A tiny current detector for magnetic ring coils

Abstract

The present invention provides a micro-current detector for a magnetic ring coil, which comprises a magnetic ring coil and a detection circuit. The magnetic ring coil is connected to the detection circuit. The magnetic ring coil includes a magnetic ring and a secondary winding, and the secondary winding is wound around the magnetic ring. The detection circuit includes a power supply circuit, an oscillation circuit, a sampling circuit, a filter amplification circuit, and a signal processing circuit. The input end of the power supply circuit is connected to the input and output interface of the power supply, and the output end of the power supply circuit is respectively connected to the oscillation circuit, the signal processing circuit, and the filter amplification circuit. The oscillation circuit is connected to the magnetic ring coil, and the magnetic ring coil, the sampling circuit, the first filter amplification circuit, and the signal processing circuit are connected in sequence. The output end of the signal processing circuit is connected to the input and output interface of the power supply. The beneficial effects of the present invention are as follows: The present invention has a simple structure, stable operation, low power consumption, high detection accuracy for micro-current, and is applicable to both AC and DC.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and particularly to a micro-current detector for a magnetic ring coil. Background Art

[0002] In engineering measurement, alternating current can be conveniently measured in a non-contact manner through a current transformer. Its principle is the electromagnetic induction principle discovered by Michael Faraday in 1831. However, direct current, especially tiny direct current, is often not easily measured accurately in a non-contact state.

[0003] In a pipeline for transporting flammable and explosive media, static electricity is often generated due to friction during transportation. Part of the static electricity will be led to the ground through the metal pipeline. If there is too much static electricity, electrostatic discharge may occur during this process, and then an explosion may occur. If the tiny current on the pipeline can be measured, it can be used to warn and prevent accidents.

[0004] During pneumatic conveying or gravity conveying, static electricity is generated on the material due to the friction between the material and the material, the material and the pipeline, the material and the conveying medium, and the conveying medium and the pipeline. Under the conditions of explosive dust or gas, when the charge amount between the charged material and metal objects such as pipelines and silos exceeds the critical value, electrostatic discharge will occur, and then an explosion may occur. If the tiny current on the pipeline can be measured, the charging situation of the material can be calculated, so as to warn and prevent accidents.

[0005] In production and research, it is often necessary to measure the combined current of multiple wires to judge the working state of the system or measure the leakage current. If the tiny current on the pipeline can be measured, the charging situation of the material can be calculated, so as to warn and prevent accidents.

[0006] With the increasing demand, in many cases, traditional ferrite materials can no longer meet the requirements. Nano-crystalline magnetic rings made of a new type of material have been widely used in fields such as household air conditioners, rail transit, solar energy, and wind power generation. Most of the nano-crystalline magnetic rings on the market now are made of an iron-based nano-crystalline soft magnetic alloy. It has good high-frequency characteristics, lower coercivity, and lower losses. Its manufacturing process is to mix five elements of iron, silicon, boron, copper, and niobium in a fixed ratio, heat them to 1400 degrees, and then rapidly cool them to make a strip material. Subsequently, it is wound into a circular magnetic core. Then, heat treatment is carried out to make it crystallize again, and it will have good soft magnetic properties. Summary of the Invention

[0007] The present invention provides a micro-current detector for a magnetic ring coil, which includes a magnetic ring coil and a detection circuit. The magnetic ring coil is connected to the detection circuit. The magnetic ring coil includes a magnetic ring and a secondary winding, and the secondary winding is wound around the magnetic ring. The detection circuit includes a power supply circuit, an oscillation circuit, a sampling circuit, a first filter amplification circuit, and a signal processing circuit. The input end of the power supply circuit is connected to the input and output interface of the power supply, and the output end of the power supply circuit is respectively connected to the oscillation circuit, the signal processing circuit, and the filter amplification circuit. The oscillation circuit is connected to the magnetic ring coil, and the magnetic ring coil, the sampling circuit, the first filter amplification circuit, and the signal processing circuit are connected in sequence. The output end of the signal processing circuit is connected to the input and output interface of the power supply.

[0008] As a further improvement of the present invention, the magnetic ring coil includes a feedback winding, and the feedback winding is wound around the magnetic ring.

[0009] As a further improvement of the present invention, the micro-current detector for the magnetic ring coil includes an on-site zero adjustment circuit, and the on-site zero adjustment circuit is connected to the signal processing circuit.

[0010] As a further improvement of the present invention, the micro-current detector for the magnetic ring coil includes an on-site calibration circuit, and the on-site calibration circuit is connected to the signal processing circuit.

[0011] As a further improvement of the present invention, the micro-current detector for the magnetic ring coil includes a frequency conversion circuit and a second filter amplification circuit. The magnetic ring coil is connected to the frequency conversion circuit, the frequency conversion circuit is connected to the second filter amplification circuit, the second filter amplification circuit is connected to the signal processing circuit, and the power supply circuit supplies power to the frequency conversion circuit and the second filter amplification circuit.

[0012] As a further improvement of the present invention, the magnetic ring is made of a material with low coercivity and high magnetic permeability.

[0013] As a further improvement of the present invention, the magnetic ring is made of permalloy or amorphous and nanocrystalline materials.

[0014] As a further improvement of the present invention, the number of the feedback windings is one or more.

[0015] As a further improvement of the present invention, the first filter amplification circuit is connected to the magnetic ring coil through the feedback winding.

[0016] The beneficial effects of the present invention are as follows: 1. Simple structure, stable operation, low power consumption, high detection accuracy for microcurrents, applicable to both AC and DC; 2. No contact with the measured primary wire, can measure various currents such as the current of ordinary wires, the combined current of multiple wires in a wire tube, the current generated by the movement of charged particles in a pipeline, and the leakage current of a pipeline, with wide applications; 3. Can be zeroed and calibrated on-site to eliminate on-site fixed interference; 4. Can add a feedback winding to improve measurement accuracy; 5. Can add frequency-assisted measurement to improve measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the axial view of the magnetic ring coil of the present invention;

[0018] Figure 2 is the structural diagram of the magnetic ring coil of the present invention;

[0019] Figure 3 is the principle block diagram of the microcurrent detector of the magnetic ring coil of the present invention;

[0020] Figure 4 is an example circuit diagram of an implementation of the present invention;

[0021] Figure 5 is an example circuit diagram of a power supply circuit of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention discloses a microcurrent detector of a magnetic ring coil, including a magnetic ring coil 1 and a detection circuit, and the magnetic ring coil 1 is connected to the detection circuit.

[0023] As Figures 1-3 shown, the magnetic ring coil 1 includes a magnetic ring 4 and a secondary winding 10, and the secondary winding 10 is wound around the magnetic ring 4. The detection circuit includes a power supply circuit 20, an oscillation circuit 21, a sampling circuit 22, a filter amplification circuit 23, and a signal processing circuit 24. The input end of the power supply circuit 20 is connected to the input-output interface 3 of the power supply. The output end of the power supply circuit 20 is respectively connected to the oscillation circuit 21, the signal processing circuit 24, and the first filter amplification circuit 23. The oscillation circuit 21 is connected to the magnetic ring coil 1. The magnetic ring coil 1, the sampling circuit 22, the first filter amplification circuit 23, and the signal processing circuit 24 are connected in sequence. The output end of the signal processing circuit 24 is connected to the input-output interface 3 of the power supply.

[0024] The power supply is introduced into the system through the input / output interface 29 and adapted by the power supply circuit 20. The oscillation circuit 21 generates an appropriate waveform, which is connected to the secondary winding 10 of the toroidal coil 1. Under the excitation of this signal, the toroid 4 will repeatedly enter the magnetic saturation state. When there is no current passing through the primary wire 3, its waveform is symmetric up and down; when there is current passing through the primary wire 3, a magnetic field will be generated around the primary wire 3, and the magnetic field will change the saturation point of the toroid, and its waveform will shift. The sampling circuit 22 obtains the offset amount, and then it can be amplified by the filter amplification circuit 23 to obtain a signal linearly related to the current of the primary wire.

[0025] The toroidal coil 1 includes a feedback winding 2, and the feedback winding 2 is wound around the toroid 4. One or more feedback windings 2 can be set, and the measured primary wire 3 passes through the middle of the toroidal coil 1. For more accurate measurement, a feedback winding 2 can be added to the toroidal coil 1, and the output point is reversely introduced into this feedback winding 2. A magnetic field opposite to the magnetic field formed by the current of the primary wire 3 will be formed on the feedback winding 2. When the two magnetic fields are just equal, they will cancel each other out, and the output will be zero, which is equivalent to introducing negative feedback into the toroidal coil 1, and can improve the measurement accuracy and stability.

[0026] The first filter amplification circuit 23 is connected to the toroidal coil 1 through the feedback winding 2. The signal output from the first filter amplification circuit 23 can form negative feedback on the toroidal coil 1 through the feedback winding 2. Using the negative feedback mechanism can improve the detection accuracy.

[0027] This toroidal coil micro-current detector includes a on-site zero adjustment circuit 25, and the on-site zero adjustment circuit 25 is connected to the signal processing circuit 24.

[0028] This toroidal coil micro-current detector includes a on-site calibration circuit 26, and the on-site calibration circuit 26 is connected to the signal processing circuit 24.

[0029] This toroidal coil micro-current detector is provided with a on-site zero adjustment circuit 25 and a on-site calibration circuit 26, and zero adjustment and calibration can be performed after the installation of this toroidal coil micro-current detector to eliminate on-site interference.

[0030] The micro-current detector for the magnetic ring coil includes a frequency conversion circuit 27 and a second filter amplification circuit 28. The magnetic ring coil is connected to the frequency conversion circuit 27, the frequency conversion circuit 27 is connected to the second filter amplification circuit 28, the second filter amplification circuit 28 is connected to the signal processing circuit 24, and the power supply circuit 20 supplies power to the frequency conversion circuit 27, the oscillation circuit 21, the signal processing circuit 24, the first filter amplification circuit 23, and the second filter amplification circuit 28. In addition to affecting the saturation point of the magnetic ring coil 1, the magnetic field of the current in the primary wire 3 will also cause a slight change in the frequency of the oscillation circuit 21. Therefore, a frequency conversion circuit 27 can be introduced. After being filtered and amplified by the second filter circuit 28, it is fed into the signal processing circuit 24 for auxiliary measurement.

[0031] Key points of the present invention:

[0032] 1. The magnetic ring coil is composed of a magnetic ring 4 and a secondary winding 10. One or more feedback windings 2 can be provided, and the measured primary wire 3 passes through the middle of the magnetic ring coil 1.

[0033] 2. The magnetic ring 4 of the magnetic ring coil 1 uses materials with low coercivity and high magnetic permeability, including but not limited to permalloy, amorphous, and nanocrystalline materials.

[0034] 3. The present invention measures the influence of a specific magnetic field on the magnetic saturation point of the coil.

[0035] 4. The present invention is equipped with zero adjustment and calibration devices that can be adjusted multiple times for zero adjustment and calibration to offset the interference of the detection site environment.

[0036] 5. The present invention can be provided with a frequency auxiliary measurement circuit to improve the detection performance.

[0037] 6. The present invention can be provided with a feedback winding 2 to form a negative feedback closed-loop measurement in the magnetic ring coil 1, with high measurement accuracy.

[0038] 7. The measurement object ( Figure 1 the primary wire 3 therein) is an object capable of forming a directional movement of charges, including but not limited to conductors, metal conveying pipelines, non-metal conveying pipelines, and wire harnesses.

[0039] Advantages of the present invention: 1. Simple structure, stable operation, low power consumption, high detection accuracy for micro-currents, applicable to both AC and DC; 2. No contact with the measured primary wire 3, can measure various currents such as the current of ordinary wires, the combined current of multiple wires in a wire tube, the current generated by the movement of charged particles in a pipeline, and the leakage current of a pipeline, with wide applications; 3. Can be zero-adjusted and calibrated on-site to eliminate fixed on-site interference; 4. Can add a feedback winding to improve the measurement accuracy; 5. Can add frequency auxiliary measurement to improve the measurement effect.

[0040] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as falling within the protection scope of the present invention.

Claims

1. A micro current detector for magnetic ring coils, characterized in that: It includes a magnetic ring coil (1) and a detection circuit, and the magnetic ring coil (1) is connected to the detection circuit; the magnetic ring coil (1) includes a magnetic ring (4) and a secondary winding (10), the secondary winding (10) is wound around the magnetic ring (4), the detection circuit includes a power supply circuit (20), an oscillation circuit (21), a sampling circuit (22), a filter amplification circuit (23), and a signal processing circuit (24), the input end of the power supply circuit (20) is connected to the input-output interface (3) of the power supply, the output end of the power supply circuit (20) is respectively connected to the oscillation circuit (21), the signal processing circuit (24), and the first filter amplification circuit (23), the oscillation circuit (21) is connected to the magnetic ring coil (1), the magnetic ring coil (1), the sampling circuit (22), the first filter amplification circuit (23), and the signal processing circuit (24) are connected in sequence, and the output end of the signal processing circuit (24) is connected to the input-output interface (3) of the power supply; This micro-current detector of the magnetic ring coil includes a on-site zero-adjustment circuit (25), and the on-site zero-adjustment circuit (25) is connected to the signal processing circuit (24); This micro-current detector of the magnetic ring coil includes a on-site calibration circuit (26), and the on-site calibration circuit (26) is connected to the signal processing circuit (24); This micro-current detector of the magnetic ring coil includes a frequency conversion circuit (27) and a second filter amplification circuit (28), the magnetic ring coil is connected to the frequency conversion circuit (27), the frequency conversion circuit (27) is connected to the second filter amplification circuit (28), the second filter amplification circuit (28) is connected to the signal processing circuit (24), and the power supply circuit (20) supplies power to the frequency conversion circuit (27) and the second filter amplification circuit (28).

2. The micro current detector of a magnetic ring coil according to claim 1, characterized in that: The magnetic ring coil (1) includes a feedback winding (2), and the feedback winding (2) is wound around the magnetic ring (4).

3. The micro-current detector for magnetic ring coil according to claim 1, characterized in that: The magnetic ring (4) is made of a material with low coercivity and high magnetic permeability.

4. The micro current detector of the magnetic ring coil according to claim 3, characterized in that: The material of the magnetic ring (4) includes permalloy, amorphous, and nanocrystalline.

5. The magnetic ring coil micro-current detector according to claim 2, characterized in that: The number of the feedback windings (2) is one or more.

6. The micro current detector of the magnetic ring coil according to claim 2, characterized in that: The first filter amplification circuit (23) is connected to the magnetic ring coil (1) through the feedback winding (2).

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