Current detection method, current detection device, signal correction method for current detection device, and signal correction device for current detection device

Patent metadata

Field	Value
Publication number	US-10996246-B2
Application number	US-201415517614-A
Country	US
Kind code	B2
Filing date	Oct 10, 2014
Priority date	Oct 10, 2014
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A current detection method for a current detection device including magnetism detection elements that detect magnetic flux density and output a voltage signal corresponding to the magnetic flux density is provided. The method includes acquiring measured value data that is obtained as a result of providing magnetic flux density in a detectable range of the magnetism detection elements that indicates the relationship between the magnetic flux density and an output voltage signal from the current detection device. Next, computational processing is performed so as to fit the acquired measured value data to a formula that includes plural factors and indicates the output voltage of the magnetism detection elements, thereby calculating the plural factors, and correcting the output voltage signal from the magnetism detection elements in accordance with the calculated factors so as to be approximately linear with respect to the magnetic flux density. Finally, a corrected voltage signal obtained by the correction is outputted.

First claim

The invention claimed is:

1. A current detection method for a current detection device comprising magnetism detection elements that detect magnetic flux density and output a voltage signal corresponding to the magnetic flux density, the method comprising:
acquiring measured value data that is obtained as a result of providing magnetic flux density in a detectable range of the magnetism detection elements and indicates the relationship between the magnetic flux density and an output voltage signal from the current detection device;
performing computational processing so as to fit the acquired measured value data to a formula that includes a plurality of factors for a measured magnetic field B and indicates an output voltage signal V f of the magnetism detection elements, thereby calculating the plurality of factors; and
correcting the output voltage signal from the magnetism detection elements in accordance with the calculated plurality of factors so as to be approximately linear with respect to the magnetic flux density, and then outputting a corrected voltage signal obtained by the correction,
wherein the formula is expressed by:

V
f

=

A
⁢
1

+

A
⁢
4
×
B

+

A
⁢
5

B
1

+

A
⁢
2
×
B

+

A
⁢
3

and each of the factors A 1 to A 5 is calculated so that the output voltage signal V f obtained by the formula is fitted to an output voltage signal of the measured value data.

2. The current detection method according to claim 1 , wherein in the formula, the factor A 1 is an output offset factor V off , the factor A 2 is 2·B b ·sin(α−φ), the factor A 3 is a square of B b , the factor A 4 is V sat ·cos φ and the factor A 5 is B b ·V sat ·sin α, and in the factors A 2 to A 5 , V sat is a saturation output factor, B b is a bias magnetic field strength factor, φ is an angular offset factor of a direction of the measured electromagnetic field, and a is an angular offset factor of a direction of the bias magnetic field.

3. The current detection method according to claim 1 , wherein the output voltage signal from the magnetism detection elements is corrected using a voltage correction unit, coupled to an output of the magnetism detection elements to receive the output voltage signal from the magnetism detection elements, and configured to correct the output voltage signal from the magnetism detection elements and output the corrected voltage signal, and wherein the corrected voltage signal V L is output in accordance with a formula for expressing the corrected voltage signal V L =m×B(V 1 )+n (where the factor m is any given value except 0, and the factor n is any given value) and the plurality of factors calculated by the computational processing, the formula being obtained using the formula under the conditions that the output voltage signal V f is replaced with an output voltage signal V 1 and the measured magnetic field B is a function of the output voltage signal V 1 (=B(V 1 )).

4. A current detection device, comprising:
magnetism detection elements that detect magnetic flux density and output a voltage signal corresponding to the magnetic flux density; and
a signal correction means that corrects the output voltage signal from the magnetism detection elements so as to be approximately linear with respect to the magnetic flux density and then outputs a corrected voltage signal obtained by the correction, the correction being performed in accordance with a plurality of factors calculated by computational processing that is performed so that measured value data obtained as a result of providing the magnetic flux density to the magnetism detection elements and indicating the relationship between the magnetic flux density and an output voltage signal is fitted to a formula including the plurality of factors for a measured magnetic field B and indicating an output voltage signal V f of the magnetism detection elements,
wherein the formula is expressed by:

V
f

=

A
⁢
1

+

A
⁢
4
×
B

+

A
⁢

⁢
5

B
2

+

A
⁢
2
×
B

+

A
⁢
3

and each of the factors A 1 to A 5 is calculated so that the output voltage signal V f obtained by the formula is fitted to an output voltage signal of the measured value data.

5. The current detection device according to claim 4 , wherein in the formula, the factor A 1 is an output offset factor V off , the factor A 2 is 2·B b ·sin(α−φ), the factor A 3 is a square of B 0 , the factor A 4 is V sat ·cos φ and the factor A 5 is B b ·V sat ·sin α, and in the factors A 2 to A 5 , V sat is a saturation output factor, B b is a bias magnetic field strength factor, φ is an angular offset factor of a direction of the measured electromagnetic field, and α is an angular offset factor of a direction of the bias magnetic field.

6. The current detection device according to claim 4 , wherein the corrected voltage signal V L is output in accordance with a formula for expressing the corrected voltage signal V L =m×B(V 1 )+n (where the factor m is any given value except 0, and the factor n is any given value) and the plurality of factors calculated by the computational processing, the formula being obtained using the formula under the conditions that the output voltage signal V f is replaced with an output voltage signal V 1 and the measured magnetic field B is a function of the output vol

Assignees

• Hitachi Metals Ltd

Inventors

• Futakuchi Naoki
• Chiwata Naofumi
• Akimoto Katsuya

Classifications

• G01R33/093 Primary

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• G01R15/20 Primary

  using galvano-magnetic devices, e.g. Hall-effect devices {, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices} · CPC title

• G01R33/09

  Magnetoresistive devices · CPC title