Current sensor

Patent metadata

Field	Value
Publication number	US-9459293-B2
Application number	US-201414328748-A
Country	US
Kind code	B2
Filing date	Jul 11, 2014
Priority date	Jul 16, 2013
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A current sensor includes: four magnetic sensor elements arranged within a plane orthogonal to a measured current, having a symmetrical magnetic characteristics curve, and adapted to convert a magnitude of a magnetic field into an electrical signal and output the electrical signal; a bridge circuit including the four magnetic sensor elements; and a bias magnetic field application member adapted to applying a bias magnetic field to the magnetic sensor elements.

First claim

What is claimed is:

1. A current sensor, comprising:
four magnetic sensor elements arranged within a plane orthogonal to a measured current, having a symmetrical magnetic characteristics curve, and adapted to convert a magnitude of a magnetic field into an electrical signal and output the electrical signal;
a bridge circuit including the four magnetic sensor elements; and
a bias magnetic field application member adapted to applying a bias magnetic field to the magnetic sensor elements,
wherein
each of the magnetic sensor elements has a corresponding magnetic sensitive direction exhibiting a maximum sensitivity, and
the magnetic sensitive directions of the magnetic sensor elements are four different directions arranged in the plane orthogonal to the measured current.

2. The current sensor according to claim 1 , wherein the magnetic sensor elements are magneto-resistance elements electric resistances of which change in response to application of a magnetic field.

3. The current sensor according to claim 1 , wherein the magnetic sensor elements are magneto-impedance elements electric impedances of which change in response to application of a magnetic field.

4. The current sensor according to claim 1 , wherein the bias magnetic field application member includes a permanent magnet.

5. The current sensor according to claim 1 , further comprising:
a sensor substrate made of a non-magnetic material on which the magnetic sensor elements are mounted.

6. The current sensor according to claim 5 , wherein the magnetic sensor elements are mounted on one surface of the sensor substrate and the bias magnetic field application member is arranged on the other surface of the sensor substrate.

7. The current sensor according to claim 6 , further comprising:
an attachment member made of a magnetic material and attaching the bias magnetic field application member to the sensor substrate.

8. The current sensor according to claim 1 , wherein a magnetic pole direction of the bias magnetic field application member is parallel to the plane in which the magnetic sensitive directions of the magnetic sensor elements are arranged.

9. The current sensor according to claim 1 , wherein the bridge circuit is arranged so that a cable in which the measured current flows is located therein.

10. The current sensor according to claim 1 , further comprising:
a cable in which the measured current flows,
wherein
the four magnetic sensor elements are arranged on a circumference of a circle centering around the cable,
the magnetic sensitive direction of each of the magnetic sensor elements is in a tangent to the circle, and
the four magnetic sensor elements are located at each vertex of a square inscribed in the circle.

11. The current sensor according to claim 10 , wherein
directions in which the bias magnetic field is applied to the magnetic sensor elements neighboring to each other are opposite to each other along the circumference of the circle.

12. A current sensor, comprising:
four magnetic sensor elements arranged within a plane orthogonal to a measured current, having a symmetrical magnetic characteristic curve, and adapted to convert a magnitude of a magnetic field into an electrical signal and output the electrical signal;
a bridge circuit including the four magnetic sensor elements;
a bias magnetic field application member adapted to apply a bias magnetic field to the magnetic sensor elements; and
a cable in which the measured current flows,
wherein
the bridge circuit is arranged so that the cable in which the measured current flows is located therein,
the four magnetic sensor elements are arranged on a circumference of an ellipse centering around the cable,
a magnetic sensitive direction exhibiting a maximum sensitivity of each of the magnetic sensor elements is in a tangent to the ellipse,
the four magnetic sensor elements are located at each vertex of a rectangle inscribed in the ellipse, and
directions in which the bias magnetic field is applied to the magnetic sensor elements neighboring to each other are opposite to each other along the circumference of the ellipse.

13. A current sensor, comprising:
four magnetic sensor elements arranged within a plane orthogonal to a measured current, having a symmetrical magnetic characteristic curve, and adapted to convert a magnitude of a magnetic field into an electrical signal and output the electrical signal;
a bridge circuit including the four magnetic sensor elements;
a bias magnetic field application member adapted to apply a bias magnetic field to the magnetic sensor elements; and
a cable in which the measured current flows,
wherein
the bridge circuit is arranged so that the cable in which the measured current flows is located therein,
the four magnetic sensor elements are arranged on a circumference of a circle centering around the cable,
a magnetic sensitive direction exhibiting a maximum sensitivity of each of the magnetic sensor elements is in a tangent to the circle,
the four magnetic sensor elements are located at each vertex of a rectangle inscribed in the circle, and
directions in which the bias magnetic field is applied to the magnetic sensor elements neighboring to each other are opposite to each other along the circumference of the circle.

Assignees

• Yokogawa Electric Corp

Inventors

• Mito Shinya
• Takenaka Kazuma
• Kato Satoshi

Classifications

• G01R33/091 Primary

  Constructional adaptation of the sensor to specific applications · CPC title

• G01R15/207

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

• G01R15/205

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

• G01R19/0092 Primary

  Measuring current only · CPC title