CN207067224U - A kind of leakage current sensor - Google Patents
A kind of leakage current sensor Download PDFInfo
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- CN207067224U CN207067224U CN201720533669.6U CN201720533669U CN207067224U CN 207067224 U CN207067224 U CN 207067224U CN 201720533669 U CN201720533669 U CN 201720533669U CN 207067224 U CN207067224 U CN 207067224U
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Abstract
A kind of leakage current sensor, including fluxgate magnetic core, the fluxgate magnetic core include toroidal core, main coil are arranged with toroidal core；On toroidal core, the position relative with main coil is arranged with detection coil, and detection coil is connected with constant-current source circuit；Also include the signal processing system being connected with fluxgate magnetic core, the signal processing system includes exciting circuit and detection circuit two parts.The utility model provides a kind of leakage current sensor, wire through toroidal core is passed through after electric current and produces magnetic field, detected by specific sensing element and by driving the special electronic device of hysteresis curve and resulting magnetic effect to detect electric current, fluxgate detection probe detects primary current by magnetic field caused by detecting tested electric current i.e. primary current.
Description
Technical field
Current detection technology field is the utility model is related to, particularly a kind of leakage current sensor.
Background technology
DC system insulating monitoring is significant, and DC leakage current detection method is because device installation is simple, configuration spirit
Live therefore furtherd investigate, but as the development of Power Electronic Technique, the application of high precision electric current transducer are wider
It is general, especially non-contact current sensor, there is extensive DEVELOPMENT PROSPECT in commercial Application.Non-contact current measurement can be protected
The personal safety of card measurement staff and the stable operation of system.Estimated current measuring method mainly has：Divider resistance, electric current
Transformer, Hall current sensor, fluxgate current sensor and magneto-impedance effect Magnetic Sensor.Wherein Hall current sensor
AC and DC can be detected with fluxgate current sensor.Hall current sensor can detect tens electricity for arriving several kiloamperes
Stream, accuracy rating is poor in low current detection field precision between 0.5% and 2%, and by temperature and external magnetic field shadow
Sound is larger, and which limits the application of Hall element.
Existing fluxgate sensor is mainly used in weak magnetic field testing, such as earth's magnetic field detection, iron ore detection, displacement
Detection and Non-Destructive Testing.Compared with Hall sensor, fluxgate sensor has that resolving power is high, measurement low-intensity magnetic field scope is wide, can
Lean on, be capable of the component in direct measurement magnetic field and the features such as suitable for being used in fast kinematic system.
In the world it has been reported that the structure of several fluxgate current sensors, by using microcontroller, measuring magnetic flux
The saturation time interval of gate current sensor coil inductance and load current, reach the purpose of measurement DC current.The device
Alternating current can only be measured, function is single, and application is narrower, price, and is restricted.
Current most fluxgate current sensors use dual power supply, more multiple for the application of single supply system
It is miscellaneous.
In view of technology present in above-mentioned existing fluxgate current sensor with deficiency, ultimately result in existing magnetic flux
There is larger measurement error in gate current sensor, it is impossible to meet actual requirement in actually measuring.
The content of the invention
Technical problem to be solved in the utility model is to provide a kind of leakage current sensor, is examined by unicoil fluxgate
DC leakage is surveyed, it is simple in construction, cost is low.
In order to solve the above technical problems, technical scheme is used by the utility model：A kind of leakage current sensor, including
Fluxgate magnetic core, the fluxgate magnetic core include toroidal core, main coil are arranged with toroidal core；On toroidal core,
The position relative with main coil is arranged with detection coil, and detection coil is connected with constant-current source circuit；Also include and fluxgate magnetic core
The signal processing system being connected, the signal processing system include exciting circuit and detection circuit two parts, the excitation electricity
Road part includes exiting signal generating circuit, RL oscillating circuits and power amplification circuit, and exiting signal generating circuit driving RL shakes
Circuit is swung, one end of main coil is connected and another termination sampling resistor with power amplification circuit, another termination 2.5v of sampling resistor
Virtually；The detection circuit part includes two stage filter circuit, gain adjusting circuit and zero adjustment circuit successively.
Preferably, the toroidal core is made of nanocrystalline or permalloy material.
Preferably, the number of turn of the main coil is 20 ~ 150 circles.
Preferably, the number of turn of the detection coil is 10 ~ 25 circles.
Preferably, the signal processing system is powered using single supply, using 2.5V as mean voltage.
Preferably, the main coil and material used in detection coil are enamel-covered wire.
Preferably, the toroidal core uses annular closed magnetic core.
Preferably, distance between the pin of the skeleton both ends.
Preferably, the toroidal core is positioned in skeleton, and skeleton is connected in four pins, is welded on circuit board.
Distance is more than e, f between pin g, h, and g, h are connected with a, b, and e, f are connected with c, d.
The utility model provides a kind of leakage current sensor, and the wire through toroidal core is passed through after electric current and produces magnetic
, detected by specific sensing element and by the special electronic device for driving hysteresis curve and resulting magnetic effect
To detect electric current, fluxgate detection probe detects primary electrical by magnetic field caused by detecting tested electric current i.e. primary current
Stream.The toroidal core material selection soft magnetic materials of high magnetic permeability, low-coercivity and easy saturation；Encourage winding and sensing winding equal
Even to be wrapped on toroidal core, frequency is that f alternating currents flow through excitation winding, causes toroidal core magnetic flux alternately to change, works as friendship
When stream excitation number of ampere turns is sufficiently large, periodicity saturation and undersaturated condition is presented in toroidal core；When there is leakage current to pass through magnet ring,
Magnetic field caused by the leakage current is just added on excitation coil, therefore this leakage current can be produced by special circuit structure
Magnetic field signal just extract and amplify, calculate the size of leakage current.Fluxgate current sensor has Low Drift Temperature and low drift
The advantages of shifting.
The utility model carries Check functions, facilitates user to inspect periodically, and makes the utility model safety and reliability；Power supply
Voltage is 5V ± 5%, and single supply is powered, 3 ‰ linearity error.In structure by the way of skeleton and coil combine, installation is non-
Often convenient, for utility model without shielding material, without encapsulating, technique is very simple, convenient batch production, saves cost in addition.
Brief description of the drawings
The utility model is described in further detail with reference to the accompanying drawings and examples：
Fig. 1 is the utility model leakage current sensor winding wiring figure.
Fig. 2 is structured flowchart of the present utility model.
Fig. 3 is the utility model RL oscillating circuits and power amplification circuit circuit theory diagrams.
Fig. 4 is the utility model detection coil circuit theory diagrams.
Fig. 5 is the utility model zeroing circuit schematic diagram.
Fig. 6 is the utility model two stage filter circuit and gain adjusting circuit schematic diagram.
Fig. 7 is the utility model 2.5V and 3V voltage acquisition circuit.
Fig. 8 is the utility model external structure schematic diagram.
Embodiment
As Fig. 1 shows, a kind of leakage current sensor, including fluxgate magnetic core, the fluxgate magnetic core include toroidal core 1,
Main coil 2 is arranged with toroidal core 1；On toroidal core 1, the position relative with main coil 2 is arranged with detection coil 3,
Detection coil 3 is connected with constant-current source circuit；Also include the signal processing system being connected with fluxgate magnetic core, the signal transacting
System includes exciting circuit and detection circuit two parts, and the exciting circuit part includes exiting signal generating circuit, RL vibrates
Circuit and power amplification circuit, exiting signal generating circuit driving RL oscillating circuits, one end of main coil 2 and power amplification circuit
Connect and another termination sampling resistor, another termination 2.5v of sampling resistor is virtually；The detection circuit part includes successively
Two stage filter circuit, gain adjusting circuit and zero adjustment circuit.
Preferably, the toroidal core 1 is made of nanocrystalline or permalloy material.Its saturation flux density is Bs
＞ 1.2T, coercivity H ＜ 3A/m, saturation magnetostriction constant are s=10-8~10-6, and initial permeability is
4000~200000H/m, core loss (100KHz, 0.3T) PFe=80W/Kg, squareness ratio are more than 0.85.
Preferably, the number of turn of the main coil 2 is 20 ~ 150 circles.
Preferably, the number of turn of the detection coil 3 is 10 ~ 25 circles.
Preferably, the signal processing system is powered using single supply, using 2.5V as mean voltage.
Preferably, the main coil 2 and material used in detection coil 3 are enamel-covered wire.
Preferably, the toroidal core 1 uses annular closed magnetic core.Magnetic core loop leakage field very little, can be detected exactly
Low current, while reduce external magnetic field interference.
Preferably, as shown in figure 8, the toroidal core 1 is positioned in skeleton 5, skeleton 5 is connected in four pins, weldering
It is connected on circuit board.Distance is more than e, f between pin g, h, and g, h are connected with a, b, and e, f are connected with c, d.
RL is load resistance, and R1 loads for electric leakage, the electric current flowed under normal circumstances side equal with the size of current of outflow
To on the contrary, the magnetic field of reversal is zero, if leaking electricity so, the both threads gone through from coil just have difference between current, production
Raw magnetic field will be detected, excitation field intensity Hs=Ns*Is/L
Magnetic field intensity caused by leakage current is that the so total magnetic field intensities of HP are in H=Hs+Hp formulas：Ns is excitation
Coil turn, Is are the electric current in excitation coil, and L is effective magnetic circuit length, and the induced electromotive force in coil is：E（t）= -NS*
N is the winding coil number of turn in dB/dt=- NSutd * dH/dt formulas, and S is that the sectional area utd of toroidal core is magnetic conductivity, is passed through
Two-stage LPF weakens fundamental signal, then amplifies measured signal, thus can be by the voltage of linear convergent rate come anti-
Reflect the size of electric current to be measured.
Dc source both threads or three-phase and four-line electric wire are also cross this practical new sensor, normally without leakage current
In the case of, Ia and Ib are equal in magnitude in opposite direction（See Fig. 1）, the magnetic field in such both threads cancels out each other, total magnetic field zero.Such as
Fruit has electric leakage, and such Ia is not equal to Ib, and Ia-Ib just has a difference, and this difference current can produce a magnetic field quilt
The utility model sensor detects and produces a signal, it is possible to disconnects the circuit, can thus protect human body and its
His electrical equipment.Detection coil connects a constant-current circuit, carries out self-test to sensor to simulate a leakage current, makes this practicality new
Type safety and reliability.
As shown in Fig. 2 exiting signal generating circuit produces a fixed frequency square-wave signal, square-wave signal driving RL shakes
Circuit is swung, if fluxgate magnetic core detects external magnetic field so this magnetic field signal and will be added to the magnetic core of leakage current sensor
On, the magnetic core is reached saturation in advance, fundamental signal is removed by two stage filter, can be square by gain and zero adjustment circuit
Just the technical parameter of the utility model single supply leakage current sensor is controlled.
As shown in figure 3, RL vibrations are produced and then exported by power amplifier, electricity is sampled finally by a sampling resistor R8
Press signal, one end of the utility model single supply leakage current sensor sampling resistor use 2.5V virtual earths, by control gain with
Zero point final output is that 2.5V ± 2V measurement ranges are ± 600mA.
As shown in figure 4, make detection coil by a constant current 5mA, for example detection coil is 50 circles, then equivalent to mould
Intend Ip=5mA*50 electric current, using formula Vout=k*Ip+b, with regard to a fixed voltage value can be exported, thus can
Whether normal detect the working sensor, k represents gain, and b represents zero point, and Ip is through magnet ring total current.
As shown in figure 5, by resistor network, zero point can be easily adjusted, increase zero point can burn-on suitable resistance
R33, reduce zero point regulation R30 resistance.Specific formula for calculation is：
Increase zero point (3-Vout) * (R31+R33)/R31*R33=Vout/(R32+R35)+(Vout-2.5)/
R27；
Reduction zero point (3-Vout)/R31+(2.5-Vout)/R27=Vout/(R32*R30/ (R32+R30)+
R35)；
As shown in fig. 6, the signal on sampling resistor R8 is handled by two stage filter, then can by R14, R15
Easily to adjust gain, specific formula for calculation is：
Increase gain：G*3/10 = R20*(R21+R15)/R21*R15 ;
Reduce gain：G*3/10 = R20*R14/((R20+R14)*R21) ;
G is current gain, can determine different target gains according to the different use occasion of sensor.
Shown in Fig. 7, by amplifier all the way and 2.5V reference voltage sources, 3V, and 2.5V voltages are produced, is provided to zeroing circuit
3V voltages.
The above embodiments are only optimal technical scheme of the present utility model, and are not construed as limit of the present utility model
System, the technical scheme that the scope of protection of the utility model should be recorded with claim, including the technical scheme that claim is recorded
The equivalents of middle technical characteristic are protection domain.Equivalent substitution i.e. within this range is improved, also in the utility model
Protection domain within.
Claims (8)
- A kind of 1. leakage current sensor, it is characterised in that：Including fluxgate magnetic core, the fluxgate magnetic core includes toroidal core （1）, in toroidal core（1）On be arranged with main coil（2）；In toroidal core（1）On, with main coil（2）Relative position winding There is detection coil（3）, detection coil（3）It is connected with constant-current source circuit；Also include the signal transacting being connected with fluxgate magnetic core System, the signal processing system include exciting circuit and detection circuit two parts, and the exciting circuit part includes excitation and believed Number circuit, RL oscillating circuits and power amplification circuit, exiting signal generating circuit driving RL oscillating circuits, main coil occurs（2） One end be connected and another termination sampling resistor with power amplification circuit, another termination 2.5v of sampling resistor is virtually；It is described Detection circuit part includes two stage filter circuit, gain adjusting circuit and zero adjustment circuit successively.
- A kind of 2. leakage current sensor according to claim 1, it is characterised in that：The toroidal core（1）Using nanocrystalline Or permalloy material is made.
- A kind of 3. leakage current sensor according to claim 1, it is characterised in that：The main coil（2）The number of turn for 20 ~ 150 circles.
- A kind of 4. leakage current sensor according to claim 1, it is characterised in that：The detection coil（3）The number of turn for 10 ~ 25 circles.
- A kind of 5. leakage current sensor according to claim 1, it is characterised in that：The signal processing system uses single supply Power supply, using 2.5V as mean voltage.
- A kind of 6. leakage current sensor according to claim 1, it is characterised in that：The main coil（2）And detection coil（3） Material used is enamel-covered wire.
- A kind of 7. leakage current sensor according to claim 1, it is characterised in that：The toroidal core（1）Closed using annular Close magnetic core.
- A kind of 8. leakage current sensor according to claim 1, it is characterised in that：The toroidal core（1）It is positioned over skeleton （5）It is interior, skeleton（5）It is connected in four pins, is welded on circuit board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720533669.6U CN207067224U (en) | 2017-05-15 | 2017-05-15 | A kind of leakage current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720533669.6U CN207067224U (en) | 2017-05-15 | 2017-05-15 | A kind of leakage current sensor |
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| Publication Number | Publication Date |
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| CN207067224U true CN207067224U (en) | 2018-03-02 |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110412336A (en) * | 2019-07-22 | 2019-11-05 | 中国科学院上海应用物理研究所 | A kind of detection probe of high precision electric current transducer |
| CN110456142A (en) * | 2019-08-13 | 2019-11-15 | 上海应用技术大学 | Magnetic modulation type DC leakage flow sensor |
| CN112198456A (en) * | 2020-10-16 | 2021-01-08 | 国网河北省电力有限公司雄安新区供电公司 | Leakage current detection method and circuit based on fluxgate self-adaptive excitation source |
| CN112213546A (en) * | 2020-09-02 | 2021-01-12 | 国网内蒙古东部电力有限公司检修分公司 | Grounding electrode micro-current measuring device based on fluxgate current-voltage sensor |
| CN113281553A (en) * | 2021-04-23 | 2021-08-20 | 上海电机学院 | Weak direct current detection system and method based on fluxgate |
| CN114026439A (en) * | 2019-07-12 | 2022-02-08 | 莱姆国际股份有限公司 | Current transformer for measuring residual current |
| US11808793B2 (en) | 2021-07-16 | 2023-11-07 | Delta Electronics (Shanghai) Co., Ltd. | Detection device, inverter and detection method |
-
2017
- 2017-05-15 CN CN201720533669.6U patent/CN207067224U/en active Active
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114026439A (en) * | 2019-07-12 | 2022-02-08 | 莱姆国际股份有限公司 | Current transformer for measuring residual current |
| CN114026439B (en) * | 2019-07-12 | 2022-08-19 | 莱姆国际股份有限公司 | Current transformer for measuring residual current |
| CN110412336A (en) * | 2019-07-22 | 2019-11-05 | 中国科学院上海应用物理研究所 | A kind of detection probe of high precision electric current transducer |
| CN110412336B (en) * | 2019-07-22 | 2021-12-10 | 中国科学院上海应用物理研究所 | Detection probe of high-precision current sensor |
| CN110456142A (en) * | 2019-08-13 | 2019-11-15 | 上海应用技术大学 | Magnetic modulation type DC leakage flow sensor |
| CN112213546A (en) * | 2020-09-02 | 2021-01-12 | 国网内蒙古东部电力有限公司检修分公司 | Grounding electrode micro-current measuring device based on fluxgate current-voltage sensor |
| CN112198456A (en) * | 2020-10-16 | 2021-01-08 | 国网河北省电力有限公司雄安新区供电公司 | Leakage current detection method and circuit based on fluxgate self-adaptive excitation source |
| CN113281553A (en) * | 2021-04-23 | 2021-08-20 | 上海电机学院 | Weak direct current detection system and method based on fluxgate |
| US11808793B2 (en) | 2021-07-16 | 2023-11-07 | Delta Electronics (Shanghai) Co., Ltd. | Detection device, inverter and detection method |
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