CN219392247U - Configurable magnetic modulation type direct current leakage current alarm device - Google Patents
Configurable magnetic modulation type direct current leakage current alarm device Download PDFInfo
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- CN219392247U CN219392247U CN202320076535.1U CN202320076535U CN219392247U CN 219392247 U CN219392247 U CN 219392247U CN 202320076535 U CN202320076535 U CN 202320076535U CN 219392247 U CN219392247 U CN 219392247U
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Abstract
The utility model provides a configurable magnetic modulation type direct current leakage current alarm device which solves the problems of poor detection precision of direct current detection on small current signals and the like. The utility model has the advantages of high detection precision, simple structure and the like.
Description
Technical Field
The utility model belongs to the technical field of direct current measurement, and particularly relates to a configurable magnetic modulation type direct current leakage current alarm device.
Background
The direct current detection method is generally divided into a direct type and an indirect type, wherein the direct type is a method for detecting voltage through a series resistor; indirect measurement is generally achieved by detecting a magnetic field generated by a current, and since a magnetic field is generated around the current, we can indirectly obtain the magnitude of the current to be measured by measuring the magnitude of the magnetic field. Direct measurement mainly refers to a shunt; the indirect measurement mainly comprises a Hall current sensor and a direct current transformer. At present, the direct current measurement is mainly shunt measurement, hall transformer measurement and magnetic modulation transformer measurement. Wherein the shunt measurement requires destruction of the bus bar, has an effect on both the line connection and the impedance, and cannot be used in many situations. The Hall transformer is easy to receive external signal interference, and meanwhile, the detection precision of a small current signal is not high, and the leakage current measurement requirement cannot be met.
In order to solve the defects existing in the prior art, long-term exploration is performed, and various solutions are proposed. For example, chinese patent literature discloses a magnetic modulation type current transformer [201420410337.5], which includes a magnetic core, a square wave voltage source exciting circuit, a square wave effective value difference circuit, a zeroing circuit and an integrating circuit, wherein a detection winding and a feedback winding are formed on the magnetic core, the detection winding is connected with the square wave voltage source exciting circuit, the feedback winding is connected with the integrating circuit, and the square wave effective value difference circuit and the zeroing circuit are sequentially connected between the square wave voltage source exciting circuit and the integrating circuit.
The scheme solves the problem of direct current detection to a certain extent, but the scheme still has a plurality of defects, such as the problem that the existing direct current detection mode has insufficient detection precision for small current signals.
Disclosure of Invention
The utility model aims to solve the problems and provides a configurable magnetic modulation type direct current leakage current alarm device which is reasonable in design and high in detection precision for small current signals.
In order to achieve the above purpose, the present utility model adopts the following technical scheme: the configurable magnetic modulation type direct current leakage current alarm device comprises a magnetic modulation transformer, wherein the magnetic modulation transformer adopts a 32-bit RISC-V single chip microcomputer, the single chip microcomputer is connected with an operational amplifier follower circuit, and the operational amplifier follower circuit is provided with a self-checking circuit and a communication circuit. The operational amplifier follower circuit in the application is matched with the singlechip to sample signals, filtering and integral operation on signal change are realized without using a traditional low-pass filter, rapid waveform measurement is realized through the 32-bit singlechip, and accurate measurement on an external bus is realized through algorithms such as internal period comparison, pulse duty ratio calculation, anti-interference electronic filtering, multi-data difference average filtering and the like.
In the configurable magnetic modulation type direct current leakage current alarm device, the magnetic modulation transformer adopts a single magnetic core and single coil structure.
In the above-mentioned configurable magnetic modulation type direct current leakage current alarm device, the operational amplifier follower circuit includes a first operational amplifier and a second operational amplifier.
In the above-mentioned configurable magnetic modulation type dc leakage current alarm device, the output end of the second operational amplifier is connected with the inverting input end of the second operational amplifier and a resistor R5 is connected in series between the output end and the inverting input end of the first operational amplifier, a resistor R1 is connected in series between the inverting input end and the inverting input end of the first operational amplifier, a resistor R2 is connected in series between the inverting input end of the first operational amplifier and the output end of the second operational amplifier, and a magnetic induction coil L is connected between the output end and the inverting input end of the first operational amplifier.
In the above-mentioned configurable magnetic modulation type direct current leakage current alarm device, the output end of the second operational amplifier is connected with the reverse input end, and the non-inverting input end of the second operational amplifier is grounded through the resistor R4 and connected with the singlechip through the resistor R3.
In the above-mentioned configurable magnetic modulation type direct current leakage current alarm device, the self-checking circuit includes a first triode Q1, a second triode Q2 and a third triode Q3, the first triode Q1, the second triode Q2 and the third triode Q3 are NPN type triodes, the first triode Q1 is connected with the second triode Q2 and the third triode Q3 through a connector J2, and the third triode Q3 is connected with the singlechip through a connector J1.
In the above-mentioned configurable magnetic modulation type direct current leakage current alarm device, a resistor R10 is connected between the emitter and the base of the first transistor Q1, the emitter of the first transistor Q1 is grounded, the base of the first transistor Q1 is connected with a resistor R9 and is connected with a relay, and the first transistor Q1 is connected with a connector J2 through a resistor R13.
In the above-mentioned configurable magnetic modulation type direct current leakage current alarm device, a resistor R12 is connected between the emitter and the base of the second triode Q2, the emitter of the second triode Q2 is grounded, the base of the second triode Q2 is connected with a resistor R11 and is connected with a relay, and the second triode Q2 is connected with a connector J2 through a resistor R14.
In the above-mentioned configurable magnetic modulation type direct current leakage current alarm device, a resistor R6 and a resistor R7 are connected between a base electrode of a third triode Q3 and a connector J2, a grounded diode Z1 is connected between the resistor R6 and the resistor R7, and an external self-checking terminal is connected between the emitter electrode of the third triode Q3 and the base electrode, a resistor R8 is connected between the emitter electrode of the third triode Q3 and the base electrode, a collector electrode of the third triode Q3 is connected with the connector J2, and the connector J2 is connected with the singlechip through a resistor R16.
In the above-mentioned configurable magnetic modulation type dc leakage current alarm device, the connector J2 is connected to a UART communication interface through a resistor R15.
Compared with the prior art, the utility model has the advantages that: by utilizing the magnetic modulation principle, when the tested bus passes through direct current, accurate detection of bus current is realized by a singlechip measuring mode; the operational amplifier following circuit is adopted to realize direct current bias of the reference voltage, so that the power supply of an operational amplifier single power supply is realized, and the circuit is simpler and the cost is lower; the single magnetic core and single coil structure are adopted, and the single chip microcomputer is used for detecting the change of the exciting winding, so that a middle complex circuit is omitted, and the current detection with higher precision is realized by fewer devices.
Drawings
FIG. 1 is a schematic diagram of an operational amplifier follower circuit of the present utility model;
fig. 2 is a schematic diagram of the self-checking circuit and the communication circuit according to the present utility model.
Detailed Description
The utility model will be described in further detail with reference to the drawings and the detailed description.
As shown in fig. 1-2, a configurable magnetic modulation type direct current leakage current alarm device comprises a magnetic modulation transformer, wherein the magnetic modulation transformer adopts a 32-bit RISC-V single chip microcomputer, the single chip microcomputer is connected with an operational amplifier follower circuit, the operational amplifier follower circuit is provided with a self-checking circuit and a communication circuit, and the magnetic modulation transformer adopts a single magnetic core and single coil structure. The device adopts the magnetic modulation principle, and uses a single magnetic core to generate self-excitation waveforms to realize signal modulation. When the tested bus passes through direct current, the coil modulation signal changes, and the bus current is detected in an MCU pulse measurement mode.
Obviously, the 32-bit RISC-V single chip microcomputer, namely the MCU module, is internally provided with a clock safety mechanism, a multi-stage power management and a general DMA controller, and is provided with a plurality of groups of interfaces so as to be convenient for externally connecting other devices.
In depth, the operational amplifier follower circuit comprises a first operational amplifier and a second operational amplifier, and the operational amplifier follower circuit realizes direct current bias of reference voltage, so that single power supply of the operational amplifier is realized, negative voltage is omitted, a circuit is simpler and the cost is lower, and accurate measurement of micro leakage current by non-contact is realized through smaller devices.
Further, the output end of the second operational amplifier is connected with the reverse input end of the second operational amplifier in series with a resistor R5, the output end of the first operational amplifier is connected with the same-direction input end in series with a resistor R1, the same-direction input end of the first operational amplifier is connected with the output end of the second operational amplifier in series with a resistor R2, and the output end of the first operational amplifier is connected with a magnetic induction coil L. The first operational amplifier and the second operational amplifier in the operational amplifier follower circuit are matched, so that the front circuit and the rear circuit can be isolated, and mutual interference of the front circuit and the rear circuit is avoided. Matching with a subsequent circuit is realized through series resistors. Through the rail-to-rail operational amplifier with high precision, direct current bias is realized, when R1=R2, periodic change of the coil charge-discharge comparison voltage is equal, and therefore excitation signal 1 is realized in a bus-free current state: 1. The value of the resistor R5 is required to be determined according to the magnetic core material and the number of turns of the coil, and the magnetic core is required to enter a saturated state under the output current of the operational amplifier, so that the magnetic field generated by the bus current is measured.
Furthermore, the output end of the second operational amplifier is connected with the reverse input end, and the non-inverting input end of the second operational amplifier is grounded through a resistor R4 and is connected with the singlechip through a resistor R3. When r3=r4, the output voltage of the operational amplifier follower is half of the power supply voltage, so that the positive and negative change of the signal at 1/2Vmcu voltage under the power supply of the operational amplifier single voltage is realized.
In addition, the self-checking circuit includes a first triode Q1, a second triode Q2 and a third triode Q3, the first triode Q1, the second triode Q2 and the third triode Q3 are NPN type triodes, the first triode Q1 is connected with the second triode Q2 and the third triode Q3 through a connector J2, and the third triode Q3 is connected with the singlechip through a connector J1. When the bus current passes through the direct current, a magnetic field in one direction acts on the magnetic core, so that the self-balanced state is broken, the bus current enters a saturated state more quickly because of the existence of an additional magnetic field, and from the reaction to the waveform, the square wave is not in 1:1 output.
Meanwhile, a resistor R10 is connected between the emitter and the base of the first transistor Q1, the emitter of the first transistor Q1 is grounded, the base of the first transistor Q1 is connected with a resistor R9 and is connected with a relay, and the first transistor Q1 is connected with a connector J2 through a resistor R13.
The resistor R12 is connected between the emitter and the base of the second triode Q2, the emitter of the second triode Q2 is grounded, the base of the second triode Q2 is connected with the resistor R11 and is connected with the relay, and the second triode Q2 is connected with the connector J2 through the resistor R14.
Obviously, be connected with resistance R6 and resistance R7 between the base of third triode Q3 and the connector J2, be connected with grounded diode Z1 and external self-checking end between resistance R6 and the resistance R7, third triode Q3's projecting pole ground and be connected with resistance R8 between the base, third triode Q3's collecting electrode is connected with connector J2, and connector J2 passes through resistance R16 and is connected with the singlechip. And after the self-checking circuit is measured through the signal, the related alarm output is realized according to a preset threshold value. By inputting the self-checking state, the warning classification output is realized, and a user can conveniently know whether the warning is generated by the self-checking signal or the real leakage current warning.
Preferably, the connector J2 is connected to a UART communication interface through a resistor R15. According to the method and the device, the single-wire UART communication interface is reserved, and under the state of the preset value, the threshold value of the product can be conveniently modified and set through single-wire communication, so that wider and more flexible application is realized.
In summary, the principle of the present application is: the magnetic modulation transformer adopts a single magnetic core and single coil structure, no subsequent filtering circuit is adopted, a single chip microcomputer is utilized to sample signals, a built-in algorithm of the magnetic modulation transformer accurately measures small-signal direct current leakage, a provided UART communication interface modifies a threshold value, and the single chip microcomputer realizes warning output according to requirements through a programmed threshold value.
The specific embodiments described herein are offered by way of example only to illustrate the spirit of the utility model. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the utility model or exceeding the scope of the utility model as defined in the accompanying claims.
Although terms such as magnetic modulation transformers, op-amp follower circuits, etc. are used more herein, the possibility of using other terms is not precluded. These terms are used merely for convenience in describing and explaining the nature of the utility model; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present utility model.
Claims (10)
1. The configurable magnetic modulation type direct current leakage current alarm device is characterized by comprising a magnetic modulation transformer, wherein the magnetic modulation transformer adopts a 32-bit RISC-V single chip microcomputer, the single chip microcomputer is connected with an operational amplifier follower circuit, and the operational amplifier follower circuit is provided with a self-checking circuit and a communication circuit.
2. The configurable magnetic modulation type direct current leakage current alarm device according to claim 1, wherein the magnetic modulation transformer adopts a single magnetic core and single coil structure.
3. The configurable magnetic modulation type direct current leakage current alarm device according to claim 1, wherein the operational amplifier follower circuit comprises a first operational amplifier and a second operational amplifier.
4. The configurable magnetic modulation type direct current leakage current alarm device according to claim 3, wherein the output end of the second operational amplifier is connected with the reverse input end of the second operational amplifier in series with a resistor R5, the output end of the first operational amplifier is connected with the same-direction input end in series with a resistor R1, the same-direction input end of the first operational amplifier is connected with the output end of the second operational amplifier in series with a resistor R2, and the output end of the first operational amplifier is connected with a magnetic induction coil L.
5. The configurable magnetic modulation type direct current leakage current alarm device according to claim 4, wherein the output end of the second operational amplifier is connected with the reverse input end, and the non-inverting input end of the second operational amplifier is grounded through a resistor R4 and connected with the singlechip through a resistor R3.
6. The configurable magnetic modulation type direct current leakage current alarm device according to claim 1, wherein the self-checking circuit comprises a first triode Q1, a second triode Q2 and a third triode Q3, the first triode Q1, the second triode Q2 and the third triode Q3 are NPN type triodes, the first triode Q1, the second triode Q2 and the third triode Q3 are connected through a connector J2, and the third triode Q3 is connected with the singlechip through the connector J1.
7. The configurable magnetic modulation type direct current leakage current alarm device according to claim 6, wherein a resistor R10 is connected between an emitter and a base of the first transistor Q1, the emitter of the first transistor Q1 is grounded, a resistor R9 is connected with a base of the first transistor Q1 and is connected with a relay, and the first transistor Q1 is connected with a connector J2 through a resistor R13.
8. The configurable magnetic modulation type direct current leakage current alarm device according to claim 6, wherein a resistor R12 is connected between an emitter and a base of the second triode Q2, the emitter of the second triode Q2 is grounded, a resistor R11 is connected with a base of the second triode Q2 and is connected with a relay, and the second triode Q2 is connected with a connector J2 through a resistor R14.
9. The configurable magnetic modulation type direct current leakage current alarm device according to claim 6, wherein a resistor R6 and a resistor R7 are connected between a base electrode of the third triode Q3 and a connector J2, a grounded diode Z1 is connected between the resistor R6 and the resistor R7, the grounded diode Z is externally connected with a self-checking end, a resistor R8 is connected between an emitter electrode of the third triode Q3 and the base electrode, a collector electrode of the third triode Q3 is connected with the connector J2, and the connector J2 is connected with the singlechip through a resistor R16.
10. The device of claim 6, wherein the connector J2 is connected to a UART communication interface via a resistor R15.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320076535.1U CN219392247U (en) | 2023-01-10 | 2023-01-10 | Configurable magnetic modulation type direct current leakage current alarm device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320076535.1U CN219392247U (en) | 2023-01-10 | 2023-01-10 | Configurable magnetic modulation type direct current leakage current alarm device |
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| Publication Number | Publication Date |
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| CN219392247U true CN219392247U (en) | 2023-07-21 |
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| CN202320076535.1U Active CN219392247U (en) | 2023-01-10 | 2023-01-10 | Configurable magnetic modulation type direct current leakage current alarm device |
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| CN (1) | CN219392247U (en) |
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- 2023-01-10 CN CN202320076535.1U patent/CN219392247U/en active Active
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