A mass spectrometer magnetic field intensity control system based on integrating circuit

Abstract

The present invention discloses a mass spectrometer magnetic field intensity control system based on an integration circuit, belonging to the technical field of mass spectrometers. The system comprises an electromagnet and an electromagnet control system. When the magnetic field intensity of the electromagnet changes, the induction coil outputs an induced electromotive force E to a stabilizer. The stabilizer outputs a stable voltage U to a shaper according to the magnitude of the induced electromotive force E. The stable voltage U includes a fluctuating voltage U generated by the induced electromotive force E. E And the set voltage value U generated by setting different integration times t through the microcontroller C The shaper outputs a drive voltage U1 to the electromagnet based on the magnitude of the stable voltage U, completing feedback control and driving of the electromagnet. The present invention controls the stability of the electromagnet through negative feedback. Simultaneously, by precisely controlling the integration time of the integrator, it outputs a stable voltage, which in turn outputs a high-precision drive voltage, achieving precise control of the electromagnet.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometers, and in particular to a mass spectrometer magnetic field intensity control system based on an integration circuit. Background Art

[0002] Electromagnets are key components of mass spectrometers. When energized, they generate a magnetic field that is used to separate ions. A stable magnetic field is required to obtain a stable charge signal, and high-precision control of the magnetic field strength is necessary to accommodate ions with varying mass-to-charge ratios. As a bottleneck product, the stability and high-precision design of electromagnets are particularly important for mass spectrometers. Currently, there is little research in China on electromagnet control technology for mass spectrometers. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a mass spectrometer magnetic field intensity control system based on an integration circuit.

[0004] The objective of the present invention is achieved through the following technical solution: a mass spectrometer magnetic field intensity control system based on an integrating circuit, comprising an electromagnet, the electromagnet being connected to an electromagnet control system, the electromagnet comprising an induction coil, the electromagnet control system comprising a stabilizer and a shaper; the input end of the stabilizer being connected to the output end of the electromagnet, the output end of the stabilizer being connected to the input end of the shaper, and the output end of the shaper being connected to the input end of the electromagnet;

[0005] When the magnetic field strength of the electromagnet changes, the induction coil outputs the induced electromotive force E to the stabilizer, and the stabilizer outputs a stable voltage U to the shaper according to the magnitude of the induced electromotive force E; the stable voltage U includes the fluctuating voltage U generated by the induced electromotive force E. E And the set voltage value U generated by setting different integration times t through the microcontroller C The shaper outputs the driving voltage U1 to the electromagnet according to the size of the stable voltage U, completing the feedback control and driving of the electromagnet.

[0006] Preferably, the stabilizer includes a first constant current source circuit, a second constant current source circuit and an integrating amplifier; the first constant current source circuit and the second constant current source circuit are used to generate constant current source I1 and constant current source I2; the inflow direction of constant current source I1 and constant current source I2 is controlled by pins PWM1 and PWM2 of the single-chip microcomputer, thereby obtaining an integral current I, and the integral current I and the induced electromotive force E are input into the integrating amplifier to obtain the required stable voltage U.

[0007] Preferably, the first constant current source circuit includes an operational amplifier D1, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a field effect transistor VT1, a transistor VT2, and a transistor VT3; the second constant current source circuit includes a resistor R2, a resistor R3, a resistor R6, a resistor R7, an operational amplifier D2, a transistor VT4, a transistor VT5, and a field effect transistor VT6; the resistor R2, the resistor R3, and the resistor R6, the first constant current source circuit and the second constant current source circuit are used together;

[0008] The positive input terminal of the operational amplifier D1 is connected to the first terminal of the resistor R2 and the resistor R3, the negative input terminal of the operational amplifier D1 is connected to the first terminal of the resistor R1 and the source of the field effect transistor VT1, the output terminal of the operational amplifier D1 is connected to the gate of the field effect transistor VT1, the second terminals of the resistor R1 and the resistor R2 are connected to the power supply; the second terminal of the resistor R3 is connected to the positive input terminal of the operational amplifier D2 and the first terminal of the resistor R6; the negative input terminal of the operational amplifier D2 is connected to the source of the field effect transistor VT6 and the first terminal of the resistor R7, the output terminal of the operational amplifier D2 is connected to the gate of the field effect transistor VT6; the second terminals of the resistor R6 and the resistor R7 are connected to the positive input terminal of the operational amplifier D2 and the first terminal of the resistor R6; the negative input terminal of the operational amplifier D2 is connected to the source of the field effect transistor VT6 and the first terminal of the resistor R7; the output terminal of the operational amplifier D2 is connected to the gate of the field effect transistor VT6; the The second end is connected to the power supply; the drain of the field effect transistor VT1 is connected to the emitters of the transistor VT2 and the transistor VT3; the collector of the transistor VT2 is connected to the base of the transistor VT2 and the pin PWM1 of the single chip microcomputer; the collector of the transistor VT3 is connected to the emitter of the transistor VT4 and the base of the transistor VT3, and the base of the transistor VT3 outputs the integral current I to the integral amplifier; the emitter of the transistor VT4 is connected to the drain of the field effect transistor VT6, the base of the transistor VT4, the collector of the transistor VT5 and the base of the transistor VT5; the emitter of the transistor VT5 is connected to the pin PWM2 of the single chip microcomputer.

[0009] Preferably, the integrating amplifier comprises an operational amplifier D3, a capacitor C1, a resistor R4 and a resistor R5;

[0010] The negative input terminal of the operational amplifier D3 is connected to the resistor R4 and the first terminal of the capacitor C1, and receives the integrated current I; the second terminal of the resistor R4 receives the induced electromotive force E; the positive input terminal of the operational amplifier D3 is connected to the ground GND, and the output terminal of the operational amplifier D3 is connected to the second terminal of the capacitor C1 and the first terminal of the resistor R5; the second terminal of the resistor R5 outputs a stable voltage U to the shaper.

[0011] Preferably, the shaper includes a comparator D4, a field effect transistor Q1, a triangular wave generator and an average converter; the positive input end of the comparator D4 receives a stable voltage U, and the negative input end of the comparator D4 receives a triangular wave signal output by the triangular wave generator. The stable voltage U and the triangular wave signal are compared by the comparator D4, and then the output end of the comparator D4 outputs a square wave U3 to the gate of the field effect transistor Q1; the source of the field effect transistor Q1 receives the driving voltage U2, and the drain of the field effect transistor Q1 outputs the driving voltage U4 to the average converter; the average converter converts the driving voltage U4 from a square wave signal to a DC voltage signal to obtain a driving voltage U1 and outputs it to the electromagnet.

[0012] The beneficial effects of the present invention are:

[0013] 1) Mass spectrometer is a "bottleneck" product, and the control technology of electromagnet is particularly critical. The present invention uses conventional and easily purchased domestic components to design a stabilizer and a shaper; the stability of the electromagnet is controlled by negative feedback, and at the same time, the PWM wave signal generated by the single-chip microcomputer is used to accurately control the integration time of the integrator, output a high-precision stable voltage, and further output a high-precision driving voltage to achieve precise control of the electromagnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the principle block diagram of the mass spectrometer magnetic field intensity control system based on the integration circuit;

[0015] Figure 2 The diagram is a structural diagram of a mass spectrometer magnetic field intensity control system based on an integration circuit;

[0016] Figure 3 This is the schematic diagram of the stabilizer circuit;

[0017] Figure 4 This is the schematic diagram of the shaper circuit. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work shall fall within the scope of protection of the present invention.

[0019] See Figure 1-Figure 4The present invention provides a technical solution: a mass spectrometer magnetic field intensity control system based on an integrating circuit, comprising an electromagnet, the electromagnet being connected to an electromagnet control system, the electromagnet comprising an induction coil, the electromagnet control system comprising a stabilizer and a shaper; the input end of the stabilizer being connected to the output end of the electromagnet, the output end of the stabilizer being connected to the input end of the shaper, and the output end of the shaper being connected to the input end of the electromagnet;

[0020] When the magnetic field strength of the electromagnet changes, the induction coil outputs the induced electromotive force E to the stabilizer, and the stabilizer outputs a stable voltage U to the shaper according to the magnitude of the induced electromotive force E; the stable voltage U includes the fluctuating voltage U generated by the induced electromotive force E. E And the set voltage value U generated by setting different integration times t through the microcontroller C The shaper outputs the driving voltage U1 to the electromagnet according to the size of the stable voltage U, completing the feedback control and driving of the electromagnet.

[0021] In this embodiment, if Figure 1 and Figure 2 As shown in the figure, the electromagnet control system includes a stabilizer and a shaper. The induced electromotive force E output by the electromagnet's induction coil is transmitted to the stabilizer via cable 1. The stabilizer outputs a stable voltage U based on the magnitude of the induced electromotive force E. The stable voltage U is transmitted to the shaper via cable 2. The shaper outputs a drive voltage U1 based on the magnitude of the stable voltage U. The drive voltage U1 is output to the electromagnet via cable 3.

[0022] The working principle of this scheme is: when the magnetic field strength of the electromagnet changes, it causes the induction coil to output an induced electromotive force E. The greater the change in the magnetic field strength of the electromagnet (the worse the stability), the greater the induced electromotive force E output by the induction coil, and vice versa. In order to detect the magnitude of the induced electromotive force E, the induced electromotive force E needs to be input into the stabilizer through cable 1, and a corresponding stable voltage U is output at the same time. This stable voltage value U includes the fluctuating voltage U generated by the induced electromotive force E. E And the set voltage value U generated by setting different integration times t through the microcontroller C ; In order to detect the size of the stable voltage value U, the stable voltage U needs to be input into the shaper through cable 2. The stable voltage U will control the driving voltage U1 of the shaper. The larger the stable voltage value U, the smaller the driving voltage U1, and vice versa; in order to complete the feedback control and drive of the electromagnet, the driving voltage U1 output by the stabilizer needs to be input into the electromagnet.

[0023] In some embodiments, the stabilizer includes a first constant current source circuit, a second constant current source circuit and an integrating amplifier; the first constant current source circuit and the second constant current source circuit are used to generate a constant current source I1 and a constant current source I2; the inflow direction of the constant current source I1 and the constant current source I2 is controlled by the pins PWM1 and PWM2 of the microcontroller, thereby obtaining the integral current I, and the integral current I and the induced electromotive force E are input into the integrating amplifier to obtain the required stable voltage U.

[0024] In this embodiment, if Figure 3 As shown, the integrating amplifier includes an operational amplifier D3, a capacitor C1, and a resistor R4. The first constant current source circuit includes D1, R1, R2, R3, R6, VT1, VT2, and VT3. The voltage value of pin 3 of operational amplifier D1 is V1 = {[15V-(-15V)] × (R3+R6)} / (R2+R3+R6)+(-15V), and the constant current source I1 = (15V-V1) / R1.

[0025] The second constant current source circuit includes R2, R3, R6, R7, D2, VT4, VT5, and VT6. The voltage value of pin 3 of the operational amplifier D2 is V2={[15V-(-15V)]×(R6)} / (R2+R3+R6)+(-15V), and the constant current source I2=(-15V-V2) / R7.

[0026] In order to select the inflow direction of constant current sources I1 and I2, the microcontroller pins PWM1 and PWM2 are designed for control; when PWM1 is low, the transistor VT2 is turned on, and the constant current source I1 flows directly into the microcontroller PWM1 port. Without considering the constant current source I2, the integral current I=0; when PWM1 is high, the transistor VT2 is cut off. Without considering the constant current source I2, the integral current I=constant current source I1; when PWM2 is low, the transistor VT5 is cut off. Without considering the constant current source I1, the integral current I=constant current source I2; when PWM2 is high, VT5 is turned on, and the constant current source I2 flows directly out of the microcontroller PWM2 port. Without considering the constant current source I1, the integral current I=0; when the system is in static state, PWM1 is low, PWM2 is high, the constant current source I1 and I2 flows into the single-chip microcomputer; when the system is in working state, it is necessary to set the output current required by the electromagnet, and the capacitor C1 needs to be charged. Assuming that the period of the PWM wave output by PWM1 is T and the number of charging cycles is N, the charge Q on the capacitor C1 is Q=I1NT / 2, and the voltage value U on C1 is U=Q / C=INT / (2C1). If it is necessary to reduce the voltage value U on the capacitor C1, assuming that the period of the PWM wave output by PWM2 is T1 and the number of discharge cycles is N1, the charge Q on the capacitor C1 is Q=I1NT / 2-I2N1T1 / 2, and the voltage value U on C1 is U=Q / C=(I1NT-I2N1T1) / (2C1). The voltage value U on C1 is reduced. The higher the frequency of PWM1 and PWM2, the higher the change accuracy of the voltage value U on C1. This voltage is the stable voltage U of the stabilizer.

[0027] In some embodiments, the first constant current source circuit includes an operational amplifier D1, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a field effect transistor VT1, a transistor VT2, and a transistor VT3; the second constant current source circuit includes a resistor R2, a resistor R3, a resistor R6, a resistor R7, an operational amplifier D2, a transistor VT4, a transistor VT5, and a field effect transistor VT6; the resistors R2, R3, and R6, the first constant current source circuit and the second constant current source circuit are used together;

[0028] The positive input terminal of the operational amplifier D1 is connected to the first terminal of the resistor R2 and the resistor R3, the negative input terminal of the operational amplifier D1 is connected to the first terminal of the resistor R1 and the source of the field effect transistor VT1, the output terminal of the operational amplifier D1 is connected to the gate of the field effect transistor VT1, the second terminals of the resistor R1 and the resistor R2 are connected to the power supply; the second terminal of the resistor R3 is connected to the positive input terminal of the operational amplifier D2 and the first terminal of the resistor R6; the negative input terminal of the operational amplifier D2 is connected to the source of the field effect transistor VT6 and the first terminal of the resistor R7, the output terminal of the operational amplifier D2 is connected to the gate of the field effect transistor VT6; the second terminals of the resistor R6 and the resistor R7 are connected to the positive input terminal of the operational amplifier D2 and the first terminal of the resistor R6; the negative input terminal of the operational amplifier D2 is connected to the source of the field effect transistor VT6 and the first terminal of the resistor R7; the output terminal of the operational amplifier D2 is connected to the gate of the field effect transistor VT6; the The second end is connected to the power supply; the drain of the field effect transistor VT1 is connected to the emitters of the transistor VT2 and the transistor VT3; the collector of the transistor VT2 is connected to the base of the transistor VT2 and the pin PWM1 of the single chip microcomputer; the collector of the transistor VT3 is connected to the emitter of the transistor VT4 and the base of the transistor VT3, and the base of the transistor VT3 outputs the integral current I to the integral amplifier; the emitter of the transistor VT4 is connected to the drain of the field effect transistor VT6, the base of the transistor VT4, the collector of the transistor VT5 and the base of the transistor VT5; the emitter of the transistor VT5 is connected to the pin PWM2 of the single chip microcomputer.

[0029] In some embodiments, the integrating amplifier includes an operational amplifier D3, a capacitor C1, a resistor R4, and a resistor R5;

[0030] The negative input terminal of the operational amplifier D3 is connected to the resistor R4 and the first terminal of the capacitor C1, and receives the integrated current I; the second terminal of the resistor R4 receives the induced electromotive force E; the positive input terminal of the operational amplifier D3 is connected to the ground GND, and the output terminal of the operational amplifier D3 is connected to the second terminal of the capacitor C1 and the first terminal of the resistor R5; the second terminal of the resistor R5 outputs a stable voltage U to the shaper.

[0031] In some embodiments, the shaper includes a comparator D4, a field-effect transistor Q1, a triangular wave generator, and an average converter; the positive input terminal of the comparator D4 receives a stable voltage U, and the negative input terminal of the comparator D4 receives a triangular wave signal output by the triangular wave generator. The stable voltage U and the triangular wave signal are compared by the comparator D4, and then the output terminal of the comparator D4 outputs a square wave U3 to the gate of the field-effect transistor Q1; the source of the field-effect transistor Q1 receives the driving voltage U2, and the drain of the field-effect transistor Q1 outputs the driving voltage U4 to the average converter; the average converter converts the driving voltage U4 from a square wave signal to a DC voltage signal to obtain a driving voltage U1, which is output to the electromagnet.

[0032] In this embodiment, if Figure 4As shown, D4 is a comparator and Q1 is a field effect tube. The triangle wave function generator outputs a triangle wave signal to pin 2 of D4. To compare the stabilized voltage U with the triangle wave signal, the stabilizer's stabilized voltage U is input through pin 3 of D1. The stabilized voltage U and the triangle wave are compared by comparator D4. D4's output pin 6 outputs a square wave U3. The higher the stabilized voltage U, the shorter the duration t during which D4's output pin 6 outputs the high-level square wave U3, and vice versa. To control the on / off of field-effect transistor Q1, pin 6 of D1 is connected to Q1's gate as a control signal. To output drive voltage U4 at Q1's drain, the source of Q1 is connected to drive voltage U2. To convert drive voltage U4 at Q1's drain from a square wave signal to a DC voltage (i.e., drive voltage U1), the drain of Q1 is connected to an average value converter. The higher the level of drive voltage U4, the higher the value of drive voltage U1, and vice versa. To feed drive voltage U1 back to the electromagnet, drive voltage U1 is connected directly to the electromagnet. The higher the drive voltage U1, the stronger the electromagnet, and vice versa.

[0033] The foregoing description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Rather, the present invention can be used in various other combinations, modifications, and environments and can be modified within the scope of the concept described herein through the above teachings or techniques or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be protected by the appended claims.

Claims

1. A mass spectrometer magnetic field intensity control system based on an integrating circuit, characterized in that: The electromagnet includes an electromagnet connected to an electromagnet control system, the electromagnet includes an induction coil, and the electromagnet control system includes a stabilizer and a shaper; the input end of the stabilizer is connected to the output end of the electromagnet, the output end of the stabilizer is connected to the input end of the shaper, and the output end of the shaper is connected to the input end of the electromagnet; When the magnetic field strength of the electromagnet changes, the induction coil outputs the induced electromotive force E to the stabilizer, and the stabilizer outputs a stable voltage U to the shaper according to the magnitude of the induced electromotive force E; the stable voltage U includes the fluctuating voltage U generated by the induced electromotive force E. E And the set voltage value U generated by setting different integration times t through the microcontroller C The shaper outputs the driving voltage U1 to the electromagnet according to the size of the stable voltage U, completing the feedback control and driving of the electromagnet; The stabilizer includes a first constant current source circuit, a second constant current source circuit, and an integrating amplifier; the first constant current source circuit and the second constant current source circuit are used to generate constant current sources I1 and I2; the flow directions of the constant current sources I1 and I2 are controlled by the PWM1 and PWM2 pins of the single-chip microcomputer to obtain an integral current I, and the integral current I and the induced electromotive force E are input into the integrating amplifier to obtain the required stable voltage U; The first constant current source circuit includes an operational amplifier D1, a resistor R1, a resistor R2, a resistor R3, a resistor R6, a field effect transistor VT1, a transistor VT2, and a transistor VT3; the second constant current source circuit includes a resistor R2, a resistor R3, a resistor R6, a resistor R7, an operational amplifier D2, a transistor VT4, a transistor VT5, and a field effect transistor VT6; the resistor R2, the resistor R3, and the resistor R6, the first constant current source circuit and the second constant current source circuit are used together; The positive input terminal of the operational amplifier D1 is connected to the first terminal of the resistor R2 and the resistor R3, the negative input terminal of the operational amplifier D1 is connected to the first terminal of the resistor R1 and the source of the field effect transistor VT1, the output terminal of the operational amplifier D1 is connected to the gate of the field effect transistor VT1, the second terminals of the resistor R1 and the resistor R2 are connected to the power supply; the second terminal of the resistor R3 is connected to the positive input terminal of the operational amplifier D2 and the first terminal of the resistor R6; the negative input terminal of the operational amplifier D2 is connected to the source of the field effect transistor VT6 and the first terminal of the resistor R7, the output terminal of the operational amplifier D2 is connected to the gate of the field effect transistor VT6; the second terminals of the resistor R6 and the resistor R7 are connected to the positive input terminal of the operational amplifier D2 and the first terminal of the resistor R6; the negative input terminal of the operational amplifier D2 is connected to the source of the field effect transistor VT6 and the first terminal of the resistor R7; the output terminal of the operational amplifier D2 is connected to the gate of the field effect transistor VT6; the The second end is connected to a power supply; the drain of the field effect transistor VT1 is connected to the emitters of the transistor VT2 and the transistor VT3; the collector of the transistor VT2 is connected to the base of the transistor VT2 and the pin PWM1 of the single-chip microcomputer; the collector of the transistor VT3 is connected to the emitter of the transistor VT4 and the base of the transistor VT3, and the base of the transistor VT3 outputs the integral current I to the integrating amplifier; the emitter of the transistor VT4 is connected to the drain of the field effect transistor VT6, the base of the transistor VT4, the collector of the transistor VT5 and the base of the transistor VT5; the emitter of the transistor VT5 is connected to the pin PWM2 of the single-chip microcomputer; The integrating amplifier includes an operational amplifier D3, a capacitor C1, a resistor R4 and a resistor R5; The negative input terminal of the operational amplifier D3 is connected to the resistor R4 and the first terminal of the capacitor C1, and receives the integrated current I; the second terminal of the resistor R4 receives the induced electromotive force E; the positive input terminal of the operational amplifier D3 is connected to the ground GND, and the output terminal of the operational amplifier D3 is connected to the second terminal of the capacitor C1 and the first terminal of the resistor R5; the second terminal of the resistor R5 outputs a stable voltage U to the shaper; The shaper includes a comparator D4, a field-effect transistor Q1, a triangular wave generator, and an average converter. The positive input of the comparator D4 receives a stable voltage U, and the negative input of the comparator D4 receives a triangular wave signal output by the triangular wave generator. The stable voltage U and the triangular wave signal are compared by the comparator D4, and then the output of the comparator D4 outputs a square wave U3 to the gate of the field-effect transistor Q1. The source of the field-effect transistor Q1 receives a driving voltage U2, and the drain of the field-effect transistor Q1 outputs the driving voltage U4 to the average converter. The average converter converts the driving voltage U4 from a square wave signal into a DC voltage signal to obtain a driving voltage U1, which is output to the electromagnet.

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