CN217278609U - Automatic calibration formula direct current sensor - Google Patents
Automatic calibration formula direct current sensor Download PDFInfo
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- CN217278609U CN217278609U CN202220108940.2U CN202220108940U CN217278609U CN 217278609 U CN217278609 U CN 217278609U CN 202220108940 U CN202220108940 U CN 202220108940U CN 217278609 U CN217278609 U CN 217278609U
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Abstract
An automatic calibration type direct current sensor belongs to the technical field of current sensors. Including magnetic core (4), sampling coil (3) winding is on the surface of magnetic core (4), its characterized in that: be provided with calibration coil (5), calibration coil (5) winding is on magnetic core (4) surface, still is provided with microprocessor and is used for sending into calibration current signal's calibration source circuit (6) to calibration coil (5), and the input of calibration source circuit (6) is connected to microprocessor's output, and the both ends of calibration coil (5) are connected to the output of calibration source circuit (6), microprocessor's input is connected to the output of sampling circuit (1). In the automatic calibration type direct current sensor, the calibration coil is arranged and the calibration source circuit which sends the calibration current signal to the calibration coil is arranged, and the sampling signal is calibrated by comparing the calibration current signal with the output current signal of the sampling coil, so that the measurement precision and accuracy are improved.
Description
Technical Field
An automatic calibration type direct current sensor belongs to the technical field of current sensors.
Background
The current sensor is a common electrical element, when a to-be-measured feed-through wire penetrates through a center hole of the current sensor, a sampling coil in the current sensor can sense current information in the feed-through wire, the sampling coil outputs the sensed current information to a sampling circuit, the output end of the sampling circuit is used as the output end of the current sensor and is connected with an upper computer, the current information sensed by the sampling coil is converted into a standard electrical signal through the sampling circuit and is output to the upper computer, and the purpose of measuring the current in the feed-through wire is achieved.
The existing direct current sensor generally adopts a hall principle or a fluxgate principle. Regardless of the Hall principle or the fluxgate principle, the output value of the sensor is deviated due to the influence (such as temperature) of the external environment, and the change has certain discreteness and is difficult to correct in an upper computer, so that the measurement precision and accuracy are greatly influenced.
Disclosure of Invention
The to-be-solved technical problem of the utility model is: the defects of the prior art are overcome, the calibration source circuit for sending the calibration current signal to the calibration coil by setting the calibration coil is provided, the sampling signal is calibrated by comparing the calibration current signal with the output current signal of the sampling coil, and the measurement precision and accuracy are improved.
The utility model provides a technical scheme that its technical problem adopted is: this automatic calibration formula direct current sensor, including the magnetic core, sampling coil winding is on the surface of magnetic core, and sampling circuit's input, its characterized in that are connected to sampling coil's output: the calibration coil is arranged on the surface of the magnetic core, the calibration coil is wound on the surface of the magnetic core, the calibration source circuit is further provided with a microprocessor and a calibration source circuit, the calibration source circuit is used for sending a calibration current signal to the calibration coil, the output end of the microprocessor is connected with the input end of the calibration source circuit, the output end of the calibration source circuit is connected with the two ends of the calibration coil, and the output end of the sampling circuit is connected with the input end of the microprocessor.
Preferably, the output end of the microprocessor is further connected with a communication module.
Preferably, the calibration source circuit comprises integrated operational amplifiers U1-U2, a reference voltage signal at the output end of the microprocessor is connected with a homodromous input end of the integrated operational amplifier U1, an inverting input end and an output end of the integrated operational amplifier U1 are simultaneously connected with one end of a resistor R3, and the other end of a resistor R3 is simultaneously connected with one end of a resistor R4 and a homodromous input end of the integrated operational amplifier U2;
the reverse input end of the integrated operational amplifier U2 is simultaneously connected with one end of resistors R1-R2, the other end of the resistor R1 is grounded, the output end of the integrated operational amplifier U2 is connected with the base of a triode Q1 after being connected with a resistor R5 in series, the collector of the triode Q1 is connected with a power supply Vcc, the emitter of the triode Q1 is connected with the other end of a resistor R2 and one end of the resistor R6, the other end of the resistor R6 is simultaneously connected with the other end of the resistor R4 and the emitter of a triode Q2, the base of the triode Q2 is connected with a control signal of the output end of a microprocessor, the emitter of the triode Q2 is simultaneously connected with one end of the calibration coil, and the other end of the calibration coil is grounded.
Preferably, a zener diode is further connected in parallel to two ends of the calibration coil, a cathode of the zener diode is connected to the emitter of the transistor Q2, and an anode of the zener diode is grounded.
Preferably, the resistances of the resistors R1-R4 are the same.
Compared with the prior art, the utility model discloses the beneficial effect who has is:
in the automatic calibration type direct current sensor, the calibration coil is arranged and the calibration source circuit which sends the calibration current signal to the calibration coil is arranged, and the sampling signal is calibrated by comparing the calibration current signal with the output current signal of the sampling coil, so that the measurement precision and accuracy are improved.
Drawings
Fig. 1 is a schematic structural diagram of an automatic calibration type dc current sensor.
Fig. 2 is a schematic block diagram of an auto-calibrating dc current sensor.
Fig. 3 is a schematic diagram of the calibration source power of the self-calibrating dc current sensor.
Wherein: 1. the device comprises a sampling circuit 2, a feed-through wire 3, a sampling coil 4, a magnetic core 5, a calibration coil 6 and a calibration source circuit.
Detailed Description
Fig. 1 to 3 are preferred embodiments of the present invention, and the present invention will be further explained with reference to fig. 1 to 3.
As shown in fig. 1, an automatic calibration type dc current sensor (hereinafter referred to as a current sensor) includes a magnetic core 4, and a core line 2 passes through the magnetic core 4. The sampling coil 3 is wound on the outer ring of the magnetic core 4, the sampling circuit 1 is connected to the output end of the sampling coil 3, the sampling coil 3 is used for inducing a current signal in the core wire 2, outputting the induced current signal to the sampling circuit 1, and outputting the current signal after the current signal is converted (for example, converted into a voltage signal) by the sampling circuit 1, and the specific circuit structure of the sampling circuit 1 belongs to the common general knowledge in the field and is not described herein again. The magnetic core is further provided with a calibration coil 5 and a calibration source circuit 6, the calibration coil 5 is wound on the outer ring of the magnetic core 4, and the output end of the calibration source circuit 6 is connected to the input end of the calibration coil 5.
Referring to fig. 2, a microprocessor is provided, an output terminal of the sampling circuit 1 is connected to an input terminal of the microprocessor, an output terminal of the microprocessor is connected to an input terminal of the calibration source circuit 6, an output terminal of the calibration source circuit 6 is connected to the calibration coil 5, an output terminal of the microprocessor is further connected to an input terminal of the communication module, and an output terminal of the communication module is connected to an upper computer (not shown) as an output terminal of the current sensor.
As shown in FIG. 3, the calibration source circuit 6 comprises integrated operational amplifiers U1-U2, a terminal A is connected with a same-direction input end of an integrated operational amplifier U1, an inverting input end and an output end of the integrated operational amplifier U1 are simultaneously connected with one end of a resistor R3, and the other end of a resistor R3 is simultaneously connected with one end of a resistor R4 and the same-direction input end of the integrated operational amplifier U2. The inverting input end of the integrated operational amplifier U2 is simultaneously connected with one end of the resistors R1-R2, and the other end of the resistor R1 is grounded. The output end of the integrated operational amplifier U2 is connected with the base of a triode Q1 after being connected with a resistor R5 in series, the collector of the triode Q1 is connected with a power supply Vcc, the emitter of the triode Q1 is connected with the other end of a resistor R2 and one end of a resistor R6, the other end of the resistor R6 is connected with the other end of the resistor R4 and the emitter of a triode Q2, the base connection terminal B of the triode Q2, the emitter of the triode Q2 is connected with one end of a coil L1 and the cathode of a diode D1, and the anode of a diode D1 and the other end of the coil L1 are grounded.
The integrated operational amplifiers U1-U2 are implemented by common chips such as LM 358. Coil L1 represents calibration coil 5 described above. Diode D1 is a voltage regulator for protecting transistor Q2. Terminal a is the reference voltage signal output by the microprocessor, and terminal B is the control signal output by the microprocessor for driving the conduction of the transistor Q2.
The integrated operational amplifiers U1-U2, the resistors R1-R6 and the triodes Q1-Q2 form a calibration source circuit 6. The reference voltage signal Vu output by the microprocessor Is input to the inverting input end of the integrated operational amplifier U1, and when the resistances of the resistors R1-R4 are the same, the current value Is = Vu/R6 output by the calibration source circuit 6. Since the reference voltage provided by the microprocessor is very constant and the resistor R6 is a precision resistor, the calibration source circuit 6 can output a stable dc current.
The specific working process and working principle are as follows:
the microprocessor performs calibration according to a predetermined trigger condition (e.g., a time interval), and when performing calibration, the microprocessor first reads a current value acquired by the sampling coil 3 through the sampling circuit 1. A control signal is then output to transistor Q2 to drive transistor Q2 into conduction. Transistor Q2 is turned on and outputs a current signal to coil L1 (calibration coil 5). When a current signal is input into the calibration coil 5, the sampling coil 3 simultaneously induces the signal and outputs the signal to the microprocessor through the sampling circuit 1. And the microprocessor compares the difference value of the current values of the sampling coil 3 acquired at the previous time and the current value of the input calibration coil 5 (for example, calculates the ratio) to obtain the calibration coefficient of the current sensor under the current environment.
When the current sensor measures the current signal in the through wire 2, the current signal acquired by the sampling coil 3 is calibrated according to the latest acquired calibration coefficient, and the calibrated current signal is acquired. And then the microprocessor sends the value of the calibrated rear-end current signal to an upper computer through a communication module by using a conventional communication interface (such as RS 485).
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical substance of the present invention still belong to the protection scope of the technical solution of the present invention.
Claims (5)
1. The utility model provides an automatic calibration formula direct current sensor, includes magnetic core (4), and sampling coil (3) winding is on the surface of magnetic core (4), and the input of sampling circuit (1), its characterized in that are connected to the output of sampling coil (3): be provided with calibration coil (5), calibration coil (5) winding is on magnetic core (4) surface, still is provided with microprocessor and is used for sending into calibration current signal's calibration source circuit (6) to calibration coil (5), and the input of calibration source circuit (6) is connected to microprocessor's output, and the both ends of calibration coil (5) are connected to the output of calibration source circuit (6), microprocessor's input is connected to the output of sampling circuit (1).
2. The self-calibrating dc current sensor of claim 1, wherein: and the output end of the microprocessor is also connected with a communication module.
3. The self-calibrating dc current sensor of claim 1, wherein: the calibration source circuit (6) comprises integrated operational amplifiers U1-U2, a reference voltage signal at the output end of the microprocessor is connected with a homodromous input end of the integrated operational amplifier U1, an inverting input end and an output end of the integrated operational amplifier U1 are simultaneously connected with one end of a resistor R3, and the other end of a resistor R3 is simultaneously connected with one end of a resistor R4 and a homodromous input end of the integrated operational amplifier U2;
the reverse input end of the integrated operational amplifier U2 is simultaneously connected with one end of resistors R1-R2, the other end of the resistor R1 is grounded, the output end of the integrated operational amplifier U2 is connected with the base of a triode Q1 after being connected with a resistor R5 in series, the collector of the triode Q1 is connected with a power supply Vcc, the emitter of the triode Q1 is connected with the other end of a resistor R2 and one end of a resistor R6, the other end of the resistor R6 is simultaneously connected with the other end of the resistor R4 and the emitter of a triode Q2, the base of the triode Q2 is connected with a microprocessor output end control signal, the emitter of the triode Q2 is simultaneously connected with one end of the calibration coil (5), and the other end of the calibration coil (5) is grounded.
4. The self-calibrating dc current sensor of claim 3, wherein: and two ends of the calibration coil (5) are also connected with a voltage stabilizing diode in parallel, the cathode of the voltage stabilizing diode is connected with the emitting electrode of the triode Q2, and the anode of the voltage stabilizing diode is grounded.
5. The self-calibrating dc current sensor of claim 3, wherein: the resistances of the resistors R1-R4 are the same.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220108940.2U CN217278609U (en) | 2022-01-17 | 2022-01-17 | Automatic calibration formula direct current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220108940.2U CN217278609U (en) | 2022-01-17 | 2022-01-17 | Automatic calibration formula direct current sensor |
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| Publication Number | Publication Date |
|---|---|
| CN217278609U true CN217278609U (en) | 2022-08-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202220108940.2U Active CN217278609U (en) | 2022-01-17 | 2022-01-17 | Automatic calibration formula direct current sensor |
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| CN (1) | CN217278609U (en) |
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- 2022-01-17 CN CN202220108940.2U patent/CN217278609U/en active Active
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