CN201429644Y - large current Hall detection device - Google Patents

Abstract

The utility model relates to a large current Hall detection device, which is characterized in that: a large current passes through windows on upper surfaces of magnetic cores of a soft magnet like a Chinese character 'Ri'; the soft magnet like a Chinese character 'Ri' is provided with a main air gap, a branch air gap and a detection air gap in turn from top to bottom; the magnetic cores positionedon both sides of the detection air gap are provided with compensating coils; a Hall device is arranged in the detection air gap. A voltage detected by the Hall device generates a compensating currentto be acted on the compensating coils through a circuit with a power tube so that a magnetic flux direction generated by the compensating current is opposite to the magnetic flux direction generatedby a detected current in the air gap. Information of calculating a current value of the large current is acquired by detecting the compensating current required by the Hall device positioned in the detection air gap under the condition of detecting the zero magnetic flux so as to acquire the current value of the large current. Compared with the prior art, the utility model has the advantages of large current detection, high linearity and high detection precision.

Description

A kind of ultra-high current Hall pick-up unit

Technical field:

The utility model relates to a kind of method and device that detects electric current, particularly a kind of current Hall pick-up unit.

Background technology:

Hall effect and hall device Hall effect are the theoretical foundation of this patent, when the wafer that is connected with little electric current places magnetic field, charge carrier in the semiconductor is deflected by the effect of Lorentz force, make the semiconductor both sides produce electric potential difference, this electric potential difference is Hall voltage VH, VH is directly proportional with magnetic induction density B and Control current IC, through theoretical calculate formula (1) relation is arranged.

VH＝(RH/d)×B×IC(1)

In the formula: B is a magnetic induction density; IC is a Control current; RH is a Hall coefficient; D is a semiconductor thickness.By formula (1) as can be seen,,, can extrapolate the size of magnetic induction density under certain condition, set up getting in touch of magnetic field and voltage signal thus by measuring Hall voltage if retentive control electric current I C is constant.

The magnetic balance type current sensor also claims compensation sensor, and promptly major loop measured current I p compensates by the magnetic field that secondary current produced in the magnetic field of magnetism gathering rings place generation, thereby makes hall device be in the duty that detects zero magnetic flux.The concrete course of work of magnetic balance type current sensor is: when major loop has an electric current to pass through, assembled by magnetism gathering rings in the magnetic field that produces on the lead and sense on the hall device, the signal output that is produced is used to drive corresponding power tube and makes its conducting, thereby obtain this electric current of offset current Is. and produce magnetic field by multicircuit winding again, this magnetic field is just in time opposite with the magnetic field that tested electric current produces, thereby compensated original magnetic field, the output of hall device is reduced gradually. when multiplying each other the magnetic field that produced when equating with Ip and the number of turn, Is no longer increases, at this moment hall device plays indication zero magnetic flux, in case can come balance this moment by Is. any variation of tested electric current all can destroy this balance. the magnetic field out of trim, hall device just has signal output. after power amplification, just there is corresponding electric current to flow through secondary winding immediately so that unbalance magnetic field is compensated. unbalance from magnetic field to balance once more, less than 1 μ s, this is the process of a mobile equilibrium on the required time theory.

The magnetic balance type current sensor mainly contains following characteristics:

1) can measure the random waveform electric current simultaneously, as: direct current, interchange, pulse current;

2) complete electrical isolation between the tested electric current of compensating measure electric current and former limit, insulation voltage is generally 2kV～12kV;

3) current measuring range is wide, can measure specified 1mA～50kA electric current;

4) tracking velocity di/dt＞50A/ μ s;

5) linearity is better than 0.1%IN;

6) response time＜1 μ s;

7) frequency response 0～100kHz.

At present, known Hall element has such deficiency in detecting electric current: precision is low, the linearity is good inadequately, thereby or sensed current is little can't satisfy the big current detecting occasion of some high requests.

Summary of the invention:

Goal of the invention of the present utility model is to provide a kind of can detect big electric current and that the linearity is high, that precision is high ultra-high current Hall pick-up unit.

Ultra-high current Hall pick-up unit of the present utility model is to realize like this, comprise fixed support, the day font soft magnetic bodies magnetic core that constitutes by two mountain font soft magnetic bodies that are oppositely arranged on the support, compensating coil, hall device, comprise the circuit part that has millivolt voltage amplification and current signal output, gap between the termination that faces from top to bottom of two relative mountain font soft magnetic bodies is main air gap successively, the shunting air gap, detect air gap, two compensating coils are arranged on the soft magnetic bodies that detects the air gap both sides, the control signal output of hall device links to each other with the control signal input of circuit part, and the electric current output of circuit part links to each other with the electric current input of two compensating coils.During work, make the big electric current that needs to detect through main air gap, magnet ring window between the shunting air gap, when the magnetic flux in detecting air gap is non-vanishing, be positioned at the hall device that detects air gap and can produce an electric signal, the power tube of driving circuit section output offset current produce to the compensating coil one with the detection air gap in the opposite magnetic flux of magnetic flux, magnetic flux in detecting air gap is zero, at this moment, just can obtain the value of offset current by the current signal output of circuit part, (N1 * I1)/(δ 3/ δ 2)=N2 * I2 just can obtain the value of the big electric current of needs detection by formula then, N1 is the primary coil number of turn (is the number of turn of sensed current, is generally 1) in the formula; I1 is detected big electric current; δ 3/ δ 2 is for detecting air gap and the ratio of shunting air gap; N2 is the compensating coil number of turn; I2 is offset current (being output current).Owing to detect air gap and shunting air gap by adjusting, make the detection air gap and the ratio of shunting air gap reach several times even pick up several times, like this, just can reduce the compensating coil number of turn significantly, under the situation in same line footpath, just can reduce the resistance of compensating coil significantly, thereby guarantee in reference power supply voltage and little power consumption to make this device can detect the electric current of super large with the output current of standard with under the volume.Owing to main air gap, shunting air gap are set on the magnet ring, detect air gap, shunting by the shunting air gap, the field shunting that big electric current is responded to has been smaller to detecting in the air gap, like this, hall device is in and neededly when detecting zero magnetic flux is used for offsetting the electric current that acts on the compensating coil that detects air gap magnetic field and does not just need very big, making super-large current detect becomes possibility, through the conversion of fixing mathematical relation, just can converse the current value of the big electric current that is detected exactly.

Here, in order to guarantee to be operated in linear condition, main air-gap separation δ 1 should meet the following conditions:

B≈H×μ0×S1/δ1≤B0

In the formula: B is an assembly main magnetic circuit magnetic induction density;

B0 is a Hall element maximum linear magnetic induction density;

H is the sensed current ampere turns;

S1 is that the main cross-section of air gap is long-pending;

μ 0 is an air permeability.

The utility model compared with the prior art owing to adopted the technology of shunt magnetic, therefore, have can detect big electric current and linearity height, advantage that accuracy of detection is high.

Description of drawings:

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a circuit controling drawing.

Embodiment:

Now in conjunction with the accompanying drawings and embodiments the utility model is described in further detail:

As shown in the figure, ultra-high current Hall pick-up unit of the present utility model is to realize like this, comprise support 1, the day font soft magnetic bodies magnetic core 3 that constitutes by two mountain font soft magnetic bodies 2 that are oppositely arranged on the support 1, compensating coil 4, hall device 5, comprise the circuit part 6 that has millivolt voltage amplification and current signal output, gap between the termination that faces from top to bottom of two relative mountain font soft magnetic bodies 2 is assembly air gap delta 1 successively, shunting air gap delta 2, assemble air gap delta 3, two compensating coils 4 are arranged on the soft magnetic bodies 2a that assembles air gap delta 3 both sides, hall device 5 is arranged on to be assembled in the air gap delta 3, the control signal output of hall device 5 links to each other with the control signal input of circuit part 6, and the electric current output of circuit part 6 links to each other with the electric current input of two compensating coils 4.

Main air-gap separation δ 1 should meet the following conditions:

B≈H×μ0×S1/δ1≤B0

In the formula: B is an assembly main magnetic circuit magnetic induction density;

B0 is a Hall element maximum linear magnetic induction density;

H is the sensed current ampere turns;

S1 is that the main cross-section of air gap is long-pending;

μ 0 is an air permeability.

Claims (2)

1, a kind of ultra-high current Hall pick-up unit, it is characterized in that comprising fixed support, the day font soft magnetic bodies magnetic core that constitutes by two mountain font soft magnetic bodies that are oppositely arranged on the support, compensating coil, hall device, comprise the circuit part that has millivolt voltage amplification and current signal output, gap between the termination that faces from top to bottom of two relative mountain font soft magnetic bodies is main air gap successively, the shunting air gap, detect air gap, two compensating coils are arranged on the soft magnetic bodies that detects the air gap both sides, the control signal output of hall device links to each other with the control signal input of circuit part, and the electric current output of circuit part links to each other with the electric current input of two compensating coils.

2, ultra-high current Hall pick-up unit according to claim 1 is characterized in that main air-gap separation δ 1 should meet the following conditions:

B≈H×μ0×S1/δ1≤B0

In the formula: B is an assembly main magnetic circuit magnetic induction density;

B0 is a Hall element maximum linear magnetic induction density;

H is the sensed current ampere turns;

S1 is that the main cross-section of air gap is long-pending;

μ 0 is an air permeability.

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