An anti-interference system based on current sensor

Abstract

The application discloses a kind of anti-interference systems based on current sensor, it is related to the field of measuring instrument anti-interference, the anti-interference system based on current sensor includes temperature self-compensation module, temperature self-compensation module includes: current detection unit, for detecting load current information by current sensor, conversion is first voltage signal, output to first-order temperature compensation unit;First-order temperature compensation unit is used to compensate the first-order temperature drift of current sensor sensitivity, compared with prior art, the beneficial effects of the application are: the temperature drift of current sensor sensitivity is compensated in the application, reduces the deviation of output to electrical instrument measuring signal under different ambient temperature, guarantees the measurement accuracy of electrical instrument;Design temperature detection control module, cooling control module, temperature control module, change ambient temperature, avoid the deviation of measurement signal based on ambient temperature, ensure the measurement accuracy of electrical instrument.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of anti-interference of measuring instruments, and particularly relates to an anti-interference system based on a current sensor. BACKGROUND

[0002] Temperature change can cause the voltage-ampere characteristic of a semiconductor device (diode, transistor, etc.) to deviate, for example, the forward voltage drop of a diode decreases by 2-2.5 mV per 1℃ increase in temperature, the collector current of a transistor increases, and the static working point of a circuit drifts. The capacitance or resistance of a passive element such as a capacitor or a resistor fluctuates with temperature, directly affecting the stability of an electrical instrument circuit.

[0003] This causes the data detected by an electrical instrument to be biased at different temperature conditions, affecting the detection accuracy of the electrical instrument, and needs to be improved. SUMMARY

[0004] The present application aims to provide an anti-interference system based on a current sensor to solve the problems presented in the background.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0006] An anti-interference system based on a current sensor, comprising a temperature self-compensation module, the temperature self-compensation module comprising:

[0007] a current detection unit for detecting load current information through a current sensor and converting the load current information into a first voltage signal and outputting the first voltage signal to a first-order temperature compensation unit;

[0008] the first-order temperature compensation unit for compensating for the first-order temperature drift of the sensitivity of the current sensor, changing the size of the first voltage signal, obtaining a second voltage signal, and outputting the second voltage signal to a second-order temperature compensation unit;

[0009] the second-order temperature compensation unit for compensating for the second-order temperature drift of the sensitivity of the current sensor, changing the size of the second voltage signal, obtaining a third voltage signal, and outputting the third voltage signal as a measurement signal of an electrical instrument;

[0010] The output end of the current detection unit is connected to the input end of the first-order temperature compensation unit, and the output end of the first-order temperature compensation unit is connected to the input end of the second-order temperature compensation unit.

[0011] As a further scheme of the present application, the current detection unit comprises a current sensor, one end of the current sensor is grounded, and the other end of the current sensor is connected to the input end of the first-order temperature compensation unit.

[0012] As a further scheme of the present application: the first temperature compensation unit comprises a first resistor, a first temperature sensitive resistor, a first amplifier, a first capacitor, a second resistor, one end of the first resistor is connected to the output end of the current detection unit, the other end of the first resistor is connected to one end of the first temperature sensitive resistor and the non-inverting terminal of the first amplifier, the other end of the first temperature sensitive resistor is grounded, the inverting terminal of the first amplifier is connected to one end of the first capacitor and one end of the second resistor, the other end of the first capacitor is grounded, and the output end of the first amplifier is connected to the other end of the second resistor and the input end of the second temperature compensation unit.

[0013] As a further scheme of the present application: the second temperature compensation unit comprises a second amplifier, a third resistor, a second temperature sensitive resistor, a fourth resistor, and a fifth switch, the non-inverting terminal of the second amplifier is connected to the output end of the first temperature compensation unit, the inverting terminal of the second amplifier is connected to one end of the second temperature sensitive resistor and one end of the fourth resistor, the other end of the second temperature sensitive resistor is connected to one end of the third resistor, the other end of the third resistor is grounded, the output end of the second amplifier is connected to the other end of the fourth resistor and one end of the fifth switch, and the other end of the fifth switch outputs the third voltage signal.

[0014] As a further scheme of the present application: the anti-interference system based on the current sensor further comprises an output monitoring protection module for monitoring the size of the third voltage signal output by the temperature self-compensation module, and when the third voltage signal exceeds the voltage threshold, the loop between the temperature self-compensation module and the electrical instrument is disconnected.

[0015] The output monitoring protection module comprises a fifth resistor, a sixth resistor, a second capacitor, a first diode, a first triode, a seventh resistor, a second diode, and a fifth relay, one end of the fifth resistor is connected to the output end of the second temperature compensation unit, the other end of the fifth resistor is connected to one end of the sixth resistor, one end of the second capacitor, and the negative electrode of the first diode, the other end of the sixth resistor is grounded, the other end of the second capacitor is grounded, the positive electrode of the first diode is connected to the base of the first triode, the emitter of the first triode is grounded through the seventh resistor, the collector of the first triode is connected to the positive electrode of the second diode and one end of the fifth relay, the negative electrode of the second diode is connected to the other end of the fifth relay and the power supply voltage.

[0016] As a further scheme of the present application: the anti-interference system based on the current sensor further comprises:

[0017] The temperature detection control module is used for detecting environmental temperature information, and when the environmental temperature is higher than the upper temperature threshold, the cooling control module is controlled to work, and when the environmental temperature is lower than the lower temperature threshold, the heating control module is controlled to work.

[0018] The cooling control module is used for constructing a Wheatstone bridge to control whether the refrigerator works, and when the environmental temperature is higher than the set temperature, the refrigerator is controlled to work.

[0019] The temperature detection control module is connected with the temperature self-compensation module.

[0020] The first output end of the temperature detection control module is connected with the first input end of the temperature reduction control module, the second output end of the temperature detection control module is connected with the first input end of the temperature increase control module, the output end of the temperature reduction control module is connected with the first input end of the temperature self-compensation module, and the output end of the temperature increase control module is connected with the second input end of the temperature self-compensation module.

[0021] The temperature detection control module comprises an eighth resistor, a fifth temperature-sensitive resistor, a fourth amplifier, a fifth amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a third diode, a fourth diode, a first relay, a third relay, a second triode and a third triode.

[0022] As a further scheme of the present application: the cooling control module comprises a first switch, a second switch, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a third temperature-sensitive resistor, a sixth amplifier, a fifth diode, a fourth triode, a seventeenth resistor, one end of the first switch is connected with a power supply voltage, the other end of the first switch is connected with one end of the thirteenth resistor, the other end of the thirteenth resistor is connected with one end of the fourteenth resistor and a non-inverting terminal of the sixth amplifier, the other end of the fourteenth resistor is grounded, an inverting terminal of the sixth amplifier is connected with one end of the third temperature-sensitive resistor, one end of the fifteenth resistor and one end of the sixteenth resistor, the other end of the third temperature-sensitive resistor is grounded, the other end of the fifteenth resistor is connected with one end of the second switch, the other end of the second switch is connected with the power supply voltage, the other end of the sixteenth resistor is connected with an output terminal of the sixth amplifier and a positive electrode of the fifth diode, a negative electrode of the fifth diode is connected with a base of the fourth triode and a collector of the fourth triode which is connected with the power supply voltage through the seventeenth resistor, an emitter of the fourth triode is grounded through the refrigerator.

[0023] As a further scheme of the present application: the heating control module comprises a third switch, a fourth switch, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a fourth temperature-sensitive resistor, a seventh amplifier, a sixth diode, a fifth triode, one end of the third switch is connected with a power supply voltage, the other end of the third switch is connected with one end of the nineteenth resistor, the other end of the nineteenth resistor is connected with one end of the twentieth resistor and a non-inverting terminal of the seventh amplifier, the other end of the twentieth resistor is grounded, an inverting terminal of the seventh amplifier is connected with one end of the eighteenth resistor and one end of the twenty-first resistor, the other end of the eighteenth resistor is connected with one end of the fourth temperature-sensitive resistor, one end of the fourth temperature-sensitive resistor is connected with one end of the fourth switch, the other end of the fourth switch is connected with the power supply voltage, an output terminal of the seventh amplifier is connected with the other end of the twenty-first resistor and a positive electrode of the sixth diode, a negative electrode of the sixth diode is connected with a base of the fifth triode, a collector of the fifth triode is connected with the power supply voltage through the twenty-second resistor, an emitter of the fifth triode is grounded through the heater.

[0024] As a further scheme of the present application: the anti-interference system based on the current sensor further comprises a manual control module, which is used for detecting the temperature drift compensation effect of the sensitivity of the current sensor by manually controlling the cooling control module or the heating control module to work forcibly.

[0025] The manual control module comprises a twenty-third resistor and a sixth switch, one end of the twenty-third resistor is connected with a power supply voltage, the other end of the twenty-third resistor is connected with one end of the sixth switch, the other end of the sixth switch is connected with a common point A1, a common point A2 or a common point A3, the common point A3 is suspended, the common point A1 is connected with a second input end of the cooling control module, and the common point A2 is connected with a second input end of the heating control module.

[0026] Compared with the prior art, the application has the beneficial effects that: the application compensates the temperature drift of the current sensor, reduces the deviation of the output signal to the electrician instrument under different ambient temperatures, and ensures the measurement accuracy of the electrician instrument; the temperature detection control module, the cooling control module and the heating control module are designed to change the ambient temperature, avoid the deviation of the measurement signal caused by the ambient temperature, and ensure the measurement accuracy of the electrician instrument. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of an anti-interference system based on a current sensor.

[0028] Figure 2 It is a schematic diagram of a temperature self-compensation module.

[0029] Figure 3 It is a circuit diagram of the temperature self-compensation module.

[0030] Figure 4 It is a circuit diagram of the output monitoring protection module.

[0031] Figure 5 It is a circuit diagram of the temperature detection control module.

[0032] Figure 6 It is a circuit diagram of the cooling control module.

[0033] Figure 7 It is a circuit diagram of the heating control module.

[0034] Figure 8 It is a circuit diagram of the manual control module. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0036] Please refer to Figure 1 and Figure 2 , an anti-interference system based on a current sensor, comprising a temperature self-compensation module 1, the temperature self-compensation module 1 comprising:

[0037] A current detection unit 11 is configured to detect load current information through a current sensor U3, convert the load current information into a first voltage signal, and output the first voltage signal to a first temperature compensation unit 12.

[0038] The first temperature compensation unit 12 is used to compensate the first order temperature drift of the current sensor U3 sensitivity, change the size of the first voltage signal, obtain the second voltage signal, and output to the second temperature compensation unit 13.

[0039] The second temperature compensation unit 13 is used to compensate the second order temperature drift of the current sensor U3 sensitivity, change the size of the second voltage signal, obtain the third voltage signal, and output as the measurement signal of the electrical instrument.

[0040] The output end of the current detection unit 11 is connected to the input end of the first temperature compensation unit 12, and the output end of the first temperature compensation unit 12 is connected to the input end of the second temperature compensation unit 13.

[0041] In the embodiment, please refer to Figure 3 The current detection unit 11 includes the current sensor U3, one end of the current sensor U3 is grounded, and the other end of the current sensor U3 is connected to the input end of the first temperature compensation unit 12.

[0042] In the embodiment, please refer to Figure 3 The first temperature compensation unit 12 includes the first resistor R1, the first temperature sensitive resistor RW1, the first amplifier U1, the first capacitor C1, and the second resistor R2, one end of the first resistor R1 is connected to the output end of the current detection unit 11, the other end of the first resistor R1 is connected to one end of the first temperature sensitive resistor RW1 and the non-inverting terminal of the first amplifier U1, the other end of the first temperature sensitive resistor RW1 is grounded, the inverting terminal of the first amplifier U1 is connected to one end of the first capacitor C1 and one end of the second resistor R2, the other end of the first capacitor C1 is grounded, and the output end of the first amplifier U1 is connected to the other end of the second resistor R2 and the input end of the second temperature compensation unit 13.

[0043] In the embodiment, please refer to Figure 3 The second temperature compensation unit 13 includes the second amplifier U2, the third resistor R3, the second temperature sensitive resistor RW2, the fourth resistor R4, and the fifth switch S5, the non-inverting terminal of the second amplifier U2 is connected to the output end of the first temperature compensation unit 12, the inverting terminal of the second amplifier U2 is connected to one end of the second temperature sensitive resistor RW2 and one end of the fourth resistor R4, the other end of the second temperature sensitive resistor RW2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is grounded, the output end of the second amplifier U2 is connected to the other end of the fourth resistor R4 and one end of the fifth switch S5, and the other end of the fifth switch S5 outputs the third voltage signal.

[0044] The sensitivity (or zero point) of the current sensor U3 usually changes approximately linearly with temperature. For example, the sensitivity decreases by 0.1% for every 1°C increase in temperature. In order to offset this one-way, uniform change drift (e.g. temperature rise causes sensitivity to decrease). A first temperature compensation unit 12 is constructed using a first temperature-sensitive resistor RW1, temperature ↑→ first temperature-sensitive resistor RW1 resistance ↓→ circuit gain ↑, by design, let the rising amplitude of the gain (via the voltage drop amplitude of the first temperature-sensitive resistor) be exactly equal to the decreasing amplitude of the sensor sensitivity (the voltage rising amplitude of the sensor output), so that the final output remains stable.

[0045] The temperature drift of the actual current sensor U3 is often not a perfect straight line, and there may be problems such as: fast drift in low temperature zone, slow drift in high temperature zone (or vice versa), inflection point at a specific temperature point, etc.; Therefore, it is also necessary to solve the non-linear drift (i.e. the phenomenon that the temperature drift rate changes with temperature). Therefore, a second temperature compensation unit 13 is constructed by introducing a second temperature-sensitive resistor RW2 (different characteristics), and the resistance-temperature curve of the second temperature-sensitive resistor RW2 has stronger nonlinearity (high B value). Through circuit design, the adjustment amount of the gain is less at low temperature and more at high temperature (or vice versa).

[0046] Specifically, the current sensor U3 detects the current information of the load (not shown in the load diagram), converts it into a voltage signal and outputs it to the first temperature compensation unit 12. When the ambient temperature rises, the resistance of the first temperature-sensitive resistor RW1 decreases (all temperature-sensitive resistors in this application are negative temperature coefficient temperature-sensitive resistors), which reduces the total impedance of the first temperature-sensitive resistor RW1 and the first resistor R1, and the voltage output by the first amplifier U1 decreases, which is a first-order compensation. After first-order compensation, there is still a non-linear residual error. When the temperature rises, the resistance of the second temperature-sensitive resistor RW2 decreases due to temperature changes, which adjusts the amplification multiple of the second voltage signal and the size of the third voltage signal output, which is a second-order compensation. Through the first temperature compensation unit 12 and the second temperature compensation unit 13, the voltage signal output by the current sensor U3 under the change of ambient temperature is compensated, reducing the influence of ambient temperature.

[0047] The resistance values of the first temperature-sensitive resistor RW1 and the first resistor R1 are matched to ensure sufficient sensitivity to temperature changes, for example, the first resistor R1 = 10kΩ, and the first temperature-sensitive resistor RW1 = 10kΩ@20℃. The B value (resistivity change with temperature) of the first temperature-sensitive resistor RW1 and the second temperature-sensitive resistor RW2 is different, and the B value of the second temperature-sensitive resistor RW2 is larger. The third resistor R3 is a precision resistor to avoid the fluctuation of the resistance value of an ordinary resistor when the temperature changes, which distorts the preset compensation curve. The first amplifier U1 and the second amplifier U2 are zero-drift amplifiers, such as AD8629.

[0048] In another embodiment: the working power supply of the first amplifier U1 and the second amplifier U2 is not shown in the figure, which can be supplied by a voltage stabilizer.

[0049] In the embodiment: please refer to Figure 4 , the anti-interference system based on current sensor further comprises an output monitoring protection module 2 for monitoring the size of the third voltage signal output by the temperature self-compensation module 1, and when the third voltage signal exceeds the voltage threshold, the loop of the temperature self-compensation module 1 and the electrical instrument is disconnected;

[0050] The output monitoring protection module 2 comprises a fifth resistor R5, a sixth resistor R6, a second capacitor C2, a first diode D1, a first triode V1, a seventh resistor R7, a second diode D2, and a fifth relay J5. One end of the fifth resistor R5 is connected to the output end of the second temperature compensation unit 13, the other end of the fifth resistor R5 is connected to one end of the sixth resistor R6, one end of the second capacitor C2, and the negative electrode of the first diode D1, the other end of the sixth resistor R6 is grounded, the other end of the second capacitor C2 is grounded, the positive electrode of the first diode D1 is connected to the base of the first triode V1, the emitter of the first triode V1 is grounded through the seventh resistor R7, the collector of the first triode V1 is connected to the positive electrode of the second diode D2 and one end of the fifth relay J5, the negative electrode of the second diode D2 is connected to the other end of the fifth relay J5 and the supply voltage VCC.

[0051] When the third voltage signal is normal, the voltage at the common point A4 is normal, the voltage on the sixth resistor R6 cannot turn on the first diode D1, the first triode V1 is cut off, the fifth relay J5 does not work, the fifth switch S5 maintains a closed state, and the third voltage signal is transmitted to the electrical instrument through the fifth switch S5; when the third voltage signal is too large, there is a possibility of damaging the electrical instrument, the voltage on the sixth resistor R6 is sufficient to turn on the first diode D1, the first triode V1 works, the fifth relay J5 works, the fifth switch S5 is opened, and the input of the third voltage signal to the electrical instrument is stopped, ensuring safety.

[0052] In another embodiment: the supply voltage VCC can be obtained by battery power supply, or by converting alternating current to direct current for voltage stabilization.

[0053] In the embodiment: please refer to Figure 1 , the anti-interference system based on current sensor further comprises:

[0054] The temperature detection control module 3 is used for detecting environmental temperature information, and when the environmental temperature is higher than the upper temperature threshold, the cooling control module 4 is controlled to work, and when the environmental temperature is lower than the lower temperature threshold, the heating control module 5 is controlled to work;

[0055] The temperature decreasing control module 4 is used to build a Wheatstone bridge to control the operation of the refrigerator, and when the ambient temperature is higher than the set temperature, the refrigerator is controlled to operate;

[0056] The temperature increasing control module 5 is used to build a variable Wheatstone bridge to control the operation of the heater, and when the ambient temperature is lower than the set temperature, the heater is controlled to operate;

[0057] The first output end of the temperature detection control module 3 is connected to the first input end of the temperature decreasing control module 4, the second output end of the temperature detection control module 3 is connected to the first input end of the temperature increasing control module 5, the output end of the temperature decreasing control module 4 is connected to the first input end of the temperature self-compensation module 1, and the output end of the temperature increasing control module 5 is connected to the second input end of the temperature self-compensation module 1.

[0058] In the embodiment, please refer to Figure 5 The temperature detection control module 3 comprises an eighth resistor R8, a fifth temperature-sensitive resistor RW5, a fourth amplifier U4, a fifth amplifier U5, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a third diode D3, a fourth diode D4, a first relay J1, a third relay J3, a second triode V2 and a third triode V3. One end of the eighth resistor R8 is connected to a power supply voltage VCC, the other end of the eighth resistor R8 is connected to one end of the fifth temperature-sensitive resistor RW5, the non-inverting terminal of the fourth amplifier U4 and the inverting terminal of the fifth amplifier U5, the inverting terminal of the fourth amplifier U4 is connected to a first reference voltage VREF1, the non-inverting terminal of the fifth amplifier U5 is connected to a second reference voltage VREF2, the output end of the fourth amplifier U4 is connected to one end of the ninth resistor R9, the other end of the ninth resistor R9 is connected to the base of the second triode V2, the collector of the second triode V2 is connected to the positive pole of the third diode D3 and one end of the third relay J3, the negative pole of the third diode D3 is connected to the other end of the third relay J3 and the power supply voltage VCC, the emitter of the second triode V2 is grounded through the eleventh resistor R11, the output end of the fifth amplifier U5 is connected to one end of the tenth resistor R10, the other end of the tenth resistor R10 is connected to the base of the third triode V3, the collector of the third triode V3 is connected to the positive pole of the fourth diode D4 and one end of the first relay J1, the negative pole of the fourth diode D4 is connected to the other end of the first relay J1 and the power supply voltage VCC, the emitter of the third triode V3 is connected to one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is grounded.

[0059] Normally, if the ambient temperature can be adjusted, the current sensor U3 sensitivity temperature drift can be avoided (but for the ambient temperature is too high or too low, the heater, the refrigeration power is small, not enough to adjust the ambient temperature to the current sensor U3 sensitivity does not shift, at this time the temperature self compensation module 1 ensures that the output signal of the current sensor U3 is still reliable); the fifth temperature sensitive resistor RW5 detects the ambient temperature, when the ambient temperature is high, the voltage on the fifth temperature sensitive resistor RW5 is small, less than the second reference voltage VREF2, the fifth amplifier U5 outputs high level, control the third triode V3 turns on, and then trigger the first relay J1 work, drive cooling control module 4 work; when the ambient temperature is low, the voltage on the fifth temperature sensitive resistor RW5 is large, greater than the first reference voltage VREF1, the fourth amplifier U4 outputs high level, control the second triode V2 turns on, trigger the third relay J3 work, drive the heating control module 5 work.

[0060] In another embodiment: the first reference voltage VREF1, the second reference voltage VREF2 is obtained by fixed voltage through resistance division.

[0061] In this embodiment: please refer to Figure 6 , cooling control module 4 includes first switch S1, second switch S2, thirteenth resistor R13, fourteenth resistor R14, fifteenth resistor R15, sixteenth resistor R16, third temperature sensitive resistor RW3, sixth amplifier U6, fifth diode D5, fourth triode V4, seventeenth resistor R17, one end of the first switch S1 is connected with the power supply voltage VCC, the other end of the first switch S1 is connected with one end of the thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected with one end of the fourteenth resistor R14 and the same phase end of the sixth amplifier U6, the other end of the fourteenth resistor R14 is grounded, the opposite phase end of the sixth amplifier U6 is connected with one end of the third temperature sensitive resistor RW3, one end of the fifteenth resistor R15 and one end of the sixteenth resistor R16, the other end of the third temperature sensitive resistor RW3 is grounded, the other end of the fifteenth resistor R15 is connected with one end of the second switch S2, the other end of the second switch S2 is connected with the power supply voltage VCC, the other end of the sixteenth resistor R16 is connected with the output end of the sixth amplifier U6 and the positive electrode of the fifth diode D5, the negative electrode of the fifth diode D5 is connected with the base of the fourth triode V4, the collector of the fourth triode V4 is connected with the power supply voltage VCC through the seventeenth resistor R17, and the emitter of the fourth triode V4 is grounded through the refrigeration.

[0062] When the first relay J1 works, the first switch S1 and the second switch S2 are closed, the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15 and the third temperature-sensitive resistor RW3 form a Wheatstone bridge, through the design of resistance, when the third temperature-sensitive resistor RW3 is at the set temperature (for example, 20℃), the voltage of the same phase terminal and the opposite phase terminal of the sixth amplifier U6 is the same, and no output voltage is outputted, when the temperature is higher than the set temperature, the voltage of the opposite phase terminal of the sixth amplifier U6 is reduced, the balance is broken, an output voltage is generated, the fourth triode V4 is turned on, the refrigerator works to reduce the temperature, and until the ambient temperature reaches the set temperature.

[0063] In another embodiment, the first switch S1 and the second switch S2 can be replaced by a double-pole double-throw switch.

[0064] In the embodiment, please refer to Figure 7 , the temperature rising control module 5 comprises the third switch S3, the fourth switch S4, the eighteenth resistor R18, the nineteenth resistor R19, the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, the fourth temperature-sensitive resistor RW4, the seventh amplifier U7, the sixth diode D6 and the fifth triode V5, one end of the third switch S3 is connected with the power supply voltage VCC, the other end of the third switch S3 is connected with one end of the nineteenth resistor R19, the other end of the nineteenth resistor R19 is connected with one end of the twentieth resistor R20 and the same phase terminal of the seventh amplifier U7, the other end of the twentieth resistor R20 is grounded, the opposite phase terminal of the seventh amplifier U7 is connected with one end of the eighteenth resistor R18 and one end of the twenty-first resistor R21, the other end of the eighteenth resistor R18 is connected with one end of the fourth temperature-sensitive resistor RW4, the other end of the fourth temperature-sensitive resistor RW4 is connected with one end of the fourth switch S4, the other end of the fourth switch S4 is connected with the power supply voltage VCC, the output terminal of the seventh amplifier U7 is connected with the other end of the twenty-first resistor R21 and the positive electrode of the sixth diode D6, the negative electrode of the sixth diode D6 is connected with the base of the fifth triode V5, the collector of the fifth triode V5 is connected with the power supply voltage VCC through the twenty-second resistor R22, and the emitter of the fifth triode V5 is grounded through the heater.

[0065] When the third relay J3 works, the third switch S3 and the fourth switch S4 are closed, the eighteenth resistor R18, the nineteenth resistor R19, the twentieth resistor R20 and the fourth temperature-sensitive resistor RW4 form a variant Wheatstone bridge, through the design of resistance, when the fourth temperature-sensitive resistor RW4 is at the set temperature (for example, 20℃), the voltage of the same phase terminal and the opposite phase terminal of the seventh amplifier U7 is the same, and no output voltage is outputted, when the temperature is lower than the set temperature, the voltage of the opposite phase terminal of the seventh amplifier U7 is reduced, the balance is broken, an output voltage is generated, the fifth triode V5 is turned on, the heater works to rise the temperature, and until the ambient temperature reaches the set temperature.

[0066] In another embodiment: the heater of the embodiment is powered by direct current, and an AC-powered heater can also be selected.

[0067] In the embodiment: please refer to Figure 8 The anti-interference system based on the current sensor further comprises a manual control module 6 for detecting the temperature drift compensation effect of the sensitivity of the current sensor U3 by manually controlling the cooling control module 4 or the heating control module 5 to work forcibly.

[0068] The manual control module 6 comprises a twenty-third resistor R23 and a sixth switch S6, one end of the twenty-third resistor R23 is connected to the power supply voltage VCC, the other end of the twenty-third resistor R23 is connected to one end of the sixth switch S6, the other end of the sixth switch S6 is connected to the common point A1 or the common point A2 or the common point A3, the common point A3 is suspended, the common point A1 is connected to the second input end of the cooling control module 4, and the common point A2 is connected to the second input end of the heating control module 5.

[0069] The sixth switch S6 is a single-pole three-throw switch, which can make the common point A1 or A2 be at a high level, triggering the refrigerator or the heater to work; therefore, the change of the ambient temperature is detected to determine whether the deviation of the output signal of the temperature self-compensation module 1 under different temperature conditions is acceptable when the load current is unchanged.

[0070] In another embodiment: a light-emitting diode can be added to indicate the wiring state of the single-pole three-throw switch.

[0071] The working principle of the application is that: the current detection unit 11 is used for detecting the load current information through the current sensor U3, converting the load current information into a first voltage signal, and outputting the first voltage signal to the first temperature compensation unit 12; the first temperature compensation unit 12 is used for compensating the first-order temperature drift of the sensitivity of the current sensor U3, changing the size of the first voltage signal, obtaining a second voltage signal, and outputting the second voltage signal to the second temperature compensation unit 13; the second temperature compensation unit 13 is used for compensating the second-order temperature drift of the sensitivity of the current sensor U3, changing the size of the second voltage signal, obtaining a third voltage signal, and taking the third voltage signal as a measurement signal of an electrical instrument.

[0072] It is obvious for those skilled in the art that the application is not limited to the details of the above-mentioned exemplary embodiments, and the application can be implemented in other specific forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view.

[0073] Furthermore, it should be understood that although the specification is described in terms of embodiments, not every embodiment includes every feature described. The specification can include implicit combinations of explicitly mentioned features and / or explicit combinations of implicitely mentioned features. Each embodiment depends on the explicit combinations of features and / or the implicit combinations of features made specifically within that embodiment, and each such embodiment can be combined with every other such embodiment to create further embodiments.

Claims

1. An anti-interference system based on a current sensor, characterized in that, The current sensor-based anti-interference system includes a temperature self-compensation module, which comprises: The current detection unit is used to detect load current information through a current sensor, convert it into a first voltage signal, and output it to the first-level temperature compensation unit. The first-level temperature compensation unit is used to compensate for the first-order temperature drift of the current sensor sensitivity, change the magnitude of the first voltage signal to obtain the second voltage signal, and output it to the second-level temperature compensation unit. The secondary temperature compensation unit is used to compensate for the second-order temperature drift of the current sensor sensitivity, change the magnitude of the second voltage signal, and obtain the third voltage signal as the measurement signal of electrical instruments. The output of the current detection unit is connected to the input of the first-stage temperature compensation unit, and the output of the first-stage temperature compensation unit is connected to the input of the second-stage temperature compensation unit. The first-stage temperature compensation unit includes a first resistor, a first thermistor, a first amplifier, a first capacitor, and a second resistor. One end of the first resistor is connected to the output terminal of the current detection unit, and the other end of the first resistor is connected to one end of the first thermistor and the non-inverting input of the first amplifier. The other end of the first thermistor is grounded. The inverting input of the first amplifier is connected to one end of the first capacitor and one end of the second resistor. The other end of the first capacitor is grounded. The output terminal of the first amplifier is connected to the other end of the second resistor and the input terminal of the second-stage temperature compensation unit.

2. The anti-interference system based on a current sensor according to claim 1, characterized in that, The current detection unit includes a current sensor, one end of which is grounded and the other end is connected to the input terminal of a primary temperature compensation unit.

3. The anti-interference system based on a current sensor according to claim 1, characterized in that, The secondary temperature compensation unit includes a second amplifier, a third resistor, a second thermistor, a fourth resistor, and a fifth switch. The non-inverting input of the second amplifier is connected to the output of the primary temperature compensation unit. The inverting input of the second amplifier is connected to one end of the second thermistor and one end of the fourth resistor. The other end of the second thermistor is connected to one end of the third resistor. The other end of the third resistor is grounded. The output of the second amplifier is connected to the other end of the fourth resistor and one end of the fifth switch. The other end of the fifth switch outputs a third voltage signal.

4. The anti-interference system based on a current sensor according to any one of claims 1 to 3, characterized in that, The anti-interference system based on the current sensor also includes an output monitoring and protection module, which monitors the magnitude of the third voltage signal output by the temperature self-compensation module and disconnects the circuit between the temperature self-compensation module and the electrical instruments when the third voltage signal exceeds the voltage threshold. The output monitoring and protection module includes a fifth resistor, a sixth resistor, a second capacitor, a first diode, a first transistor, a seventh resistor, a second diode, and a fifth relay. One end of the fifth resistor is connected to the output terminal of the secondary temperature compensation unit. The other end of the fifth resistor is connected to one end of the sixth resistor, one end of the second capacitor, and the cathode of the first diode. The other end of the sixth resistor is grounded, and the other end of the second capacitor is grounded. The anode of the first diode is connected to the base of the first transistor, and the emitter of the first transistor is grounded through the seventh resistor. The collector of the first transistor is connected to the anode of the second diode and one end of the fifth relay. The cathode of the second diode is connected to the other end of the fifth relay and the power supply voltage.

5. The anti-interference system based on a current sensor according to claim 1, characterized in that, The current sensor-based anti-interference system also includes: The temperature detection and control module is used to detect ambient temperature information. When the ambient temperature is higher than the upper temperature threshold, it controls the cooling control module to work. When the ambient temperature is lower than the lower temperature threshold, it controls the heating control module to work. The cooling control module is used to construct a Wheatstone bridge to control whether the cooler works. When the ambient temperature rises above the set temperature, the cooler is controlled to work. The heating control module is used to construct a variant of the Wheatstone bridge to control whether the heater is working. When the ambient temperature drops from the set temperature, the heater is controlled to work. The first output terminal of the temperature detection and control module is connected to the first input terminal of the cooling control module, the second output terminal of the temperature detection and control module is connected to the first input terminal of the heating control module, the output terminal of the cooling control module is connected to the first input terminal of the temperature self-compensation module, and the output terminal of the heating control module is connected to the second input terminal of the temperature self-compensation module.

6. The anti-interference system based on a current sensor according to claim 5, characterized in that, The temperature detection and control module includes an eighth resistor, a fifth thermistor, a fourth amplifier, a fifth amplifier, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a third diode, a fourth diode, a first relay, a third relay, a second transistor, and a third transistor. One end of the eighth resistor is connected to the power supply voltage, and the other end is connected to one end of the fifth thermistor, the non-inverting input of the fourth amplifier, and the inverting input of the fifth amplifier. The inverting input of the fourth amplifier is connected to the first reference voltage, and the non-inverting input of the fifth amplifier is connected to the second reference voltage. The output of the fourth amplifier is connected to one end of the ninth resistor, and the other end of the ninth resistor... The first transistor's collector is connected to the base of the second transistor, the collector of the second transistor is connected to the anode of the third diode and one end of the third relay, the cathode of the third diode is connected to the other end of the third relay and the power supply voltage, the emitter of the second transistor is grounded through the eleventh resistor, the output terminal of the fifth amplifier is connected to one end of the tenth resistor, the other end of the tenth resistor is connected to the base of the third transistor, the collector of the third transistor is connected to the anode of the fourth diode and one end of the first relay, the cathode of the fourth diode is connected to the other end of the first relay and the power supply voltage, the emitter of the third transistor is connected to one end of the twelfth resistor, and the other end of the twelfth resistor is grounded.

7. The anti-interference system based on a current sensor according to claim 5, characterized in that, The cooling control module includes a first switch, a second switch, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a third thermistor, a sixth amplifier, a fifth diode, a fourth transistor, and a seventeenth resistor. One end of the first switch is connected to the power supply voltage, and the other end of the first switch is connected to one end of the thirteenth resistor. The other end of the thirteenth resistor is connected to one end of the fourteenth resistor and the non-inverting input of the sixth amplifier. The other end of the fourteenth resistor is grounded. The inverting input of the sixth amplifier is connected to one end of the third thermistor, one end of the fifteenth resistor, and one end of the sixteenth resistor. The other end of the third thermistor is grounded. The other end of the fifteenth resistor is connected to one end of the second switch, and the other end of the second switch is connected to the power supply voltage. The other end of the sixteenth resistor is connected to the output terminal of the sixth amplifier and the anode of the fifth diode. The cathode of the fifth diode is connected to the base of the fourth transistor. The collector of the fourth transistor is connected to the power supply voltage through the seventeenth resistor. The emitter of the fourth transistor is grounded through the cooler.

8. The anti-interference system based on a current sensor according to claim 5, characterized in that, The temperature control module includes a third switch, a fourth switch, an eighteenth resistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a fourth thermistor, a seventh amplifier, a sixth diode, and a fifth transistor. One end of the third switch is connected to the power supply voltage, and the other end of the third switch is connected to one end of the nineteenth resistor. The other end of the nineteenth resistor is connected to one end of the twentieth resistor and the non-inverting input of the seventh amplifier. The other end of the twentieth resistor is grounded. The inverting input of the seventh amplifier is connected to one end of the eighteenth resistor and one end of the twenty-first resistor. The other end of the eighteenth resistor is connected to one end of the fourth thermistor. The other end of the fourth thermistor is connected to one end of the fourth switch. The other end of the fourth switch is connected to the power supply voltage. The output of the seventh amplifier is connected to the other end of the twenty-first resistor and the anode of the sixth diode. The cathode of the sixth diode is connected to the base of the fifth transistor. The collector of the fifth transistor is connected to the power supply voltage through the twenty-second resistor, and the emitter of the fifth transistor is grounded through the heater.

9. The anti-interference system based on a current sensor according to any one of claims 5 to 8, characterized in that, The current sensor-based anti-interference system also includes a manual control module, which is used to manually switch the cooling control module or the heating control module to force it to work, so as to detect the temperature drift compensation effect of the current sensor sensitivity. The manual control module includes a 23rd resistor and a 6th switch. One end of the 23rd resistor is connected to the power supply voltage, and the other end of the 23rd resistor is connected to one end of the 6th switch. The other end of the 6th switch is connected to a common point A1, A2, or A3. Common point A3 is left floating. Common point A1 is connected to the second input terminal of the cooling control module, and common point A2 is connected to the second input terminal of the heating control module.

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