Electronic current stabilizing control device and method suitable for multi-component gas mixture

Abstract

The application discloses an electronic steady flow control device and method suitable for multi-element mixed gas inflation, which comprises a plurality of gas sources, each of which is connected with a gas flow control module through a pressure reducing valve, the gas outputs of the plurality of gas flow control modules are connected with a same buffer tank, the mixed gas outlet of the buffer tank is connected with a variable frequency compressor, the variable frequency compressor is used for outputting the mixed gas of the buffer tank, a first pressure monitoring module is connected with the gas input port of one of the gas flow control modules, the gas output port of the one gas flow control module is connected with a second pressure monitoring module, the monitoring signal outputs of the first pressure monitoring module and the second pressure monitoring module are connected with a feedback control module, the control output of the feedback control module is connected with the variable frequency compressor, and the feedback control module outputs a control signal to adjust the rotating speed of the variable frequency compressor so that the pressure of the gas input port and the gas output port of the gas flow control module returns to a balanced state.

Description

TECHNICAL FIELD

[0001] The present application relates to an electronic current stabilizing control device and method suitable for multi-component mixed gas charging. BACKGROUND

[0002] The State Grid Corporation of China is vigorously promoting a mixed gas reform project, using mixed gas (for example, SF6 / N2, SF6 / CF4, C4F7N / CO2, etc.) to replace pure sulfur hexafluoride gas (SF6) to reduce the use and emission of greenhouse gas SF6. The mixing ratio is an important indicator affecting the insulation performance and breaking performance of power equipment, and ensuring that it is within the specified range is the basic condition for the safe and stable operation of mixed gas equipment. The State Grid Corporation of China has made strict regulations on the mixing ratio of different types of mixed gas, for example, the mixing ratio of SF6 / N2 is 30%:70%, and the SF6 deviation cannot exceed ±1%. However, the mixing ratio of the mixed gas prepared by the mixed gas charging device currently used by the power grid company often does not meet the requirements, the main reason being that the gas flow control module has a certain error when controlling the gas flow output, resulting in a large deviation in the mixing ratio of the prepared mixed gas.

[0003] Currently, the gas flow in the mixed gas charging device is mostly controlled by differential pressure method, the working principle of which is to calculate the pressure difference between the inlet and outlet of the gas flow control module installed in the pipeline and the size of the pipeline, both of which are positively correlated with the gas flow, and to control the internal electronic valve to adjust the gas flow.

[0004] However, in actual operation, the work of the compressor will cause the gas pressure in the buffer tank directly connected to the outlet of the gas flow control module to change, causing the pressure difference between the inlet and outlet of the gas flow control module to fluctuate, the instantaneous gas flow to deviate from the set value, and ultimately resulting in a mixed gas mixture ratio that does not meet the standard when filling the gas chamber. SUMMARY

[0005] The purpose of the present application is to provide an electronic current stabilizing control device and method suitable for multi-component mixed gas charging, which controls the inlet / outlet pressure difference to a preset value through a feedback control module, thereby improving the accuracy of mixed gas preparation.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the present application is:

[0007] The application relates to an electronic steady flow control device suitable for multi-element mixed gas inflation, which comprises a multi-path gas source, a gas flow control module connected with each path of the gas source through a pressure reducing valve, a gas output of the multi-path gas flow control module connected with a same buffer tank, a mixed gas outlet of the buffer tank connected with a variable frequency compressor, and wherein: under the condition of meeting the multi-path gas proportioning, the pressure reducing valves of each path of the gas source are adjusted to make the gas input ports of the multi-path gas flow control modules have the same gas pressure and the gas output ports of the multi-path gas flow control modules have the same gas pressure, the gas input port of one of the multi-path gas flow control modules is connected with a first pressure monitoring module, the gas output port of the one of the multi-path gas flow control modules is connected with a second pressure monitoring module, the monitoring signal outputs of the first pressure monitoring module and the second pressure monitoring module are connected with a feedback control module, the control output of the feedback control module is connected with the variable frequency compressor, and when the pressure difference between the gas input port and the gas output port of the gas flow control module changes beyond a balance state threshold value, the feedback control module outputs a control signal to adjust the rotating speed of the variable frequency compressor so that the pressure of the gas input port and the gas output port of the gas flow control module returns to the balance state.

[0008] The application further relates to the following scheme: the first pressure monitoring module and the second pressure monitoring module are pressure sensors of the same type, and the gas flow control module is a flow meter.

[0009] The application further relates to the following scheme: the feedback control module comprises a pressure difference receiving module, the input of the pressure difference receiving module receives the signal outputs of the first pressure monitoring module and the second pressure monitoring module, the output of the pressure difference receiving module is divided into two paths, one path is connected with a speed increasing control circuit of the variable frequency compressor, and the other path is connected with a speed decreasing control circuit of the variable frequency compressor, when the pressure of the gas input port of the gas flow control module is higher than the pressure of the gas output port of the gas flow control module and the pressure difference exceeds a balance state value, the speed increasing control circuit outputs a speed increasing signal to increase the rotating speed of the variable frequency compressor, and when the pressure of the gas input port of the gas flow control module is higher than the pressure of the gas output port of the gas flow control module and the pressure difference exceeds the balance state value, the speed decreasing control circuit outputs a speed decreasing signal to decrease the rotating speed of the variable frequency compressor.

[0010] The application further relates to the following scheme: the pressure difference receiving module comprises a differential amplifier, the negative input of the differential amplifier is connected with the signal output of the first pressure monitoring module, the positive input of the differential amplifier is connected with the signal output of the second pressure monitoring module, the output of the differential amplifier is connected with a voltage comparator, the negative input of the voltage comparator is connected with a first reference voltage, the positive input of the voltage comparator is connected with the output of the differential amplifier, the output of the voltage comparator is divided into two paths, and the two paths are respectively connected with the speed increasing control circuit and the speed decreasing control circuit.

[0011] The scheme is further characterized in that: the two-way output is connected to the speed-up control circuit and the speed-down control circuit through a triode amplification circuit; the emitter of the two triodes is connected to the positive input of the voltage comparator; the base of the two triodes is connected to the output of the voltage comparator; and the collector of the two triodes is connected to the speed-up control circuit and the speed-down control circuit respectively.

[0012] The scheme is further characterized in that: the triode is a MOSFET field effect triode, the base is the gate of the field effect triode, and the collector is the drain of the field effect triode.

[0013] The scheme is further characterized in that: the speed-up control circuit comprises a speed-up differential amplification circuit, the speed-down control circuit comprises a speed-down differential amplification circuit, the positive input of the speed-up differential amplification circuit is connected to one-way output of the voltage comparator, the negative input of the speed-up differential amplification circuit is connected to the second reference voltage, the positive input of the speed-down differential amplification circuit is connected to the third reference voltage, the output of the speed-up differential amplification circuit and the speed-down differential amplification circuit is connected to the variable frequency control circuit, and the variable frequency control circuit output is connected to the variable frequency compressor, wherein: the second reference voltage is an acceleration balance threshold of the balance state value, and the third reference voltage is a deceleration balance threshold of the balance state value.

[0014] The scheme is further characterized in that: the variable frequency control circuit is a variable frequency control circuit chip of model AD654.

[0015] A flow control method based on the electronic flow stabilizing control device, the method comprising: adjusting the speed of the variable frequency compressor to draw the mixed gas in the buffer tank to the mixed gas storage tank, obtaining the balance state pressure difference ΔP between the gas input port pressure P1 of the gas flow control module and the gas output port pressure P2 of the gas flow control module at this moment, and the flow control method is characterized in that:

[0016] Continuously obtaining the gas input port pressure P1 of the gas flow control module and the gas output port pressure P2 of the gas flow control module;

[0017] If the current pressure difference P1-P2<△P-a, the feedback control module sends a signal to the variable frequency compressor to increase the speed of the variable frequency compressor, so as to speed up the filling of the mixed gas in the buffer tank to the storage tank, thereby reducing the gas output port pressure P2 of the gas flow control module and increasing the actual pressure difference;

[0018] If the current pressure difference P1-P2>△P+b, the feedback control module sends a signal to the variable frequency compressor to reduce the speed of the variable frequency compressor, so as to slow down the filling of the mixed gas in the buffer tank to the storage tank, thereby increasing the gas output port pressure P2 of the gas flow control module and reducing the actual pressure difference;

[0019] If the current pressure difference P1-P2 is between △P-a and △P+b, i.e., △P+b

[0020] The scheme further comprises: the pressure difference receiving module comprises a differential amplifier, the negative input of the differential amplifier is connected to the signal output of the first pressure monitoring module, the positive input of the differential amplifier is connected to the signal output of the second pressure monitoring module, the output of the differential amplifier is connected to a voltage comparator, the negative input of the voltage comparator is connected to a first reference voltage, the positive input of the voltage comparator is the output of the differential amplifier, the output of the voltage comparator is divided into two paths, and the two paths are respectively connected to the speed-up control circuit and the speed-down control circuit; the speed-up control circuit comprises a speed-up differential amplification circuit, the speed-down control circuit comprises a speed-down differential amplification circuit, the positive input of the speed-up differential amplification circuit is connected to one path of the output of the voltage comparator, the negative input of the speed-down differential amplification circuit is connected to the other path of the output of the voltage comparator, the negative input of the speed-up differential amplification circuit is connected to a second reference voltage, the positive input of the speed-down differential amplification circuit is connected to a third reference voltage, the outputs of the speed-up differential amplification circuit and the speed-down differential amplification circuit are connected to a variable frequency control circuit, and the variable frequency control circuit is connected to the variable frequency compressor; wherein the second reference voltage is an acceleration balance threshold of the balance state value, and the third reference voltage is a deceleration balance threshold of the balance state value.

[0021] The acceleration balance threshold and the deceleration balance threshold are set as threshold values that guarantee that the mixing ratio of the mixed gas is within an error.

[0022] The application has the beneficial effect that the feedback control module is used to control the inlet / outlet pressure difference to be stable at a preset value, thereby improving the accuracy of mixed gas preparation.

[0023] The application will be described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 FIG. 1 is a structural schematic diagram of an electronic current stabilizing control device according to the application;

[0025] Figure 2 FIG. 5 is a logic circuit schematic diagram of a feedback control module according to the application. DETAILED DESCRIPTION

[0026] Embodiment 1

[0027] An electronic current stabilizing control device suitable for multi-element mixed gas charging, as shown in FIG. 1, comprises a feedback control module, a variable frequency compressor, a first pressure monitoring module, a second pressure monitoring module, a variable frequency control circuit, a speed-up control circuit and a speed-down control circuit. Figure 1 and Figure 2As shown, the electronic current stabilizing control device comprises a plurality of gas sources A, B, and C, each of which is connected to a gas flow control module 2 of each gas source through a pressure reducing valve 1, the gas output of the plurality of gas flow control modules is connected to the same buffer tank 3, the mixed gas outlet of the buffer tank 3 is connected to the variable frequency compressor 4, and the variable frequency compressor 4 is used to output the mixed gas of the buffer tank 3 from the gas outlet 5, wherein: under the condition of meeting the multi-path gas ratio, the pressure of the gas input port of each gas flow control module is adjusted to be the same, and the pressure of the gas output port of the plurality of gas flow control modules is adjusted to be the same, the gas input port of one of the gas flow control modules 2 is connected to the first pressure monitoring module 6, the gas output port of the gas flow control module is connected to the second pressure monitoring module 7, the monitoring signal output of the first pressure monitoring module 6 and the second pressure monitoring module 7 is connected to the feedback control module 8, and the control output of the feedback control module 8 is connected to the variable frequency compressor 4, when the pressure difference between the gas input port and the gas output port of the gas flow control module changes beyond the threshold value of the balanced state, the feedback control module outputs a control signal to adjust the rotating speed of the variable frequency compressor to make the pressure of the gas input port and the gas output port of the gas flow control module return to the balanced state.

[0028] Among them: the first pressure monitoring module and the first pressure monitoring module are pressure sensors of the same type, and the gas flow control module is a flow meter.

[0029] In the embodiment, as shown in the figure, Figure 2 The feedback control module comprises a differential pressure receiving module 9, the input of the differential pressure receiving module receives the signal output P1 of the first pressure monitoring module and the signal output P2 of the second pressure monitoring module, the output of the differential pressure receiving module is divided into two paths, one of which is connected to the speed increasing control circuit 10 of the variable frequency compressor 4, and the other of which is connected to the speed reducing control circuit 11 of the variable frequency compressor 4, when the pressure of the gas input port of the gas flow control module is higher than the pressure of the gas output port of the gas flow control module and is lower than the balanced state value, the speed increasing control circuit outputs a speed increasing signal to increase the speed of the variable frequency compressor; on the contrary, when the pressure of the gas input port of the gas flow control module is higher than the pressure of the gas output port of the gas flow control module and exceeds the balanced state value, the speed reducing control circuit outputs a speed reducing signal to reduce the speed of the variable frequency compressor.

[0030] In the embodiment, the differential pressure receiving module comprises a differential amplifier 901, the negative input of the differential amplifier 901 is connected to the signal output of the pressure of the first pressure monitoring module P1, the positive input of the differential amplifier 901 is connected to the signal output of the pressure of the second pressure monitoring module P2, the output of the differential amplifier 901 is connected to a voltage comparator 902, the negative input of the voltage comparator 902 is connected to the first reference voltage Vref1, the positive input of the voltage comparator is connected to the output of the differential amplifier 901, the output of the voltage comparator 902 is divided into two paths, and the two paths are respectively connected to the speed-up control circuit 10 and the speed-down control circuit 11. Among them: the two paths are respectively connected to the speed-up control circuit 10 through the transistor amplification circuit Q1 and connected to the speed-down control circuit 11 through the transistor amplification circuit Q2, the emitters of the two transistors are connected to the positive input of the voltage comparator, the bases of the two transistors are connected to the output of the voltage comparator, the collectors of the two transistors are respectively connected to the speed-up control circuit and the speed-down control circuit, and the emitters of the two transistors are connected to the positive input of the voltage comparator 902. The transistor used in the embodiment is a MOSFET field effect transistor, the base is the gate of the field effect transistor, the collector is the drain of the field effect transistor, and the emitter is the source of the field effect transistor.

[0031] In the embodiment, the speed-up control circuit 10 comprises a speed-up differential amplifier circuit, the speed-down control circuit 11 comprises a speed-down differential amplifier circuit, the positive input of the speed-up differential amplifier circuit 10 is connected to one path output of the voltage comparator through the transistor amplification circuit Q1, the negative input of the speed-down differential amplifier circuit 11 is connected to the other path output of the voltage comparator through the transistor amplification circuit Q2, the negative input of the speed-up differential amplifier circuit 10 is connected to the second reference voltage Vref2, the positive input of the speed-down differential amplifier circuit 11 is connected to the third reference voltage Vref3, and the outputs of the speed-up differential amplifier circuit 10 and the speed-down differential amplifier circuit 11 are connected to a variable frequency control circuit 12. The variable frequency control circuit 12 is a variable frequency control circuit chip with a model of AD654, and the output of the variable frequency control circuit is connected to the variable frequency compressor 4. Among them: the second reference voltage is an acceleration balance threshold of the balance state value, and the third reference voltage is a speed-down balance threshold of the balance state value.

[0032] Embodiment 2

[0033] An electronic current stabilizing control method suitable for multi-element mixed gas inflation is based on the current stabilizing control method of the electronic current stabilizing control device in embodiment 1, so the content of embodiment 1 is applicable to this embodiment. First: adjust the variable frequency compressor speed to extract the mixed gas in the buffer tank to the mixed gas storage tank, obtain the balance state pressure difference ΔP between the gas input port pressure P1 of the gas flow control module and the gas output port pressure P2 of the gas flow control module at this moment, and the current stabilizing control method is:

[0034] Continuously acquire the gas pressure P1 of the gas input port of the gas flow control module and the gas pressure P2 of the gas output port of the gas flow control module;

[0035] If the current pressure difference P1-P2 is less than △P-a, the feedback control module sends a signal to the variable frequency compressor to increase the rotation speed of the variable frequency compressor, so as to accelerate the filling of the mixed gas in the buffer tank into the gas storage tank, thereby reducing the gas pressure P2 of the gas output port of the gas flow control module and increasing the actual pressure difference;

[0036] If the current pressure difference P1-P2 is greater than △P+b, the feedback control module sends a signal to the variable frequency compressor to reduce the rotation speed of the variable frequency compressor, so as to slow down the filling of the mixed gas in the buffer tank into the gas storage tank, thereby increasing the gas pressure P2 of the gas output port of the gas flow control module and reducing the actual pressure difference;

[0037] If the current pressure difference P1-P2 is between △P-a and △P+b, i.e. △P+b

[0038] The pressure difference receiving module in Embodiment 1 comprises a differential amplifier, the negative input of the differential amplifier is connected to the signal output of the first pressure monitoring module, the positive input of the differential amplifier is connected to the signal output of the second pressure monitoring module, the output of the differential amplifier is connected to a voltage comparator, the negative input of the voltage comparator is connected to a first reference voltage, the positive input of the voltage comparator is connected to the output of the differential amplifier, the output of the voltage comparator is divided into two paths, and the two paths are respectively connected to an acceleration control circuit and a deceleration control circuit; the acceleration control circuit comprises an acceleration differential amplification circuit, the deceleration control circuit comprises a deceleration differential amplification circuit, the positive input of the acceleration differential amplification circuit is connected to one path of the output of the voltage comparator, the negative input of the deceleration differential amplification circuit is connected to the other path of the output of the voltage comparator, the negative input of the acceleration differential amplification circuit is connected to a second reference voltage, the positive input of the deceleration differential amplification circuit is connected to a third reference voltage, the outputs of the acceleration differential amplification circuit and the deceleration differential amplification circuit are connected to a variable frequency control circuit, and the output of the variable frequency control circuit is connected to the variable frequency compressor; wherein the second reference voltage is an acceleration balance threshold of the balance state value, and the third reference voltage is a deceleration balance threshold of the balance state value;

[0039] The acceleration balance threshold and the deceleration balance threshold are set to be threshold values within an error range in which the mixed ratio of the mixed gas is ensured.

[0040] The gas flow meter in the above embodiment can be selected according to the front end pressure range, which is generally not more than 1 MPa. In this pressure range, the flow meter can accurately output gas according to the set flow rate. The back end is generally fixed at 1 standard atmosphere, and is usually taken as 0.1 MPa. In the present embodiment, the pressure of the gas A, B and C inlet branches is reduced to the same pressure value P1 by using a pressure reducing valve, so as to control the pressure of different inlet branches at the same pressure. The pressure after the pressure reducing valve is generally stable and does not fluctuate. The three-way gas A and B, C pass through the corresponding gas flow meter and then enter the buffer tank, and the back end pressure of the flow meter is equal to the pressure P2 in the buffer tank. Therefore, the inlet / outlet end pressure of the gas flow meter of the gas A can represent the inlet / outlet end pressure of the gas flow meter of each gas branch. More multi-gas, by reducing the pressure of the front end pressure reducing valve to the same pressure value, only the pressure difference before and after the flow meter needs to be measured to represent the pressure difference before and after all the flow meters.

[0041] The gas A and B, C are reduced to the same pressure value by the pressure reducing valve, and there is almost no pressure fluctuation;

[0042] According to the pressure ratio result, the control program built-in is used to control the frequency conversion compressor speed. When the frequency conversion compressor speed is large, the pressurization effect is more obvious, which can reduce the gas pressure P2 in the buffer tank; on the contrary, it can increase the gas pressure P2 in the buffer tank. Therefore, the preset pressure difference ΔP can be indirectly controlled by adjusting the frequency conversion compressor speed to stabilize the inlet / outlet end pressure, so as to ensure that the gas instantaneous flow rate is also stabilized at the preset value.

[0043] Frequency conversion compressor speed control method:

[0044] The formula for calculating the speed n (r / min) of the frequency conversion compressor is:

[0045] n=60f(1-s) / p

[0046] Wherein, f is the voltage frequency, unit Hz; s is the slip ratio, the present embodiment is direct current frequency conversion, s=0; p is the number of motor pole pairs.

[0047] From the above formula, it can be seen that the motor speed can be controlled by adjusting the voltage frequency f, so as to speed up or reduce the compressor exhaust speed, and change the pressure in the front end buffer tank.

[0048] For example Figure 2As shown, V1 and V2 are two pressure sensor voltage (voltage proportional to pressure) of P1 and P2; resistance R1=R2 and R3=R4, differential amplifier 1 amplification factor: R2 / R3, differential voltage V3= (V1-V2) R2 / R3 after amplification; the voltage is compared with the reference voltage Vref1 (the voltage value corresponding to the preset pressure difference), if greater than Vref1, then the voltage comparator output voltage V4 is high voltage, the voltage value is greater than the maximum value of the front end subtracter output voltage (to ensure that the back-end MOSFET tube can be safely opened); if less than Vref1, then V4 is low voltage;

[0049] When output high voltage, two MOSFET collector and gate voltage difference V4-V3 is negative, at this time P-type MOSFET Q1 opens, voltage V3 is transmitted to the positive of differential amplifier 2; similarly, R5=R6 and R7=R8, differential amplifier 2 amplification factor: R6 / R7, output voltage Vin=Vref2-V3×R6 / R7; on the contrary, when output low voltage, two MOSFET collector and gate voltage difference V4-V3 is positive, at this time N-type MOSFET Q2 opens, voltage V3 is transmitted to the negative of differential amplifier 3; similarly, R9=R10 and R11=R12, differential amplifier 3 amplification factor: R10 / R11, output voltage Vin=V3×R10 / R11-Vref3.

[0050] The function of frequency control circuit AD654 is to convert voltage into frequency signal, so as to control the engine speed through the frequency modulation interface of variable frequency compressor. According to the working principle of AD654, the greater the Vin, the higher the output frequency, and the calculation formula is: f=Vin / C×R13.

[0051] Speed control principle:

[0052] According to the technical parameters of AD654 chip, the V / F conversion formula is: f=Vin / (R13×C)

[0053] When V1-V2 is large, it means that the pressure at the back end of the flowmeter is too small, and the compressor speed needs to be reduced. The greater the deviation from the standard pressure difference, the lower the compressor speed required. In this case, MOSFET Q1 is turned on, and the speed is:

[0054]

[0055] When V1-V2 is small, it means that the pressure at the back end of the flowmeter is too large, and the compressor speed needs to be increased. The greater the deviation from the standard pressure difference, the higher the compressor speed required. In this case, MOSFET Q2 is turned on, and the speed is:

[0056]

[0057] According to the actual situation, different resistance and capacitance can be selected to achieve the desired engine speed.

Claims

1. An electronic flow control device suitable for filling multi-component mixed gases, comprising multiple gas sources, each gas source being connected to a gas flow control module via a pressure reducing valve, the gas outputs of the multiple gas flow control modules being connected to a common buffer tank, the mixed gas outlet of the buffer tank being connected to a variable frequency compressor, the variable frequency compressor being used for the mixed gas output from the buffer tank, characterized in that, Under the condition of satisfying the multi-gas ratio, the pressure reducing valve of each gas source is adjusted to make the gas inlet pressure and the gas outlet pressure of the multi-gas flow control module the same. The gas inlet of one gas flow control module is connected to the first pressure monitoring module, and the gas outlet of this gas flow control module is connected to the second pressure monitoring module. The monitoring signal outputs of the first and second pressure monitoring modules are connected to the feedback control module, and the control output of the feedback control module is connected to the variable frequency compressor. When the pressure difference between the gas inlet and the gas outlet of the gas flow control module exceeds the equilibrium threshold, the feedback control module outputs a control signal to adjust the speed of the variable frequency compressor so that the pressure at the gas inlet and the gas outlet of the gas flow control module returns to the equilibrium state. The first and second pressure monitoring modules are pressure sensors of the same model, and the gas flow control module is a flow meter. The feedback control module includes a differential pressure receiving module. The differential pressure receiving module receives signal outputs from the first pressure monitoring module and the second pressure monitoring module. The output of the differential pressure receiving module is divided into two paths: one path connects to the speed-up control circuit of the variable frequency compressor, and the other path connects to the speed-down control circuit of the variable frequency compressor. When the pressure at the gas inlet of the gas flow control module is higher than the pressure at the gas outlet of the gas flow control module but lower than the equilibrium value, the speed-up control circuit outputs a speed-up signal to increase the speed of the variable frequency compressor. Conversely, when the pressure at the gas inlet of the gas flow control module is higher than the pressure at the gas outlet of the gas flow control module but exceeds the equilibrium value, the speed-down control circuit outputs a speed-down signal to decrease the speed of the variable frequency compressor. The differential pressure receiving module includes a differential amplifier. The negative input of the differential amplifier is connected to the signal output of the first pressure monitoring module, and the positive input is connected to the signal output of the second pressure monitoring module. The output of the differential amplifier is connected to a voltage comparator. The negative input of the voltage comparator is connected to a first reference voltage, and the positive input is connected to the output of the differential amplifier. The output of the voltage comparator is divided into two paths, which are respectively connected to the acceleration control circuit and the deceleration control circuit. The acceleration control circuit includes an acceleration differential amplifier circuit, and the deceleration control circuit includes a deceleration differential amplifier circuit. The positive input of the acceleration differential amplifier circuit is connected to one output of a voltage comparator, and the negative input of the deceleration differential amplifier circuit is connected to the other output of the voltage comparator. The negative input of the acceleration differential amplifier circuit is connected to a second reference voltage, and the positive input of the deceleration differential amplifier circuit is connected to a third reference voltage. The outputs of the acceleration and deceleration differential amplifier circuits are connected to a frequency converter control circuit, and the output of the frequency converter control circuit is connected to a frequency converter compressor. The second reference voltage is the acceleration balance threshold of the equilibrium state value, and the third reference voltage is the deceleration balance threshold of the equilibrium state value.

2. The electronic current control device according to claim 1, characterized in that, The two outputs are connected to the speed-up control circuit and the speed-down control circuit respectively through a transistor amplifier circuit. The emitters of the two transistors are connected to the positive input of the voltage comparator, the bases of the two transistors are connected to the output of the voltage comparator, and the collectors of the two transistors are connected to the speed-up control circuit and the speed-down control circuit respectively.

3. The electronic current control device according to claim 2, characterized in that, The transistor is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), with the base being the gate of the MOSFET and the collector being the drain of the MOSFET.

4. The electronic current stabilization control device according to claim 1, characterized in that, The frequency conversion control circuit is an AD654 frequency conversion control circuit chip.

5. A flow control method based on the electronic flow control device of claim 1, comprising adjusting the speed of a variable frequency compressor to extract mixed gas from a buffer tank to a mixed gas storage tank, and obtaining the equilibrium pressure difference ΔP between the gas input pressure P1 and the gas output pressure P2 of the gas flow control module at this moment, characterized in that, The current stabilization control method is as follows: Continue to obtain the gas input pressure P1 and the gas output pressure P2 of the gas flow control module; If the current pressure difference P1-P2<△P-a, the feedback control module sends a signal to the variable frequency compressor to increase the speed of the variable frequency compressor, accelerate the filling of the mixed gas in the buffer tank into the gas storage tank, thereby reducing the gas output pressure P2 of the gas flow control module and increasing the actual pressure difference. If the current pressure difference P1-P2>△P+b, the feedback control module sends a signal to the variable frequency compressor to reduce the speed of the variable frequency compressor. The mixed gas in the buffer tank is filled into the gas storage tank, thereby increasing the gas output pressure P2 of the gas flow control module and reducing the actual pressure difference. If the current pressure difference P1-P2 is between ΔP-a and ΔP+b, i.e., ΔP+b < P1-P2 < ΔP-a, then the current speed of the variable frequency compressor will remain unchanged; where a is the acceleration balance threshold and b is the deceleration balance threshold.

6. The current stabilization control method according to claim 5, characterized in that, The differential pressure receiving module includes a differential amplifier. The negative input of the differential amplifier is connected to the signal output of the first pressure monitoring module, and the positive input is connected to the signal output of the second pressure monitoring module. The output of the differential amplifier is connected to a voltage comparator. The negative input of the voltage comparator is connected to a first reference voltage, and the positive input of the voltage comparator is connected to the output of the differential amplifier. The output of the voltage comparator is divided into two paths, which are respectively connected to an acceleration control circuit and a deceleration control circuit. The acceleration control circuit includes an acceleration differential amplifier circuit, and the deceleration control circuit includes a deceleration differential amplifier circuit. The positive input of the acceleration differential amplifier circuit is connected to one output of the voltage comparator, and the negative input of the deceleration differential amplifier circuit is connected to the other output of the voltage comparator. The negative input of the acceleration differential amplifier circuit is connected to a second reference voltage, and the positive input of the deceleration differential amplifier circuit is connected to a third reference voltage. The outputs of the acceleration and deceleration differential amplifier circuits are connected to a frequency converter control circuit, and the output of the frequency converter control circuit is connected to a frequency converter compressor. The second reference voltage is the acceleration equilibrium threshold of the equilibrium state value, and the third reference voltage is the deceleration equilibrium threshold of the equilibrium state value. Wherein: the acceleration balance threshold and the deceleration balance threshold are set as thresholds to ensure that the mixing ratio of the mixed gas is within the error range.

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