CN201152886Y - Dot-matrix Hall current sensor - Google Patents

Abstract

The utility model relates to a dot-matrix Hall current sensor which consists of an array made up of N Hall components, a printed circuit board (PCB ), a gain-adjusting circuit and a cumulative output circuit; a magnetic field distribution model with a one-time current-carrying wire as the long straight wire is adopted to array N Hall components on the PCB evenly and symmetrically according to the path; the plane where each Hall component is positioned passes through the central shaft of the path; the gain-adjusting circuit is still arranged on the PCB to determine the weighting coefficient of each Hall component corresponding to the Hall electric potential and add the processed signals directly through the cumulative output circuit to obtain a normalized total Hall electric potential, and N represents any natural number larger than zero. The dot-matrix Hall current sensor overcomes the defects caused to the Hall current sensor by ferromagnetic materials that the linearity is worsened; the dynamic range is narrowed; the volume weight is increased; the cost is highly raised, etc.

Description

Lattice type Hall electric current transducer

Technical field

The present invention relates to a kind of lattice type Hall electric current mutual inductor that utilizes the Hall effect principle, be used to measure alternating current or DC current.

Background technology

Hall current sensor is a kind of current measuring device commonly used, and its adopts Hall element as sensing unit, and the size in the magnetic field that produces by tested electric current realizes the measurement to electric current.Hall element is known as Hall plate again, because it is a kind of wafer.As a kind of technology maturation and widely used magnetic field detection element, Hall element is the Hall voltage that produces in magnetic field according to the current-carrying semiconductor for the basis.Open loop type Hall current sensor with ferromagnetic material as magnetic conductor, and Hall element is placed in the air gap of magnetic conductor, clearly, the ferromagnetic part magnetic resistance is far smaller than the magnetic resistance of air gap, within the specific limits, magnetic induction density in the air gap and tested electric current keep stable linear relation, measure the magnetic induction density in the air gap, can obtain the size of tested electric current in conjunction with the transduction factor of air-gap iron core.Adopt the main effect of ferromagnetic material to have two: 1, ferromagnetic material can effectively shield external magnetic field, eliminates the influence that ring-like current sensor is split in extraneous electric current or magnetic field, thereby make sensor total Hall voltage to external world magnetic field or electric current be sensed as zero.2, play the effect of poly-magnetic, strengthen the magnetic induction density that tested electric current produces.Open loop type Hall current sensor often precision is not high, generally can reach 10 ^-2Level, tested electric current is compared with the mutual inductor rated current hour, measuring error can sharply increase, its main cause is: because ferromagnetic material exists magnetic hysteresis and loss, when tested electric current changes in a big way, magnetic induction density and the linear relationship between the electric current in the air gap can change a lot, and during particularly less electric current, this deviation is particularly evident.

The closed-loop type Hall current sensor has been continued to use the zero magnetic flux principle of comparator, a series of improvement on the basis of open loop type Hall current sensor, have been carried out, at first be on the ferromagnetic material of band air gap, evenly to arrange a balance winding, secondly Hall element is no longer in order to the size of direct detection electric current, and as a residual flux detecting unit, a certain size electric current of the output Hall voltage controlling and driving of Hall element is by the balance winding.Under the stable state, balance winding and tested electric current keep good linear relationship, and scale-up factor is the number of turns of balance winding and the ratio of tested electric current number of turns, can obtain the size of tested electric current by the size of current in the detection balance winding.The closed-loop type current sensor is reliable and stable, and accuracy can be up to 10 ^-3Level even higher, still, the driving force of balancing circuitry is limited, and making big current closed-loop Hall current sensor is comparison difficulty and very expensive.

Open loop type Hall current sensor is owing to air-gap iron core is non-linear, and accuracy is not high, and dynamic range is little, and response speed is slow; The accuracy of closed-loop type Hall current sensor increases, but obtains relatively difficulty and very uneconomical of bigger offset current, not too is suitable for Super-Current Measurement.

Summary of the invention

The invention provides a kind of novel lattice type Hall electric current transducer, it has overcome the defective of traditional Hall current sensor fully, the major defect of traditional Hall current sensor is all relevant with iron core, this novel lattice type Hall electric current transducer fundamentally gets rid of the existence of iron core, thus overcome ferromagnetic material to Hall current sensor bring such as linearity variation, dynamic range is little, volume weight increases, cost is crossed high aspect defective.

Lattice type Hall electric current transducer, comprise an array of forming by N Hall element, printed circuit board (PCB), gain adjustment circuit and output summation circuit, it is characterized in that: the Distribution of Magnetic Field model that to adopt current carrying conductor be long straight conductor, be distributed on the printed circuit board (PCB) symmetrically N Hall element by path, and the central shaft in path is passed on each plane, Hall element place, gain adjustment circuit and output summation circuit also are distributed on the printed circuit board (PCB), gain adjustment circuit is made up of N amplifying circuit, amplifying circuit is by N operational amplifier, several resistance are formed, each operational amplifier connects into and Hall element amplifying circuit one to one with resistance respectively, and amplifying circuit adopts existing amplifying circuit, each amplifying circuit is connected one to one with Hall element, and then the output summation circuit that constitutes by 1 operational amplifier and several resistance directly adds up the back as the output of this lattice type Hall electric current transducer mutually with the output of each amplifying circuit, and N be greater than zero natural number.

If lattice type Hall electric current transducer uses occasion closer at adjacent phase current or that external interference magnetic field is stronger and complicated, the array that N Hall element formed is put in the columnar shielding cylinder, and N is the natural number greater than zero.

On N the Hall element printed circuit board (PCB) that is distributed in a certain size closed path symmetrically, and each plane, Hall element place passes the central shaft of closed path, and N is the natural number greater than zero.

On N the Hall element printed circuit board (PCB) that is distributed in a certain size circumference symmetrically, and each plane, Hall element place passes the central shaft of circumference, and N is the natural number greater than zero.

N Hall element is distributed on the printed circuit board (PCB) of a non-closed path, N is the natural number greater than zero, according to circuital law as can be known N Hall element should be distributed in the printed circuit board (PCB) of a closed path, in fact also can obtain certain results of measuring if not a closed path, can be applied in accuracy requirement and be not under the very high occasion.

Lattice type Hall electric current transducer mainly is made up of Hall element array and gain adjustment circuit and output summation circuit, lattice type Hall electric current transducer does not use ferromagnetic material, the Distribution of Magnetic Field model that to be based on current carrying conductor be long straight conductor, when the Hall element quantity that adopts abundant, on all Hall elements circumference that is distributed in a certain size symmetrically, and when the central shaft of this circumference is passed on plane, single Hall element place, according to Amp, the measurement result of the lattice type Hall electric current transducer of structure and the shape and the location independent of current carrying conductor, and any electric current or the magnetic field response on this sensor in this lattice type Hall electric current transducer outside is zero.Therefore, the present invention is from technique effect, has and contains the same anti-external magnetic field effects of jamming of cored Hall current sensor, it is good also to have the linearity simultaneously, wide dynamic range, volume is little, and grade in light weight contains the advantage that cored Hall current sensor does not possess.

Lattice type Hall electric current transducer ultimate principle of the present invention is as follows:

Four basic assumptions that desirable lattice type Hall electric current transducer need satisfy are: the Hall element quantity of use is abundant; Hall element distributes on a certain size circumference symmetrically and evenly; The magnetosensitive sense characteristic unanimity of Hall element; The central shaft of the circumference that Hall element constitutes is on the plane, magnetic sensitive film place of all Hall elements.

With adopt symmetrically rounded of 16 Hall elements be distributed in current carrying conductor around be example, as shown in Figure 1, be the basic model of lattice type Hall electric current transducer.The magnetic induction density note of i Hall element loca is made B _i, by Hall effect, can get:

e _i＝KgB _i

The Hall voltage that can be obtained all Hall elements by assumed condition equates that total Hall voltage sum is:

$e_{\mathrm{Sensor}}=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{e}_i=\mathrm{Kg}\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{B}_i=\frac{{\mathrm{\μ}}_0\mathrm{NK}}{2\mathrm{\πr}}i=K^{*}\mathrm{gi}$ $K^{*}=\frac{{\mathrm{\μ}}_0\mathrm{NK}}{2\mathrm{\πr}}$

The total Hall voltage and the scale-up factor between the tested electric current of lattice type Hall electric current transducer are K ^*, K ^*With the magnetic permeability μ in the vacuum ₀, Hall element number N, the transduction factor K of single Hall element, Hall element be relevant apart from factors such as r to the current carrying conductor central shaft, can be easy to find the solution the transduction factor K of sensor by known parameter ^*, lattice type Hall electric current transducer is by measuring the exact value that total Hall voltage can obtain tested electric current.

Record the Hall coefficient K of each Hall element _i, it is modified to unified Hall coefficient K by correction factor.Fig. 3 is gain adjustment circuit and the output summation circuit model that adopts, when satisfying following formula, the output summation circuit that signal after handling is constituted by operational amplifier is with the output of each amplifying circuit output of back as this lattice type Hall electric current transducer that directly adds up mutually, can obtain the total Hall voltage after the normalization, this adjustment circuit has effectively been eliminated the difference between the Hall coefficient of single Hall element.

$\frac{R}{R_i}=\frac{K^{*}}{K_i}$ $\mathrm{\Σ}{e_i}^{*}=\mathrm{\Σ}\frac{R}{R_i}{K}_i{B}_i=K^{*}\mathrm{\Σ}{B}_i$

Lattice type Hall electric current transducer of the present invention:

1, this novel lattice type Hall electric current transducer has thoroughly been got rid of ferromagnetic material, when the Hall element quantity that adopts abundant, on all Hall elements circumference that is distributed in a certain size symmetrically, and when the central shaft of this circumference is passed on plane, single Hall element place, according to Amp, the measurement result of the lattice type Hall electric current transducer of structure and the shape and the location independent of current carrying conductor, and any electric current or the magnetic field response on this sensor in this lattice type Hall electric current transducer outside is zero, and promptly this current sensor model has the ability of very strong anti-external interference.

2, this novel lattice type Hall electric current transducer adopts printed-board technology to solve the problem that a plurality of Hall elements distribute symmetrically, and the central shaft that can guarantee the circumference that Hall element constitutes is on the plane, magnetic sensitive film place of all Hall elements.

3, this novel lattice type Hall electric current transducer employing gain adjustment circuit solves the different problem of Hall coefficient of a plurality of Hall elements, has guaranteed the magnetosensitive sense characteristic unanimity of Hall element.To the gain output of adjusted each amplifying circuit of the output summation circuit that constitutes by 1 operational amplifier directly adds up afterwards mutually as the output of this lattice type Hall electric current transducer, can obtain the total Hall voltage after the normalization.

4, this novel lattice type Hall electric current transducer has adopted based on the arrangements of elements method of printed circuit board (PCB) and the indemnifying measure of gain adjustment circuit, is two topmost gordian techniquies that lattice type Hall electric current sensing model is realized based on the Hall element placement technique of PCB and the adjustment technology that gains.

5, according to circuital law as can be known N Hall element should be distributed in the printed circuit board (PCB) of a closed path, in fact also can obtain certain results of measuring if not a closed path, can be applied in accuracy requirement and not be under the very high occasion.

Lattice type Hall electric current transducer of the present invention does not use ferromagnetic material, the Distribution of Magnetic Field model that to be based on current carrying conductor be long straight conductor, when the Hall element quantity that adopts abundant, adopt pcb board with all Hall elements being distributed on the closed path symmetrically, and when the central shaft of closed path is passed on plane, single Hall element place, according to Amp, the measurement result of the lattice type Hall electric current transducer of structure and the shape and the location independent of current carrying conductor, and any electric current or the magnetic field response on this sensor in this lattice type Hall electric current transducer outside is zero.And the employing gain adjustment circuit solves the different problem of Hall coefficient of a plurality of Hall elements, has solved the conforming problem of magnetosensitive sense characteristic of Hall element.Four conditions of desirable lattice type Hall electric current transducer have so just been satisfied.

Description of drawings

Fig. 1 is a schematic diagram of the present invention.

Fig. 2 is a structural representation of the present invention.

Fig. 3 is gain adjustment circuit of the present invention and output summation circuit schematic diagram.

Embodiment

The present invention has abandoned traditional core construction, and the Distribution of Magnetic Field model that current carrying conductor of foundation is a long straight conductor has been constructed desirable lattice type Hall electric current transducer.Four basic assumptions that this desirable lattice type Hall electric current transducer need satisfy are: the Hall element quantity of use is abundant; Hall element distributes on closed path symmetrically and evenly; The magnetosensitive sense characteristic unanimity of Hall element; The central shaft of the closed path that Hall element constitutes is on the plane, magnetic sensitive film place of all Hall elements.

The Distribution of Magnetic Field model that current carrying conductor of the present invention's foundation is a long straight conductor, when Hall element quantity abundant, adopt pcb board with on all Hall elements circumference that is distributed in a certain size symmetrically, and when the central shaft of this circumference is passed on plane, single Hall element place, according to Amp, the measurement result of the lattice type Hall electric current transducer of structure and the shape and the location independent of current carrying conductor, and any electric current or the magnetic field response on this sensor in this lattice type Hall electric current transducer outside is zero.And the employing gain adjustment circuit solves the different problem of Hall coefficient of a plurality of Hall elements, has solved the conforming problem of magnetosensitive sense characteristic of Hall element.Therefore the technological means taked of the present invention has satisfied four conditions of desirable lattice type Hall electric current transducer.

Ten six Hall element current sensors with rated current 3kA are example, and concrete steps are:

1, determines the size of Hall element distribution circumference.The application of lattice type Hall electric current transducer is the measurement of big amplitude, lower frequency electric current, and the Hall element of selecting for use should have less size, bigger dynamic range, good linearty, desirable temperature stabilization performance, cheap price.

The characteristic of the hall device of taking all factors into consideration rated current and selecting for use, determine that substantially the formula of Hall element distribution circumferential size is as follows:

$R_{\min }=\frac{{\mathrm{\&mu;}}_0{i}_{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="Y20082006543500091.png"\; state="\{\{state\}\}">e</figure-callout>}}}{2\mathrm{\&pi;}{B}_{\max }}$

Wherein, R _MinBe the least radius of circumference, i _eBe rated current, B _MaxMaximum magnetic induction for the Hall element range of linearity.Following formula provides the roughly criterion of definite circumferential size, and for the accuracy that guarantees that lattice type Hall electric current transducer is measured, the circumferential size of Hall element must be considered certain surplus, and generally getting real radius is 2R _MinEven the skew of current carrying conductor causes that indivedual Hall elements present position magnetic induction density is greater than mean value like this, also or the magnetic field that produces of external interference current such as adjacent phase current increased the magnetic induction density at indivedual Hall elements place, all be unlikely to because indivedual Hall elements have influenced the accuracy of measurement of whole sensor array because being in nonlinear area.

It should be noted that and use closer or during occasion that external interference magnetic field is stronger and complicated, it is very necessary that whole sensor array is in the columnar shielding when lattice type Hall electric current transducer at adjacent phase current.

2, designing gain is adjusted circuit.The effect of gain adjustment circuit is the actual Hall coefficient that records each Hall element, utilizes the method for weighting to adopt gain circuitry that the Hall voltage of all Hall elements is carried out normalized.Gain adjustment circuit is characterised in that the weighting coefficient of determining the corresponding Hall voltage of each Hall element.

3, determine parameter, eliminate the electromotive force at zero point.Standard Magnetic Field is produced by an open core with certain winding, and the opening of iron core is 2mm, and Hall element be able to be put into and stationkeeping, passes to the electric current of amplitude 1A frequency of operation 50Hz on the winding.The magnetic field that produces of the alternating current of selection work frequency 50Hz why, be in order to get rid of the influence of Hall element electromotive force at zero point, as semiconductor devices, when Hall element under certain voltage or current excitation, when residing magnetic induction density is zero, the output Hall voltage is often also non-vanishing, and the signal of this basicly stable amplitude approximate number mV is called as the electromotive force at zero point, and elimination electromotive force at zero point is a basic guarantee of accurately measuring Hall coefficient.One by one Hall element is placed in the air gap of iron core, driving voltage on the Hall element remains unchanged, measure the component of 50Hz in the Hall voltage of each Hall element, note absolute value, these absolute values are compared the relative weighting coefficient that can obtain gain adjustment circuit, determine R among Fig. 3 by the coefficient that calculates ₁-R ₁₆Value, determine that the foundation of resistance value is: under the effect of same magnetic induction, the output Hall voltage of all Hall elements is through the adjusted equal and opposite in direction that gains.

4, the output summation circuit of operational amplifier formation is with the direct output of back as this lattice type Hall electric current transducer that adds up mutually of the above-mentioned adjusted amplifying circuit output that respectively gains.

More than be to be the example explanation with the circumference lattice type Hall electric current transducer that 16 Hall elements constitute, if Hall element is not a circumference of formation but constitutes a long a of being, wide is the rectangle of b, and a 〉=b, then embodiment is determined size with round different except the first step, and designing gain is adjusted circuit, determined that the output summation circuit of parameter and operational amplifier formation is all with round identical.Embodiment is as follows:

Because $R_{\min }=\frac{{\mathrm{\&mu;}}_0{\mathrm{<figure-callout\; id="2"\; label="i\; e"\; filenames="Y20082006543500091.png"\; state="\{\{state\}\}">i</figure-callout>}}_e}{2\mathrm{\&pi;}{B}_{\max }}$

Wherein, i _eBe rated current, B _MaxBe the maximum magnetic induction of the Hall element range of linearity, R _MinBe the least radius of the circumference of maximum magnetic induction, can both be in the range of linearity and obtain maximum magnetic induction, consider surplus, desirable b=4R in order to guarantee each Hall element _Min

Structure of the present invention mainly is made up of two parts: Hall element array 1, gain adjustment circuit and output summation circuit 2.Lattice type Hall electric current transducer with 16 Hall elements is an example, mainly by 16 Hall elements, one printed circuit board 3,17 operational amplifiers, 81 resistance are formed, one time current carrying conductor 4 passes from Hall element array 1 center, printed circuit board (PCB) 3 has been carried out accurate localization for Hall element, be Hall element simultaneously, operational amplifier and resistance provide solid and reliable support, a stabilivolt is housed on the printed circuit board (PCB) presses excitation, realized that by the gain adjustment circuit that operational amplifier constitutes gain is adjusted and the double effects of calibration for Hall element provides galvanic current.This Hall current sensor needs the external world that direct supply is provided so that Hall element and gain adjustment circuit operate as normal.

If lattice type Hall electric current transducer uses occasion closer at adjacent phase current or that external interference magnetic field is stronger and complicated, whole Hall element array is put in the columnar shielding cylinder 5.

Claims (5)

1, lattice type Hall electric current transducer, comprise an array of forming by N Hall element, printed circuit board (PCB), gain adjustment circuit and output summation circuit, it is characterized in that: the Distribution of Magnetic Field model that to adopt current carrying conductor be long straight conductor, be distributed on the printed circuit board (PCB) symmetrically N Hall element by path, and the central shaft in path is passed on each plane, Hall element magnetic sensitive film place, gain adjustment circuit and output summation circuit also distribute on the printed circuit board (PCB), gain adjustment circuit is made up of N amplifying circuit, N amplifying circuit is by N operational amplifier, several resistance are formed, each operational amplifier connects into and Hall element amplifying circuit one to one with resistance respectively, each amplifying circuit is connected one to one with Hall element, adopt output summation circuit that 1 operational amplifier and several resistance constitute that the output of each amplifying circuit is directly added up the back mutually as the output of this lattice type Hall electric current transducer again, N be greater than zero natural number.

2, according to the described lattice type Hall electric current transducer of claim 1, it is characterized in that: the array that N Hall element formed is put in the columnar shielding cylinder, and N is the natural number greater than zero.

3, according to claim 1 or 2 described lattice type Hall electric current transducers, it is characterized in that: on N the Hall element printed circuit board (PCB) that is distributed in a certain size closed path symmetrically, and the central shaft of closed path is passed on each plane, Hall element place, and N is the natural number greater than zero.

4, according to the described lattice type Hall electric current transducer of claim 3, it is characterized in that: on N the Hall element printed circuit board (PCB) that is distributed in a certain size circumference symmetrically, and the central shaft of circumference is passed on each plane, Hall element place, and N is the natural number greater than zero.

5, according to claim 1 or 2 described lattice type Hall electric current transducers, it is characterized in that: N Hall element is distributed on the printed circuit board (PCB) of a non-closed path, and N is the natural number greater than zero.

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