Control box matching circuit and system of magnetic suspension molecular pump system

Abstract

The application relates to the technical field of magnetic suspension molecular pumps, and discloses a control box matching circuit and system of a magnetic suspension molecular pump system, wherein the magnetic suspension molecular pump system comprises a pump body and a control box; the control box matching circuit comprises the following: the signal pre-correction module is configured to perform amplitude modulation and frequency offset processing on original sampling signals output by sensors in the pump body to obtain corrected sampling signals, so that the corrected sampling signals match preset standard signal conditions; and the signal matching module is configured to perform amplitude modulation and frequency offset processing on the corrected sampling signals to obtain target sampling signals, so that the target sampling signals match signal input conditions of the control box. The application improves the compatibility between the pump body and the control box, thereby greatly improving maintenance and equipment interchange efficiency.

Description

Technical Field

[0001] This application relates to the field of magnetic levitation molecular pump technology, and in particular to a control box matching circuit and system for a magnetic levitation molecular pump system. Background Technology

[0002] Magnetic levitation molecular pumps typically use position sensors to detect radial, axial, or attitude-related parameters of the rotor. The control box performs signal conditioning, analog-to-digital conversion, control calculations, and output based on the collected sensor signals, thereby achieving stable levitation of the rotor.

[0003] Due to inconsistencies in the internal sensors and installation status of different pump bodies, a one-to-one matching process is often required between the pump body and the control box. Furthermore, differences in the front-end input structure of different control boxes can further amplify these inconsistencies. Consequently, after replacing the pump body or control box on-site, recalibration is often required, which seriously affects the compatibility between the pump body and the control box and reduces the efficiency of maintenance and equipment exchange. Summary of the Invention

[0004] This application provides a control box matching circuit and system for a magnetic levitation molecular pump system, which solves the technical problems of poor interchangeability, low maintenance and replacement efficiency, and insufficient spare parts universality between the pump body and control box of the current magnetic levitation molecular pump. It improves the compatibility between the pump body and control box, thereby greatly improving the efficiency of maintenance and equipment interchangeability.

[0005] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, this application provides a control box matching circuit for a magnetic levitation molecular pump system, the magnetic levitation molecular pump system including a pump body and a control box, and the control box matching circuit including: A signal pre-calibration module is configured to perform amplitude modulation and bias modulation processing on the original sampling signal output by the sensor in the pump body to obtain a calibrated sampling signal, so that the calibrated sampling signal matches the preset standard signal conditions. A signal matching module is configured to perform amplitude modulation and bias modulation processing on the corrected sampling signal to obtain a target sampling signal, such that the target sampling signal matches the signal input conditions of the control box.

[0006] The control box matching circuit proposed in this application pre-calibrates the original sensor outputs using a signal pre-calibration module, ensuring that the outputs of various sensors from different pumps are pre-calibrated to a unified standard range. Then, the signal matching module performs secondary amplitude modulation and bias adjustment on the calibrated sampled signals, thereby matching the pump outputs with the control box input conditions. Through the synergistic effect of these two-stage signal conditioning, the outputs of different pumps are unified into a standard signal that can be stably received by the same control box. This significantly reduces the impact of individual sensor differences between different pumps and variations in cable length on signal quality, enabling different control boxes to adapt to different magnetic levitation molecular pumps. This achieves interchangeable connection and control between the magnetic levitation molecular pumps and the control box from a hardware signal consistency perspective, effectively improving the compatibility and versatility between the control box and different magnetic levitation molecular pumps, thus greatly improving maintenance and equipment interchangeability efficiency.

[0007] Optionally, the signal pre-calibration module is disposed in the pump body, and the signal matching module is disposed in the control box.

[0008] This application integrates a signal pre-calibration module within the pump body, enabling the original sampled signal output from the sensor to undergo pre-amplitude and offset modulation processing within the pump itself, thus reducing the risk of distortion and interference during long-distance transmission of the sensor's sampled signal. Simultaneously, a signal matching module is integrated into the control box to perform secondary processing on the calibrated sampled signal from the pump body, achieving matching between the pump body's output and the control box's input conditions. This allows for interchangeable use between different pump bodies and different control boxes.

[0009] Optionally, the signal pre-calibration module includes: A reference signal generation unit is configured to generate a reference signal based on a preset reference power supply. A first signal processing unit is configured to perform amplitude modulation processing on the original sampled signal to obtain a first conditioning signal, and generate the corrected sampled signal based on the reference signal and the first conditioning signal.

[0010] This application utilizes a first signal processing unit to adjust the gain of the original sampled signal and a reference signal generation unit to provide a stable reference zero point. Then, the first conditioning signal after amplitude modulation is compared and superimposed with the reference signal to realize the zero point offset adjustment of the sensor output, so that the sensor output of different pump bodies completes the uniform standard preprocessing within the pump.

[0011] Optionally, the reference signal generation unit includes a first adjustable resistor and a voltage follower. The first end of the first adjustable resistor is adapted to be connected to a preset reference power supply. The second end of the first adjustable resistor is connected to the non-inverting input of the voltage follower. The inverting input of the voltage follower is connected to the output of the voltage follower. The output of the voltage follower is adapted to output the reference signal. The reference signal generation unit is configured to divide the preset reference power supply by adjusting the first adjustable resistor to generate the reference signal according to the voltage division result, and to buffer and output the reference signal through the voltage follower.

[0012] This application utilizes a reference signal to provide an adjustable zero-point reference, which, in conjunction with a voltage follower, performs impedance transformation and buffered output, ensuring that the reference signal has a stable potential and low output impedance. This guarantees that subsequent circuits will not significantly pull the potentiometer slider voltage when calling the reference signal, which is beneficial for the long-term stability of the reference zero point. On the one hand, by providing a reference signal, it can offset the DC bias caused by sensor installation gaps, individual probe differences, and the output of the pre-stage detector, enabling the subsequent first signal processing unit to organize the signal around a unified zero-point reference, providing a reliable reference for consistent matching of different pump bodies. On the other hand, the reference signal is generated by the voltage division effect of the preset reference power supply through the first adjustable resistor, effectively improving the flexibility of reference signal generation.

[0013] Optionally, the first signal processing unit includes a first operational amplifier and a second adjustable resistor, wherein the non-inverting input of the first operational amplifier is adapted to receive the original sampled signal, the inverting input of the first operational amplifier is connected to the first terminal of the second adjustable resistor, and the output of the first operational amplifier is connected to the second terminal of the second adjustable resistor. The first signal processing unit is configured to adjust the closed-loop gain parameter of the first operational amplifier by adjusting the resistance value of the second adjustable resistor, and to perform amplitude modulation processing on the original sampled signal according to the closed-loop gain parameter to obtain the first conditioning signal.

[0014] This application constructs an adjustable gain structure by setting an operational amplifier with an adjustable feedback resistor, and uses a second adjustable resistor to adjust the closed-loop gain to compensate for the sensitivity differences between sensors of different probes, different installation states and different pump bodies, so that the output amplitude of the same channel of each pump body falls into a unified target range, and the sensor output consistency matching is completed.

[0015] Optionally, the first signal processing unit further includes a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor. The first conditioning signal is input to the non-inverting input terminal of the second operational amplifier via the first resistor. The reference signal is input to the inverting input terminal of the second operational amplifier via the second resistor. The output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier via the third resistor. The output terminal of the second operational amplifier is connected to the first terminal of the fourth resistor. The second terminal of the fourth resistor is adapted to output the correction sampling signal, and the second terminal of the fourth resistor is grounded via the first capacitor. The first signal processing unit is further configured to obtain the corrected sampling signal by performing zero-point offset adjustment and signal shaping processing on the first conditioning signal according to the reference signal through the second operational amplifier.

[0016] This application uses a second operational amplifier, along with a resistor network and a capacitor, to differentially combine the amplitude-modulated first conditioning signal with the reference signal, achieving zero-point shift and level window matching. At the same time, it uses the first capacitor and the third resistor to form an RC network to suppress high-frequency glitches and cable coupling spikes. This allows the calibration sampling signal to complete the unified processing of amplitude modulation and bias adjustment within the pump, providing a standardized signal foundation for subsequent secondary signal conditioning in the control box.

[0017] Optionally, the signal matching module includes an isolation unit and a second signal processing unit, wherein the isolation unit is configured to buffer and transmit the corrected sampling signal to the second signal processing unit, and the second signal processing unit is configured to perform amplitude modulation processing on the corrected sampling signal to obtain a second conditioning signal, and generate the target sampling signal according to the reference signal and the second conditioning signal.

[0018] This application significantly reduces additional errors introduced by variations in the length of the connecting cable, differences in interface contact, and variations in the load of subsequent circuits by setting an isolation unit in the signal matching module to buffer and isolate the correction sampling signal from the pump body. Simultaneously, a second signal processing unit performs secondary amplitude modulation and bias adjustment on the buffered correction sampling signal, achieving precise matching between the pump body output and the signal input conditions of the control box.

[0019] Optionally, the isolation unit includes a third operational amplifier, the non-inverting input of which is adapted to receive the correction sampling signal, the inverting input of which is connected to the output of which is connected to the second signal processing unit.

[0020] This application sets up a third operational amplifier that operates as a unity-gain voltage follower. It can first perform high-impedance input and low-impedance output buffering on the correction sampling signal transmitted from the pump body to the control box via the connecting cable. This makes the front end of the control box present a high-impedance input to the front-end signal that is approximately open, without needing to directly drive the complex back-end network in the control box. Therefore, it can improve the interchangeability and compatibility between different control boxes and different pump bodies.

[0021] Optionally, the second signal processing unit includes: A fourth operational amplifier is configured to perform amplitude modulation processing on the correction sampling signal to obtain a second conditioning signal, wherein the non-inverting input of the fourth operational amplifier is connected to the output of the third operational amplifier, the inverting input of the fourth operational amplifier is connected to the output of the fourth operational amplifier, and the output of the fourth operational amplifier is adapted to output the second conditioning signal. A fifth operational amplifier is configured to bias the second conditioning signal according to the reference signal to obtain a third conditioning signal, wherein the non-inverting input of the fifth operational amplifier is adapted to receive the reference signal, the inverting input of the fifth operational amplifier is connected to the output of the fourth operational amplifier and the output of the fifth operational amplifier respectively, and the output of the fifth operational amplifier is adapted to output the third conditioning signal. A sixth operational amplifier is configured to filter the third conditioning signal to obtain the target sampling signal, wherein the non-inverting input of the sixth operational amplifier is connected to the output of the fifth operational amplifier, the inverting input of the sixth operational amplifier is connected to the output of the sixth operational amplifier, and the output of the sixth operational amplifier is adapted to output the target sampling signal.

[0022] This application uses a fourth operational amplifier, a fifth operational amplifier, and a sixth operational amplifier to form a cascaded amplitude modulation stage circuit, a bias adjustment stage circuit, and a filter stage circuit. The amplitude modulation stage circuit eliminates the residual channel differences after signal conditioning within the pump. The bias adjustment stage circuit shifts the signal level to within the analog-to-digital sampling range of the digital signal processor (DSP) chip in the control box. At the same time, the filter stage circuit filters out high-frequency oscillation residues and coupling noise from the air cable transmission. Through the coordinated processing of these three stages, the target sampling signal input to the DSP chip meets the sampling accuracy and control accuracy requirements, enabling stable interchange between the control box and the magnetic levitation molecular pump.

[0023] Secondly, embodiments of this application provide a magnetically levitated molecular pump system, comprising: Pump body; Control box; And the control box matching circuit of the aforementioned magnetic levitation molecular pump system.

[0024] The magnetic levitation molecular pump system proposed in this application incorporates a control box matching circuit on top of the pump body and control box. This circuit unifies the outputs of different pump bodies into a standard signal that can be stably received by the same control box. This significantly reduces the impact of individual sensor differences between different pump bodies and variations in the length of the connecting cable on signal quality. It enables different control boxes to be compatible with different magnetic levitation molecular pumps, achieving interchangeable connection and control between the magnetic levitation molecular pump and the control box from the perspective of hardware signal consistency. This effectively improves the compatibility and versatility between the control box and different magnetic levitation molecular pumps, thereby greatly improving maintenance and equipment interchangeability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the control box matching circuit of a magnetic levitation molecular pump system provided in this application embodiment; Figure 2 Another schematic diagram of the control box matching circuit of a magnetic levitation molecular pump system provided in the embodiments of this application; Figure 3 A schematic diagram of the circuit structure of the reference signal generation unit provided in an embodiment of this application; Figure 4 A schematic diagram of the circuit structure of the first signal processing unit provided in an embodiment of this application; Figure 5 This is a schematic diagram of the circuit structure of the signal matching module provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0029] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0030] Currently, magnetic levitation molecular pump systems typically include a pump body and a control box. The pump body has built-in sensors to detect the rotor position, and the DSP chip in the control box performs signal conditioning, analog-to-digital conversion, control calculations, and drives the magnetic bearing based on the sensor signals, thereby achieving stable levitation of the rotor.

[0031] In related technologies, pump bodies and control boxes generally adopt a one-to-one matching mode. The reason is that different pump bodies have discrete internal sensors and installation status, resulting in inconsistencies in zero point, gain and output amplitude. Moreover, when sensor signals are transmitted over long distances via avionics cables, they are easily affected by cable distributed capacitance, load effect and external interference. In addition, the differences in the front-end input structure of different control boxes will further amplify the above inconsistencies, so that recalibration is often required after replacing the pump body or control box in the field.

[0032] However, as the demand for rapid on-site maintenance and universal spare parts for magnetic levitation molecular pump systems becomes increasingly prominent, this one-to-one matching mode means that after replacing the pump body or control box, on-site calibration and parameter matching must be performed again, which seriously affects the compatibility between the pump body and the control box and reduces the efficiency of maintenance and equipment interchange.

[0033] Therefore, there is an urgent need for a solution that enables different control boxes to be adapted to different magnetic levitation molecular pumps in application scenarios that allow for rapid maintenance and modular replacement.

[0034] This application provides a control box matching circuit 10 for a magnetic levitation molecular pump system, such as... Figure 1As shown, the control box matching circuit 10 can be used in a magnetic levitation molecular pump system, which includes a pump body 20 and a control box 30. The control box matching circuit 10 includes a signal pre-calibration module 11 and a signal matching module 12. The signal pre-calibration module 11 is configured to perform amplitude modulation and bias modulation processing on the raw sampling signal UF_SAX output by the sensor 21 within the pump body 20 to obtain a calibrated sampling signal Ax_OUT, such that the calibrated sampling signal Ax_OUT matches a preset standard signal condition. The signal matching module 12 is configured to perform amplitude modulation and bias modulation processing on the calibrated sampling signal Ax_OUT to obtain a target sampling signal, such that the target sampling signal matches the signal input condition of the control box 30.

[0035] Specifically, the preset standard signal conditions refer to the pre-set voltage range and zero-point reference voltage (i.e., the signal voltage value corresponding to the rotor center) used to unify the output signal characteristics of different pump bodies 20. This ensures that the calibration sampling signal Ax_OUT corresponding to the sensor 21 of different pump bodies 20 is consistent under the same operating state, thereby eliminating the output dispersion caused by differences in the sensitivity of the sensor 21 and the differences in the installation state between different pump bodies 20. For example, the preset standard signal conditions can be set to a voltage range of 0V to 5V, and the voltage corresponding to the rotor being in the center position is 2.5V.

[0036] In some embodiments of this application, the signal pre-calibration module 11 is connected to each sensor 21 within the pump body 20. It receives the original sampling signal UF_SAX output by the sensor 21, changes the amplitude of the original sampling signal UF_SAX through amplitude modulation processing, so that it falls within the voltage range specified by the preset standard signal conditions, and changes the zero-point level of the original sampling signal UF_SAX through bias adjustment processing. That is, the calibrated sampling signal Ax_OUT obtained when the rotor is in the center position should be equal to the zero-point reference voltage required by the preset standard signal conditions. Thus, the calibrated sampling signals Ax_OUT output by the signal pre-calibration module 11 from different sensors 21 under the same rotor displacement all fall within the uniform range specified by the preset standard signal conditions and have a uniform zero-point reference voltage. In this way, different pump bodies 20 present consistent signal interface characteristics to the outside world. The signal input conditions of the control box 30 refer to the analog input voltage range and zero-point level required by the analog-to-digital converter (ADC) of the DSP chip in the control box 30 for analog-to-digital sampling. The ADC input range of the DSP chip may vary between different models or manufacturers of the control box 30. For example, some DSP chips require an analog input voltage range of 0V to 3.3V and also have different requirements for the zero-point reference voltage.

[0037] The aforementioned signal matching module 12 is connected to the aforementioned signal pre-calibration module 11 via a connecting cable to receive the calibration sampling signal Ax_OUT output by the signal pre-calibration module 11. Subsequently, the signal matching module 12 performs amplitude modulation and bias adjustment processing on the calibration sampling signal Ax_OUT again, further conditioning the calibration sampling signal Ax_OUT, which has already been unified to the preset standard signal conditions, into a target sampling signal that perfectly matches the actual ADC sampling window of the control box 30, thereby ensuring that the DSP chip can acquire and process the signal with high precision.

[0038] Therefore, the control box matching circuit 10 provided in this embodiment, through the above-described two-stage conditioning architecture, eliminates the need for one-to-one matching between the pump body 20 and the control box 30. The signal pre-calibration module 11 ensures that different pump bodies 20 exhibit consistent signal characteristics, which facilitates the rapid adaptation of the pump body 20 to the signal input conditions of different control boxes 30. Simultaneously, the signal matching module 12 further conditions the uniformly characteristic calibration sampling signal Ax_OUT into a target sampling signal that matches the input conditions of the control box 30's own DSP chip, enabling interchangeable use between the control box 30 and the magnetic levitation molecular pump.

[0039] It should be noted that the specific numerical ranges of the preset standard signal conditions and the specific numerical ranges of the signal input conditions of the control box 30 involved in the above embodiments are only illustrative examples. In practical applications, other suitable numerical ranges or fixed values ​​can be selected according to the system design requirements. This application does not limit this.

[0040] The control box matching circuit 10 provided in this embodiment performs pre-amplitude modulation and bias adjustment on the original sampling signal of the sensor 21 by setting a signal pre-calibration module 11, so that the output of each sensor 21 of different pump bodies 20 is pre-calibrated to a unified standard range. Then, the signal matching module 12 performs secondary amplitude modulation and bias adjustment on the calibrated sampling signal Ax_OUT, thereby achieving matching between the output of the pump body 20 and the input conditions of the control box 30. In this way, through the synergistic effect of two-stage signal conditioning, the output of different pump bodies 20 is unified into a standard signal that can be stably received by the same control box 30. This can significantly reduce the impact of individual differences of the sensor 21 between different pump bodies 20 and the variation of the flight line length on signal quality, so that different control boxes 30 can be adapted to different magnetic levitation molecular pumps. From the perspective of hardware signal consistency, it realizes the interchangeable connection and interchangeable control between the magnetic levitation molecular pump and the control box 30, effectively improving the compatibility and universality between the control box 30 and different magnetic levitation molecular pumps, thereby greatly improving the efficiency of maintenance and equipment interchangeability.

[0041] Optionally, the signal pre-calibration module 11 is located in the pump body 20, and the signal matching module 12 is located in the control box 30.

[0042] Specifically, the signal pre-calibration module 11 is located inside the pump body 20 and its input terminal is connected to the sensor 21 inside the pump body 20. This shortens the signal transmission distance between the sensor 21 and the signal pre-calibration module 11, so that the original sampling signal UF_SAX output by the sensor 21 can complete the pre-amplitude modulation and bias adjustment processing inside the pump, reducing the risk of distortion and interference in the long-distance transmission of the sampling signal of the sensor 21.

[0043] Simultaneously, the signal matching module 12 is configured inside the control box 30. The output of the signal pre-calibration module 11 is connected to the input of the signal matching module 12 via a connector cable, and the output of the signal matching module 12 is connected to the DSP chip inside the control box 30. The signal matching module 12 performs secondary processing on the calibration sampling signal Ax_OUT from the pump body 20 to match the output of the pump body 20 with the input conditions of the control box 30, thereby allowing different pump bodies 20 and different control boxes 30 to be used interchangeably.

[0044] In some embodiments of this application, the sensor 21 within the pump body 20 can be an eddy current displacement sensor. The eddy current probe generates an alternating magnetic field under high-frequency oscillation excitation. When the rotor's metal detection surface approaches the probe, an eddy current effect is formed, thereby changing the probe coil impedance and causing the detection signal amplitude to vary with the detection gap. Preferably, a crystal oscillator is used at the front end of the sensor 21 to generate a high-frequency oscillation signal, which is then converted into a sinusoidal excitation signal by an internal oscillation circuit. The excitation frequency is preferably 2MHz to 7MHz. After half-wave detection by a diode, the high-frequency amplitude change is converted into a displacement-related DC sampling signal. Furthermore, to suppress temperature drift and enhance noise immunity, two symmetrically arranged eddy current probes are preferably provided in each detection direction.

[0045] It should be noted that each of the radial, axial, or attitude-related parameters of the rotor of the pump body 20 corresponds to a sensor channel, and each sensor channel corresponds to a control box matching circuit 10. The following description uses the sensor channel corresponding to the radial (AX direction) rotor inside the pump body 20 as an example to illustrate the embodiment of this application. The same applies to the sensor channels corresponding to the rotor axial direction and other attitude-related parameters, and will not be described in detail here.

[0046] Figure 2 This paper shows another structural schematic diagram of the control box matching circuit 10 in an embodiment of this application, as shown below. Figure 2 As shown, in some embodiments of this application, the signal pre-calibration module 11 includes a reference signal generation unit 111 and a first signal processing unit 112. The reference signal generation unit 111 is configured to generate a reference signal based on a preset reference power supply, and the first signal processing unit 112 is configured to perform amplitude modulation processing on the original sampled signal UF_SAX to obtain a first conditioning signal, and generate a calibration sampled signal Ax_OUT based on the reference signal and the first conditioning signal.

[0047] Specifically, the reference signal generation unit 111 is responsible for generating a reference signal, which represents the zero-point reference voltage in the aforementioned preset standard signal conditions and is used for subsequent bias adjustment processing. The first signal processing unit 112 is connected to both the sensor 21 and the reference signal generation unit 111. On one hand, it receives the original sampling signal UF_SAX output by the sensor 21 and performs amplitude modulation processing on the original sampling signal UF_SAX to obtain a first conditioning signal, in order to compensate for the sensitivity differences between different probes, different installation states, and different pump bodies 20 and sensors 21, so that the amplitude of the output first conditioning signal falls within a unified target range. On the other hand, the first signal processing unit 112 receives the aforementioned reference signal and the first conditioning signal, and by differentially combining the first conditioning signal and the reference signal, it enables the subsequent signal shaping of the first conditioning signal to be performed around the unified zero-point reference corresponding to the reference signal, thereby outputting a corrected sampling signal Ax_OUT.

[0048] In this embodiment, the first signal processing unit 112 is used to adjust the gain of the original sampling signal UF_SAX, and the reference signal generation unit 111 is used to provide a stable reference zero point. Then, the first conditioning signal after amplitude modulation is compared and superimposed with the reference signal to realize the zero point offset adjustment of the sensor 21 output, so that the sensor 21 output of different pump bodies 20 completes the uniform standard preprocessing within the pump.

[0049] Figure 3 A schematic diagram of the circuit structure of the reference signal generation unit 111 in an embodiment of this application is shown, as follows: Figure 3 As shown, the reference signal generation unit 111 includes a first adjustable resistor RJ1 and a voltage follower UPD. The first end of the first adjustable resistor RJ1 is adapted to connect to a preset reference power supply, the second end of the first adjustable resistor RJ1 is connected to the non-inverting input of the voltage follower UPD, the inverting input of the voltage follower UPD is connected to the output of the voltage follower UPD, and the output of the voltage follower UPD is adapted to output a reference signal. The reference signal generation unit 111 is configured to divide the preset reference power supply by adjusting the first adjustable resistor RJ1 to generate a reference signal based on the voltage division result, and then buffer and output the reference signal through the voltage follower UPD.

[0050] Specifically, the first adjustable resistor RJ1 can be a sliding potentiometer with a maximum resistance of 100kΩ, or one or more of a precision surface-mount resistor network, a DIP switch resistor network, or a laser-adjustable resistor network. The two ends of the first adjustable resistor RJ1 are connected to a preset reference power supply and a reference ground, respectively. By adjusting the position of the sliding arm of the first adjustable resistor RJ1, its voltage division effect on the preset reference power supply is changed, thereby obtaining an adjustable reference signal REF+T. Subsequently, the reference signal REF+T is buffered and output through a voltage follower UPD to obtain the reference signal REF+Ax. The voltage follower UPD is composed of an operational amplifier; in one example of this application embodiment, an operational amplifier with a signal of LM2902 is used. Since the reference signal REF+Ax has a low output impedance after being output through the voltage follower UPD, subsequent stages will not significantly pull the voltage of the potentiometer sliding arm when calling the reference signal REF+Ax, thus contributing to the stability of the reference zero point.

[0051] In this embodiment of the application, when the pump body 20 is calibrated at the factory, the rotor is placed in the standard center position or the standard protection gap position, the zero-point voltage output by the corresponding channel of the sensor 21 is monitored, and the resistance value of the first adjustable resistor RJ1 is adjusted according to the zero-point voltage until the voltage of the reference signal REF+Ax output by the reference signal generation unit 111 matches the zero-point voltage.

[0052] This application embodiment utilizes a reference signal to provide an adjustable zero-point reference. Combined with a voltage follower UPD for impedance transformation and buffered output, the reference signal has a stable potential and low output impedance. This ensures that subsequent circuits do not significantly pull the potentiometer slider voltage when calling the reference signal, which is beneficial for the long-term stability of the reference zero point. On one hand, by providing a reference signal, it can offset the DC bias caused by the sensor 21 mounting gap, individual probe differences, and the output of the pre-stage detector, enabling the subsequent first signal processing unit 112 to organize the signal around a unified zero-point reference, providing a reliable reference for consistent matching of different pump bodies 20. On the other hand, the reference signal is generated by the voltage division effect of the first adjustable resistor RJ1 on the preset reference power supply, effectively improving the flexibility of reference signal generation.

[0053] Figure 4 A schematic diagram of the circuit structure of the first signal processing unit 112 in an embodiment of this application is shown, as follows: Figure 4As shown, the first signal processing unit 112 includes a first operational amplifier U1 and a second adjustable resistor RJ2. The non-inverting input of the first operational amplifier U1 is adapted to receive the original sampled signal UF_SAX. The inverting input of the first operational amplifier U1 is connected to the first terminal of the second adjustable resistor RJ2, and the output of the first operational amplifier U1 is connected to the second terminal of the second adjustable resistor RJ2. The first signal processing unit 112 is configured to adjust the closed-loop gain parameter of the first operational amplifier U1 by adjusting the resistance value of the second adjustable resistor RJ2, and to perform amplitude modulation processing on the original sampled signal UF_SAX according to the closed-loop gain parameter to obtain a first conditioning signal.

[0054] Specifically, the input side of the first operational amplifier U1 is provided with a voltage divider input network consisting of resistors R7 and R8. The feedback side of the first operational amplifier U1 adopts a closed-loop feedback network consisting of resistor R9 and a second adjustable resistor RJ2. In one example of this application embodiment, the resistance values ​​of resistors R7 and R8 can be 10kΩ each, the resistance value of resistor R9 can be 20kΩ, the maximum resistance value of the second adjustable resistor RJ2 can be 100kΩ, and the model of the first operational amplifier U1 is LM2904. The original sampling signal UF_SAX is input through the non-inverting input terminal of the first operational amplifier U1. The first operational amplifier U1 determines the closed-loop gain according to the resistance value of the second adjustable resistor RJ2 between its inverting input terminal and output terminal, amplifies the original sampling signal UF_SAX, and outputs it from its output terminal to obtain the first conditioning signal.

[0055] During factory calibration, using the standard displacement position or standard protection gap as a reference, the output voltage of each sensor channel within the current pump body 20 is measured, and the second adjustable resistor RJ2 corresponding to each channel is adjusted to ensure that the output voltage amplitude of each channel in different pump bodies 20 falls within a uniform voltage range, thereby achieving consistent matching of the sensor 21 output. In this way, by changing the closed-loop gain of the operational amplifier through the adjustable feedback resistor, the sensitivity differences of the sensors 21 in different pump bodies 20 are pre-corrected within the pump.

[0056] This embodiment of the application sets up an operational amplifier with an adjustable feedback resistor to form an adjustable gain structure, and uses the second adjustable resistor RJ2 to adjust the closed-loop gain to compensate for the sensitivity differences between different probes, different installation states and different pump bodies 20 and sensors 21, so that the output amplitude of each channel of each pump body 20 falls into a unified target range, and the output consistency matching of sensor 21 is completed.

[0057] like Figure 4As shown, the first signal processing unit 112 further includes a second operational amplifier U2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first capacitor C1. A first conditioning signal is input to the non-inverting input of the second operational amplifier U2 via the first resistor R1. A reference signal is input to the inverting input of the second operational amplifier U2 via the second resistor R2. The output of the second operational amplifier U2 is connected to the inverting input via the third resistor R3, and the output of the second operational amplifier U2 is connected to the first terminal of the fourth resistor R4. The second terminal of the fourth resistor R4 is adapted to output the corrected sampling signal Ax_OUT, and the second terminal of the fourth resistor R4 is grounded via the first capacitor C1. The first signal processing unit 112 is further configured to obtain the corrected sampling signal Ax_OUT by performing zero-point offset adjustment and signal shaping processing on the first conditioning signal based on the reference signal using the second operational amplifier U2.

[0058] Specifically, in this embodiment, a shaping network consisting of a second operational amplifier U2 and resistors R1 to R5 is used to further refine the first conditioning signal. The non-inverting input of the second operational amplifier U2 receives the first conditioning signal, and the inverting input receives the reference signal. A differential subtraction operation is used to compensate for the zero-point offset of the output signal. The relationship is that the amplitude of the corrected sampling signal Ax_OUT represents the amplitude difference between the first conditioning signal Vout1 and the reference signal REF+Ax. This uses the reference signal REF+Ax to offset the DC bias caused by the sensor 21 mounting gap, individual probe differences, and the output of the pre-stage detector. Simultaneously, an RC network consisting of a fourth resistor R4 and a first capacitor C1 is formed on the output side of the second operational amplifier U2 to suppress high-frequency glitches and cable coupling spikes, outputting the filtered corrected sampling signal Ax_OUT. Furthermore, in some embodiments of this application, resistor R6 is also provided to form a test load branch on the output side of the second operational amplifier U2 to output a detection signal TEST_SAX corresponding to the corrected sampling signal, facilitating consistency detection.

[0059] In one example of an embodiment of this application, the resistance values ​​of resistors R1, R2, R3 and R5 are 100kΩ, the resistance value of resistor R4 is 100Ω, the resistance value of resistor R6 is 7.5kΩ, the capacitance value of capacitor C1 is 100nF, and the model of the second operational amplifier U2 is LM2904.

[0060] In this embodiment, the second operational amplifier U2, in conjunction with a resistor network and a capacitor, differentially combines the amplitude-modulated first conditioning signal with the reference signal to achieve zero-point shift and level window matching. This allows the calibration sampling signal Ax_OUT to complete the unified processing of amplitude modulation and bias adjustment within the pump, providing a standardized signal basis for the subsequent secondary signal conditioning in the control box 30.

[0061] like Figure 2 As shown, in some embodiments of this application, the signal matching module 12 includes an isolation unit 121 and a second signal processing unit 122. The isolation unit 121 is configured to buffer and transmit the correction sampling signal Ax_OUT to the second signal processing unit 122. The second signal processing unit 122 is configured to perform amplitude modulation processing on the correction sampling signal Ax_OUT to obtain a second conditioning signal, and generate a target sampling signal based on the reference signal and the second conditioning signal.

[0062] Specifically, the signal pre-correction module 11 and the signal matching module 12 are connected by a flight cable to achieve signal transmission. In this embodiment, an isolation unit 121 is set in front of the signal matching module 12 for buffer isolation of signal transmission. This can significantly reduce the loading effect caused by the change of distributed capacitance and distributed resistance caused by the change of the length of the flight cable, the change of the input impedance of the subsequent circuit, and the additional voltage drop and signal distortion caused by the fluctuation of the contact state of the connector.

[0063] The second signal processing unit 122 receives the correction sampling signal Ax_OUT buffered out by the isolation unit 121 and performs amplitude adjustment, zero-point offset correction and anti-interference processing on the correction sampling signal Ax_OUT to obtain the target sampling signal that matches the range of the DSP chip in the control box 30. Finally, the DSP chip completes analog-to-digital acquisition, control calculation and subsequent control logic processing.

[0064] Therefore, this embodiment of the application buffers and isolates the correction sampling signal Ax_OUT from the pump body 20 by setting an isolation unit 121 in the signal matching module 12, thereby significantly reducing the additional errors introduced by changes in the length of the connecting cable, differences in interface contact, and changes in the load of subsequent circuits. At the same time, the second signal processing unit 122 performs secondary amplitude modulation and bias adjustment processing on the buffered correction sampling signal Ax_OUT, achieving precise matching between the output of the pump body 20 and the signal input conditions of the control box 30.

[0065] Figure 5 A schematic diagram of the circuit structure of the signal matching module 12 in an embodiment of this application is shown, as follows: Figure 5 As shown, the isolation unit 121 includes a third operational amplifier U3. The non-inverting input of the third operational amplifier U3 is adapted to receive the correction sampling signal Ax_OUT. The inverting input of the third operational amplifier U3 is connected to the output of the third operational amplifier U3, and the output of the third operational amplifier U3 is connected to the second signal processing unit 122.

[0066] Specifically, the third operational amplifier U3 is used as a voltage follower to provide buffer isolation. In one example of this application embodiment, the third operational amplifier U3 is model TL084. The correction sampling signal Ax_OUT is connected to the non-inverting input of the third operational amplifier U3, and the output of the third operational amplifier U3 is directly fed back to the inverting input, forming a unity-gain closed-loop structure. Simultaneously, a ±15V dual power supply is used, and 100nF decoupling capacitors are placed at both the positive and negative power supply terminals to ensure the stable operation of the isolation unit 121.

[0067] Understandably, the output signal of the third operational amplifier U3 is approximately equal to the calibration sampling signal Ax_OUT. Due to its high input impedance and low output impedance, this structure buffers the analog signal transmitted via the air cable, allowing for high-impedance input and low-impedance output. The subsequent precision second signal processing unit 122 then processes the calibration sampling signal Ax_OUT. This way, the pump body 20 only needs to face a nearly open-circuit high-impedance input terminal, without directly driving the complex subsequent network within the control box 30. Consequently, the calibration sampling signal Ax_OUT transmitted via the air cable provides almost no drive current to the subsequent stage of the signal matching module 12, and the subsequent second signal processing unit 122 does not directly load the air cable and the pump sensor 21.

[0068] Therefore, the embodiment of this application sets a third operational amplifier U3 that operates as a unity-gain voltage follower. This amplifier can first perform high-impedance input and low-impedance output buffering on the correction sampling signal Ax_OUT transmitted from the pump body 20 to the control box 30 via the connecting cable. This makes the front end of the control box 30 present a high-impedance input to the front-end signal that is approximately open-circuited, without needing to directly drive the complex back-end network inside the control box 30. Therefore, it can improve the interchangeability and compatibility between different control boxes 30 and different pump bodies 20.

[0069] like Figure 5 As shown, the second signal processing unit 122 includes a fourth operational amplifier U4, a fifth operational amplifier U5, and a sixth operational amplifier U6.

[0070] The fourth operational amplifier U4 is configured to perform amplitude modulation processing on the correction sampling signal Ax_OUT to obtain the second conditioning signal. The non-inverting input of the fourth operational amplifier U4 is connected to the output of the third operational amplifier U3, the inverting input of the fourth operational amplifier U4 is connected to the output of the fourth operational amplifier U4, and the output of the fourth operational amplifier U4 is adapted to output the second conditioning signal.

[0071] Specifically, an amplitude modulation stage circuit is constructed using the fourth operational amplifier U4 and related resistors. This stage is used to further eliminate the remaining channel differences after the internal pump resistor matching, ensuring that the amplitude of the output second conditioning signal meets the uniform requirements. Resistor R10 determines the closed-loop gain parameter of this amplitude modulation stage circuit. During factory testing, the resistance value of resistor R10 is set according to the analog input voltage range required by the corresponding signal input conditions of the DSP chip in the control box 30, so that the amplitude of the calibration sampling signals Ax_OUT from different pump bodies 20 and different channels remains within the same target range after conditioning by the fourth operational amplifier U4.

[0072] The fifth operational amplifier U5 is configured to bias the second conditioning signal according to the reference signal to obtain the third conditioning signal. The non-inverting input of the fifth operational amplifier U5 is adapted to receive the reference signal, the inverting input of the fifth operational amplifier U5 is connected to the output of the fourth operational amplifier U4 and the output of the fifth operational amplifier U5 respectively, and the output of the fifth operational amplifier U5 is adapted to output the third conditioning signal.

[0073] Specifically, a biasing stage circuit is constructed using a fifth operational amplifier U5 and four resistors R11 to R14 with identical resistance values. In one example of this application embodiment, the resistance values ​​of resistors R11 to R14 are all 100kΩ, used to differentially combine the second conditioning signal with the reference signal REF+Ax to achieve zero-point shifting and level window matching. The relationship is that the amplitude of the third conditioning signal Vout3 represents the amplitude difference between the reference signal REF+Ax and the aforementioned second conditioning signal Vout2. Through this biasing stage circuit, the center level of the second conditioning signal can be shifted to the range allowed by the analog-to-digital sampling of the DSP chip, so that the final output third conditioning signal no longer oscillates around the analog ground, but moves to the positive voltage window required by the single-supply ADC.

[0074] The sixth operational amplifier U6 is configured to filter the third conditioning signal to obtain the target sampling signal. The non-inverting input of the sixth operational amplifier U6 is connected to the output of the fifth operational amplifier U5, the inverting input of the sixth operational amplifier U6 is connected to the output of the sixth operational amplifier U6, and the output of the sixth operational amplifier U6 is suitable for outputting the target sampling signal.

[0075] Specifically, an active low-pass filter stage circuit is constructed using the sixth operational amplifier U6, resistors R15 and R16, the second capacitor C2, and the third capacitor C3. This circuit filters out high-frequency oscillation residue, diode detection ripple, transmission coupling noise from the aviation connector, and high-frequency glitches introduced by the preceding operational amplifier, ultimately outputting a stable target sampling signal, Filtered_SAX, for sampling by the DSP chip. In one example of this application embodiment, the resistance values ​​of resistors R15 and R16 are both 3.3kΩ, and the capacitance values ​​of capacitors C2 and C3 are both 10nF.

[0076] In this embodiment, a cascaded amplitude modulation stage circuit, a bias modulation stage circuit, and a filter stage circuit are constructed using a fourth operational amplifier U4, a fifth operational amplifier U5, and a sixth operational amplifier U6. The amplitude modulation stage circuit eliminates the residual channel differences after signal conditioning within the pump. The bias modulation stage circuit shifts the signal level to within the allowable analog-to-digital sampling range of the DSP chip in the control box 30. Simultaneously, the filter stage circuit filters out high-frequency oscillation residues and coupling noise from the air-to-air cable transmission. Through the coordinated processing of these three stages, the target sampling signal input to the DSP chip finally meets the sampling accuracy and control accuracy requirements, achieving stable interchange between the control box 30 and the magnetic levitation molecular pump.

[0077] Accordingly, such as Figure 1 As shown in the figure, this application embodiment also provides a magnetic levitation molecular pump system, which includes a pump body 20, a control box 30, and the control box matching circuit 10 of the magnetic levitation molecular pump system described above.

[0078] The specific configurations and further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0079] The magnetic levitation molecular pump system proposed in this embodiment sets up a control box matching circuit 10 on the basis of the pump body 20 and the control box 30. This circuit unifies the output of different pump bodies 20 into a standard signal that can be stably received by the same control box 30. This can significantly reduce the impact of individual differences in the sensors 21 between different pump bodies 20 and the changes in the length of the connecting cable on the signal quality. This allows different control boxes 30 to be adapted to different magnetic levitation molecular pumps. From the perspective of hardware signal consistency, this enables interchangeable connection and interchangeable control between the magnetic levitation molecular pump and the control box 30. This effectively improves the compatibility and versatility between the control box 30 and different magnetic levitation molecular pumps, thereby greatly improving the efficiency of maintenance and equipment interchangeability.

[0080] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0081] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0082] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0083] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0084] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A control box matching circuit for a magnetic levitation molecular pump system, characterized in that, The magnetic levitation molecular pump system includes a pump body and a control box, and the matching circuit of the control box includes: A signal pre-calibration module is configured to perform amplitude modulation and bias modulation processing on the original sampling signal output by the sensor in the pump body to obtain a calibrated sampling signal, so that the calibrated sampling signal matches the preset standard signal conditions. A signal matching module is configured to perform amplitude modulation and bias modulation processing on the corrected sampling signal to obtain a target sampling signal, such that the target sampling signal matches the signal input conditions of the control box.

2. The control box matching circuit of the magnetic levitation molecular pump system according to claim 1, characterized in that, The signal pre-calibration module is located in the pump body, and the signal matching module is located in the control box.

3. The control box matching circuit of the magnetic levitation molecular pump system according to claim 1, characterized in that, The signal pre-calibration module includes: A reference signal generation unit is configured to generate a reference signal based on a preset reference power supply. A first signal processing unit is configured to perform amplitude modulation processing on the original sampled signal to obtain a first conditioning signal, and generate the corrected sampled signal based on the reference signal and the first conditioning signal.

4. The control box matching circuit of the magnetic levitation molecular pump system according to claim 3, characterized in that, The reference signal generation unit includes a first adjustable resistor and a voltage follower. The first end of the first adjustable resistor is adapted to be connected to a preset reference power supply. The second end of the first adjustable resistor is connected to the non-inverting input of the voltage follower. The inverting input of the voltage follower is connected to the output of the voltage follower, and the output of the voltage follower is adapted to output the reference signal. The reference signal generation unit is configured to divide the preset reference power supply by adjusting the first adjustable resistor to generate the reference signal according to the voltage division result, and to buffer and output the reference signal through the voltage follower.

5. The control box matching circuit of the magnetic levitation molecular pump system according to claim 3, characterized in that, The first signal processing unit includes a first operational amplifier and a second adjustable resistor, wherein the non-inverting input of the first operational amplifier is adapted to receive the original sampled signal, the inverting input of the first operational amplifier is connected to the first terminal of the second adjustable resistor, and the output of the first operational amplifier is connected to the second terminal of the second adjustable resistor. The first signal processing unit is configured to adjust the closed-loop gain parameter of the first operational amplifier by adjusting the resistance value of the second adjustable resistor, and to perform amplitude modulation processing on the original sampled signal according to the closed-loop gain parameter to obtain the first conditioning signal.

6. The control box matching circuit of the magnetic levitation molecular pump system according to claim 3, characterized in that, The first signal processing unit further includes a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, and a first capacitor. The first conditioning signal is input to the non-inverting input terminal of the second operational amplifier via the first resistor. The reference signal is input to the inverting input terminal of the second operational amplifier via the second resistor. The output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier via the third resistor. The output terminal of the second operational amplifier is connected to the first terminal of the fourth resistor. The second terminal of the fourth resistor is adapted to output the correction sampling signal, and the second terminal of the fourth resistor is grounded via the first capacitor. The first signal processing unit is further configured to obtain the corrected sampling signal by performing zero-point offset adjustment and signal shaping processing on the first conditioning signal according to the reference signal through the second operational amplifier.

7. The control box matching circuit of the magnetic levitation molecular pump system according to claim 3, characterized in that, The signal matching module includes an isolation unit and a second signal processing unit. The isolation unit is configured to buffer and transmit the correction sampling signal to the second signal processing unit. The second signal processing unit is configured to perform amplitude modulation processing on the correction sampling signal to obtain a second conditioning signal, and generate the target sampling signal based on the reference signal and the second conditioning signal.

8. The control box matching circuit of the magnetic levitation molecular pump system according to claim 7, characterized in that, The isolation unit includes a third operational amplifier, the non-inverting input of which is adapted to receive the correction sampling signal, the inverting input of which is connected to the output of which is connected to the second signal processing unit.

9. The control box matching circuit of the magnetic levitation molecular pump system according to claim 8, characterized in that, The second signal processing unit includes: A fourth operational amplifier is configured to perform amplitude modulation processing on the correction sampling signal to obtain a second conditioning signal, wherein the non-inverting input of the fourth operational amplifier is connected to the output of the third operational amplifier, the inverting input of the fourth operational amplifier is connected to the output of the fourth operational amplifier, and the output of the fourth operational amplifier is adapted to output the second conditioning signal. A fifth operational amplifier is configured to bias the second conditioning signal according to the reference signal to obtain a third conditioning signal, wherein the non-inverting input of the fifth operational amplifier is adapted to receive the reference signal, the inverting input of the fifth operational amplifier is connected to the output of the fourth operational amplifier and the output of the fifth operational amplifier respectively, and the output of the fifth operational amplifier is adapted to output the third conditioning signal. A sixth operational amplifier is configured to filter the third conditioning signal to obtain the target sampling signal, wherein the non-inverting input of the sixth operational amplifier is connected to the output of the fifth operational amplifier, the inverting input of the sixth operational amplifier is connected to the output of the sixth operational amplifier, and the output of the sixth operational amplifier is adapted to output the target sampling signal.

10. A magnetically levitated molecular pump system, characterized in that, The magnetic levitation molecular pump system includes: Pump body; Control box; And the control box matching circuit of the magnetic levitation molecular pump system as described in any one of claims 1 to 9.

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