CN110940389B - Thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control - Google Patents

Thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control Download PDF

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CN110940389B
CN110940389B CN201911147951.0A CN201911147951A CN110940389B CN 110940389 B CN110940389 B CN 110940389B CN 201911147951 A CN201911147951 A CN 201911147951A CN 110940389 B CN110940389 B CN 110940389B
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resistor
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temperature
speed sensor
temperature sensor
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CN110940389A (en
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叶建平
王钰炜
黄晓霞
吴明光
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Zhejiang University ZJU
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
    • G01F1/86—Indirect mass flowmeters, e.g. measuring volume flow and density, temperature or pressure
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume

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Abstract

The invention discloses a thermal gas mass flowmeter controlled by Fuzzy-PI dual-mode undisturbed switching, which comprises a flowmeter measuring rod, a temperature sensor constant current source module, a temperature sensor signal conditioning module, a speed sensor PWM driving module, a speed sensor signal conditioning module, a signal processing and main control module and an annular flow equalizing plate. Power supply and R at measurementEXTTaking values to make the deviation min of the gas temperature measurement value; the compensation/speed resistor is positioned at the bottom/middle part of the measuring rod, so that the influence of the high temperature of the measuring rod on the measuring rod is reduced; the annular flow equalizing plate is arranged, so that the uniformity of air flow distribution is improved, and the flow measurement precision is improved. The Fuzzy-PI dual-mode control gives consideration to the gas temperature fast/slow changing working condition; by limiting the change amount delta U of the control amount U, undisturbed switching of dual-mode control is realized. The compensation/speed resistor is a platinum resistor with the same specification, and the precision resistor is a resistor with the same specification, so that the production is facilitated; and voltage and current data of the compensation resistor are mined, and self-checking and fault diagnosis of the flowmeter are realized.

Description

Thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control
Technical Field
The invention belongs to the technical field of thermal gas mass flowmeters. In particular to a thermal gas mass flowmeter which is based on constant temperature difference Fuzzy-PI undisturbed control and adopts an annular flow equalizing plate, and a speed/temperature sensor is positioned at an upper measuring hole and a lower measuring hole.
Background
With the progress of scientific technology and the improvement of the automation degree of the process industry, the requirement of flow measurement is higher and higher. The flow measurement history is long, and the observation of the Nile river water by the ancient Egypt people can be traced; flow measurement in the modern sense begins in 1738 with the first bernoulli equation being a differential pressure flow measurement of the keystone. The flow meter can be divided into: differential pressure type flowmeter, positive displacement flowmeter, speed type flowmeter and quality type flowmeter; a thermal gas mass flowmeter belongs to a mass flowmeter.
Thermal gas mass flow meters originate from Hot-Wire anemometers (Hot-Wire anemometers) at the beginning of the 20 th century. Thermal Gas Mass flow meters (TGF for short) are designed and completed firstly by Thomas (America) leaders; the problems of candle corrosion, abrasion, explosion prevention and the like exist because the flowmeter sensor is directly contacted with gas, and the industrial application is limited; contact gas mass flowmeters have been gradually replaced by non-contact hot film gas mass flowmeters. Thermal gas mass flowmeters are based on the principle of heat transfer, i.e. on the mechanism of heat exchange between the fluid in the pipe and the flow sensor to measure the flow. The flow meter utilizing the heat transfer and transfer effect is called a thermal distribution type gas mass flow meter; the flow meter utilizing the heat dissipation effect is a submerged gas mass flow meter. According to different implementation circuits, the immersion type gas mass flow meter is further subdivided into: constant power (current) and constant temperature differential thermal gas mass flow meter; the constant temperature differential thermal gas mass flowmeter for the main flow is positioned, and is hereinafter referred to as a thermal gas mass flowmeter for short. Thermal gas mass flow meter relates to four heat exchange methods: forced convection, natural convection, heat conduction and radiation heat transfer, and the forced convection heat transfer is the main. Known manufacturers of thermal gas mass flowmeters have: brooks, FCI (thermal flow switch was first introduced in 1964), Hitachi, germany BOSCH, etc.; and Shanghai Huaqiang instruments, Kunming Ehribot, etc.
The thermal gas mass flowmeter has the advantages of low cost, simple principle and structure, no movable part, small pressure loss and large measurement range; due to the insufficient research of the error mechanism of the domestic thermal gas mass flowmeter, a short plate with poor measurement precision exists. The shortening board is a system engineering, which comprises structural optimization of a sensor, improvement of a compensation method and research of a signal processing algorithm, and the countermeasure for eliminating or reducing errors is explored from the source of flow meter errors by cut-in.
The theoretical model of a thermal gas mass flowmeter is shown as follows:
Figure BDA0002282742340000021
in the formula, qmIs the mass flow rate; i isHHeating current for speed sensor, RHIs the resistance of the speed sensor, THIs the temperature of the speed sensor; t isL0Is the temperature of the gas to be measured, TLMeasured gas temperature measured by the flowmeter temperature sensor (not shown in the formula)) Engineering of TLApproximate TL0(ii) a A. B is an empirical constant.
At present, bridge temperature compensation is a main temperature compensation method of a constant temperature differential thermal type gas mass flowmeter, and the temperature compensation is compensation for temperature change of the environment of a pipeline where measured gas is located. Bridge temperature compensation method by means of compensation resistor RLRealizing the balance of the Wheatstone bridge; so that the output of the bridge measuring circuit is only related to the flow speed of the measured gas and not to the temperature of the measured gas. In other words, there is an assumption for the establishment of a thermal gas mass flow meter model, assuming a compensation resistance RLTemperature T ofLTemperature T of measured gasL0(ii) a Assuming perfect, the temperature T of the gas measured by the temperature sensorLTemperature T of measured gasL0Temperature T measured by a temperature sensorLIn effect, the compensation resistor RLThe temperature of (a); t isL＞TL0Resulting in a decrease in the accuracy of the thermal gas mass flowmeter. T isL≠TL0The reasons for (2) are two: 1. compensation resistor R of temperature sensorLSpeed resistance R next to speed sensorHHeating element RHAs a high temperature source, RHHigh temperature influence compensation resistor RLTo a temperature TLComparing the temperature T of the gas to be measuredL0Slightly higher. 2. Speed bridge ratio Ra/R of Wheatstone bridgeHTemperature bridge arm ratio Rb/RLIn general, Rb > Ra, R are takenL＞RH(ii) a When the bridge is balanced, the current flows through speed bridge arms Ra and RHCurrent Ia ofHBridge arm Rb and R for temperature higher thanLCurrent IbL(ii) a Although the current IbL＜IaHBut IbLFlows through RLGenerating heat
Figure BDA0002282742340000022
Will push up RLTemperature T ofLFurther raising the temperature T of the measured gasL0。
Setting a compensation resistor RLThe Wheatstone bridge is essentially an analog circuit temperature compensation technology, so the method has the advantages of simplicity and convenience. On the other hand, in the case of a liquid,the temperature compensation technology of the analog circuit has inherent defects which cannot be overcome: firstly, an analog circuit is limited by nonlinearity of a compensation resistor and component precision; accurate ideal compensation cannot be realized, so the temperature compensation precision is limited. Secondly, once the analog circuit is built, all components are fixed, the compensation model is also fixed, and the circuit of each thermal gas mass flowmeter needs to be independently debugged; therefore, the compensation operation is complex and time-consuming, and the flexibility and the consistency of the measured data are lacked. As mentioned above, ideal bridge temperature compensation requires a temperature compensating resistor RLTemperature T ofLTemperature T of measured gasL0(ii) a If and only if RLNot heated, RLTemperature TLMeasured gas temperature TL0I.e. TL＝TL0This is true. The existing bridge compensation circuit is shown in TL≈TL0Taking into consideration that Rb > Ra, RL＞RHCircuit design is limited; the larger the resistance is, the more noise is increased, and the difference between the values of Rb and Ra is inconvenient for production and application. If the value of the compensation resistor of the bridge design does not influence the temperature compensation, the circuit design has advantages; for example, the same type of resistors are selected for Rb and Ra, which is significant for improving the production efficiency and the consistency of measurement data and reducing spare parts.
The non-uniform distribution characteristic of the measured gas flow velocity also affects the accuracy of the thermal gas mass flowmeter. The measured gas flows along the pipeline, and the flow velocity distribution of the measured gas at each point on the axial section of the pipeline obeys: in a laminar flow state, the flow velocity distribution is a symmetrical paraboloid around the center of the circular pipe; under the turbulent flow state, the flow velocity distribution presents a symmetrical exponential curved surface with the center of the circular pipe. To date, there has been no satisfactory answer on how to determine the installation positions of the speed sensor and the temperature sensor, or the insertion depths of the speed sensor and the temperature sensor, so that the flow rate at the position of the speed sensor can correctly represent the mass flow of the gas to be measured. Three basic methods are used for reference of a speed area method: the equal torus method, the chebyshev integral method and the log-linear method determine the installation positions of the speed sensor and the temperature sensor, and the effect of improving the precision of the thermal gas mass flowmeter is limited. The source of the analysis error is the basis, and the purpose is to complement the short board with poor measurement precision.
Target 1, TL→TL0，THL＝TH－TL0Constant; the measurement accuracy of the thermal gas mass flowmeter is improved. Optimizing sensor structure, speed and temperature sensors located at upper/lower measuring holes of measuring rod, speed resistor RHHigh temperature source upper and compensation resistor RLUnder the above-mentioned condition; reducing the rate resistance RHHigh temperature compensation resistor RLInfluence of (1), TL→TL0. Digging and abandoning an electric bridge temperature compensation circuit, and designing an independent temperature measurement module of the gas to be measured; make the flow pass through RLIb ofL↓, heat generation
Figure BDA0002282742340000031
TL→TL0(ii) a Meanwhile, the value restriction of Rb and Ra is eliminated, and the consistency of the circuit is improved. Temperature compensation of a constant temperature difference Fuzzy-PI undisturbed switching dual-mode control replacing bridge analog circuit is researched, and T is achievedHL＝TH－TL0Constant. And the target 2 is used for eliminating the negative influence of the non-uniform distribution characteristic of the flow velocity of the measured gas on the measurement precision. An annular flow equalizing plate is arranged on a pipeline of the gas to be measured, and a measuring rod of the flowmeter is positioned behind the annular flow equalizing plate; compensation resistor R of temperature sensorLMeasuring hole at the bottom of measuring rod, speed resistance R of speed sensorHThe distance between the two measuring holes is L ≈ 1/3D (D is the diameter of the pipeline); the flow velocity at the location of the velocity sensor can correctly characterize the mass flow of the gas being measured. A summary of representative intellectual property achievements of thermal gas mass flowmeters is as follows:
the invention discloses a constant-current method thermal gas mass flowmeter and a measuring method thereof (ZL2014103018810), and provides the constant-current method thermal gas mass flowmeter, wherein a sensor consists of a speed/temperature probe platinum thermal resistor Rw/Rc and two reference resistors Ra and Rb and outputs four voltage signals.
The invention patent of a multi-sensor thermal type gas flow measurement circuit based on MSP430 (ZL2012104196642) proposes a combined thermal membrane probe as a gas flow sensor and adopts a multi-sensor fusion algorithm; the measuring circuit consists of four parts: the bridge sensor, the voltage conversion circuit and the singlechip are formed by connecting a feedback circuit, four paths of sensing elements.
The exploration of the related intellectual property has reference value, but the achievement still has limitation; further innovative designs are necessary.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control.
The thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control comprises a flowmeter measuring rod, a temperature sensor constant current source module, a temperature sensor signal conditioning module, a speed sensor PWM driving module, a speed sensor signal conditioning module, a signal processing and main control module and an annular flow equalizing plate, wherein the temperature sensor constant current source module, the temperature sensor signal conditioning module, the speed sensor PWM driving module, the speed sensor signal conditioning module, the signal processing and main control module; under the action of the temperature sensor constant current source module, the compensation resistor R of the temperature sensor moduleLPrecision resistor Rb output voltage VLAnd VbLVoltage V ofLAnd VbLThe signals are output to a signal processing and main control module through a temperature sensor signal conditioning module; under the drive of the speed sensor PWM drive module, the speed resistance R of the speed sensor moduleHPrecision resistor Ra output voltage VHAnd VaHVoltage V ofHAnd VaHThe signals are output to a signal processing and main control module through a speed sensor signal conditioning module; the signal processing and main control module is used for processing the voltage VL，VH、VaHCalculating the compensation resistance RLResistance value, speed resistance RHResistance value, temperature T of temperature sensorLTemperature T of speed sensorHAnd according to THL＝TH－TL0≈TH－TLBased on a Fuzzy-PI dual-mode undisturbed switching control algorithm, the constant temperature difference requirement is met, a PWM control signal is generated, the output of a PWM driving module of the speed sensor is regulated, and T isL0Is the temperature of the gas to be measured;
pipe for gas to be measuredThe pipeline is provided with an annular flow equalizing plate, the gas to be measured is rectified by the annular flow equalizing plate, so that the speed distribution of the gas flow at each point on the axial section of the pipeline is uniform, and a measuring rod of the flowmeter is positioned behind the annular flow equalizing plate; two rectangular measuring through holes are arranged on the measuring rod of the flowmeter, the distance between the two through holes is approximately equal to 1/3D, and D is the diameter of the pipeline; compensation resistor RLMeasuring hole at the bottom of measuring rod, speed resistor RHThe measuring hole is positioned in the middle of the measuring rod, and the measured gas flows through the measuring hole; the two rectangular measuring through holes are isolated by heat-insulating polytetrafluoroethylene to block the compensating resistor RLAnd a velocity resistance RHHeat conduction of (2).
The circuit of the temperature sensor module comprises a precision resistor Rb and a compensation resistor R which are connected in seriesL(ii) a The other end of the precision resistor Rb and the terminals Point _ IS, Point _ VbL1 connected to output voltage VbLThe output of the temperature sensor constant current source module IS connected with a terminal Point _ IS; compensation resistor RLThe other end of the resistor is grounded, and a precision resistor Rb and a compensation resistor R are connectedLAnd the series Point of (1) and the terminal Point _ VL1 connected to each other, output voltage VL(ii) a The circuit of the speed sensor module comprises a precision resistor Ra and a speed resistor R which are connected in seriesH(ii) a The other end of the precision resistor Ra is connected with the terminals Point _ PWM2 and Point _ VaH1 connected to output voltage VaHThe output of the speed sensor PWM driving module is connected to the terminal Point _ PWM 2; velocity resistor RHThe other end of the resistor is grounded, and a precision resistor Ra and a speed resistor R are connectedHAnd the series Point of (1) and the terminal Point _ VH1 connected to each other, output voltage VH(ii) a Compensation resistor RLAnd a velocity resistance RHThe resistor is a Pt20 platinum resistor with the same resistance value, and the precise resistors Rb and Ra are resistors with the same type and the same resistance value; constant temperature difference THL＝TH－TL0The temperature was set at 100 ℃.
The temperature sensor constant current source module takes an MC1403 reference voltage chip, a CD4051 one-out-of-eight analog switch chip and an XTR110 voltage and current conversion chip as cores; pin 1 of MC1403 is connected with VCC, pin 3 is grounded, and pin 2 is connected with pin 13 of CD 4051; pins 14, 10 and 9 of CD4051 are grounded, pin 11 is connected to terminal Point _ Switch, and pin 3 is connected to pin 5 of XTR 110; XTR110 pins 2, 3, 4, 9 are grounded, pins 12 and 15 are connected, pins 16 and 36V and resistor REXTIs connected to pin 13, resistor REXTThe other end of the pin 14 IS connected with the gate of the field effect transistor G, and the drain of the field effect transistor G IS connected with the terminal Point _ IS; when the temperature sensor module stops detecting, the signal processing and main control module outputs a high level signal to the terminal Point _ Switch, the analog Switch CD4051 gates the grounded X1 input end, the drain of the field effect transistor G has no current output to the terminal Point _ IS, namely no current output to the compensation resistor R of the temperature sensor moduleLDoes not generate heat
Figure BDA0002282742340000051
When the temperature sensor module measures the state, the signal processing and main control module outputs a low level signal to the terminal Point _ Switch, the analog Switch CD4051 gates an X0 channel, 2.5V provided by the MC1403 reference voltage chip IS output to the grid of the field effect transistor G through X0 and X, and the drain current of the field effect transistor G IS output to the terminal Point _ IS, namely to the compensation resistor R of the temperature sensor moduleL(ii) a The drain current of the field effect transistor G is a constant current source with a constant current value IbL＝0.5/REXT，REXTValue of IbL《IaH，IaHIs the current flowing through Ra;
the speed sensor PWM driving module takes a triode Q410 and a triode Q420 as cores; the emitter of Q410 is grounded and the base is connected with a resistor R410Connected to terminal Point _ PWM1, the collector via a resistor R420Is connected with the base of Q420; the emitter of Q420 is connected to 7.5V, and the collector is connected to terminal Point _ PWM 2; the signal processing and main control module outputs a PWM control signal to a terminal Point _ PWM1, triodes Q410 and Q420 are both conducted at a high level, the triodes Q410 and Q420 are both cut off at a low level, the PWM drive signal is transmitted to the speed sensor module through the terminal Point _ PWM2 to control a speed resistor RHTemperature T ofH。
The temperature sensor signal conditioning module comprises a 1 st temperature sensor signal conditioning module and a 2 nd temperature sensor signal conditioning module which are arranged in parallel; the 1 st temperature sensor signal conditioning module is a filter capacitor C311，C311One end of (A) is grounded, C311Another end of (1) and terminal Point _ VL1、Point_V L2 are connected; the 2 nd temperature sensor signal conditioning module comprises a voltage dividing resistor R connected in series321、R322Filter capacitor C321；R321、R322In series, R322And the other end of (1) and the terminal Point _ VbL1 is connected to C321One end of (A), R321And R322And the series Point of (1) and the terminal Point _ Vb L2 is connected to C321And R321The other end of the first and second electrodes is grounded;
the speed sensor signal conditioning module comprises a 1 st speed sensor signal conditioning module and a 2 nd speed sensor signal conditioning module which are parallel; the 1 st speed sensor signal conditioning module comprises a divider resistor R connected in series611、R612And a two-stage RC filter circuit: resistance R613Capacitor C611Resistance R614Capacitor C612；R611、R612In series, R612Another end of (1) and terminal Point _ VH1 is linked to R611And R612Is connected in series through a resistor R613And a resistor R614One terminal of (1), a capacitor C611Is connected to one end of a resistor R614Another terminal of (1) and a capacitor C612One end of (1), terminal Point _ V H2 are connected, a resistor R611Another terminal of (1), a capacitor C611And C612The other end of the first and second electrodes is grounded; the 2 nd speed sensor signal conditioning module is similar to the 1 st speed sensor signal conditioning module and is equal to the input terminal Point _ VaH1. Output terminal Point _ VaH2 are connected.
The signal processing and main control module takes an STM32F103CB microcontroller chip as a core; a pin 23 of the STM32F103CB is connected to a terminal Point _ PWM1, and outputs a PWM control signal to the speed sensor PWM driving module to control on/off of the transistor Q410; a pin 24 of the STM32F103CB is connected with a terminal Point _ Switch, outputs a low/high level control signal to the temperature sensor constant current source module, and controls an analog Switch CD4051 to gate an X0/X1 channel; pins 15 and 16 of STM32F103CB and terminal Point _ V, respectivelyL2、Point_Vb L2 connected to each other and respectively collecting compensation resistors R of temperature sensor moduleLV after precision resistor Rb is conditioned by temperature sensor signal conditioning moduleL、VbL(ii) a Pins 17 and 18 of STM32F103CB and terminal Point _ V, respectivelyH2、Point_Va H2 connected to each other for respectively acquiring speed resistance R of speed sensor moduleHV after precision resistor Ra is conditioned by speed sensor signal conditioning moduleH、VaH(ii) a The signal processing and main control module is used for processing the voltage VLVoltage V ofH、VaHCalculating the compensation resistance RLResistance value, speed resistance RHResistance value, temperature T of temperature sensorLTemperature T of speed sensorHAnd according to THL＝TH－TL0Implementing Fuzzy-PI dual-mode undisturbed switching control according to the requirement of constant temperature difference; calculating the mass flow q according to the formula (1)m。
The constant temperature difference Fuzzy-PI dual-mode undisturbed switching control algorithm comprises the following steps:
Figure BDA0002282742340000061
Figure BDA0002282742340000062
THL0given value of constant temperature difference, Δ THL＝THL－THL0For deviation of controlled variable, Δ THLThe _ threshold is the deviation threshold of the controlled variable; t isHIs the temperature of the speed sensor; t isL0Is the temperature of the gas to be measured, TLFor the temperature of the measured gas measured by a flowmeter temperature sensor, T is used in engineeringLApproximate TL0(ii) a The thermal gas mass flowmeter is self-checked when being started, and the fault diagnosis of the constant current source of the temperature sensor is carried out at regular time during measurement;
the Fuzzy-PI dual-mode undisturbed switching control system comprises 4 units: the device comprises a Fuzzy control unit, a PI control unit, a Fuzzy-PI distinguishing unit and an undisturbed switching unit; the Fuzzy-PI discrimination unit is based on Delta THLMagnitude of absolute value: if ABS (Δ T)HL)≥ΔTHLThreshold, the Fuzzy control unit is selected if ABS (Δ T)HL)＜ΔTHLSelecting a PI control unit; fuzzy control unit or PI control unitThe undisturbed switching unit tracks the output value of a Fuzzy-PI dual-mode control algorithm, and undisturbed switching is realized by limiting the change delta U of the output quantity U.
Compared with the background technology, the invention has the following beneficial effects:
power supply and R for gas temperature measurementEXTTaking a value, and deviating the gas temperature measured by the flowmeter from the gas temperature min; the compensation/speed resistor is positioned at the bottom/middle part of the measuring rod, so that the influence of the high temperature of the measuring rod on the measuring rod is reduced; the annular flow equalizing plate is arranged to improve the uniformity of air flow distribution; the three contribute to the improvement of the flow measurement accuracy. The Fuzzy-PI dual-mode control considers the requirement of the fast/slow change of the gas temperature on the constant temperature difference, and the dual-mode switching jitter realizes undisturbed switching by a method of limiting the change delta U of the control quantity. The compensation/speed resistor is a platinum resistor with the same resistance value, and the precision resistor is a resistor with the same type and the same resistance value; the production is simplified; and voltage and current data of the compensation resistor are mined, and self-checking and fault diagnosis functions of the flowmeter are provided.
Drawings
FIG. 1(a) is a functional block diagram of a thermal gas mass flow meter;
fig. 1(b) is an installation diagram of a thermal gas mass flow meter;
FIG. 2 is a circuit diagram of a temperature and speed sensor module;
fig. 3(a) is a circuit diagram of a temperature sensor constant current source module;
FIG. 3(b) is a circuit diagram of a speed sensor PWM drive module;
FIG. 4 is a circuit diagram of a temperature and speed sensor signal conditioning module;
FIG. 5 is a circuit diagram of a signal processing and master control module;
FIG. 6 is a schematic diagram of a differential thermostat Fuzzy-PI dual-mode undisturbed switching control algorithm.
Detailed Description
As shown in fig. 1(a) and 1(b), the thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control comprises a flowmeter measuring rod, a temperature sensor constant current source module 100 mounted on the flowmeter measuring rod, a temperature sensor module 200, and a temperature sensor signalThe speed sensor comprises a conditioning module 300, a speed sensor PWM driving module 400, a speed sensor module 500, a speed sensor signal conditioning module 600, a signal processing and main control module 700 and an annular flow equalizing plate 800; under the action of the temperature sensor constant current source module 100, the compensation resistor R of the temperature sensor module 200LPrecision resistor Rb output voltage VLAnd VbLVoltage V ofLAnd VbLThe signal is output to the signal processing and main control module 700 through the temperature sensor signal conditioning module 300; speed resistance R of speed sensor module 500 driven by speed sensor PWM driving module 400HPrecision resistor Ra output voltage VHAnd VaHVoltage V ofHAnd VaHThe signals are output to the signal processing and main control module 700 through the speed sensor signal conditioning module 600; the signal processing and main control module 700 is based on the voltage VL，VH、VaHCalculating the compensation resistance RLResistance value, speed resistance RHResistance value, temperature T of temperature sensorLTemperature T of speed sensorHAnd according to THL＝TH－TL0≈TH－TLBased on a Fuzzy-PI dual-mode undisturbed switching control algorithm, the constant temperature difference requirement is met, a PWM control signal is generated, the output of the speed sensor PWM driving module 400 is adjusted, and TL0Is the temperature of the gas to be measured;
the pipeline of the gas to be measured is provided with an annular flow equalizing plate 800, the gas to be measured is rectified by the annular flow equalizing plate 800, so that the speed of the gas flow at each point on the axial section of the pipeline is uniformly distributed, and a measuring rod of a flowmeter is positioned behind the annular flow equalizing plate 800; two rectangular measuring through holes are arranged on the measuring rod of the flowmeter, the distance between the two through holes is approximately equal to 1/3D, and D is the diameter of the pipeline; compensation resistor RLMeasuring hole at the bottom of measuring rod, speed resistor RHThe measuring hole is positioned in the middle of the measuring rod, and the measured gas flows through the measuring hole; the two rectangular measuring through holes are isolated by heat-insulating polytetrafluoroethylene to block the compensating resistor RLAnd a velocity resistance RHHeat conduction of (2).
Description 1: obtaining TL、THNeed to collect voltage VL、VHAnd VaHThen V → R can be performedEstimation process of → T. Collecting voltage VbLThe application is as follows: fault diagnosis of the temperature sensor constant current source module 100, and self-checking of the thermal gas mass flow meter.
As shown in FIG. 2, the circuit of the temperature sensor module 200 includes a precision resistor Rb and a compensation resistor R connected in seriesL(ii) a The other end of the precision resistor Rb and the terminals Point _ IS, Point _ VbL1 connected to output voltage VbLThe output of the temperature sensor constant current source module 100 IS connected to the terminal Point _ IS; compensation resistor RLThe other end of the resistor is grounded, and a precision resistor Rb and a compensation resistor R are connectedLAnd the series Point of (1) and the terminal Point _ VL1 connected to each other, output voltage VL(ii) a The circuit of the speed sensor module 500 includes a precision resistor Ra and a speed resistor R connected in seriesH(ii) a The other end of the precision resistor Ra is connected with the terminals Point _ PWM2 and Point _ VaH1 connected to output voltage VaHThe output of the speed sensor PWM driving module 400 is connected to the terminal Point _ PWM 2; velocity resistor RHThe other end of the resistor is grounded, and a precision resistor Ra and a speed resistor R are connectedHAnd the series Point of (1) and the terminal Point _ VH1 connected to each other, output voltage VH(ii) a Compensation resistor RLAnd a velocity resistance RHThe resistor is a Pt20 platinum resistor with the same resistance value, and the precise resistors Rb and Ra are resistors with the same type and the same resistance value; constant temperature difference THL＝TH－TL0The temperature was set at 100 ℃.
Description 2: the circuit structure of Wheatstone bridge temperature compensation is abandoned, and an independent measured gas temperature measuring circuit is designed; the temperature measurement circuit continues to follow the terminology and notation of the bridge temperature compensation circuit.
As shown in fig. 3(a) and 3(b), the temperature sensor constant current source module 100 takes an MC1403 reference voltage chip, a CD4051 one-out-of-eight analog switch chip, and an XTR110 voltage-current conversion chip as cores; pin 1 of MC1403 is connected with VCC, pin 3 is grounded, and pin 2 is connected with pin 13 of CD 4051; pins 14, 10 and 9 of CD4051 are grounded, pin 11 is connected to terminal Point _ Switch, and pin 3 is connected to pin 5 of XTR 110; XTR110 pins 2, 3, 4 and 9 are grounded, pins 12 and 15 are connected, pins 16 and 36V and resistor REXTIs connected to pin 13, resistor REXTThe other end of the first electrode is connected with the source electrode of the field effect tube G,the pin 14 IS connected with the grid electrode of the field effect transistor G, and the drain electrode of the field effect transistor G IS connected with the terminal Point _ IS; when the temperature sensor module 200 stops detecting, the signal processing and main control module 700 outputs a high level signal to the terminal Point _ Switch, the analog Switch CD4051 gates the grounded X1 input terminal, and the drain of the field effect transistor G outputs no current to the terminal Point _ IS, i.e. no current IS output to the compensation resistor R of the temperature sensor module 200LDoes not generate heat
Figure BDA0002282742340000091
When the temperature sensor module 200 measures the state, the signal processing and main control module 700 outputs a low level signal to the terminal Point _ Switch, the analog Switch CD4051 gates the X0 channel, 2.5V provided by the MC1403 reference voltage chip IS output to the gate of the field effect transistor G through X0 and X, and the drain current of the field effect transistor G IS output to the terminal Point _ IS, that IS, to the compensation resistor R of the temperature sensor module 200L(ii) a The drain current of the field effect transistor G is a constant current source with a constant current value IbL＝0.5/REXT，REXTValue of IbL《IaH，IaHIs the current flowing through Ra;
the speed sensor PWM driving module 400 uses a transistor Q410 and a transistor Q420 as cores; the emitter of Q410 is grounded and the base is connected with a resistor R410Connected to terminal Point _ PWM1, the collector via a resistor R420Is connected with the base of Q420; the emitter of Q420 is connected to 7.5V, and the collector is connected to terminal Point _ PWM 2; the signal processing and main control module 700 outputs a PWM control signal to the terminal Point _ PWM1, the transistors Q410 and Q420 are both turned on at a high level, the transistors Q410 and Q420 are both turned off at a low level, the PWM driving signal is transmitted to the speed sensor module 500 through the terminal Point _ PWM2 to control the speed resistor RHTemperature T ofH。
Description 3: the CD4051 analog switch gates the constant current source of the measurement temperature sensor module 200 and the compensation resistor R if and only if the temperature of the gas being measured is measuredLAnd electrifying for min, and measuring current heating for min.
As shown in FIG. 4, the temperature sensor signal conditioning module 300 comprises a No. 1 temperature sensor signal conditioning module 310 and a No. 1 temperature sensor signal conditioning module2 temperature sensor signal conditioning module 320; the 1 st temperature sensor signal conditioning module 310 is a filter capacitor C311，C311One end of (A) is grounded, C311Another end of (1) and terminal Point _ VL1、Point_V L2 are connected; the 2 nd temperature sensor signal conditioning module 320 comprises a series-connected voltage dividing resistor R321、R322Filter capacitor C321；R321、R322In series, R322And the other end of (1) and the terminal Point _ VbL1 is connected to C321One end of (A), R321And R322And the series Point of (1) and the terminal Point _ Vb L2 is connected to C321And R321The other end of the first and second electrodes is grounded;
the speed sensor signal conditioning module 600 comprises a 1 st speed sensor signal conditioning module 610 and a 2 nd speed sensor signal conditioning module 620 which are arranged in parallel; the 1 st speed sensor signal conditioning module 610 includes a series of voltage dividing resistors R611、R612And a two-stage RC filter circuit: resistance R613Capacitor C611Resistance R614Capacitor C612；R611、R612In series, R612Another end of (1) and terminal Point _ VH1 is linked to R611And R612Is connected in series through a resistor R613And a resistor R614One terminal of (1), a capacitor C611Is connected to one end of a resistor R614Another terminal of (1) and a capacitor C612One end of (1), terminal Point _ V H2 are connected, a resistor R611Another terminal of (1), a capacitor C611And C612The other end of the first and second electrodes is grounded; the 2 nd speed sensor signal conditioning module 620 is similar to the 1 st speed sensor signal conditioning module 610 and is the same as the input terminal Point _ VaH1. Output terminal Point _ Va H2 are connected.
Description 4: the independent measured gas temperature measuring module and speed resistor R are designedHA temperature measurement module; output voltage VL、VbL，VH、VaH. The voltage V is easy to be disordered due to excessive symbols of the variables, and on the premise of not generating ambiguityL、VbLVoltage conditioned by the temperature sensor signal conditioning module 300，VH、VaHThe voltage conditioned by the speed sensor signal conditioning module 600 is still denoted as VL、VbL，VH、VaH。
As shown in fig. 5, the signal processing and master control module 700 takes an STM32F103CB microcontroller chip as a core; a pin 23 of the STM32F103CB is connected to a terminal Point _ PWM1, and outputs a PWM control signal to the speed sensor PWM driving module 400 to control on/off of the transistor Q410; a pin 24 of the STM32F103CB is connected to a terminal Point _ Switch, outputs a low/high level control signal to the temperature sensor constant current source module 100, and controls an analog Switch CD4051 to gate an X0/X1 channel; pins 15 and 16 of STM32F103CB and terminal Point _ V, respectivelyL2、Point_VbL2 connected to each other and respectively collecting compensation resistors R of the temperature sensor module 200LV after precision resistor Rb is conditioned by temperature sensor signal conditioning module 300L、VbL(ii) a Pins 17 and 18 of STM32F103CB and terminal Point _ V, respectivelyH2、Point_VaH2 connected to each other and respectively collecting speed resistance R of speed sensor module 500HV of precision resistor Ra conditioned by speed sensor signal conditioning module 600H、VaH(ii) a The signal processing and main control module 700 is based on the voltage VLVoltage V ofH、VaHCalculating the compensation resistance RLResistance value, speed resistance RHResistance value, temperature T of temperature sensorLTemperature T of speed sensorHAnd according to THL＝TH－TL0Implementing Fuzzy-PI dual-mode undisturbed switching control according to the requirement of constant temperature difference; calculating the mass flow q according to the formula (1)m。
Description 5: known values of Rb, Ra and IbL＝0.5/REXT(ii) a Measuring the voltage drop of the precision resistor Ra to obtain the current Ia flowing through the RaH(ii) a Measuring compensation resistance RLVelocity resistor RHVoltage drop, obtaining compensation resistance RLVelocity resistor RHResistance value; from the compensation resistance RLVelocity resistor RHResistance value, find Pt20 platinum resistor RL、RHCorresponding TL、TH. Known compensation resistor RLAnd a velocity resistance RHIs a Pt20 Pt resistor with the same resistance value, the precision resistors Rb and Ra are resistors with the same type and the same resistance value, and the compensation resistor RLConstant current source I of precision resistor RbbL＝0.5/REXT(ii) a Therefore, during startup/fault diagnosis, the voltage drop of the precision resistor Rb is measured, and self-checking/fault diagnosis of the temperature sensor constant current source module 100 can be performed; cause T when starting upL＝THMeasuring the voltage drop and speed resistance R of the precision resistor RaHVoltage drop, estimated velocity resistance, and compensation resistance RLThe comparison can be self-checked (R)HHigh temperature and vulnerability).
As shown in fig. 6, the thermal gas mass flowmeter adopts a constant temperature difference Fuzzy-PI dual-mode undisturbed switching control algorithm:
Figure BDA0002282742340000101
THL0given value of constant temperature difference, Δ THL＝THL－THL0For deviation of controlled variable, Δ THLThe _ threshold is the deviation threshold of the controlled variable; t isHIs the temperature of the speed sensor; t isL0Is the temperature of the gas to be measured, TLFor the temperature of the measured gas measured by a flowmeter temperature sensor, T is used in engineeringLApproximate TL0(ii) a The thermal gas mass flowmeter is self-checked when being started, and the fault diagnosis of the constant current source of the temperature sensor is carried out at regular time during measurement;
the Fuzzy-PI dual-mode undisturbed switching control system comprises 4 units: a Fuzzy control unit 710, a PI control unit 720, a Fuzzy-PI discriminating unit 730, and an undisturbed switching unit 740; the Fuzzy-PI discrimination unit 730 discriminates from the Δ THLMagnitude of absolute value: if ABS (Δ T)HL)≥ΔTHLThreshold, the Fuzzy control unit 710 is selected if ABS (Δ T)HL)＜ΔTHLA threshold, selecting PI control unit 720; the output of the Fuzzy control unit 710 or the PI control unit 720 is sent to the undisturbed switching unit 740, and the undisturbed switching unit 740 tracks the output value of the Fuzzy-PI dual-mode control algorithm and realizes undisturbed switching by limiting the change delta U of the output quantity U.
Description 6: in view of the fact that a measuring object (measured gas) of the thermal gas mass flowmeter has two working conditions of slow temperature change and fast temperature change, a Fuzzy-PI dual-mode undisturbed switching algorithm is designed to meet the requirements of different working conditions on control. The shaking phenomenon exists during dual-mode control switching, and a sliding mode curve can be designed for solving the problem; however, considering the large time constant of the temperature object, the model is relatively simple, so a simple method of limiting the change rate of the control amount is adopted for solving the problem. The Fuzzy and PI control are well known and will not be discussed herein.

Claims (5)

1. A thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control is characterized by comprising a flowmeter measuring rod, a temperature sensor constant current source module (100) arranged on the flowmeter measuring rod, a temperature sensor module (200), a temperature sensor signal conditioning module (300), a speed sensor PWM driving module (400), a speed sensor module (500), a speed sensor signal conditioning module (600), a signal processing and main control module (700) and an annular flow equalizing plate (800); under the action of the temperature sensor constant current source module (100), the compensation resistor R of the temperature sensor module (200)LThe precision resistor Rb respectively outputs a voltage VLAnd VbLVoltage V ofLAnd VbLThe signals are output to a signal processing and main control module (700) through a temperature sensor signal conditioning module (300); the speed resistance R of the speed sensor module (500) is driven by the speed sensor PWM driving module (400)HThe precision resistors Ra respectively output voltage VHAnd VaHVoltage V ofHAnd VaHThe signals are output to a signal processing and main control module (700) through a speed sensor signal conditioning module (600); the signal processing and main control module (700) is used for processing the voltage VL，VH、VaHCalculating the compensation resistance RLResistance value, speed resistance RHResistance value, temperature T of temperature sensorLTemperature T of speed sensorHAnd according to THL＝TH－TL0≈TH－TLBased on a Fuzzy-PI dual-mode undisturbed switching control algorithm, a PWM control signal is generated, the output of a PWM driving module (400) of the speed sensor is adjusted, and T is the constant temperature difference requirementL0Is the temperature of the gas to be measured; speed sensor PWM drive module (400) with threeThe polar tube Q410 and the triode Q420 are cores; the emitter of the Q410 is grounded, the base is connected with a terminal Point _ PWM1 through a resistor R410, and the collector is connected with the base of the Q420 through a resistor R420; the emitter of Q420 is connected to 7.5V, and the collector is connected to terminal Point _ PWM 2; the signal processing and main control module (700) outputs a PWM control signal to a terminal Point _ PWM1, triodes Q410 and Q420 are both conducted at a high level, the triodes Q410 and Q420 are both cut off at a low level, the PWM drive signal is transmitted to the speed sensor module (500) through the terminal Point _ PWM2 to control the temperature T of the speed resistor RHH；
The constant temperature difference Fuzzy-PI dual-mode undisturbed switching control algorithm specifically comprises the following steps:
Figure FDA0002744206400000011
Figure FDA0002744206400000012
THL0given value of constant temperature difference, Δ THL＝THL－THL0For deviation of controlled variable, Δ THLThe _ threshold is the deviation threshold of the controlled variable; t isHIs the temperature of the speed sensor; t isL0Is the temperature of the gas to be measured, TLFor the temperature of the measured gas measured by a flowmeter temperature sensor, T is used in engineeringLApproximate TL0(ii) a The thermal gas mass flowmeter is self-checked when being started, and the fault diagnosis of the constant current source of the temperature sensor is carried out at regular time during measurement;
the Fuzzy-PI dual-mode undisturbed switching control system comprises 4 units: a Fuzzy control unit (710), a PI control unit (720), a Fuzzy-PI discrimination unit (730), and an undisturbed switching unit (740); a Fuzzy-PI discrimination unit (730) based on the delta THLMagnitude of absolute value: if ABS (Δ T)HL)≥ΔTHL-threshold, choose Fuzzy control unit (710), if ABS (Δ T)HL)＜ΔTHL-threshold, selecting a PI control unit (720); the output of the Fuzzy control unit (710) or the PI control unit (720) is transmitted to the undisturbed switching unit (740), the undisturbed switching unit (740) tracks the output value of the Fuzzy-PI dual-mode control algorithm, and undisturbed switching is realized by limiting the change delta U of the output quantity U;
gas to be measuredThe pipeline is provided with an annular flow equalizing plate (800), the measured gas is rectified by the annular flow equalizing plate (800), so that the speed of the gas flow at each point on the axial section of the pipeline is uniformly distributed, and a measuring rod of the flowmeter is positioned behind the annular flow equalizing plate (800); two rectangular measuring through holes are arranged on the measuring rod of the flowmeter, the distance between the two through holes is approximately equal to 1/3D, and D is the diameter of the pipeline; compensation resistor RLMeasuring hole at the bottom of measuring rod, speed resistor RHThe measuring hole is positioned in the middle of the measuring rod, and the measured gas flows through the measuring hole; the two rectangular measuring through holes are isolated by heat-insulating polytetrafluoroethylene to block the compensating resistor RLAnd a velocity resistance RHHeat conduction of (2).
2. Thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control according to claim 1, characterized in that the circuit of the temperature sensor module (200) comprises a precision resistor Rb and a compensation resistor R connected in seriesL(ii) a The other end of the precision resistor Rb and the terminals Point _ IS, Point _ VbL1 connected to output voltage VbLThe output of the temperature sensor constant current source module (100) IS connected with a terminal Point _ IS; compensation resistor RLThe other end of the resistor is grounded, and a precision resistor Rb and a compensation resistor R are connectedLAnd the series Point of (1) and the terminal Point _ VL1 connected to each other, output voltage VL(ii) a The circuit of the speed sensor module (500) comprises a precision resistor Ra and a speed resistor R which are connected in seriesH(ii) a The other end of the precision resistor Ra is connected with the terminals Point _ PWM2 and Point _ VaH1 connected to output voltage VaHThe output of the speed sensor PWM driver module (400) is connected to the terminal Point _ PWM 2; velocity resistor RHThe other end of the resistor is grounded, and a precision resistor Ra and a speed resistor R are connectedHAnd the series Point of (1) and the terminal Point _ VH1 connected to each other, output voltage VH(ii) a Compensation resistor RLAnd a velocity resistance RHThe resistor is a Pt20 platinum resistor with the same resistance value, and the precise resistors Rb and Ra are resistors with the same type and the same resistance value; constant temperature difference THL＝TH－TL0The temperature was set to 100 ℃.
3. Thermal gas body constitution based on Fuzzy-PI dual-mode undisturbed switching control according to claim 1The flow meter is characterized in that the temperature sensor constant current source module (100) takes an MC1403 reference voltage chip, a CD4051 one-out-of-eight analog switch chip and an XTR110 voltage current conversion chip as cores; pin 1 of MC1403 is connected with VCC, pin 3 is grounded, and pin 2 is connected with pin 13 of CD 4051; pins 14, 10 and 9 of CD4051 are grounded, pin 11 is connected to terminal Point _ Switch, and pin 3 is connected to pin 5 of XTR 110; XTR110 pins 2, 3, 4 and 9 are grounded, pins 12 and 15 are connected, pins 16 and 36V and resistor REXTIs connected to pin 13, resistor REXTThe other end of the pin 14 IS connected with the gate of the field effect transistor G, and the drain of the field effect transistor G IS connected with the terminal Point _ IS; when the temperature sensor module (200) stops detecting, the signal processing and main control module (700) outputs a high level signal to the terminal Point _ Switch, the analog Switch CD4051 gates the grounded X1 input end, the drain of the field effect tube G outputs no current to the terminal Point _ IS, that IS, no current IS output to the compensation resistor R of the temperature sensor module (200)LAlso without thermal power
Figure FDA0002744206400000031
When the temperature sensor module (200) measures the state, the signal processing and main control module (700) outputs a low level signal to the terminal Point _ Switch, the analog Switch CD4051 gates an X0 channel, 2.5V provided by the MC1403 reference voltage chip IS output to the grid of the field effect transistor G through X0 and X, the drain current of the field effect transistor G IS output to the terminal Point _ IS, namely, the drain current IS output to the compensation resistor R of the temperature sensor module (200)L(ii) a The drain current of the field effect transistor G is a constant current source with a constant current value IbL＝0.5/REXT，REXTValue of IbL＜＜IaH，IaHIs the current flowing through Ra.
4. The thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control of claim 1, wherein the temperature sensor signal conditioning module (300) comprises a 1 st temperature sensor signal conditioning module (310) and a 2 nd temperature sensor signal conditioning module (320) which are arranged in parallel; the 1 st temperature sensor signal conditioning module (310) is a filter capacitor C311，C311One end of (A) is grounded, C311Another end of (1) and terminal Point _ VL1、Point_VL2 are connected; the 2 nd temperature sensor signal conditioning module (320) comprises a voltage dividing resistor R connected in series321、R322Filter capacitor C321；R321、R322In series, R322And the other end of (1) and the terminal Point _ VbL1 is connected to C321One end of (A), R321And R322And the series Point of (1) and the terminal Point _ VbL2 is connected to C321And R321The other end of the first and second electrodes is grounded;
the speed sensor signal conditioning module (600) comprises a 1 st speed sensor signal conditioning module (610) and a 2 nd speed sensor signal conditioning module (620) which are arranged in parallel; the 1 st speed sensor signal conditioning module (610) comprises a series-connected voltage dividing resistor R611、R612And a two-stage RC filter circuit: resistance R613Capacitor C611Resistance R614Capacitor C612；R611、R612In series, R612Another end of (1) and terminal Point _ VH1 is linked to R611And R612Is connected in series through a resistor R613And a resistor R614One terminal of (1), a capacitor C611Is connected to one end of a resistor R614Another terminal of (1) and a capacitor C612One end of (1), terminal Point _ VH2 are connected, a resistor R611Another terminal of (1), a capacitor C611And C612The other end of the first and second electrodes is grounded; the 2 nd speed sensor signal conditioning module (620) is similar to the 1 st speed sensor signal conditioning module (610) and is the same as the input terminal Point _ VaH1. Output terminal Point _ VaH2 are connected.
5. The thermal gas mass flowmeter based on Fuzzy-PI dual-mode undisturbed switching control of claim 1, wherein the signal processing and main control module (700) is centered on an STM32F103CB microcontroller chip; a pin 23 of the STM32F103CB is connected to a terminal Point _ PWM1, and outputs a PWM control signal to the speed sensor PWM driving module (400) to control on/off of the transistor Q410; the pin 24 of the STM32F103CB is connected to the terminal Point _ Switch, outputting a low/high levelA control signal is sent to a temperature sensor constant current source module (100) to control an analog switch CD4051 to gate an X0/X1 channel; pins 15 and 16 of STM32F103CB and terminal Point _ V, respectivelyL2、Point_VbL2 connected to each other and respectively collecting compensation resistors R of the temperature sensor module (200)LV after precision resistor Rb is conditioned by temperature sensor signal conditioning module (300)L、VbL(ii) a Pins 17 and 18 of STM32F103CB and terminal Point _ V, respectivelyH2、Point_VaH2 connected to each other and respectively collecting speed resistance R of speed sensor module (500)HV after precision resistor Ra is conditioned by speed sensor signal conditioning module (600)H、VaH(ii) a The signal processing and master control module (700) is based on the voltage VLVoltage V ofH、VaHCalculating the compensation resistance RLResistance value, speed resistance RHResistance value, temperature T of temperature sensorLTemperature T of speed sensorHAnd according to THL＝TH－TL0Implementing Fuzzy-PI dual-mode undisturbed switching control according to the requirement of constant temperature difference; calculating the mass flow q according to the formula (1)m：
Figure FDA0002744206400000041
In the formula, qmIs the mass flow rate; i isHHeating current for speed sensor, RHIs the resistance of the speed sensor, THIs the temperature of the speed sensor; t isL0Is the temperature of the gas to be measured; A. b is an empirical constant.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61105422A (en) * 1984-10-29 1986-05-23 Matsushita Electric Ind Co Ltd Flow rate measuring instrument
JP2010107328A (en) * 2008-10-30 2010-05-13 Hitachi Automotive Systems Ltd Thermal flow rate measuring device
CN103884391A (en) * 2014-03-11 2014-06-25 浙江大学 Double-feedback gas flow sensor
CN104034378A (en) * 2014-06-27 2014-09-10 天津大学 Constant-current thermal gas mass flow meter and measuring method implemented by same
CN205640875U (en) * 2016-04-15 2016-10-12 中国大唐集团科学技术研究院有限公司西北分公司 Overheated steam temperature controlling means based on fuzzy -PI control
CN108020283A (en) * 2017-12-01 2018-05-11 中国计量大学 A kind of two-speed probe thermal type gas quality flow meter and its measuring method
CN207423284U (en) * 2017-02-15 2018-05-29 苏州库睿斯自动化设备有限公司 A kind of single-sensor gas flow measurement circuit of temperature control type

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61105422A (en) * 1984-10-29 1986-05-23 Matsushita Electric Ind Co Ltd Flow rate measuring instrument
JP2010107328A (en) * 2008-10-30 2010-05-13 Hitachi Automotive Systems Ltd Thermal flow rate measuring device
CN103884391A (en) * 2014-03-11 2014-06-25 浙江大学 Double-feedback gas flow sensor
CN104034378A (en) * 2014-06-27 2014-09-10 天津大学 Constant-current thermal gas mass flow meter and measuring method implemented by same
CN205640875U (en) * 2016-04-15 2016-10-12 中国大唐集团科学技术研究院有限公司西北分公司 Overheated steam temperature controlling means based on fuzzy -PI control
CN207423284U (en) * 2017-02-15 2018-05-29 苏州库睿斯自动化设备有限公司 A kind of single-sensor gas flow measurement circuit of temperature control type
CN108020283A (en) * 2017-12-01 2018-05-11 中国计量大学 A kind of two-speed probe thermal type gas quality flow meter and its measuring method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
基于热扩散式恒功率流量测量研究;刘伟帅;《中国优秀硕士学位论文全文数据库 工程科技II辑》;20160415;全文 *

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