the combining of the digital signals over the first time period is by means of a first decimator, and the combining of the digital signals over the second time period is by means of a second decimator.

11. The device according to claim 8 ,
characterized in that
each of the first combiner and the second combiner is a decimator.

Assignees

• Fraunhofer Ges Forschung
• Fraunhofer Ges Forschung

Inventors

• Hackner Michael
• Hohe Hans-Peter
• Sand Markus

Classifications

• G01R33/075

  Hall devices configured for spinning current measurements · CPC title

• G01R33/0017

  Means for compensating offset magnetic fields or the magnetic flux to be measured; Means for generating calibration magnetic fields · CPC title

• G01R15/202 Primary

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

• G01D5/142

  using Hall-effect devices (measuring magnetic variables using Hall-effect or other galvanomagnetic devices G01R33/06) · CPC title

• G01R33/07

  Hall effect devices · CPC title