CN201053988Y - Highly antijamming AC current/ magnetic field sensor - Google Patents
Highly antijamming AC current/ magnetic field sensor Download PDFInfo
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- CN201053988Y CN201053988Y CNU2007200832200U CN200720083220U CN201053988Y CN 201053988 Y CN201053988 Y CN 201053988Y CN U2007200832200 U CNU2007200832200 U CN U2007200832200U CN 200720083220 U CN200720083220 U CN 200720083220U CN 201053988 Y CN201053988 Y CN 201053988Y
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Abstract
The utility model relates to a novel high anti-jamming alternating current/magnetic field sensor, and consists of a coil with a fenestrated iron core and an integral circuit. Using conductors, two output terminals of the coil communicate with two input terminals of a compensated differential integrator amplifying circuit. The coil with the fenestrated iron core has air gaps and the air gaps are symmetrically distributed. The two ends of the air gaps and the iron core are connected into a whole by using nonferromagnetic material, and a secondary winding is wound evenly around the air gaps. The integral circuit is the compensated differential integrator amplifying circuit and the compensated differential integrator amplifying circuit consists of a differential integrator and an amplifying and adjusting circuit. By adopting a symmetric differential input method, the differential integrator circuit is analogized to an operational amplifying integrator to constitute a differential integral circuit. The differential integrator circuit is paralleled to a parallel resistance of an integrator capacitor of the operational amplifying integrator and a compensated branch circuit is introduced. The utility model has the advantages of avoiding shape changing or relative position changing of the tested conductor and avoiding external magnetic field interference and other factors. Current leaking of the integrator capacitor passing through the parallel resistance can be effectively diminished, and the low frequency characteristics can be improved.
Description
Technical field
The utility model belongs to a kind of sensor of measuring AC magnetic field or alternating current, specifically, relates to the saturated novel alternating-current/magnetic field sensor of a kind of high anti-interference and anti-direct current.
Background technology
The Rogowski coil can be used to measure the variation in magnetic field, therefore can extrapolate the size of tested electric current by measuring the variation of tested electric current surrounding magnetic field intensity.With Rogows ki coil Secondary Winding equably on the skeleton of an annular.The lead that is loaded with tested electric current passes from the center of ring skeleton.The induced potential of Rogowski coil Secondary Winding is directly proportional with the differential that passes the tested electric current at center, so the induced potential of Rogowski coil can be obtained being proportional to the voltage signal of tested electric current through Integral Processing.Therefore just can form current sensor by Rogowski coil and two parts of integrating circuit.
In many cases, also can constitute current sensor by the Rogowski coil separately, it is free-standing Rogowski coil current sensor, at this moment the output of this current sensor is the output of Rogowski coil, be directly proportional with the differential signal of tested electric current, allowing the occasion of fixed phase drift, this Rogowski coil can independently use.After also can this signal being become digital signal, constitute digital integrator, reduce tested current signal with software with the follow-up signal treatment circuit.
The skeleton of Rogowski coil can be to constitute as sensing unit by nonferromagnetic material structure (being hollow coil) or by the Rogowski coil based on open core.
The utility model is at the Rogowski coil based on open core.
Generally speaking, measure the industry spot of irregular electric current, such as the measurement to the secondary output current of frequency converter, Hall current sensor consumption maximum at needs.Such as industry spot such as electronic electric energy meters, need the accurate measurement of realization to the alternating current more than the frequency 45Hz, require to have the occasion of higher anti-DC current saturability simultaneously again, it is more that hollow coil is used, and use seldom based on the Rogowski coil of open core.Main cause is, is subject to disturb based on the Rogowski coil of open core:
1. the factors such as external magnetic field interference variations that tested wire shape changes or changes and close on the relative position of iron core, these factors are to the influence of measuring accuracy even can reach 10%.
Open core is used widely in fields such as transformer, electric welding machine, reactors, and its relative permeability generally is designed to 10～200 between closed loop iron core and nonferromagnetic material.Under the influence of magnetic field that tested electric current produces, open core can not resemble the iron core of closed loop saturated easily, and the magnetic field intensity that produces in the air gap can not resemble so little in the nonferromagnetic material yet, generally speaking, the specified induced potential of Secondary Winding based on the Rogowski coil of open core of design is about hundreds of millivolts.But all at present Rogowski coils are all perplexed by same problem: the coefficient of mutual inductance of coil is subjected to the influence of the relative position between current carrying conductor and the coil, in some cases, this influence can reach more than 10%, make that the application of Rogowski coil is limited greatly, sometimes, the change of current carrying conductor shape even all can influence the accuracy of measurement.And the existence of adjacent phase current also can cause the influence of can not ignore to measurement.
2.Rogowski the induced potential of coil and the differential of tested electric current are directly proportional, and need the process Integral Processing can obtain being proportional to the voltage signal of tested electric current.But that designs on integrating circuit principle and the structure is unreasonable, makes to measure to be subjected to the influence of extraneous space electromagnetic interference (EMI) very big, almost can not use at the general industry scene.
At present the integrating circuit of general structure is as shown in Figure 1:
Among Fig. 1, R1 is an input resistance, and R2 is a balance resistance, and C1 is an integrating capacitor, and R3 and integrating capacitor C1 are in parallel, and can avoid integrating circuit progressively saturated under the bias voltage influence of amplifier U.This employing integrating circuit structure the most widely is very simple, but have two critical defects can not be ignored: the one, and the introducing of R3 makes the low frequency characteristic variation of integrator; The 2nd, the antijamming capability of this integrator is relatively poor, and through test of many times, this integrator at all can't steady operation in industry spot.
Rogowski coil and integrating circuit be combined to be very suitable for measuring alternating current.In many cases, also can constitute current sensor by the Rogowski coil separately, it is free-standing Rogowski coil current sensor, and because the open core relative permeability is between closed loop iron core and nonferromagnetic material, when containing flip-flop in the tested alternating current, open core can not resemble the iron core of closed loop saturated easily, promptly has higher anti-DC current saturability.But because its relative permeability is high more a lot of than the hollow coil that nonferromagnetic material skeleton constitutes, under same rated current, coil output voltage is high more a lot of than hollow coil, thereby has improved the ability of the anti-external interference of measuring greatly.So this simple in structure and cheap current sensor, be applied in such as industry spot such as electronic electric energy meters, realization requires to have the occasion of higher anti-DC current saturability again simultaneously to the accurate measurement of the alternating current more than the frequency 0.5Hz, and great application prospect is arranged.But, the accuracy of measurement of Rogowski coil is subjected to that above-mentioned tested wire shape changes or changes with the relative position of iron core and the influence of the factors such as external magnetic field interference variations of closing on, in addition, traditional poor, poor anti jamming capability of integrating circuit low frequency characteristic, industry spot at all can't be stable work.The solution of these two core technology problems is condition precedents that this cheap high reliability current sensor is achieved and promotes.It also is the key technical problem that the technological means taked of the utility model solves.
Summary of the invention
The purpose of this utility model is to provide a kind of alternating-current/magnetic field sensor of the high anti-jamming capacity of forming based on the Rogowski coil and the integrator of open core, to solve the problems referred to above that exist on the existing Rogowski coil pickoff performance, improve its antijamming capability, be applied in industry spot.
A kind of current sensor that the utility model provides is made up of Rogowski coil and high reliability integrator based on open core, but in the design of these two parts and make and all take the special technique means, to guarantee its performance.In addition, allowing the occasion of fixed phase drift, this Rogowski coil also can not need integrating circuit and independent the use, and the output of this current sensor at this moment is the output of Rogowski coil, is directly proportional with the differential signal of tested electric current.After perhaps also can this signal being become digital signal, constitute digital integrator, reduce tested current signal with software with the follow-up signal treatment circuit.
Coiling does not have specific (special) requirements to Rogowski coil in the past to Secondary Winding, so that its interference free performance is relatively poor.One of technological means of the present utility model is: the utility model has been taked the technical measures of special Secondary Winding coiling, to improve its performance.Rogowski coil based on open core of the present utility model is characterised in that: open core has one or more air gap, if an above air gap generally is defined as even number, and is symmetrically distributed; The most important thing is, the secondary coiling must be as much as possible on air gap, promptly by adopt nonferromagnetic material that air gap and iron core are connected into an integral body at the two ends of all air gaps after, again Secondary Winding is wound the line equably on air gap, rather than resemble in the past the Rogowski coil on iron core.If because the Secondary Winding number of turn individual layer can't be around intact too much and on air gap, then repeatedly sandwich wound on air gap; Perhaps unnecessary part is wound on the two ends unshakable in one's determination of as close as possible air gap equably.
The Rogowski coil that adopts above-mentioned coiling technological means to handle reduces greatly to the sensitivity of current carrying conductor and Rogowski coil relative position.Through repeatedly test, any variation of current carrying conductor position in the Rogowski coil window and cause that the variable quantity of coil coefficient of mutual inductance generally is no more than 0.2%, and to the non-inductive output of electric current beyond the window of Rogowski coils loop center, thereby the Rogowski coil that this performance greatly promotes can be used in industry spot widely.
There are two big critical defects in the integrating circuit of general type: the one, and low frequency characteristic is poor; The 2nd, the antijamming capability deficiency can't steady operation in the strong jamming occasion.Two of technological means of the present utility model is, the utility model has designed a kind of compensation differential integrating amplification circuit, its schematic diagram as shown in Figure 2, among Fig. 2, U1 is differential integrating circuit, U2 amplifies modulate circuit.Different with traditional integrating circuit is:
A. adopt differential input mode, strengthened the antijamming capability of integrator; The differential input mode of symmetry usually is used in the amplifying circuit of feeble signal, and the utility model in integrator, has constituted differential integrating circuit with the input mode analogy of this instrument amplifier.Among Fig. 2, R11, R12 equate that with the R1 of Fig. 1 among Fig. 2, C11, C12 equate that with the C1 of Fig. 1 through repeatedly test, the antijamming capability of this differential integrating circuit is extremely strong.
B. introduce the compensation branch road on the parallel resistance of integrating capacitor, improved the low frequency characteristic of integrator.
Among Fig. 2, R21, R22, R23, R24 equate with the R2 of Fig. 1, and be symmetrically distributed, and form equalizing network by R3, C2 in the centre, from the loop of output terminal, compensated the leakage current of integrating capacitor, like this under the situation that does not change the influence of amplifier dc offset voltage among the U1 through parallel resistance through R22, R3, C2 and R24 formation, leakage current on the integrating capacitor reduces greatly, and the low frequency characteristic of integrator can be greatly improved.
Three of technological means of the present utility model is to utilize the Rogowski coil of described open core and the printed circuit board (PCB) of integrating circuit to constitute an earth potential shield, all electronic devices and components all place among this shield, can effectively protect the influence of high frequency interference magnetic field to sensor.See described in the specific implementation for details.
The employing that the utility model adopts special coiling based on the Rogowski coil of open core as sensing element, compensation differential integrating amplification circuit is as modulate circuit, the output of coil changes tested current signal into the current/magnetic field sensor with high anti-jamming capacity of low voltage signal output as the input of integrating amplification circuit.Adopt air-gap iron core structure Rogowski coil, induced potential is big many than hollow coil, antijamming capability strengthens, particularly adopt the secondary coiling as much as possible on air gap, promptly by adopt nonferromagnetic material that air gap and iron core are connected into an integral body at the two ends of all air gaps after, again with Secondary Winding coiling equably on air gap, rather than resemble in the past the Rogowski coil on iron core.If because the Secondary Winding number of turn individual layer can't be around intact too much and on air gap, then repeatedly sandwich wound on air gap; Perhaps unnecessary part is wound on the two ends unshakable in one's determination of as close as possible air gap equably.This method eliminated basically that tested wire shape changes or change with the relative position of iron core and the factors such as external magnetic field interference of closing on to the influence of Rogowski coil accuracy of measurement.Allowing the occasion of fixed phase drift based on the employing of the special coiling of this technological means based on the Rogowski coil of open core, this Rogowski coil also can not need integrating circuit independently to use, at this moment the output of this current sensor is the output of Rogowski coil, is directly proportional with the differential signal of tested electric current.
The utility model has designed compensation differential integrating amplification circuit, compares with general integrating amplification circuit, and its antijamming capability greatly strengthens.In addition, integrating amplification circuit has increased symmetrical compensation formula loop, has effectively reduced the leakage current of integrating capacitor through parallel resistance, and the low frequency characteristic of integrating amplification circuit has obtained effective improvement.Adopt a kind of shielding mode flexibly and cleverly, the positive of printed circuit board (PCB) of open core and integrating circuit all is connected with the ground wire of power supply, constituting a shield thus shields all electronic devices and components, further strengthened the stability of current sensor, with sensor to external world the sensitivity of interfere with electromagnetic field drop to minimum.The above-mentioned technological means that the utility model is taked has improved the interference free performance of existing Rogowski coil greatly, has solved based on the current sensor of the Rogowski coil key technical problem in industry spot practicability.
Description of drawings
Fig. 1 is the integrating circuit figure of existing structure sensor.
Fig. 2 is compensation differential integrating amplification circuit figure of the present utility model.
Fig. 3 a is a coil Secondary Winding coiling synoptic diagram of the present utility model.
Fig. 3 b is a Rogowski coil Secondary Winding coiling partial schematic diagram of the present utility model.
Fig. 4 is that the Rogowski coil of open core of the present utility model and the printed circuit board (PCB) of integrating circuit constitute an earth potential shield synoptic diagram.
Embodiment
The utility model will be further described in conjunction with the accompanying drawings.
It at first is the design of the Rogowski coil of open core.The core configuration of open core and size, air gap quantity, openings of sizes can design according to the factors such as size of tested electric current.Generally speaking, tested electric current is big more, and core dimensions is big more, and air gap quantity is many more, and opening size is big more.If when selecting to open on the iron core more than one air gap, generally be defined as even number, and be symmetrically distributed, the equivalent relative permeability of open core generally is designed to 30～100 and is advisable.
The coiling of Rogowski coil: at first be the number of turn of determining the Secondary Winding coiling, the Secondary Winding output induced potential during with rated current calculates the secondary number of turns that the Rogowski coil needs.After the two ends of all air gaps connect into an integral body with pottery with air gap and iron core, also can air gap and iron core be connected into an integral body with plastic material, again Secondary Winding is wound the line equably on air gap, rather than resemble in the past the Rogowski coil on iron core, if because the Secondary Winding number of turn individual layer can't be around intact too much and on air gap, then repeatedly sandwich wound on air gap; Perhaps unnecessary part coiling is wound on equably the two ends unshakable in one's determination of as close as possible air gap.Shown in Fig. 3 a Rogowski coil Secondary Winding coiling synoptic diagram and Fig. 3 b Rogowski coil Secondary Winding coiling partial schematic diagram.1 is iron core among the figure, and 2 is air gap, and the Secondary Winding 3 of disperseing symmetry joins end to end between the segmentation on air gap 2, and 9 for constituting the coiling of Secondary Winding 3, finally draws through terminal 4.
The design of integrating amplification circuit.The circuit ultimate principle is followed the associated description in the summary of the invention, and in order to guarantee the low frequency characteristic of integrator, the selection of interlock circuit major parameter also will be followed following criterion:
C2, C 3 should be enough big, for example desirable 10uF;
2 л * 2R2 (R1+R2) * C1/R1＞＞1/f
L, f
LLower-cut-off frequency for tested electric current;
2 л * R4*C3＞＞1/f
L, f
LLower-cut-off frequency for tested electric current.
Shielding measure, the utility model utilizes the Rogowski coil of open core and the printed circuit board (PCB) of integrating circuit to constitute an earth potential shield, all electronic devices and components all place among this shield, can effectively protect the influence of high frequency interference magnetic field to sensor.Printed circuit board (PCB) 5 and on components and parts, as shown in Figure 4 based on the relative position of the Rogowski coil 1 of open core, the front 6 of printed circuit board (PCB) is the stratum, the back side 7 of printed circuit board (PCB) is element layer, coil secondary coiling 3 is connected with the printed circuit board (PCB) back side 7, realize by being connected the connection of lead 8 realizations on electric on open core and stratum, through this technological means, the shield of the utility model design has further improved the jamproof performance of integrating amplification circuit.
Claims (3)
1. high anti-interference alternating-current/magnetic field sensor, Rogowski coil and integrating circuit based on open core are formed, based on the Rogowski coil of open core and the annexation of integrating circuit be: coil is output as the input of integrating circuit, it is characterized in that: the Rogowski coil of open core adopts the Rogowski coil of air-gap iron core structure, open core has the air gap of one or more even numbers, and be symmetrically distributed, and with nonferromagnetic material air gap and iron core being connected into an integral body at the two ends of all air gaps, the coiling of Secondary Winding is uniformly on air gap; Integrating circuit is compensation differential integrating amplification circuit, compensation differential integrating amplification circuit is made of differential integrating circuit U1 and amplification modulate circuit U2, differential integrating circuit U1 adopts the differential input mode analogy of symmetry to constitute differential integrating circuit in the amplifier integrator, and differential integrating circuit U1 has also introduced the compensation branch road on the parallel resistance of the integrating capacitor of amplifier integrator.
2. high anti-interference alternating-current/magnetic field sensor according to claim 1 is characterized in that: the positive of printed circuit board (PCB) of open core and integrating circuit all is connected with the ground wire of power supply, constitutes a shield thus.
3. high anti-interference alternating-current/magnetic field sensor according to claim 2, it is characterized in that: the Rogowski coil of open core and the printed circuit board (PCB) of integrating circuit are positive to be the stratum, the back side of printed circuit board (PCB) is element layer, the Rogowski coil secondary coiling of open core is connected with the printed circuit board (PCB) back side, the Rogowski coil of open core and stratum realize connection on electric constituting an earth potential shield by being connected lead.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200832200U CN201053988Y (en) | 2007-01-18 | 2007-01-18 | Highly antijamming AC current/ magnetic field sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200832200U CN201053988Y (en) | 2007-01-18 | 2007-01-18 | Highly antijamming AC current/ magnetic field sensor |
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| Publication Number | Publication Date |
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| CN201053988Y true CN201053988Y (en) | 2008-04-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200832200U Expired - Lifetime CN201053988Y (en) | 2007-01-18 | 2007-01-18 | Highly antijamming AC current/ magnetic field sensor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101033983B (en) * | 2007-01-18 | 2010-04-21 | 武汉格蓝若光电互感器有限公司 | High anti-interference alternating-current/magnetic field sensor |
| CN107436616A (en) * | 2017-08-04 | 2017-12-05 | 昆山帝森克罗德光电技术有限公司 | A kind of Rogowski coil integrating circuit for power factor controller product |
| CN108594114A (en) * | 2018-05-25 | 2018-09-28 | 明阳智慧能源集团股份公司 | A kind of large size half-direct-drive wind driven generator shaft current measurement sensor |
-
2007
- 2007-01-18 CN CNU2007200832200U patent/CN201053988Y/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101033983B (en) * | 2007-01-18 | 2010-04-21 | 武汉格蓝若光电互感器有限公司 | High anti-interference alternating-current/magnetic field sensor |
| CN107436616A (en) * | 2017-08-04 | 2017-12-05 | 昆山帝森克罗德光电技术有限公司 | A kind of Rogowski coil integrating circuit for power factor controller product |
| CN108594114A (en) * | 2018-05-25 | 2018-09-28 | 明阳智慧能源集团股份公司 | A kind of large size half-direct-drive wind driven generator shaft current measurement sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20080430 Effective date of abandoning: 20070118 |