CN206020511U

CN206020511U - A kind of current sensor based on Luo-coil

Info

Publication number: CN206020511U
Application number: CN201621051381.7U
Authority: CN
Inventors: 龚勇镇; 朱亚斌; 陈英俊; 何颖东; 林国彪; 廖辉; 黄崇林; 乔东凯
Original assignee: Guangdong University of Petrochemical Technology
Current assignee: Guangdong University of Petrochemical Technology
Priority date: 2016-09-13
Filing date: 2016-09-13
Publication date: 2017-03-15
Anticipated expiration: 2026-09-13

Abstract

The utility model discloses a kind of current sensor based on Luo-coil, including amplifying circuit, integrating circuit and filter circuit, amplifying circuit, integrating circuit and filter circuit are sequentially connected；The amplifying circuit constitutes in-phase amplification circuit using amplifier OP07CP；The integrating circuit is using the active integrator with inertial element；The filter circuit adopts quadravalence Butterworth active low-pass filter circuit.The utility model has the advantages that the linearity is good, sensitivity is high, measurement range and bandwidth, certainty of measurement high, simple and light, without magnetic saturation phenomenon, safe and reliable and be easy to industrialized production, in power system, will have broad application prospects.

Description

A kind of current sensor based on Luo-coil

Technical field

The utility model is related to a kind of current sensor, specifically a kind of current sensor based on Luo-coil.

Background technology

1）Electromagnetic type current sensor：It is made up of heavy iron core and first and second winding, the general principle of employing is base In electromagnetic induction principle.I.e. when there is electric current to pass through in first winding, magnetic flux can be caused in iron core, in Secondary Winding just Induced electromotive force is induced, electric current is produced in the loop.The winding ratio of first and second side is adjusted, different grades of electric current is obtained.

2）Flexible, rigid Luo-coil current sensing head：Luo-coil：（Also known as Rogowski coils）It is one to lead Line（Enamel-covered wire）The air core coil being uniformly wound on non magnetic ring skeleton.During measurement, current carrying conductor is worn from hub of a spool Cross, according to Ampere circuit law and the law of electromagnetic induction, magnetic field will produce an induced electromotive force at the two ends of coil, its value Size is proportional to the differential of tested Current versus time.The induced electromotive force of Luo-coil is integrated after computing direct ratio is obtained Signal in tested electric current.Luo-coil better performances, applying at present more mainly has two kinds.

（a）Flexible Luo-coil：Enamel-covered wire is uniformly wound on the flexible insulating material skeleton that can be bent, and is surveyed During amount, skeleton needs to bend to the ring that head and the tail closely match.

（b）Rigid Luo-coil：I.e. fixed Luo-coil, its skeleton cross sectional shape common are track type, circle, Three kinds of rectangle, square-section application are wider.

Prior art shortcoming：

1）Because of itself structure and sensor mechanism, electromagnetic type current sensor has that easily ferromagnetic saturation, volume be big, signal is defeated Go out easy distortion, be difficult to safe insulation, digital output inconvenience, frequency band is narrow, power consumption is big, high cost the shortcomings of.

2）Flexible, rigid Luo-coil current sensing head：Coiling on flexible and rigid Luo-coil skeleton is by coiling Machine is manual completing, and based on the limitation of the technique, each coiling is difficult to ensure that completely the same, it is also not possible to make coiling absolute Uniformly, wire turn sectional area is equal everywhere.Therefore which is repeated and bad, and the uniformity of coil parameter distribution is difficult to be guaranteed, And the shortcomings of there is layer capacitance and become big and easily break.Certainty of measurement and the degree of accuracy are affected, anti-external magnetic field interference performance Weak, very unfavorable to industrialized development.

Utility model content

The purpose of this utility model is to provide a kind of current sensor based on Luo-coil, to solve above-mentioned background skill The problem proposed in art.

For achieving the above object, the utility model provides following technical scheme：

A kind of current sensor based on Luo-coil, including Luo-coil, amplifying circuit, integrating circuit and filtered electrical Road, it is characterised in that the amplifying circuit, integrating circuit and filter circuit are sequentially connected, the Luo-coil skeleton is highly 0.002m, the number of turn are 200 circles, and inside radius is 0.032m, and outer radius is 0.050m.

As further program of the utility model：The amplifying circuit is constituted homophase and amplifies electricity using amplifier OP07CP Road.

As further program of the utility model：The integrating circuit is using the active integrator with inertial element.

As the utility model further scheme：The filter circuit adopts quadravalence Butterworth active low-pass filter Circuit.

Compared with prior art, the beneficial effects of the utility model are：The utility model has that the linearity is good, sensitivity High, measurement range and bandwidth, certainty of measurement high, simple and light, without magnetic saturation phenomenon, safe and reliable and be easy to industrialize The advantages of production, in power system, will have broad application prospects.

Description of the drawings

Fig. 1 is the structural representation of the current sensor based on Luo-coil；

Fig. 2 is the circuit diagram of amplifying circuit in current sensor based on Luo-coil；

Fig. 3 is the circuit diagram of integrating circuit in current sensor based on Luo-coil；

Fig. 4 is the circuit diagram of filter circuit in current sensor based on Luo-coil；

Fig. 5 is the circuit diagram of Luo-coil in current sensor based on Luo-coil.

Specific embodiment

Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is carried out Clearly and completely describe, it is clear that described embodiment is only a part of embodiment of the utility model, rather than whole Embodiment.Embodiment in based on the utility model, those of ordinary skill in the art are not under the premise of creative work is made The every other embodiment for being obtained, belongs to the scope of the utility model protection.

Fig. 1～5 are referred to, in the utility model embodiment, a kind of current sensor based on Luo-coil, including Roche Coil, amplifying circuit, integrating circuit and filter circuit, the amplifying circuit, integrating circuit and filter circuit are sequentially connected, described Luo-coil skeleton is highly 0.002m, and the number of turn is 200 circles, and inside radius is 0.032m, and outer radius is 0.050m；The integration electricity Road is using the active integrator with inertial element；The filter circuit adopts quadravalence Butterworth active low-pass filter circuit.

Operation principle of the present utility model is：PCB types（Printed circuit board (PCB)）During Luo-coil measurement electric current, one will be exported With tested electric current into differential relationship voltage signal.Due to the mutual inductance value of PCB type Luo-coils less, so the signal is more micro- Weak, easily suffer external interference, affect measurement result, it is necessary to by the process of follow-up signal process circuit, can just obtain accurately Output signal.Follow-up signal process circuit is made up of three parts successively, is amplifying circuit, integrating circuit, filtered electrical respectively Road.

PCB types Luo-coil measurement electric current when, by output one with tested electric current into differential relationship voltage signal.Due to The mutual inductance value of PCB type Luo-coils is less, so the signal is fainter, easily suffers external interference, affects measurement result, it is necessary to By the process of follow-up signal process circuit, accurate output signal can be just obtained.Follow-up signal process circuit is big by three successively Part constitutes, and is amplifying circuit, integrating circuit, filter circuit respectively.When connecting between each circuit, constantly coupling to be passed through And debugging, require until meeting.Transducer Signal Detecting Circuit schematic diagram is as shown in Figure 1.

The weak voltage signals of PCB types Luo-coil output are mainly amplified in the effect of amplifying circuit, weaken external interference, Improve signal to noise ratio.During design, in-phase amplification circuit is constituted using amplifier OP07CP, make full use of the ultra-low drift of the components and parts Performance, makes output signal accurately, and multiplication factor is stable, it is ensured that impedance matching between front stage circuit.The amplifying circuit of design is such as Shown in Fig. 2.

From Luo-coil measuring principle, the induced voltage of coil output is differential expressions, itself and electrified wire Middle transient current is directly proportional to the derivative of time.For ensureing induced voltage and the uniformity in tested current phase, it is necessary to design One integrating circuit, integrating circuit typically do not adopt signal attenuation than more serious passive integrator.As requested, addition is devised The active integrator of inertial element, as shown in figure 3, which is substantially exactly to carry out stabilizing circuit in integrating capacitor two ends parallel feedback resistance Work, reduces integrator drift, improves certainty of measurement.

The signal induced by PCB type Luo-coils can be sent to microcomputer control by A/D conversions typically after signal condition In system processed, control system is further shown to signal and is operated.And the signal through sensor sensing out is remained and is contained There is the high-frequency signal of fundamental wave and each harmonic component, thus, before signal input Control System of Microcomputer, it is necessary to using filtered electrical Road increases the signal to noise ratio of sensor eliminating these radio-frequency components.As requested, the active low pass of one quadravalence Butterworth of design Filter circuit, as shown in Figure 4.The circuit has that input impedance is high, output impedance is low, carrying load ability is strong, circuit performance is stable, The advantages of gain is easily dimmable.In output signal frequency when more than 10KHz, decay substantially, can meet measurement request.

Design is a kind of to be based on printed circuit board (PCB)（Abbreviation PCB）The Luo-coil of skeleton, i.e. PCB types Luo-coil, PCB types Framework material temperature coefficient is little, and dimensionally stable is easy to coiling.Analyzed by modeling and simulation, structure and the electricity to Luo-coil Magnetic parameter is optimized design.As requested, suitable parameters are chosen, and the monolithic PCB type Luo-coil parameters after optimization are as follows：Bone Frame height h is 0.002m, and number of turn N is 200 circles, and inside radius b is 0.032m, and outer radius a is 0.050m.Set using area of computer aided Meter software（Protel DXP）Connected up, professional production producer is transferred to after the good line of cloth using the full-automatic production of Digit Control Machine Tool, As shown in Figure 5.Coil is machinable very accurate, it is no longer necessary to loaded down with trivial details coiling.

It is obvious to a person skilled in the art that the utility model is not limited to the details of above-mentioned one exemplary embodiment, and And in the case of without departing substantially from spirit or essential attributes of the present utility model, can realize that this practicality is new in other specific forms Type.Therefore, no matter from the point of view of which point, embodiment all should be regarded as exemplary, and is nonrestrictive, this practicality is new The scope of type is by claims rather than described above is limited, it is intended that the equivalency fallen in claim is contained All changes in justice and scope are included in the utility model.Any reference in claim should not be considered as restriction Involved claim.

Moreover, it will be appreciated that although this specification is been described by according to embodiment, not each embodiment is only wrapped Contain an independent technical scheme, this narrating mode of specification is only that those skilled in the art should for clarity Using specification as an entirety, the technical scheme in each embodiment can also form those skilled in the art through appropriately combined Understandable other embodiment.

Claims

1. a kind of current sensor based on Luo-coil, including Luo-coil, amplifying circuit, integrating circuit and filter circuit, Characterized in that, the amplifying circuit, integrating circuit and filter circuit are sequentially connected, the Luo-coil skeleton is highly 0.002m, the number of turn are 200 circles, and inside radius is 0.032m, and outer radius is 0.050m.

2. the current sensor based on Luo-coil according to claim 1, it is characterised in that the amplifying circuit is adopted Amplifier OP07CP is constituting in-phase amplification circuit.

3. the current sensor based on Luo-coil according to claim 1, it is characterised in that the integrating circuit is adopted Active integrator with inertial element.

4. the current sensor based on Luo-coil according to claim 1, it is characterised in that the filter circuit is adopted Quadravalence Butterworth active low-pass filter circuit.