A quadrupole radio frequency power supply self-tuning method and system

Abstract

The present invention relates to a self-tuning method and system for a quadrupole radio frequency power supply. The system comprises: a lower computer, a motor, and a resonant circuit, wherein the resonant circuit comprises a first adjustable inductor, a second adjustable inductor, a first fixed capacitor, and a second fixed capacitor, wherein the first fixed capacitor and the second fixed capacitor are connected in series to form a capacitor series branch, wherein the first adjustable inductor and the second adjustable inductor are respectively connected in series with the capacitor series branch, wherein the first adjustable inductor is connected to the first fixed capacitor in the capacitor series branch, and the second adjustable inductor is connected to the second fixed capacitor in the capacitor series branch, wherein the lower computer is connected to the motor, and the motor is connected to the first adjustable inductor and the second adjustable inductor. In view of the shortcomings of the original circuit adopting a manual tuning method to reach a resonant state, poor adjustment accuracy, and cumbersome operation, a recursive idea is adopted, and an automatic tuning algorithm is adopted to reach a resonant state, which has high efficiency, high accuracy, and simple operation; and the inductor is adjusted for tuning, thereby avoiding the use of high-precision adjustable capacitors and reducing costs.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometers, and in particular to a quadrupole radio frequency power supply self-tuning method and system. Background Art

[0002] As a conventional quantitative analysis instrument, quadrupole mass spectrometer is widely used in the fields of medicine, biology, chemical engineering and environmental science due to its high sensitivity, fast analysis speed and small sample consumption. Figure 1 As shown in the figure, when observing the cross section of the quadrupole, the four rods are located at the four corners of the square, and the two diagonal rods are connected into a group. Figure 2 As shown, a DC voltage U (positive rod) is applied to one group, and a DC voltage -U (negative rod) is applied to the other group. The two groups have the same voltage value but opposite polarity. An RF voltage V is applied to all quadrupole rods at the same time, and the RF voltages of the two groups of rods differ in phase by 180 degrees.

[0003] The triple quadrupole mass spectrometer uses voltage scanning to screen ions. The principle is to fix the frequency of the radio frequency voltage V and the ratio of voltages U and V. By changing the values ​​of voltages U and V, ions of different mass numbers can be allowed to reach the detector in sequence, thereby achieving ion screening. Figure 3 As shown, the RF power supply system includes a RF excitation source, a RF power amplifier circuit, a resonant amplifier circuit and a RF feedback circuit.

[0004] The main function of the resonant amplifier circuit in the RF power supply system is to resonate and amplify the RF voltage generated by the RF power amplifier circuit, and adjust the capacitance or inductance to make the series resonant circuit at the optimal frequency resonance point. The traditional series resonant circuit uses a combination of fixed inductance and adjustable capacitance. The optimal frequency resonance point is obtained by adjusting the adjustable capacitance. Its circuit structure is as follows: Figure 4 This circuit has two existing drawbacks. First, the tunable capacitors are manufactured with high precision and are expensive, increasing equipment costs. Second, the RF circuit cannot be automatically tuned, and manual tuning is inaccurate and cumbersome. If the quadrupole capacitance value is too inaccurate, the tunable capacitor alone cannot be used to return it to resonant state, thus limiting its effectiveness. Summary of the Invention

[0005] In order to achieve the above-mentioned purpose and other advantages according to the present invention, a first object of the present invention is to provide a quadrupole radio frequency power self-tuning method, comprising the following steps:

[0006] Set the initial position of the motor;

[0007] The RF power system starts working;

[0008] Read the power supply current value before adjustment Ii ;

[0009] Setting the motor to rotate in a first preset direction at a preset step length;

[0010] Read the adjusted power supply current value I i+1 ;

[0011] Determine the adjusted power supply current value I i+1 Is it greater than the power supply current value I before adjustment? i ;

[0012] If the adjusted power supply current value I i+1 Greater than the power supply current value I before adjustment i , then set the motor to rotate in the second preset direction with a preset step length, and read the adjusted power supply current value I i+2 , determine the power supply current value I after the re-adjustment i+2 Is it less than or equal to the last adjusted power supply current value I i+1 Otherwise, the inductance at resonance is determined to be the power supply current value I after the last adjustment. i+1 If the corresponding motor position is yes, the process jumps to setting the motor to rotate in a second preset direction with a preset step length;

[0013] If the adjusted power supply current value I i+1 Not greater than the power supply current value I before adjustment i , then set the motor to rotate in the first preset direction with a preset step length, and read the adjusted power supply current value I i+2 , determine the power supply current value I after the re-adjustment i+2 Is it less than or equal to the last adjusted power supply current value I i+1 Otherwise, the inductance at resonance is determined to be the power supply current value I after the last adjustment. i+1 If the corresponding motor position is yes, the process jumps to setting the motor to rotate in the first preset direction with a preset step length.

[0014] Furthermore, the initial position of the motor corresponds to an initial inductance value of the motor being within a central threshold of an inductance range.

[0015] Furthermore, when the motor rotates clockwise, the distance between the outer skeleton coil and the inner skeleton coil decreases, and the mutual inductance increases; when the motor rotates counterclockwise, the distance between the outer skeleton coil and the inner skeleton coil increases, and the mutual inductance decreases.

[0016] Furthermore, the preset step size is 5° to 15°, the first preset direction is clockwise, and the second preset direction is counterclockwise.

[0017] A second object of the present invention is to provide a quadrupole radio frequency power self-tuning system, comprising: a lower computer, a motor, and a resonant circuit, wherein the lower computer executes the quadrupole radio frequency power self-tuning method, the resonant circuit comprising a first adjustable inductor, a second adjustable inductor, a first fixed capacitor, and a second fixed capacitor, the first fixed capacitor and the second fixed capacitor being connected in series to form a capacitor series branch, the first adjustable inductor and the second adjustable inductor being connected in series with the capacitor series branch, respectively, the first adjustable inductor being connected to the first fixed capacitor in the capacitor series branch, the second adjustable inductor being connected to the second fixed capacitor in the capacitor series branch, the lower computer being connected to the motor, and the motor being connected to the first adjustable inductor and the second adjustable inductor.

[0018] Furthermore, the resonant coils of the first adjustable inductor and the second adjustable inductor include an inner skeleton, an outer skeleton, a rotating shaft, a gear, an outer skeleton coil and an inner skeleton coil, the outer skeleton coil is wound on the outer skeleton, the inner skeleton coil is wound on the inner skeleton, the initial positions of the outer skeleton coil and the inner skeleton coil do not overlap, the inner skeleton is connected to the rotating shaft, the rotating shaft is connected to the gear, and the gear is connected to the motor.

[0019] Furthermore, the inner frame and the outer frame adopt a hollow tube structure.

[0020] Furthermore, the inner frame and the outer frame are made of nylon frames.

[0021] Furthermore, the initial positions of the outer skeleton coil and the inner skeleton coil correspond to an initial inductance value of the motor being within a central threshold of an inductance range.

[0022] Furthermore, the motor is a stepping motor.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a quadrupole radio frequency power supply self-tuning method and system. In order to address the shortcomings of the original circuit adopting a manual tuning method to achieve a resonant state, which has poor adjustment accuracy and cumbersome operation, the present invention adopts a recursive idea and an automatic tuning algorithm to achieve a resonant state, which has the advantages of high efficiency, high accuracy and simple operation. The system also adopts an inductance adjustment method for tuning, avoids the use of high-precision adjustable capacitors and reduces costs.

[0025] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the description, the following preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The specific implementation methods of the present invention are given in detail by the following embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 The schematic diagram of the quadrupole;

[0028] Figure 2 Schematic diagram of the voltage applied to the quadrupole;

[0029] Figure 3 Schematic diagram of the radio frequency power supply system;

[0030] Figure 4 This is a traditional series resonant circuit diagram;

[0031] Figure 5 Schematic diagram of the quadrupole radio frequency power self-tuning system of Example 1;

[0032] Figure 6 is the resonant circuit diagram of Example 1;

[0033] Figure 7 Schematic diagram of the resonant coil structure of Example 1;

[0034] Figure 8 Schematic diagram of the internal structure of the resonant coil of Example 1;

[0035] Figure 9 This is a flow chart of the quadrupole radio frequency power supply self-tuning method of Example 2. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0037] Traditional quadrupole mass spectrometers achieve resonance in the RF circuit by manually tuning an adjustable capacitor. This method is cumbersome and inaccurate. If the quadrupole capacitance deviates significantly, optimal resonance cannot be achieved with the adjustable capacitor alone, requiring only coil inductance adjustment, which is time-consuming and labor-intensive. The present invention uses an automatic tuning algorithm to automatically determine the coil inductance at optimal resonance, eliminating the need for capacitor adjustment. This method offers the advantages of high efficiency, high precision, and simple operation.

[0038] Example 1

[0039] A quadrupole radio frequency power self-tuning system 100, such as Figure 5As shown, the present invention includes a lower computer 101, a motor 102, and a resonant circuit 103. The lower computer executes a quadrupole RF power self-tuning method. The details of the quadrupole RF power self-tuning method are described in Example 2. The lower computer controls the motor to automatically adjust the inductance of the resonant coil in the resonant circuit, thereby achieving automatic tuning of the resonant circuit.

[0040] Preferably, the motor is a stepper motor. A stepper motor is an open-loop control element that converts electrical pulse signals into angular or linear displacement. When not overloaded, the position at which the motor stops depends solely on the frequency and number of pulses in the pulse signal and is unaffected by load variations. In other words, applying one pulse signal to the motor results in one step angle. This linear relationship, coupled with the fact that stepper motors only have periodic errors and no cumulative errors, makes it very simple to use stepper motors for speed and position control.

[0041] like Figure 6 As shown, the resonant circuit includes a first adjustable inductor ( Figure 6 The inductor in the upper middle), the second adjustable inductor ( Figure 6 Inductor in the lower middle), the first fixed capacitor Cx, the second fixed capacitor Cy, the first fixed capacitor and the second fixed capacitor are connected in series to form a capacitor series branch, the first adjustable inductor and the second adjustable inductor are respectively connected in series with the capacitor series branch, the first adjustable inductor is connected to the first fixed capacitor in the capacitor series branch, the second adjustable inductor is connected to the second fixed capacitor in the capacitor series branch, the lower computer is connected to the motor, and the motor is connected to the first adjustable inductor and the second adjustable inductor.

[0042] like Figure 7 、 Figure 8 As shown, the resonant coils of the first adjustable inductor and the second adjustable inductor include an outer skeleton 1, a gear 2, a rotating shaft 3, an inner skeleton 4, an outer skeleton coil (not shown in the figure) and an inner skeleton coil (not shown in the figure). The outer skeleton coil is wound on the outer skeleton, and the inner skeleton coil is wound on the inner skeleton. The initial positions of the outer skeleton coil and the inner skeleton coil do not overlap, such as winding the outer skeleton coil on the lower half of the outer skeleton and winding the inner skeleton coil on the upper half of the inner skeleton. The inner skeleton is connected to the rotating shaft, the rotating shaft is connected to the gear, and the gear is connected to the motor. The motor rotates the inner skeleton through the gear transmission, and the distance between the inner and outer skeleton coils is adjusted to change the mutual inductance to adjust the inductance value, thereby achieving tuning of the resonant circuit.

[0043] In one embodiment, clockwise rotation of the stepper motor decreases the distance between the inner and outer coils, increasing the mutual inductance. Counterclockwise rotation increases the distance between the inner and outer coils, decreasing the mutual inductance. Rotating the motor changes the distance between the inner and outer coils so that the initial inductance is near the center of the inductance range. This position is referred to as the initial position of the motor. Therefore, the initial positions of the outer and inner coils correspond to an initial inductance value within the center threshold of the inductance range.

[0044] Preferably, the inner and outer frames are hollow tube structures. The inner and outer frames are made of nylon. Hollow coils have better frequency characteristics than coils with magnetic cores, have high output power, and require little additional heat dissipation measures.

[0045] Example 2

[0046] A quadrupole RF power self-tuning method uses a recursive method to compare the power supply current value corresponding to each inductance value step by step until the minimum value is found. The inductance value corresponding to this minimum value is the coil inductance value corresponding to the resonance. Figure 9 As shown, the following steps are included:

[0047] The initial position of the motor is set; in this embodiment, the initial position of the motor corresponds to an initial inductance value of the motor being within a center threshold of the inductance range.

[0048] The RF power system starts working;

[0049] Read the power supply current value before adjustment I i , the power supply current value is the power supply current value of the RF power amplifier circuit;

[0050] In one embodiment, when the motor rotates clockwise, the distance between the outer frame coil and the inner frame coil decreases and the mutual inductance increases; when the motor rotates counterclockwise, the distance between the outer frame coil and the inner frame coil increases and the mutual inductance decreases.

[0051] Set the motor to rotate in a first preset direction with a preset step size, ΔL>0, L i+1 >L i ;

[0052] In one embodiment, the preset step length is 5° to 15°. For example, the preset step length is set to 10°, and the first preset direction is clockwise.

[0053] Read the adjusted power supply current value I i+1 ;

[0054] Determine the adjusted power supply current value I i+1 Is it greater than the power supply current value I before adjustment? i ;

[0055] If the adjusted power supply current value I i+1 Greater than the power supply current value I before adjustment i , then set the motor to rotate in a second preset direction with a preset step length. In this embodiment, the second preset direction is counterclockwise. Read the adjusted power supply current value I i+2 , judge the power supply current value I after re-adjustment i+2Is it less than or equal to the last adjusted power supply current value I i+1 Otherwise, the inductance at resonance is determined to be the power supply current value I after the last adjustment. i+1 If the corresponding motor position is yes, the process jumps to setting the motor to rotate in a second preset direction with a preset step length;

[0056] If the adjusted power supply current value I i+1 Not greater than the power supply current value I before adjustment i , then set the motor to rotate in the first preset direction with a preset step length, and read the adjusted power current value I i+2 , judge the power supply current value I after re-adjustment i+2 Is it less than or equal to the last adjusted power supply current value I i+1 Otherwise, the inductance at resonance is determined to be the power supply current value I after the last adjustment. i+1 If the corresponding motor position is yes, the process jumps to setting the motor to rotate in a first preset direction with a preset step length.

[0057] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0058] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0059] The above description is only an example of the present invention and is not intended to limit one or more embodiments of the present invention. For those skilled in the art, various changes and variations may be made to one or more embodiments of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of the present invention shall be included in the scope of the claims of one or more embodiments of the present invention.

Claims

1. A quadrupole radio frequency power self-tuning method, characterized in that: The following steps are involved: Set the initial position of the motor; The RF power system starts working; Read the power supply current value before adjustment I i ; Setting the motor to rotate in a first preset direction at a preset step length; Read the adjusted power supply current value I i+1 ; Determine the adjusted power supply current value I i+1 Is it greater than the power supply current value I before adjustment? i ; If the adjusted power supply current value I i+1 Greater than the power supply current value I before adjustment i , then set the motor to rotate in the second preset direction with a preset step length, and read the adjusted power supply current value I i+2 , determine the power supply current value I after the re-adjustment i+2 Is it less than or equal to the last adjusted power supply current value I i+1 Otherwise, the inductance at resonance is determined to be the power supply current value I after the last adjustment. i+1 If the corresponding motor position is yes, the process jumps to setting the motor to rotate in a second preset direction with a preset step length; If the adjusted power supply current value I i+1 Not greater than the power supply current value I before adjustment i , then set the motor to rotate in the first preset direction with a preset step length, and read the adjusted power supply current value I i+2 , determine the power supply current value I after the re-adjustment i+2 Is it less than or equal to the last adjusted power supply current value I i+1 Otherwise, the inductance at resonance is determined to be the power supply current value I after the last adjustment. i+1 If the corresponding motor position is yes, the process jumps to setting the motor to rotate in the first preset direction with a preset step length; The initial inductance value of the motor corresponding to the initial position of the motor is within the center threshold of the inductance range; When the motor rotates clockwise, the distance between the outer skeleton coil and the inner skeleton coil decreases, and the mutual inductance increases; when the motor rotates counterclockwise, the distance between the outer skeleton coil and the inner skeleton coil increases, and the mutual inductance decreases.

2. The method for self-tuning a quadrupole radio frequency power supply according to claim 1, wherein: The preset step length is 5° to 15°, the first preset direction is clockwise, and the second preset direction is counterclockwise.

3. A quadrupole radio frequency power self-tuning system, characterized in that: include: A lower computer, a motor, and a resonant circuit, wherein the lower computer executes the method according to any one of claims 1 to 2, wherein the resonant circuit includes a first adjustable inductor, a second adjustable inductor, a first fixed capacitor, and a second fixed capacitor, wherein the first fixed capacitor and the second fixed capacitor are connected in series to form a capacitor series branch, the first adjustable inductor and the second adjustable inductor are respectively connected in series with the capacitor series branch, the first adjustable inductor is connected to the first fixed capacitor in the capacitor series branch, the second adjustable inductor is connected to the second fixed capacitor in the capacitor series branch, the lower computer is connected to the motor, and the motor is connected to the first adjustable inductor and the second adjustable inductor.

4. The quadrupole radio frequency power self-tuning system according to claim 3, characterized in that: The resonant coils of the first adjustable inductor and the second adjustable inductor include an inner skeleton, an outer skeleton, a rotating shaft, a gear, an outer skeleton coil and an inner skeleton coil. The outer skeleton coil is wound on the outer skeleton, and the inner skeleton coil is wound on the inner skeleton. The initial positions of the outer skeleton coil and the inner skeleton coil do not overlap. The inner skeleton is connected to the rotating shaft, the rotating shaft is connected to the gear, and the gear is connected to the motor.

5. The quadrupole radio frequency power self-tuning system according to claim 4, characterized in that: The inner frame and the outer frame adopt a hollow tube structure.

6. The quadrupole radio frequency power self-tuning system according to claim 5, characterized in that: The inner frame and the outer frame are made of nylon frames.

7. The quadrupole radio frequency power self-tuning system according to claim 4, characterized in that: The initial positions of the outer skeleton coil and the inner skeleton coil correspond to an initial inductance value of the motor being within a central threshold of an inductance range.

8. The quadrupole radio frequency power self-tuning system according to claim 3, characterized in that: The motor is a stepping motor.

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