CN111370199A

CN111370199A - Rogowski coil

Info

Publication number: CN111370199A
Application number: CN202010213538.6A
Authority: CN
Inventors: 李卫荣; 张治奎; 刘国兴; 杨泽祥; 靳飞; 冯韶辉; 贾伟志; 李国培; 韩强; 李龙
Original assignee: Hebei Weixin Electronic Technology Co ltd
Current assignee: Hebei Weixin Electronic Technology Co ltd
Priority date: 2020-03-24
Filing date: 2020-03-24
Publication date: 2020-07-03

Abstract

The invention discloses a Rogowski coil which comprises a coil and a detection circuit, wherein the coil is used for obtaining an induced current signal, and the detection circuit is used for processing the induced current signal obtained by the coil to obtain a specific current value. The outermost side of the coil is provided with a first insulating layer for protecting the structure in the coil; inwardly of the coil layers, current is induced, generating a current signal; the innermost side is a core wire layer which is a framework of the coil and supports the structure of the coil. A shielding layer is arranged between the first insulating layer and the coil layer to shield the interference of an external stray magnetic field, so that the coil layer is more sensitive in induced current and is not influenced by the outside. Therefore, the small current can be accurately measured.

Description

Rogowski coil

Technical Field

The invention relates to the field of current detection, in particular to a Rogowski coil.

Background

The rogowski coil is a hollow annular coil and can be directly sleeved on a conductor to be measured. The flow of an ac signal through a conductor creates an alternating magnetic field around the conductor, which induces an ac voltage signal in the coil that is proportional to the current. The output voltage can be expressed by the formula Vout-Mdi/dt, where M is the coil mutual inductance. Di/dt is a current transformation ratio, another alternating current voltage signal can be obtained by integrating a voltage signal output by the coil through a special detection circuit, and the measured current signal is reproduced by the waveform of the voltage signal.

The Rogowski coil has wide application range. It has no special requirements for measuring current frequency and conductor size, and can also be used for measuring current signal with complex waveform, such as transient impulse current. Compared with the common current transformer, the Rogowski coil has the advantages that the Rogowski coil does not have an iron core, so that the iron core saturation phenomenon does not exist, and a large current can be directly measured. However, because it has no iron core, the voltage signal induced by the rogowski coil is relatively weak and is very susceptible to the influence of stray magnetic fields in the external environment. Therefore, the existing rogowski coil has larger error when detecting small current and is only used for detecting large current.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides the Rogowski coil capable of detecting small current.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the utility model provides a rogowski coil, includes coil and detection circuitry, the coil outside is first insulation layer, and the inside coil layer that is of first insulation layer, the inside core wire layer that is of coil layer, the coil layer outside is equipped with the shielding layer for the shielding the interference of the stray magnetic field outside the coil layer.

Further, the shielding layer is disposed between the first insulating layer and the coil layer.

Further, a second insulating layer is arranged between the shielding layer and the coil layer.

Further, the shielding layer is a metal mesh.

Furthermore, an aviation plug is adopted as an interface of the coil outgoing line.

Furthermore, a magnetic ring is sleeved on the coil measuring interface.

Furthermore, the measuring part comprises a power supply module, a current sampling module, a signal amplification module, a metering module, a single chip microcomputer and a display module.

Further, the current sampling module adopts double-port input sampling.

Furthermore, the signal amplification module adopts an amplification circuit with two-stage amplification.

Furthermore, the power supply module adopts negative voltage stabilization for power supply.

This application adopts above technical scheme, possesses following beneficial effect at least:

the technical scheme of the invention provides a Rogowski coil which comprises a coil, a detection circuit and a measurement method. The coil is used for obtaining an induced current signal, and the detection circuit is used for processing the induced current signal obtained by the coil to obtain a specific current value. The outermost side of the coil is provided with a first insulating layer for protecting the structure in the coil; inward is a coil layer, current is induced, and a current signal is generated; the innermost side is a core wire layer which is a framework of the coil and supports the structure of the coil. A shielding layer is arranged between the first insulating layer and the coil layer to shield the interference of an external stray magnetic field, so that the coil layer is more sensitive in induced current and is not influenced by the outside. Therefore, the small current can be accurately measured.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a rogowski coil provided in an embodiment of the present invention;

fig. 2 is a cross-sectional view of a coil structure of a rogowski coil according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a detection circuit according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a two-stage amplification with dual-port input according to an embodiment of the present invention;

fig. 5 is an internal circuit diagram of a detection circuit according to an embodiment of the present invention, which includes a power supply portion.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the following detailed description of the technical solutions of the present invention is provided with reference to the accompanying drawings and examples. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present application.

The Rogowski coil has the advantages that the linearity is good, the coil is not saturated, the output signal and the input signal of the system are always linear, but most of the Rogowski coil is applied to a large-current application scene, the detected current is generally larger than the magnitude order of A, the improved technology and the circuit design are provided in the method, the measurement of the mA-level current is realized, and the current measurement range is 100 mA-1000A.

Referring to fig. 1, the rogowski coil includes a coil 10 and a detection circuit 20, as shown in fig. 2, an outermost side of the coil 10 is a first insulating layer 11, a coil layer 14 is inside the first insulating layer 11, a core wire layer 15 is inside the coil layer 14, and a shielding layer 12 is disposed outside the coil layer 14 for shielding interference of a stray magnetic field outside the coil layer 14.

The Rogowski coil provided by the embodiment of the invention comprises a coil and a detection circuit, wherein the coil is used for obtaining an induced current signal, and the detection circuit is used for processing the induced current signal obtained by the coil to obtain a specific current value. The outermost side of the coil is provided with a first insulating layer for protecting the structure in the coil; inwardly of the coil layers, current is induced, generating a current signal; the innermost side is a core wire layer which is a framework of the coil and supports the structure of the coil. A shielding layer is arranged between the first insulating layer and the coil layer to shield the interference of an external stray magnetic field, so that the coil layer is more sensitive in induced current and is not influenced by the outside. Therefore, the small current can be accurately measured.

As a supplementary explanation to the above embodiment, the shield layer 12 is provided between the first insulating layer 11 and the coil layer 14 in the embodiment of the present invention. Optionally, a second insulating layer 13 is provided between the shielding layer 12 and the coil layer 14. It should be noted that, in practical use, the shielding layer 12 is in the form of a metal mesh.

As a preferred implementation of the embodiment of the present invention, as shown in fig. 1, the coil interfaces of the rogowski coil are connected by an aviation plug 15. If the wiring mode adopts a common plugging or terminal crimping mode, the measured current signal has influence on the stress of the terminal, the terminal is stressed, the signal is changed, and when the small current is measured, the final result is seriously inaccurate due to slight change. Therefore, the interface is connected by adopting an aviation connector; of course, welding is also possible.

An aviation plug is an electromechanical component that connects electrical lines. The electrical parameters of the aviation plug itself are therefore the first consideration in selecting an aviation plug. The aviation plug is used for ensuring that the internal signal of the interface terminal cannot be changed, and the aviation plug is easier to connect and has good flexibility.

In some embodiments, a magnetic ring 16 is sleeved on the interface of the coil. The magnetic ring is a ring-shaped magnetizer. The introduction of the magnetic ring solves the problem of influence of the position of the detection current in the Rogowski coil ring on the detection precision, and meanwhile, the magnetic ring is a common anti-interference element in an electronic circuit and has a good inhibition effect on high-frequency noise. The magnetic ring is sleeved at the position of the coil interface, so that an external interference source can be prevented from interfering the coil detection current at the interface.

As shown in fig. 3, the measuring part 20 includes a power supply module 21, a current sampling module 22, a signal amplifying module 23, a metering module 24, a single chip microcomputer 25 and a display module 26. The power supply module 21 provides power for the coil, the current sampling module 22 samples current in the coil, the signal amplification module amplifies current signals obtained by the signal amplification module 23, the metering module 24 and the single chip microcomputer 25 obtain the magnitude of the current signals in the coil, and the display module 26 displays the result to a user.

In one embodiment, the display device further includes an output module, which outputs the display result to a designated address, optionally, the output may be a communication mode, may be directly displayed, or may be output by outputting a standard 4-20mA signal, where a specific circuit diagram of each module is shown in fig. 5.

Preferably, the metering module 24 samples the CS5480 chip to facilitate metering the current signal.

As an optional implementation manner of the embodiment of the present invention, as shown in fig. 4, the detection circuit samples a dual-port input two-stage amplification manner, that is, the current sampling module adopts a dual-port input sampling current, and different current ranges adopt different ports to set different amplification factors for measurement. The obtained sampling current is more accurate and is not easy to have errors; the two-stage amplification circuit can adjust the input signal to a range where the signal can be detected when measuring a small current.

It should be particularly noted that the power supply module 21 supplies power by using negative voltage stabilization, so that the ground level can be raised, a signal power supply and a signal uniformly raise a certain voltage value of the ground level, the stability of the signal is ensured, meanwhile, high-power amplification of data is realized, and accurate and stable measurement of the data is realized.

According to the Rogowski coil provided by the embodiment of the invention, the shielding layer is arranged on the outer side of the coil layer, so that the coil is not interfered by an external cluttered magnetic field when an induced current is obtained, meanwhile, an aviation plug is adopted for connection at the interface, the interface is sleeved with the magnetic ring, so that a current signal is not interfered by other factors at the interface, finally, negative voltage stabilization power supply is used, the ground level is raised, the stability of the current signal is provided, and the Rogowski coil is ensured to be capable of accurately detecting a small current signal. The improved Rogowski coil realizes the improvement of the performance of the Rogowski coil, and compared with the traditional Rogowski coil, the improved Rogowski coil increases the shielding of data, improves the stability of the data and expands the application scene of the Rogowski coil. The Rogowski coil is not only applied to a place for measuring large current, but also can realize the measurement of mA-level current.

It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.

It should be noted that, in the description of the present application, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present application, the meaning of "a plurality" means at least two unless otherwise specified.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and the scope of the preferred embodiments of the present application includes other implementations in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present application.

It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.

In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.

Claims

1. The utility model provides a rogowski coil, includes coil and detection circuitry, the coil outside is first insulating layer, and the inside coil layer that is of first insulating layer is the core wire layer in the coil layer, its characterized in that: and a shielding layer is arranged on the outer side of the coil layer and used for shielding the interference of a stray magnetic field outside the coil layer.

2. The rogowski coil of claim 1, wherein: the shielding layer is arranged between the first insulating layer and the coil layer.

3. The rogowski coil of claim 2, wherein: and a second insulating layer is arranged between the shielding layer and the coil layer.

4. A rogowski coil, according to any of claims 1-3, characterized by: the shielding layer is a metal net.

5. The rogowski coil of claim 1, wherein: and an outgoing line interface of the coil adopts an aviation plug.

6. The rogowski coil of any of claims 1 or 5, wherein: and a magnetic ring is sleeved on an interface of the coil.

7. The rogowski coil of claim 1, wherein: the detection circuit comprises a power supply module, a current sampling module, a signal amplification module, a metering module, a single chip microcomputer and a display module.

8. The rogowski coil of claim 7, wherein: the current sampling module adopts double-port input sampling.

9. The rogowski coil of claim 7, wherein: the signal amplification module adopts a two-stage amplification circuit.

10. The rogowski coil of claim 7, wherein: the power supply module adopts the negative voltage stabilizing module to raise the potential of the ground, and improves the signal stability.