Method for dynamic response anti-surge control of double-valve coordinated flow of magnetic suspension air compressor

Abstract

The application discloses a kind of magnetic suspension air compressor double valve collaborative flow dynamic response anti-surge control methods, comprising: real-time acquisition of the temperature of the intake end of magnetic suspension centrifugal compressor, the pressure difference inside and outside the pipeline of the intake end, the atmospheric pressure of the intake end;Proportional valve and solenoid valve are installed at the exhaust end of the magnetic suspension centrifugal compressor;The controller of the magnetic suspension centrifugal compressor obtains the temperature of the intake end, the pressure difference inside and outside the pipeline of the intake end, the atmospheric pressure of the intake end and calculates the current intake flow of the intake end;Based on the comparison of the current intake flow and the surge flow of the magnetic suspension centrifugal compressor under the current intake flow, the controller controls the action of the proportional valve and the solenoid valve to realize the anti-surge protection of the magnetic suspension centrifugal compressor.The present application solves the problem of slow PID adjustment reaction of the existing anti-surge method of magnetic suspension centrifugal compressor.

Description

Technical Field

[0001] This invention relates to the field of centrifugal air compressor technology, specifically to a dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors. Background Technology

[0002] Magnetic levitation centrifugal compressors, with their advantages of oil-free lubrication, high speed and efficiency, and low vibration, are widely used in semiconductor manufacturing, textiles, biology, and chemical industries. However, surge, a common problem faced by magnetic levitation centrifugal compressors during operation, remains a challenge for the industry.

[0003] Surge is essentially caused by the reverse backflow of air when the compressor's exhaust flow rate is below a critical value (e.g., less than 30% of the rated flow rate) and the system back pressure is higher than the compressor's outlet pressure. This causes periodic pressure fluctuations, severe vibrations, and noise, and in severe cases, it can lead to magnetic bearing instability, impeller damage, or even complete machine shutdown.

[0004] Existing anti-surge methods for magnetic levitation centrifugal compressors are mostly based on pressure ratio-flow threshold anti-surge control, using PID control to adjust valve opening. However, surge is not only related to back pressure and flow rate, but also involves multi-variable coupling such as motor torque, impeller stress, and airflow pulsation, resulting in multiple nonlinear and time-varying uncertainties. As a single-loop controller, PID is difficult to decouple from these nonlinear relationships. Furthermore, surge often occurs suddenly (such as when downstream back pressure rises instantaneously), while PID algorithms rely on error feedback for adjustment, requiring three stages: "error detection → output calculation → actuator action," resulting in a total delay exceeding 150ms. In contrast, surge only takes 10-30ms from triggering to severe oscillation, causing PID regulation to often be "half a beat slow," failing to promptly curb backflow. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, a dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors is provided to solve the problem of slow PID regulation response in existing anti-surge methods for magnetic levitation centrifugal compressors.

[0006] To achieve the above objectives, a dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors is provided, comprising the following steps:

[0007] The temperature at the air inlet of the magnetic levitation centrifugal compressor, the pressure difference between the inside and outside of the pipe at the air inlet, and the atmospheric pressure at the air inlet are collected in real time.

[0008] A proportional valve and a solenoid valve are installed at the exhaust end of the magnetic levitation centrifugal compressor.

[0009] The controller of the magnetic levitation centrifugal compressor acquires the temperature at the air inlet, the pressure difference between the inside and outside of the pipe at the air inlet, and the atmospheric pressure at the air inlet, and calculates the current air inlet flow rate at the air inlet.

[0010] Based on the comparison between the current intake flow rate and the surge flow rate of the magnetic levitation centrifugal compressor at the current intake flow rate, the controller controls the operation of the proportional valve and the solenoid valve to achieve anti-surge protection for the magnetic levitation centrifugal compressor.

[0011] Furthermore, the controller calculates the current intake flow rate at the intake end using a formula. The formula is:

[0012] .

[0013] Furthermore, the proportional valve is a butterfly valve.

[0014] Furthermore, based on the comparison between the current intake flow rate and the surge flow rate of the magnetic levitation centrifugal compressor at the current intake flow rate, the step of the controller controlling the operation of the proportional valve and the solenoid valve includes:

[0015] a. Construct a rectangular coordinate system with the current outlet pressure of the magnetic levitation centrifugal compressor as the vertical axis and the current intake flow rate as the horizontal axis;

[0016] b. Based on the measured outlet pressure and inlet flow rate at the two surge points of the magnetic levitation centrifugal compressor, a surge flow line is generated in the rectangular coordinate system;

[0017] c. Using the surge flow line as a reference, shift by 1m sequentially along the direction of increasing horizontal coordinate. 3 2m 3 3m 3 4m 3 Generate open air valve line, enter anti-surge protection line, end anti-surge protection line and anti-surge pre-open valve line;

[0018] d. When the operating point of the magnetic levitation centrifugal compressor enters the left side of the anti-surge pre-opening valve line, the controller controls the opening adjustment range of the proportional valve to a preset minimum opening to 100%;

[0019] e. When the current intake airflow continues to decrease and reaches the anti-surge protection line, the controller controls the proportional valve to open to the anti-surge protection opening degree. During the process of the proportional valve opening to the anti-surge protection opening degree, if the operating point returns to the right side of the anti-surge protection line, the controller stops the proportional valve from opening and maintains it at the current opening degree. If, during the process of the proportional valve opening to the anti-surge protection opening degree, the operating point enters between the open air valve line and the anti-surge protection line, the controller opens the solenoid valve and opens the proportional valve to the maximum opening degree. After the valve is fully opened, the controller ends the anti-surge protection and enters normal adjustment of the load of the magnetic levitation centrifugal compressor.

[0020] h. If the proportional valve maintains the current opening for 30 seconds, and the operating point remains to the right of the anti-surge protection line within those 30 seconds, the controller ends the anti-surge protection and enters normal adjustment of the load of the magnetic levitation centrifugal compressor; if the proportional valve maintains the current opening for 30 seconds, and the current intake flow rate continues to decrease within those 30 seconds, and the operating point re-enters the anti-surge protection line, then return to step e.

[0021] Furthermore, the preset minimum opening degree is 0% to 10%.

[0022] Furthermore, the anti-surge protection opening is 55% to 65%.

[0023] Furthermore, the temperature at the air inlet of the magnetic levitation centrifugal compressor is collected in real time by a temperature sensor installed at the air inlet.

[0024] Furthermore, the differential pressure sensor installed at the air intake end collects the pressure difference between the inside and outside of the pipe at the air intake end in real time.

[0025] Furthermore, the atmospheric pressure at the air intake end is collected in real time by a pressure sensor installed at the air intake end.

[0026] The beneficial effect of this invention is that the dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors is an anti-surge control method based on inlet flow. It utilizes the controller of the magnetic levitation centrifugal compressor to acquire sensors that collect in real time the temperature at the inlet end of the magnetic levitation centrifugal compressor, the pressure difference between the inside and outside of the inlet pipe, and the atmospheric pressure at the inlet end. Using a unique calculation method and control logic, it controls the opening and closing actions of the proportional valve and the solenoid valve to perform anti-surge protection, so as to ensure that the anti-surge target of the compressor is achieved.

[0027] The dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors of this invention possesses significant technical advantages and economic value. Practical testing has verified that, compared to traditional solutions, this method reduces hardware costs by approximately 40% and process implementation complexity by 50%. When facing surge conditions, the compressor control system employing this method achieves a response time of less than 0.3 seconds, an improvement of nearly 60% compared to conventional technologies. Attached Figure Description

[0028] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of the control system of the magnetic levitation centrifugal compressor according to an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of a rectangular coordinate system according to an embodiment of the present invention.

[0031] Figure 3 This is a flowchart illustrating the dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors according to an embodiment of the present invention.

[0032] Figure label:

[0033] Controller 1, Temperature sensor 2, Pressure sensor 3, Differential pressure sensor 4, Proportional valve 5, Solenoid valve 6, Surge flow line A, Open air valve line B, Enter anti-surge protection line C, End anti-surge protection line D, Anti-surge pre-opening valve line E, Pressure and flow line at 28080 rpm F, Pressure and flow line at 26700 rpm G, Pressure and flow line at 25272 rpm H, Pressure and flow line at 23868 rpm I. Detailed Implementation

[0034] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] Reference Figures 1 to 3 As shown, this invention provides a dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors, comprising the following steps:

[0037] S1. Real-time acquisition of the temperature at the inlet of the magnetic levitation centrifugal compressor (hereinafter referred to as the compressor), the pressure difference between the inside and outside of the pipe at the inlet, and the atmospheric pressure at the inlet.

[0038] Specifically, in this embodiment, the temperature at the compressor's intake end is collected in real time by a temperature sensor installed at the intake end.

[0039] The differential pressure sensor installed at the air intake end collects the pressure difference between the inside and outside of the pipe at the air intake end in real time.

[0040] The atmospheric pressure at the air intake is collected in real time by a pressure sensor installed at the air intake.

[0041] S2. Install a proportional valve and a solenoid valve at the discharge end of the compressor.

[0042] In this embodiment, the proportional valve is a butterfly valve.

[0043] The proportional valve and solenoid valve are respectively connected to the compressor controller. The compressor controller can regulate the load normally.

[0044] A proportional valve and a solenoid valve are installed at the exhaust end to control the pressure and flow rate of the compressor's exhaust outlet.

[0045] S3. The compressor controller obtains the temperature at the intake end, the pressure difference between the inside and outside of the intake pipe, and the atmospheric pressure at the intake end, and calculates the current intake flow rate at the intake end.

[0046] The compressor controller acquires the real-time temperature at the intake end, the real-time pressure difference between the inside and outside of the pipeline at the intake end, and the real-time atmospheric pressure at the intake end, and calculates the current intake flow rate at the intake end.

[0047] Specifically, in this embodiment, the controller calculates the current intake flow rate at the intake end using a formula. The formula is:

[0048] .

[0049] When the compressor is running, the controller acquires real-time monitoring data from the temperature sensor, pressure sensor, and differential pressure sensor, and calculates the current intake flow rate in real time according to the above formula.

[0050] S4. Based on the comparison between the current intake flow rate and the compressor surge flow rate at the current intake flow rate, the controller controls the operation of the proportional valve and the solenoid valve to achieve anti-surge protection for the compressor.

[0051] Specifically, based on the comparison between the current intake flow rate and the compressor surge flow rate at the current intake flow rate, the steps by which the controller controls the proportional valve and solenoid valve include:

[0052] a. See also Figure 2 As shown, a rectangular coordinate system is constructed with the current outlet pressure of the compressor as the vertical axis and the current intake flow rate as the horizontal axis.

[0053] b. Based on the measured outlet pressure and inlet flow rate at two surge points of the compressor, a surge flow line is generated in a rectangular coordinate system.

[0054] Generally, two surge points are measured before a magnetic levitation centrifugal compressor leaves the factory. Based on the outlet pressure and inlet flow rate at these two points, the surge flow rate curve of the magnetic levitation centrifugal compressor can be calculated.

[0055] c. Using the surge flow line as a reference, shift 1m sequentially along the direction of increasing horizontal coordinate. 3 2m 3 3m 3 4m 3 Generate an open air valve line, enter the anti-surge protection line, end the anti-surge protection line, and anti-surge pre-opening valve line.

[0056] Specifically, after obtaining the surge line, based on control requirements, the surge flow line is offset by 1m. 3 An open air valve line is installed at the location;

[0057] 2m off the surge flow line 3 An anti-asthma protection line is set up at the entrance;

[0058] 3m off the surge flow line 3 Set up an end-of-asthma protection line at the location;

[0059] 4m off the surge flow line 3 An anti-surge pre-opening valve line is installed at the location.

[0060] Figure 2 For clarity, the spacing between the control lines is larger than described above. The diagram is for illustrative purposes only. In actual engineering, the parameters should be set according to the above specifications, or set based on actual measurements of the machine model.

[0061] d. When the compressor's operating point enters the right side of the anti-surge pre-opening valve line (i.e., the current intake flow is less than the anti-surge pre-opening valve line), the controller shall ensure that the opening degree of the proportional valve is not lower than the preset minimum opening degree.

[0062] Under normal circumstances, the compressor's operating point 1 (i.e., the operating condition point, green dot) is in the area to the right of the anti-surge protection line, meaning there is still a certain margin before the surge flow.

[0063] In this embodiment, the minimum opening is preset to 10%.

[0064] Because the proportional valve is a butterfly valve, the valve opening rate between 0% and 10% has little impact on the flow rate. Therefore, even if the valve is opened to this preset value, the pressure and flow rate in the system remain basically unchanged.

[0065] e. When the current intake air flow continues to decrease and reaches the anti-surge protection line (i.e., operating point 2, purple dot), the compressor enters the anti-surge protection state, and the controller controls the proportional valve to open to the anti-surge protection opening degree.

[0066] In this embodiment, the anti-surge protection opening is 55%–65%. The anti-surge protection opening is the venting opening at which the compressor can still operate safely even when the air supply to the compressor terminal is completely shut off. This setting value will vary depending on the compressor model. During the opening of the proportional valve, the current intake air flow begins to increase rapidly, and the compressor's operating point can quickly leave the surge region.

[0067] If, during the process of the proportional valve opening to the anti-surge protection opening degree, the operating point returns to the right side of the anti-surge protection line (i.e., the current intake flow is greater than the end of the anti-surge protection line), the controller stops the proportional valve from opening and maintains it at the current opening degree.

[0068] Specifically, during the process of the proportional valve opening to the anti-surge protection opening degree, the inlet flow rate also increases rapidly. When the flow rate exceeds the end of the anti-surge protection line (i.e., operating point 3, yellow point), the proportional valve will stop opening and remain at the current opening degree for 30 seconds. During these 30 seconds, the controller continues to monitor the inlet flow rate.

[0069] During the process of the proportional valve opening to the anti-surge protection opening degree, the operating point enters between the open air valve line and the surge line. The controller opens the solenoid valve and opens the proportional valve to the maximum opening degree. After the valve is fully opened, the controller ends the anti-surge protection and enters normal adjustment of the compressor load.

[0070] Specifically, if the intake flow rate continues to decrease during the process of the proportional valve opening to the anti-surge protection opening, and when the current intake flow rate is less than the open air valve line (i.e., operating point 4, red dot), it indicates that the surge point is very close. At this time, the solenoid valve needs to be opened immediately, and the proportional valve should be opened to 100% to increase the inlet flow rate at maximum speed. In this case, the response time from the inlet flow rate approaching the surge flow line to the safe zone is only about 1 second, allowing the compressor to quickly leave the danger zone before the inlet flow rate falls below the surge flow line. After the proportional valve reaches 100%, the compressor exits the anti-surge protection state, and the controller begins to adjust its load normally.

[0071] h. If the proportional valve maintains its current opening for 30 seconds, and the operating point remains on the right side of the anti-surge protection line within 30 seconds, the controller will end the anti-surge protection and enter normal adjustment of the compressor load. If the proportional valve maintains its current opening for 30 seconds, and the current intake flow continues to decrease within 30 seconds, and the operating point re-enters the anti-surge protection line, then return to step e.

[0072] If the current intake flow rate remains above the end of the anti-surge protection line (i.e., operating point 5, brown dot) for 30 seconds, then the anti-surge protection state will be exited and the controller will begin to adjust its load normally.

[0073] If the current intake airflow decreases to the point of triggering the anti-dyspnea protection line within 30 seconds, then you should immediately return to step e.

[0074] The present invention relates to a dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors. This method is based on inlet flow and utilizes the controller of the magnetic levitation centrifugal compressor to acquire sensors that collect data in real time on the temperature at the inlet of the compressor, the pressure difference between the inside and outside of the inlet pipe, and the atmospheric pressure at the inlet. Using a unique calculation method and control logic, the opening and closing actions of the proportional valve and the solenoid valve are controlled to perform anti-surge protection, thereby ensuring that the compressor's anti-surge target is achieved.

[0075] The dual-valve coordinated flow dynamic response anti-surge control method for magnetic levitation air compressors of this invention possesses significant technical advantages and economic value. Practical testing has verified that, compared to traditional solutions, this method reduces hardware costs by approximately 40% and process complexity by 50%. When facing surge conditions, the compressor control system using this method achieves a response time of less than 0.3 seconds, an improvement of nearly 60% compared to conventional technologies. Through 1000 hours of continuous stability testing, the system reliability reaches 99.8%, significantly improving the anti-surge capability of centrifugal air compressors, effectively expanding their stable operating range, and enhancing the reliability and safety of equipment operation.

[0076] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for dynamic flow response anti-surge control of a magnetic levitation air compressor with dual valve coordination, characterized in that, Includes the following steps: The temperature at the air inlet of the magnetic levitation centrifugal compressor, the pressure difference between the inside and outside of the pipe at the air inlet, and the atmospheric pressure at the air inlet are collected in real time. A proportional valve and a solenoid valve are installed at the exhaust end of the magnetic levitation centrifugal compressor. The controller of the magnetic levitation centrifugal compressor acquires the temperature at the air inlet, the pressure difference between the inside and outside of the pipe at the air inlet, and the atmospheric pressure at the air inlet, and calculates the current air inlet flow rate at the air inlet. Based on the comparison between the current intake flow rate and the surge flow rate of the magnetic levitation centrifugal compressor at the current intake flow rate, the controller controls the operation of the proportional valve and the solenoid valve to achieve anti-surge protection for the magnetic levitation centrifugal compressor. Based on a comparison between the current intake flow rate and the surge flow rate of the magnetic levitation centrifugal compressor at the current intake flow rate, the steps by which the controller controls the operation of the proportional valve and the solenoid valve include: a. Construct a rectangular coordinate system with the current outlet pressure of the magnetic levitation centrifugal compressor as the vertical axis and the current intake flow rate as the horizontal axis; b. Based on the measured outlet pressure and inlet flow rate at the two surge points of the magnetic levitation centrifugal compressor, a surge flow line is generated in the rectangular coordinate system; c. Using the surge flow line as a reference, shift by 1m sequentially along the direction of increasing horizontal coordinate. 3 2m 3 3m 3 4m 3 Generate open air valve line, enter anti-surge protection line, end anti-surge protection line and anti-surge pre-open valve line; d. When the operating point of the magnetic levitation centrifugal compressor enters the left side of the anti-surge pre-opening valve line, the controller controls the opening adjustment range of the proportional valve to a preset minimum opening to 100%; e. When the current intake airflow continues to decrease and reaches the anti-surge protection line, the controller controls the proportional valve to open to the anti-surge protection opening degree. During the process of the proportional valve opening to the anti-surge protection opening degree, if the operating point returns to the right side of the anti-surge protection line, the controller stops the proportional valve from opening and maintains it at the current opening degree. If, during the process of the proportional valve opening to the anti-surge protection opening degree, the operating point enters between the open air valve line and the anti-surge protection line, the controller opens the solenoid valve and opens the proportional valve to the maximum opening degree. After the valve is fully opened, the controller ends the anti-surge protection and enters normal adjustment of the load of the magnetic levitation centrifugal compressor. h. If the proportional valve maintains the current opening for 30 seconds, and the operating point remains to the right of the anti-surge protection line within those 30 seconds, the controller ends the anti-surge protection and enters normal adjustment of the load of the magnetic levitation centrifugal compressor; if the proportional valve maintains the current opening for 30 seconds, and the current intake flow rate continues to decrease within those 30 seconds, and the operating point re-enters the anti-surge protection line, then return to step e.

2. The method for dual-valve coordinated flow dynamic response anti-surge control of a magnetic levitation air compressor according to claim 1, characterized in that, The controller calculates the current intake flow rate at the intake end using a formula, which is: 。 3. The method for dual-valve coordinated flow dynamic response anti-surge control of a magnetic levitation air compressor according to claim 1, characterized in that, The proportional valve is a butterfly valve.

4. The method for dual-valve coordinated flow dynamic response anti-surge control of a magnetic levitation air compressor according to claim 1, characterized in that, The preset minimum opening degree is 0% to 10%.

5. The method for dual-valve coordinated flow dynamic response anti-surge control of a magnetic levitation air compressor according to claim 1, characterized in that, The anti-surge protection opening is 55% to 65%.

6. The method for dual-valve coordinated flow dynamic response anti-surge control of a magnetic levitation air compressor according to claim 1, characterized in that, The temperature at the air inlet of the magnetic levitation centrifugal compressor is collected in real time by a temperature sensor installed at the air inlet.

7. The method for dual-valve coordinated flow dynamic response anti-surge control of a magnetic levitation air compressor according to claim 1, characterized in that, The differential pressure sensor installed at the air intake end collects the pressure difference between the inside and outside of the pipe at the air intake end in real time.

8. The method for dual-valve coordinated flow dynamic response anti-surge control of a magnetic levitation air compressor according to claim 1, characterized in that, The atmospheric pressure at the air intake end is collected in real time by a pressure sensor installed at the air intake end.

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