Radio frequency power supply for supplying power to quadrupole of mass spectrometer

Abstract

The invention relates to a radio frequency power supply for supplying power to a mass spectrometer quadrupole, and relates to the technical field of mass spectrometers. A general controller is used for generating a high-frequency sine wave signal and a low-frequency reference envelope signal; the power amplifier part receives the high-frequency sine wave signal and the modified envelope signal, and outputs the signals to the boosting part after power amplification; the boosting part comprises an air-core transformer of which the primary side is connected with the output end of the power amplifier part and the secondary side is connected with a load; the sampling part collects a voltage signal from a load and extracts an actual envelope signal; the PI part receives the low-frequency reference envelope signal and the actual envelope signal, generates a corrected envelope signal through differential operation, and feeds back the corrected envelope signal to the power amplifier part; the load adopts a quadrupole rod, the frequency of a high-frequency sine wave signal is matched with the natural resonant frequency of an LC resonant circuit formed by the secondary side of the air-core transformer and the quadrupole rod load, and a high-voltage radio frequency envelope signal is generated on the secondary side through resonant amplification. The radio frequency power supply impedance matching circuit can overcome the defects that an existing radio frequency power supply impedance matching circuit is complex, high in power consumption and high in cost.

Description

Technical Field

[0001] This invention relates to the field of mass spectrometry technology, and in particular to a power supply for providing a radio frequency envelope high voltage signal to the quadrupole of a mass spectrometer. Background Technology

[0002] As a precision analytical instrument, mass spectrometers require a stable high-frequency, high-voltage radio frequency envelope signal for their quadrupole mass analyzer to achieve accurate ion screening and control. Current technologies primarily employ multi-stage linear amplification to obtain the necessary high-voltage radio frequency envelope signal, which is a mature and widely adopted technical approach in the industry.

[0003] In existing technical solutions, the system typically generates a high-frequency sine wave signal and a low-frequency sawtooth wave signal separately based on a waveform generator. The two signals are then multiplied by a multiplier to obtain a synthesized envelope signal. This envelope signal is then initially amplified by a multi-stage linear amplifier, followed by further amplification by driving a switching transistor. Finally, a transformer steps up the voltage to output a high-voltage envelope signal of thousands of volts to a quadrupole load. To achieve effective power transfer, complex impedance matching networks must be configured at both the input and output ends of the transformer to ensure impedance matching between each stage of the circuit. The entire system relies on the coordinated operation of numerous functional modules, including the waveform generator, multiplier circuit, multi-stage amplifier, and transformer.

[0004] However, the aforementioned linear amplification technology has significant drawbacks: First, the system structure is extremely complex, with a large number of components and complex circuit design due to the multi-stage amplification architecture. Second, the impedance matching network design at the transformer input and output terminals is cumbersome, and parameter tuning is difficult, significantly increasing the development cycle and maintenance costs. Third, the multi-stage linear amplification mode has high power consumption, high heat generation, and low energy efficiency, placing higher demands on the heat dissipation system. In addition, the complex system structure not only increases material and manufacturing costs but also reduces overall reliability and makes it difficult to meet the urgent needs of modern mass spectrometers for miniaturized, lightweight, high-efficiency, and long-term stable RF power supplies. Summary of the Invention

[0005] The purpose of this invention is to provide an RF power supply for powering a quadrupole mass spectrometer, overcoming the shortcomings of existing RF power supplies that use multi-stage linear amplification, resulting in complex impedance matching circuits, high power consumption, and high cost. By employing resonant amplification technology, the fundamental frequency is matched with the resonant frequency of the transformer load terminal to generate a resonant effect, thereby simplifying the system structure, reducing power consumption and cost, and achieving efficient high-voltage RF envelope signal output.

[0006] To achieve the above objectives, the present invention provides a radio frequency power supply for powering a quadrupole of a mass spectrometer, comprising a master control unit, a power amplifier section, a boost section, a sampling section, and a PI section; The master control is used to generate high-frequency sine wave signals and low-frequency reference envelope signals; The power amplifier section receives the high-frequency sine wave signal and the corrected envelope signal, amplifies them, and outputs them to the boost section. The boost section includes a hollow transformer, whose primary side is connected to the output terminal of the power amplifier section and whose secondary side is connected to the load. The sampling section acquires voltage signals from the load and extracts the actual envelope signal; The PI section receives the low-frequency reference envelope signal and the actual envelope signal, generates the corrected envelope signal through differential operation, and feeds it back to the power amplifier section. The load is a quadrupole, and the frequency of the high-frequency sine wave signal matches the inherent resonant frequency of the LC resonant circuit formed by the secondary side of the hollow transformer and the load of the quadrupole. The high-voltage radio frequency envelope signal is generated on the secondary side through resonant amplification.

[0007] Preferably, the power amplifier section includes an adder and a switching transistor; the adder combines the high-frequency sine wave signal and the corrected envelope signal and outputs the result to the control terminal of the switching transistor; the switching transistor is powered by a DC power supply, amplifies the combined signal, and outputs it to the primary side of the boost section.

[0008] Preferably, the hollow transformer includes a hollow tube, a primary coil, a secondary coil, and a shielding box; the primary coil and the secondary coil are wound on the hollow tube.

[0009] Preferably, the hollow transformer further includes an internal coil disposed inside the hollow tube, the internal coil adjusting the effective inductance parameter of the transformer through deflection action.

[0010] Preferably, the quadrupole consists of four metal rods, with each pair of metal rods connected in series to receive positive and negative high-voltage radio frequency envelope signals, respectively, and superimposed with a high-voltage DC bias signal.

[0011] Preferably, the sampling section includes a high-voltage isolation capacitor, a rectifier circuit, and a filter circuit; the high-voltage isolation capacitor acquires the high-voltage signal from the quadrupole coupling and steps down the voltage for isolation, and the actual envelope signal is extracted after processing by the rectifier circuit and the filter circuit.

[0012] Preferably, the PI part performs a differential operation on the reference envelope signal and the actual envelope signal to obtain an error signal, and then superimposes the error signal with the reference envelope signal to generate the corrected envelope signal.

[0013] Preferably, the inherent resonant frequency of the LC resonant circuit is given by the formula

[0014] It is determined that L is the distributed inductance of the transformer secondary winding and the quadrupole, and C is the equivalent capacitance.

[0015] Preferably, it also includes a touch screen, which communicates bidirectionally with the central control unit.

[0016] Preferably, the high-frequency sine wave signal is a DDS sine wave signal with a frequency of 1MHz to 2MHz, and the reference envelope signal is a DAC sawtooth wave signal with a frequency of 50Hz to 100Hz.

[0017] In summary, the present invention has the following beneficial technical effects: This invention achieves stable output of multi-kilovolt high-voltage radio frequency envelope signals through resonant amplification technology. Traditional radio frequency power supplies rely on multi-stage linear amplification to progressively increase voltage. In contrast, this invention utilizes the fundamental frequency to match the resonant frequency of the transformer's load-side capacitor and resistor, generating a highly efficient energy exchange effect in the LC resonant circuit. Voltage multiplication can be achieved simply by frequency tuning, eliminating the need for complex impedance transformation networks. This resonant amplification mechanism easily enables the secondary-side voltage to reach the multi-kilovolt level, directly meeting the operational requirements of a quadrupole quality analyzer, fundamentally solving the technical bottlenecks of limited voltage boost and low efficiency in traditional solutions.

[0018] This invention significantly simplifies the system structure and impedance matching circuit design. Existing technologies require multi-stage LC matching networks at the transformer input and output terminals to accommodate the impedance characteristics of linear amplifiers. Resonant amplification, however, naturally utilizes the distributed parameters of the load itself to form a resonant circuit, reducing the traditionally complex matching circuit to a simple tuning element. The air-core transformer abandons the ferrite core, employing a hollow tube frame and adjustable internal coil design. The inductance parameters can be continuously adjusted through deflection, flexibly compensating for resonant frequency shifts caused by load changes or temperature drift. This further reduces the number of components and design complexity of the matching circuit, and decreases the system size and weight.

[0019] This invention significantly reduces power consumption and cost while improving overall system performance. Resonant amplification primarily utilizes reactive power exchange to boost voltage, resulting in a significant reduction in active power consumption. Combined with the high-efficiency power amplification of silicon carbide MOSFETs, the overall system efficiency is significantly improved, heat generation is reduced, and heat dissipation requirements are lowered. The simplified circuit structure and reduced component count directly lower material and manufacturing costs. Simultaneously, the all-aluminum shielded box structure effectively suppresses electromagnetic interference, improving the system's anti-interference capability and operational stability in complex environments. The overall solution features high reliability, ease of maintenance, and good economic efficiency, representing a significant technological advancement and practical value in the field of mass spectrometer RF power supplies. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the overall structure of an RF power supply for powering a quadrupole of a mass spectrometer according to the present invention; Figure 2 This is a schematic diagram of a high-frequency sinusoidal signal (1MHz~2MHz) in an RF power supply for powering a quadrupole of a mass spectrometer, according to the present invention. Figure 3 This is a schematic diagram of a low-frequency sawtooth wave signal (50~100Hz) in an RF power supply for powering a quadrupole of a mass spectrometer according to the present invention. Figure 4 This is a schematic diagram of the subdivided structure of the power amplifier section in an RF power supply for powering a quadrupole of a mass spectrometer according to the present invention. Figure 5 This is a schematic diagram of signal synthesis in an RF power supply for powering a quadrupole of a mass spectrometer, according to the present invention. Figure 6 This is a schematic diagram of the structure of a hollow transformer in an RF power supply for powering a quadrupole of a mass spectrometer, according to the present invention. Figure 7 This is a schematic diagram of the load in an RF power supply for powering a quadrupole of a mass spectrometer according to the present invention. Figure 8 This is a schematic diagram of the sampling section in an RF power supply for powering a quadrupole of a mass spectrometer according to the present invention; Figure 9 This is a schematic diagram of the PI section in an RF power supply for powering a quadrupole of a mass spectrometer according to the present invention.

[0021] Attached diagram labels: 1. Touchscreen; 2. Main control; 3. Power amplifier section; 4. PI section; 5. Sampling section; 6. Boost section; 7. Load; 8. High voltage DC; 9. DC power supply; 10. Adder; 11. Switching transistor; 12. Shielding box; 13. Hollow tube; 14. Primary coil; 15. Secondary coil; 16. Internal coil. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention discloses an RF power supply for powering a quadrupole in a mass spectrometer. It aims to solve the technical challenge of requiring complex impedance matching circuits at the transformer input and output terminals when existing RF power supplies use multi-stage linear amplification to obtain high-voltage RF envelope signals. This RF power supply provides a high-voltage RF signal to the quadrupole of the mass spectrometer through resonant amplification. It utilizes the resonant effect generated by matching the fundamental frequency with the resonant frequency of the capacitor and resistor at the 7-terminal load of the transformer to efficiently amplify the voltage to the kilovolt level, significantly reducing system complexity and power consumption costs.

[0024] like Figure 1 The system architecture shown is as follows: the present invention includes a touchscreen 1, a central control unit 2, a power amplifier section 3, a boost section 6, a load 7, a high-voltage DC power supply 8, a sampling section 5, and a PI section 4. The touchscreen 1 provides a human-machine interface, offering an intuitive control interface to the operator, displaying real-time system operating status information, and receiving operation commands through the interface to transmit them to the central control unit 2, achieving two-way information interaction. The central control unit 2, as the core control unit of the system, receives control commands from the touchscreen 1 and coordinates the collaborative work of various functional modules. Specifically, it generates two key signals: one is a high-frequency DDS sine wave signal with a frequency range of 1MHz to 2MHz, which is output to the power amplifier section 3 as an RF carrier; the other is a standard DAC sawtooth wave signal with a frequency range of 50Hz to 100Hz, which is output to the PI section 4 as a reference envelope waveform.

[0025] The PI section 4 receives the standard sawtooth wave signal from the master control 2 and the actual envelope signal fed back from the sampling section 5. It generates a corrected sawtooth wave signal through differential operation, which is then transmitted to the power amplifier section 3 to optimize the envelope linearity of the drive signal. The power amplifier section 3 simultaneously receives the high-frequency DDS sine wave signal output from the master control 2 and the corrected sawtooth wave signal provided by the PI section 4. After combining the two signals, they are amplified by the silicon carbide MOS switch 11. The amplified drive signal is then input to the primary side of the air-core transformer in the boost section 6. The secondary side of the air-core transformer in the boost section 6 is directly connected to the load 7, i.e., the quadrupole, efficiently transmitting the resonant amplified high-voltage envelope signal to the quadrupole. Simultaneously, the high-voltage DC 8 power supply is connected to the two sets of series-connected metal rod structures of the quadrupole, providing it with forward and reverse high-voltage DC 8 bias signals. Sampling section 5 is connected to load 7 (quadrupole). It acquires the raw voltage signal from the quadrupole via a high-voltage isolation capacitor. After rectification and filtering, the envelope signal is extracted and fed back to PI section 4. This envelope signal is then differentially compared with a standard sawtooth wave, forming a closed-loop negative feedback control circuit to ensure excellent linearity of the output signal envelope. These components, connected as described, constitute a complete signal transmission and control link, jointly fulfilling the core function of providing a stable high-frequency, high-voltage envelope signal for the mass spectrometer quadrupole.

[0026] The internal structure of power amplifier section 3 includes adder 10 and switching transistor 11. The high-frequency DDS sine wave signal output from master control 2 and the corrected sawtooth wave signal transmitted from PI section 4 are both input to the input terminal of adder 10. Adder 10 performs analog superposition and synthesis of the two signals, and its output terminal is directly connected to the control terminal of switching transistor 11, providing a composite drive signal for switching transistor 11. A 30V to 50V DC power supply is directly connected to the power supply terminal of switching transistor 11, providing a stable operating voltage for power amplification. The output terminal of switching transistor 11 is connected to the primary side of the air-core transformer of boost section 6, transmitting the amplified power signal to the transformer.

[0027] The function of power amplifier section 3 is as follows: Adder 10 accurately synthesizes the high-frequency carrier and low-frequency envelope signal to generate a composite signal adapted to the drive of switch 11; switch 11 fully utilizes its technical advantages of significantly lower internal resistance than traditional silicon-based MOSFETs, low switching loss, and low heat generation to efficiently amplify the drive signal under a 30V to 50V DC power supply 9, ultimately providing a stable input signal that meets the power requirements for the resonant amplification process of boost section 6, laying a solid foundation for obtaining the high-voltage RF envelope signal. As a preferred example, switch 11 is a silicon carbide MOSFET, which has the advantages of low internal resistance and low heat generation compared to traditional switch 11. This switch 11 is powered by a 30~50V DC power supply.

[0028] The boost section 6 mainly consists of a specially designed hollow transformer. This hollow transformer uses a hollow tube 13 as its magnetic core frame. Its core components include the hollow tube 13, primary coil 14, secondary coil 15, and a fully enclosed aluminum shielding box 12. An internal coil 16 for parameter adjustment can also be installed inside the hollow tube 13. The connection relationships and functional configurations of each component are as follows: the primary coil 14 is connected to the output terminal of the switching transistor 11 of the power amplifier section 3, receiving the amplified drive signal; the secondary coil 15 is connected to the load 7 (quadrupole), responsible for transmitting the amplified high-voltage signal to the quadrupole. The internal coil 16 can continuously adjust the effective inductance parameter of the transformer through deflection, thereby flexibly adapting to the precise frequency matching requirements of resonant amplification and compensating for resonant frequency shifts caused by changes in the load 7 or ambient temperature drift. The shielding box 12 adopts a fully enclosed aluminum box structure, effectively isolating external electromagnetic interference and suppressing the transformer's own leakage magnetic radiation, ensuring stable and reliable operation of the transformer in complex electromagnetic environments. This hollow tube 13 structure transformer abandons the traditional ferrite core, avoiding core saturation and nonlinear distortion problems, and is particularly suitable for high-frequency and high-voltage applications.

[0029] Resonant amplification is the core technical principle of this invention. The air-core transformer operates with a primary side and a secondary side. The primary side receives the high-frequency drive signal amplified by the MOS switch 11, while the secondary side is connected to the quadrupole load 7. The quadrupole and the transformer's secondary windings themselves possess a certain distributed inductance L and equivalent capacitance C, thus forming an LC resonant circuit. The inherent resonant frequency of this circuit is determined by the following formula:

[0030] When the frequency of the DDS sinusoidal signal generated by the main control unit 2 precisely reaches the resonant frequency f, the secondary circuit of the transformer achieves series or parallel resonance. At this time, the circuit impedance characteristics ensure that the voltage and current phases are synchronized, and energy is efficiently exchanged between the inductor and capacitor, thereby achieving the maximum resonant amplification effect at the transformer output and obtaining a high voltage. This resonant amplification mechanism can achieve voltage multiplication simply through frequency tuning, without the need for a complex impedance transformation network, fundamentally simplifying the matching circuit design.

[0031] In this embodiment, load 7 is a quadrupole. The core component of the quadrupole consists of four precision-machined rod-shaped metal parts with strict geometric accuracy and surface finish. Electrically, every two metal rods are connected in series, forming two sets of series structures, which respectively receive the positive and negative high-voltage envelope signals. In addition to the resonant amplified high-voltage envelope signal applied by the transformer, the system also applies positive and negative high-voltage DC bias signals 8 to these two sets of series-connected metal rod structures. Through the combined effect of the radio frequency high voltage and the DC bias electric field, precise control of ion movement and mass screening functions are achieved.

[0032] The sampling section 5 directly couples the raw high-voltage radio frequency voltage signal from the quadrupole via a high-voltage isolation capacitor. This high-voltage isolation capacitor serves both voltage reduction and electrical isolation functions, safely attenuating the high-voltage signal to a low-voltage range suitable for subsequent circuit processing. The acquired signal undergoes envelope detection by a rectifier circuit, followed by smoothing by a filter circuit to accurately extract the DC signal reflecting the actual output envelope shape. This envelope signal is fed back to the PI circuit, completing the isolation sampling and signal conditioning functions on the high-voltage side.

[0033] The PI section 4 receives the actual envelope signal acquired by the sampling section 5 and the standard sawtooth wave reference signal generated by the main control section 2. It performs differential operations on the two signals to obtain an error signal characterizing the deviation between the actual output and the ideal value. This error signal is then superimposed on the reference sawtooth wave to generate a corrected sawtooth wave signal. This corrected signal contains the difference information between the quadrupole terminal signal and the standard signal. This difference signal dynamically corrects the drive signal at the output terminal, enabling real-time compensation and optimization of the envelope linearity of the output signal, ultimately ensuring that the system output envelope has good linearity and stability.

[0034] This invention, through a resonant amplification technology, significantly simplifies the impedance matching circuit structure on both sides of the transformer. The complex LC matching network required by traditional multi-stage linear amplification can be reduced to simple tuning elements, significantly decreasing the number of components and design complexity of the matching circuit. Simultaneously, resonant amplification utilizes reactive power exchange to achieve voltage boost, greatly reducing active power consumption, improving overall system efficiency, and decreasing heat generation. The simplification of the circuit structure and the reduction in the number of components directly lower material and manufacturing costs, improve system reliability and maintainability, and represent a significant technological advancement and economic value in the field of mass spectrometer RF power supplies.

[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A radio frequency power supply for powering a quadrupole in a mass spectrometer, characterized in that, It includes a master control unit (2), a power amplifier section (3), a boost section (6), a sampling section (5), and a PI section (4); The master control (2) is used to generate high-frequency sine wave signals and low-frequency reference envelope signals; The power amplifier section (3) receives the high-frequency sine wave signal and the corrected envelope signal, and outputs them to the boost section (6) after power amplification. The boost section (6) includes a hollow transformer, whose primary side is connected to the output terminal of the power amplifier section (3) and whose secondary side is connected to the load (7). The sampling section (5) acquires voltage signals from the load (7) and extracts the actual envelope signal; The PI section (4) receives the low-frequency reference envelope signal and the actual envelope signal, generates the corrected envelope signal through differential operation, and feeds it back to the power amplifier section (3). The load (7) is a quadrupole, and the frequency of the high-frequency sine wave signal matches the inherent resonant frequency of the LC resonant circuit formed by the secondary side of the hollow transformer and the load (7) of the quadrupole. The high-voltage radio frequency envelope signal is generated on the secondary side through resonance amplification.

2. The radio frequency power supply for powering a quadrupole in a mass spectrometer according to claim 1, characterized in that, The power amplifier section (3) includes an adder (10) and a switch (11); the adder (10) combines the high-frequency sine wave signal and the modified envelope signal and outputs the result to the control terminal of the switch (11); the switch (11) is powered by a DC power supply, amplifies the combined signal and outputs it to the primary side of the boost section (6).

3. The radio frequency power supply for powering a quadrupole in a mass spectrometer according to claim 1, characterized in that, The hollow transformer includes a hollow tube (13), a primary coil (14), a secondary coil (15), and a shielding box (12); the primary coil (14) and the secondary coil (15) are wound on the hollow tube (13).

4. The radio frequency power supply for powering a quadrupole in a mass spectrometer according to claim 3, characterized in that, The hollow transformer also includes an internal coil (16) disposed inside the hollow tube (13), and the internal coil (16) adjusts the effective inductance parameter of the transformer by deflection action.

5. The radio frequency power supply for powering a quadrupole in a mass spectrometer according to claim 1, characterized in that, The quadrupole consists of four metal rods, with each pair of metal rods connected in series to receive positive and negative high-voltage radio frequency envelope signals respectively, and superimposed with a high-voltage DC (8) bias signal.

6. The radio frequency power supply for powering a quadrupole in a mass spectrometer according to claim 5, characterized in that, The sampling section (5) includes a high-voltage isolation capacitor, a rectifier circuit, and a filter circuit. The high-voltage isolation capacitor acquires the high-voltage signal from the quadrupole coupling and steps down the voltage for isolation. After processing by the rectifier circuit and the filter circuit, the actual envelope signal is extracted.

7. The radio frequency power supply for powering a quadrupole in a mass spectrometer according to claim 1, characterized in that, The PI part (4) performs a differential operation on the reference envelope signal and the actual envelope signal to obtain an error signal, and then superimposes the error signal with the reference envelope signal to generate the corrected envelope signal.

8. The radio frequency power supply for powering a quadrupole in a mass spectrometer according to claim 1, characterized in that, The inherent resonant frequency of the LC resonant circuit is determined by the following formula. Where L is the distributed inductance of the transformer secondary winding and the quadrupole, and C is the equivalent capacitance.

9. A radio frequency power supply for powering a quadrupole in a mass spectrometer according to any one of claims 1-8, characterized in that, It also includes a touch screen (1), which communicates bidirectionally with the main control (2) unit.

10. A radio frequency power supply for powering a quadrupole in a mass spectrometer according to any one of claims 1-8, characterized in that, The high-frequency sine wave signal is a DDS sine wave signal with a frequency of 1MHz to 2MHz, and the reference envelope signal is a DAC sawtooth wave signal with a frequency of 50Hz to 100Hz.

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