Electric current sensor

Patent metadata

Field	Value
Publication number	US-9880206-B2
Application number	US-201514600784-A
Country	US
Kind code	B2
Filing date	Jan 20, 2015
Priority date	Jan 21, 2014
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

An electric current sensor includes a plurality of bus bars arranged in parallel, a plurality of magnetic detection elements that are adapted to detect a strength of a magnetic field generated by an electric current flowing through the bus bars and to output a voltage according to the strength of the magnetic field detected, and an arithmetic operation part to arithmetically operate an electric current flowing through the bus bars based on the voltage output from the plurality of magnetic detection elements. The arithmetic operation part includes a magnetic flux density arithmetic operation part to arithmetically operate a magnetic flux density based on the voltage, and an electric current arithmetic operation part to arithmetically operate an electric current I 1 to I m flowing through each of the bus bars based on formula (1) below,
( B 1 = a 11 · I 1 + a 12 · I 2 + … + a 1 ⁢ ⁢ n · I n B 2 = a 21 · I 1 + a 22 · I 2 + … + a 2 ⁢ n · I n B 3 = a 31 · I 1 + a 32 · I 2 + … + a 3 ⁢ n · I n ⋮ ⁢ ⁢ ⋮ B m = a m ⁢ ⁢ 1 · I 1 + a m ⁢ ⁢ 2 · I 2 + … + a mn · I n ⁢
⁢ where ⁢
⁢ a 11 ⁢ ⁢ to ⁢ ⁢ a mn ⁢ ⁢ are ⁢ ⁢ coefficients , ( 1 )
B 1 to B m are a magnetic flux density and I 1 to I m are an electric current.

First claim

What is claimed is:

1. An electric current sensor, comprising:
a plurality of bus bars arranged in parallel;
a plurality of magnetic detection elements that are provided such that a number thereof is not less than a number of the bus bars, and that are adapted to detect a strength of a magnetic field generated by an electric current flowing through the bus bars and to output a voltage according to the strength of the magnetic field detected; and
an arithmetic operation part to arithmetically operate an electric current flowing through each of the bus bars based on the voltage output from the plurality of magnetic detection elements,
wherein at least one of the bus bars is provided with a through hole that penetrates the one of the bus bars,
wherein an electric current path is formed on both sides of the through hole,
wherein at least one of the magnetic detection elements is arranged in the through hole so as to detect a strength of a synthetic magnetic field obtained by synthesizing a magnetic field generated due to an electric current flowing through the electric current path formed on the both sides of the through hole,
wherein the magnetic detection element arranged in the through hole is arranged at a position in which the strength of the synthetic magnetic field is zero,
wherein the arithmetic operation part comprises a magnetic flux density arithmetic operation part to arithmetically operate a magnetic flux density based on the voltage output from the plurality of magnetic detection elements, and an electric current arithmetic operation part to arithmetically operate an electric current I 1 to I m flowing through each of the bus bars based on formula (1) below,

(

B
1

=

a
11

·

I
1

+

a
12

·

I
2

+
…
+

a

1
⁢

⁢
n

·

I
n

B
2

=

a
21

·

I
1

+

a
22

·

I
2

+
…
+

a

2
⁢
n

·

I
n

B
3

=

a
31

·

I
1

+

a
32

·

I
2

+
…
+

a

3
⁢
n

·

Assignees

• Hitachi Metals Ltd

Inventors

• Akimoto Katsuya
• Tate Hisashi
• Futakuchi Naoki
• Chiwata Naofumi
• Okuyama Ken
• Ikeda Yukio
• Takahashi Kazuhisa

Classifications

• G01R15/207 Primary

  Constructional details independent of the type of device used · CPC title

• G01R33/093

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

• G01R19/25

  using digital measurement techniques · CPC title

• G01R19/0092 Primary

  Measuring current only · CPC title

• G01R15/205

  using magneto-resistance devices, e.g. field plates · CPC title