Shielded open loop type magnetic gathering ring-free tunneling magnetoresistive sensor

Abstract

The invention discloses a shielded open loop type magnetic gathering ring-free tunneling magnetoresistive sensor which comprises a sensor shell, and a U-shaped wire, tunneling magnetoresistors and a silicon steel sheet which are arranged in the sensor shell, wherein two sides of the U-shaped wire respectively serve as a to-be-detected current input end and a to-be-detected current output end; the tunneling magnetoresistors are respectively arranged under the two sides of the U-shaped wire; a parallel magnetic field parallel to the tunneling magnetoresistors is arranged in the induction direction of each tunneling magnetoresistor; the two tunneling magnetoresistors respectively induce a magnetic field generated by current in different directions on the two sides in the U-shaped wire, and two voltage signals are output; the silicon steel sheet is embedded in the sensor shell and is used for shielding external magnetic disturbance. According to the shielded open loop type magnetic gathering ring-free tunneling magnetoresistive sensor, the influence of temperature on the current sensor output is improved, the capacity of adapting a complex working environment through a current sensor is improved, the output accuracy of the current sensor is greatly improved in a whole temperature range, and the temperature characteristics are 7 times that of a traditional identical sensor.

Description

technical field [0001] The invention relates to a magnetic sensor, in particular to a shielded open-loop tunnel magnetoresistive sensor without a magnet gathering ring. Background technique [0002] Traditional open-loop current sensors are based on the principle of the Hall effect, a phenomenon discovered by American physicist Hall in 1897 when he was studying the mechanism of metal conduction. When the current passes through the conductor perpendicular to the external magnetic field, a potential will appear between the two end faces of the conductor perpendicular to the magnetic field and the current direction. The traditional Hall open-loop current sensor generates the current flowing through the measured conductor through the magnetic gathering ring. The magnetic field is gathered in the magnetic ring with a gap, and the Hall sensing chip is placed in the gap of the magnetic gathering ring. The magnetic field in the gap passes through the Hall sensing chip vertically, an...

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Problems solved by technology

When the current passes through the conductor perpendicular to the external magnetic field, a potential will appear between the two end faces of the conductor perpendicular to the magnetic field and the current direction. The traditional Hall open-loop current sensor generates the current flowing through the measured conductor through the magnetic gathering ring. The magnetic field is gathered in the magnetic ring with a gap, and the Hall sensing chip is placed in the gap of the magnetic gathering ring. The magnetic field in the gap passes through the Hall sensing chip vertically, and a Hall potential difference is generated at both ends of the sensing chip. Through subsequent amplification The circuit increases the induction signal, and the output signal changes linearly when the current changes, and the current to be measured can be obtained through the circuit algorithm operation; however, once the core temperature exceeds its Curie temperature, the magnetic permeability of the core will drop sharply , the Curie temperature of the magnetic core of different materials is not fixed, the Curie temperature of the high magnetic permeability core is usually very low, in fact, the magnetic permeability has begun to drop sharply before reaching the defined Curie temperature, and the magnetic permeability drops It directly leads to the decline of the magnetic gathering ability of the current sensor core, inaccurate output, and the inability to accurately isolate and test the current to be measured, which greatly affects and limits the use and test environment of the current sensor.

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