Air flow regulation and anti-surge control method and system of centrifugal compressor

Abstract

The invention relates to an air flow regulation and anti-surge control method and system for a centrifugal compressor, and the method comprises the steps: taking preset target volume flow and target pressure as control targets, and dynamically generating a valve opening line independent of a surge line based on the performance characteristics of the centrifugal compressor; actual operation parameters of the centrifugal compressor are obtained in real time to determine a current operation point; the current operation point and the valve opening line are subjected to position comparison, and when the current operation point approaches the valve opening line in the flow reducing direction due to the fact that the required volume flow is reduced, the target pressure is maintained in the mode of reducing the actual rotating speed; and if the actual rotating speed is reduced to a preset safe rotating speed and the current operating point is located in an anti-surge control area defined by the valve opening line, the current rotating speed is locked, and the bypass valve is controlled to be opened, so that the current operating point returns to a normal operating range defined by the valve opening line. The industrial problem that a centrifugal compressor cannot meet the wide-range process adjusting requirement is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressor control, and particularly relates to a gas flow regulation and anti-surge control method and system for centrifugal compressors. BACKGROUND

[0002] Process compressors are key equipment to provide gas power, and their control systems are mainly divided into screw and centrifugal types according to the compressor types. Screw compressors, especially variable frequency screw compressors, have a wide range of gas flow regulation, and can usually stably operate in a load range of 40%-100%, and can better adapt to partial load conditions. However, due to the limitations of the structure and working principle, the output gas of the screw compressor is usually difficult to achieve absolute “pure oil-free” quality, and even if high-performance oil-gas separation technology is used, there is still a risk of trace lubricating oil polluting the process gas, which cannot meet the extremely harsh process requirements of the electronic, food, pharmaceutical and other industries on the oil content of the gas.

[0003] In comparison, centrifugal compressors adopt a pure mechanical non-contact compression method, can realize complete “oil-free” compression, and ensure the absolute cleanliness of the process gas to meet the needs of high-end applications. However, the traditional centrifugal compressor has a significant technical bottleneck: its stable operation load regulation range is narrow, usually between 70%-100%. When the required gas flow is lower than the minimum load (such as 70% of the rated gas flow), the compressor is prone to enter an unstable “surge” condition, producing severe airflow oscillation and pressure fluctuation, which seriously threatens the safety of the equipment and the stability of production. Therefore, in actual operation, to avoid surge, the traditional control system sets a fixed “anti-surge line” as a safety control boundary. As shown in the accompanying Figure 1 As shown in the accompanying

[0004] This traditional control method based on the translation setting of the fixed anti-surge line can effectively prevent surge, but at the cost of sacrificing the working range and operating efficiency. The conservative control strategy makes a large number of low-load condition areas (such as 10%-70% load) be actively abandoned and cannot be utilized. This leads to the centrifugal compressor being greatly limited in application scenarios requiring wide-range regulation, and being unable to stably and efficiently operate at low load, forcing enterprises to have to choose other types of compressors with lower efficiency or unable to meet the purity requirements, or adopt uneconomic operation modes such as “multiple machines matching, intermittent start-stop”.

[0005] Therefore, it is urgent to develop a centrifugal compressor gas regulation and anti-surge control scheme that can break through the lower limit of traditional load and achieve stable regulation in a super-wide gas range. SUMMARY

[0006] The purpose of the present application is to provide a centrifugal compressor gas regulation and anti-surge control method and system, aiming to solve the technical problems of narrow gas regulation range and unstable anti-surge control of the prior art.

[0007] To achieve the above purpose, the present application provides a centrifugal compressor gas regulation and anti-surge control method, comprising:

[0008] Taking the preset target volume flow rate and target pressure as control targets, based on the performance characteristics of the centrifugal compressor, a valve opening line independent of the surge line is dynamically generated, which is a control boundary line on the performance curve diagram of the centrifugal compressor;

[0009] The actual operating parameters of the centrifugal compressor, including actual volume flow rate, actual pressure and actual speed, are obtained in real time to determine the current operating point;

[0010] The current operating point is compared with the valve opening line in position, when the current operating point approaches the valve opening line in the direction of decreasing volume flow rate due to the decrease of demand volume flow rate, the target pressure is maintained by reducing the actual speed;

[0011] If the actual speed is reduced to a preset safe speed, and the current operating point is located in the anti-surge control area defined by the valve opening line, the current speed of the centrifugal compressor is locked, and the bypass valve is opened to return the current operating point to the normal operating range defined by the valve opening line.

[0012] Optionally, based on the target volume flow rate and the target pressure, a curve similar in shape to the surge line is calculated and generated as the valve opening line according to the pressure ratio-volume flow rate relationship of the centrifugal compressor.

[0013] Optionally, the control of opening the bypass valve comprises:

[0014] The opening speed of the bypass valve is dynamically adjusted according to the real-time distance between the current operating point and the surge line; the closer the current operating point is to the surge line, the faster the opening speed of the bypass valve.

[0015] Optionally, after the current operating point returns to the normal operating range defined by the valve opening line, the method further comprises:

[0016] Close the bypass valve and switch to PID control mode to control the outlet pressure of the centrifugal compressor.

[0017] Optionally, the PID control mode is a variable percentage PID control, whose control parameters are automatically adjusted according to the real-time operating status of the centrifugal compressor.

[0018] Optionally, the anti-surge control zone is the area defined by the valve opening line and the surge line.

[0019] Based on the same inventive concept, the present invention also provides a gas volume regulation and anti-surge control system for a centrifugal compressor, comprising:

[0020] The data acquisition module is configured to acquire the actual operating parameters of the centrifugal compressor in real time, including the actual volumetric flow rate, actual pressure, and actual speed.

[0021] The control module is communicatively connected to the data acquisition module, and the control module is configured as follows:

[0022] Using preset target volumetric flow rate and target pressure as control targets, and based on the performance characteristics of the centrifugal compressor, a valve opening line independent of the surge line is dynamically generated.

[0023] The current operating point is determined based on the actual operating parameters, and the position of the current operating point is compared with that of the valve opening line;

[0024] When the current operating point approaches the valve opening line in the direction of decreasing volumetric flow rate due to a decrease in demand volumetric flow rate, the target pressure is maintained by reducing the actual rotational speed by outputting a command.

[0025] If the actual speed drops to a preset safe speed, and the current operating point is already within the anti-surge control zone defined by the valve opening line, then an output command is sent to lock the current speed of the centrifugal compressor and control the bypass valve to open.

[0026] The actuator includes a frequency converter that drives the centrifugal compressor and the bypass valve. The actuator is communicatively connected to the control module and executes its commands.

[0027] Optionally, the control module is further configured to:

[0028] The opening speed of the bypass valve is dynamically adjusted based on the real-time distance between the current operating point and the surge line; wherein, the closer the current operating point is to the surge line, the faster the bypass valve opens.

[0029] Optionally, when the current operating point returns to the normal operating range defined by the valve opening line, an output command is sent to close the bypass valve and switch to PID control mode.

[0030] Based on the same inventive concept, the present invention also provides a readable storage medium having a computer program stored thereon, which, when executed, can realize the gas volume regulation and anti-surge control method of the centrifugal compressor as described above.

[0031] The centrifugal compressor gas volume regulation and anti-surge control method and system provided by the present invention have at least one of the following beneficial effects:

[0032] (1) Compared with traditional methods that can only operate stably under 70%-100% load, this invention uses a dynamically generated valve opening line independent of the surge line as a control reference, enabling the compressor to operate safely and stably in the low flow range that is traditionally considered a "forbidden zone", successfully expanding the gas volume adjustment range to 10%-100%. This solves the industry problem that pure oil-free centrifugal compressors cannot meet the wide range of process adjustment requirements;

[0033] (2) By adopting a cascaded control strategy of "first reducing the speed and then opening the bypass valve", the system always prioritizes the most energy-efficient speed regulation method to cope with load changes. The higher-energy-consuming bypass control is only activated when the speed drops to the safety lower limit and still does not meet the requirements. This strategy minimizes the opening time and degree of the bypass valve, and significantly reduces energy loss compared to the traditional method of opening the valve significantly when it is close to the anti-surge line.

[0034] (3) By dynamically adjusting the opening speed of the bypass valve according to the real-time distance between the current operating point and the surge line, an intelligent response mechanism based on risk level is formed. When the current operating point approaches the surge line and the danger increases, the valve acts quickly to resolve the risk; when the danger is small, the valve acts slowly to avoid unnecessary pressure oscillations in the system.

[0035] (4) When the operating point is out of danger and returns to the safe zone, the system can automatically close the bypass valve and accurately engage PID control. In particular, the variable percentage PID control is adopted, and its parameters can be automatically adjusted according to the real-time operating status of the compressor (such as speed and pressure), which overcomes the shortcomings of traditional fixed parameter PID in adaptability under changing operating conditions. This makes the process of recovering from the boundary protection state to normal pressure regulation fast and smooth, and avoids secondary impact. Attached Figure Description

[0036] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0037] Figure 1 This is a performance curve used in traditional control modules to illustrate surge lines and anti-surge lines;

[0038] Figure 2A flowchart illustrating a method for regulating the gas volume and preventing surge in a centrifugal compressor according to an embodiment of the present invention;

[0039] Figure 3 This invention provides a performance curve diagram illustrating the surge line and the valve opening line according to an embodiment of the invention.

[0040] Figure 4 The diagram illustrates the performance curves of the air volume regulation and anti-surge control logic provided in one embodiment of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] Furthermore, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, 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 an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes said element. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Please refer to Figures 2-3 This invention provides a method for regulating the gas volume and preventing surge in a centrifugal compressor, comprising the following steps:

[0046] S100. Using the preset target volumetric flow rate and target pressure as control targets, and based on the performance characteristics of the centrifugal compressor, dynamically generate an opening valve line independent of the surge line. The opening valve line is a control boundary line on the performance curve of the centrifugal compressor.

[0047] S200: Obtain the actual operating parameters of the centrifugal compressor in real time, including actual volumetric flow rate, actual pressure, and actual speed, in order to determine the current operating point;

[0048] S300: Compare the position of the current operating point with the valve opening line. When the current operating point approaches the valve opening line in the direction of decreasing volume flow due to the decrease in demand volume flow, maintain the target pressure by reducing the actual rotational speed.

[0049] If the actual speed drops to a preset safe speed and the current operating point is already within the anti-surge control zone defined by the valve opening line, then the current speed of the centrifugal compressor is locked, and the bypass valve is controlled to open, so that the current operating point returns to the normal operating range defined by the valve opening line.

[0050] The core innovation of this method lies in abandoning the traditional fixed anti-surge line strategy and instead dynamically generating an independent valve opening line based on the target operating condition. It employs a cascaded control strategy of "speed reduction first, valve opening later," enabling the compressor to operate safely within traditionally prohibited areas and expanding the stable operating range from 70%-100% to 10%-100%. The cascaded control strategy ensures priority is given to efficient speed regulation, only activating energy-intensive bypass control when necessary, achieving optimal energy efficiency.

[0051] In this invention, unless otherwise specified, "gas volume" refers to "volume flow rate" under standard conditions (25°C, 101kPa); "surge line" refers to the critical boundary at which a centrifugal compressor experiences surge; "valve opening line" refers to the control boundary line dynamically generated by this invention; and "anti-surge control zone" refers to the working area between the valve opening line and the surge line.

[0052] Specifically, S100 is executed first, with the preset target volumetric flow rate and target pressure as control targets. Based on the performance characteristics of the centrifugal compressor, an opening valve line independent of the surge line is dynamically generated. The opening valve line is a control boundary line on the performance curve of the centrifugal compressor.

[0053] In this embodiment, the valve opening line is dynamically calculated based on the target volumetric flow rate and target pressure, according to the performance characteristics of the centrifugal compressor (such as the pressure ratio-volume flow rate relationship). Specifically, please refer to... Figure 3 The control module calculates a control boundary that resembles the surge line but is located to the right of it, based on the current performance curve of the centrifugal compressor and with the goal of achieving optimal efficiency. This valve-opening line dynamically adjusts with changes in the target operating conditions, which is fundamentally different from the traditional fixed-offset anti-surge line. Furthermore, the "performance curve" mentioned in this invention refers to a curve plotted with volumetric flow rate (such as volumetric flow rate or mass flow rate) on the x-axis and parameters characterizing the compressor's pressure rise capability (such as pressure ratio, outlet pressure, or energy head) on the y-axis. In a preferred embodiment of this invention, volumetric flow rate and pressure ratio are used as coordinate parameters.

[0054] As a feasible implementation plan, the control module achieves dynamic calculation of the boundary line through the following steps:

[0055] First, the current performance curve of the compressor is obtained. This performance curve, with volumetric flow rate on the x-axis and pressure ratio on the y-axis, includes multiple sets of performance data measured at different speeds. The control module then establishes a mathematical model of the compressor using data fitting techniques.

[0056] Next, based on the target volumetric flow rate and target pressure set by the user, the ideal operating point is determined on the performance curve. With the principle of ensuring the optimal efficiency of the compressor, the system calculates the optimal combination of operating parameters corresponding to that operating point.

[0057] Then, based on the compressor similarity law, the system generates a dynamic boundary line that is similar in shape to the surge line but maintains a safe distance through dimensionless parameter conversion. This boundary line is the core innovation of this invention—the valve opening line.

[0058] In practical applications, the generation of the valve opening line can consider various influencing factors. In a preferred embodiment, the system uses real-time data to perform online correction of the model to ensure the accuracy of boundary calculations. In other alternatives, the generation of the valve opening line can consider changes in parameters such as inlet air temperature and gas composition, achieving more accurate boundary calculations by establishing a more complex compressor model; this invention does not limit this approach. It is understood that the control module involved in this invention has a built-in performance calculation engine, capable of automatically calculating and providing a corresponding valve opening line based on the set target volumetric flow rate, target pressure, and rotational speed.

[0059] Then, S200 is executed to obtain the actual operating parameters of the centrifugal compressor in real time, including the actual volumetric flow rate, actual pressure, and actual speed, in order to determine the current operating point.

[0060] Next, execute step 300, comparing the current operating point with the valve opening line. When the required volumetric flow rate decreases, causing the current operating point to move in the direction of decreasing volumetric flow rate (e.g., ... Figure 3 When approaching the valve opening line in the left direction:

[0061] The target pressure is maintained by first reducing the actual operating speed. This can be achieved by gradually reducing the compressor speed using a frequency converter to maintain stable outlet pressure. The speed adjustment range is from the current speed down to a preset safe speed, which is typically set as the lowest speed at which the compressor can operate stably, and is higher than the critical surge speed at that speed.

[0062] If the actual speed drops to a preset safe speed, and the current operating point is already within the anti-surge control zone defined by the valve opening line, then the current speed of the centrifugal compressor is locked, and the bypass valve is opened to return the current operating point to the normal operating range defined by the valve opening line. The anti-surge control zone here is the area defined by the valve opening line and the surge line, which is the operating area permanently abandoned in traditional control strategies to avoid surge.

[0063] This invention employs a cascaded control strategy. When the current operating point is detected approaching the valve opening line, the first stage of control is initiated: maintaining pressure stability by adjusting the compressor speed. Speed ​​regulation is the most efficient energy-saving method, and the compressor always operates in the high-efficiency range during this stage. Only when the speed drops to the safety lower limit and still cannot escape the danger zone is the second stage of control initiated: precisely controlling the opening degree of the bypass valve. This strategy minimizes the opening time and degree of the bypass valve, significantly reducing energy loss compared to the traditional method of drastically opening the valve when approaching the anti-surge line.

[0064] Preferably, the control of the bypass valve opening includes:

[0065] The opening speed of the bypass valve is dynamically adjusted based on the real-time distance between the current operating point and the surge line; wherein, the closer the current operating point is to the surge line, the faster the bypass valve opens.

[0066] By dynamically adjusting the opening speed of the bypass valve based on the real-time distance between the current operating point and the surge line, a risk-level-based intelligent response mechanism is formed. When the current operating point approaches the surge line and the danger increases, the valve acts quickly to resolve the risk rapidly; when the danger is small, the valve acts gently to avoid unnecessary pressure oscillations in the system.

[0067] Furthermore, after the current operating point returns to the normal operating range defined by the valve opening line, the method further includes:

[0068] S400. Close the bypass valve and switch to PID control mode to control the outlet pressure of the centrifugal compressor.

[0069] Preferably, variable percentage PID control is adopted, and its control parameters are automatically adjusted according to the real-time operating status of the compressor to adapt to the control requirements under different operating conditions.

[0070] Once the operating point has moved out of danger and returned to the safe zone, the system can automatically close the bypass valve and precisely engage PID control. In particular, the use of variable percentage PID control allows its parameters to automatically adjust according to the real-time operating status of the compressor (such as speed and pressure), overcoming the shortcomings of traditional fixed-parameter PID control in adapting to changing operating conditions. This makes the process of recovering from the boundary protection state to normal pressure regulation fast and smooth, avoiding secondary shocks.

[0071] The following combination Figure 4 The complete workflow of the air volume regulation and anti-surge control method proposed in this invention is described in detail.

[0072] Start-up speed increase phase

[0073] During the initial startup phase of a centrifugal compressor, the primary task of the control system is to establish a stable internal flow field and quickly overcome the inefficiency zone. At this time, the control module instructs the frequency converter to drive the compressor rotor speed to increase from zero. On the performance curve, the operating point starts near the origin and moves mainly to the upper right along a safe path to the right of the surge line. This phase corresponds to the rapid transition from a low speed line (e.g., 0 RPM) to a higher speed line (e.g., 25000 RPM) in the graph. Its purpose is to provide sufficient pressure and flow to create conditions for subsequent loading, while ensuring that the startup process stays away from the surge danger zone.

[0074] Slowly increase speed to the rated speed.

[0075] Once the centrifugal compressor has completed its initial start-up, it enters the loading preparation stage. The control module controls the compressor speed to continue to increase steadily, but at a slower rate than during the start-up stage. On the performance curve, the operating point continues to move to the upper right along a gentler trajectory, gradually approaching the compressor's rated operating range.

[0076] Slowly close the valve to the target pressure point.

[0077] After receiving the target pressure setpoint, the system enters the loading phase. At this time, the compressor speed has stabilized near its rated value. The control module increases the pipeline back pressure by slowly closing the compressor outlet valve (or equivalently closing it for downstream process gas equipment). Under constant speed conditions, according to the compressor's performance characteristics, closing the valve reduces the volumetric flow rate through the compressor. Therefore, on the performance curve, the operating point will move horizontally to the left along the current constant rated speed line. This process continues until the compressor outlet pressure reaches the preset target pressure value. At this point, the operating point stops near the intersection of the rated speed line and the target pressure line, completing the loading process.

[0078] PID automatic speed regulation and pressure stabilization (wide range of air volume adjustment)

[0079] When the required gas volume (volume flow rate) for the process further decreases from this point, the core wide-range adjustment function of this invention is activated. The system no longer maintains a high speed but switches to PID automatic speed control mode. The PID controller uses the deviation between the actual pressure and the target pressure as input, calculates in real time, and outputs speed adjustment commands. To maintain pressure stability, the control module actively reduces the compressor speed. On the performance curve, the operating point will no longer shift to the left along the original constant speed line into the danger zone, but under PID control, it will migrate from a higher constant speed line (e.g., 90,000 RPM) to a lower constant speed line (e.g., 84,000 RPM). This "speed reduction and pressure stabilization" mode is the key to achieving 10%-100% ultra-wide range gas volume adjustment in this invention. It fully utilizes the efficiency and continuity of speed adjustment, enabling the compressor to operate efficiently and stably even under low load.

[0080] The PID regulator and the valve work together at the valve opening point.

[0081] When the load continues to decrease, and the PID speed control lowers the speed to the preset minimum safe speed, if the operating point touches or crosses the threshold due to insufficient flow... Figure 4The "valve opening line" shown by the blue dashed line indicates that the system has entered the "anti-surge control zone" defined by the valve opening line and the red solid surge line. At this point, the system immediately executes boundary protection logic: first, it locks the current speed to prevent it from decreasing further and causing the operating conditions to deteriorate; simultaneously, the control module dynamically calculates and instructs the bypass valve to open at the corresponding speed based on the real-time distance between the operating point and the surge line (the closer the distance, the faster the valve opens). During this process, the PID control does not exit but works in conjunction with the valve opening control to jointly suppress pressure fluctuations, striving to stabilize the operating point within a safe range near the valve opening line, thereby achieving stable operation at extremely low loads (such as 10%) that traditional control cannot achieve.

[0082] After disengaging from the valve point, the PID controller takes over the speed increase and voltage regulation.

[0083] When the process demand for gas increases, or due to the timely action of the bypass valve, the operating point shifts to the right from the "anti-surge control zone," re-enters the "valve opening line," and returns to the "normal operating range" to its right. The control module immediately switches control modes: quickly closing the bypass valve and fully handing control back to the PID speed control system. The PID controller will then guide the compressor's speed-up process based on the new pressure balance requirements, ensuring a smooth and precise recovery and maintenance of the target pressure.

[0084] The above six stages constitute a closed loop from startup, loading, automatic speed regulation, valve opening, and PID adaptive control. The entire process is intuitively represented on the performance curve. The core innovation lies in defining a completely new control boundary through dynamically generated valve opening lines, and based on this, implementing a cascaded control strategy of "first PID speed reduction regulation, then coordinated valve opening protection," thereby greatly expanding the stable operating range of the centrifugal compressor while ensuring absolute safety.

[0085] Based on the same inventive concept, this invention also proposes a gas volume regulation and anti-surge control system for a centrifugal compressor, comprising:

[0086] The data acquisition module is configured to acquire the actual operating parameters of the centrifugal compressor in real time, including the actual volumetric flow rate, actual pressure, and actual speed.

[0087] The control module is communicatively connected to the data acquisition module, and the control module is configured as follows:

[0088] Using preset target volumetric flow rate and target pressure as control targets, and based on the performance characteristics of the centrifugal compressor, a valve opening line independent of the surge line is dynamically generated.

[0089] The current operating point is determined based on the actual operating parameters, and the position of the current operating point is compared with that of the valve opening line;

[0090] When the current operating point approaches the valve opening line in the direction of decreasing volumetric flow rate due to a decrease in demand volumetric flow rate, the target pressure is maintained by reducing the actual rotational speed by outputting a command.

[0091] If the actual speed drops to a preset safe speed, and the current operating point is already within the anti-surge control zone defined by the valve opening line, then an output command is sent to lock the current speed of the centrifugal compressor and control the bypass valve to open.

[0092] The actuator includes a frequency converter that drives the centrifugal compressor and the bypass valve. The actuator is communicatively connected to the control module and executes its commands.

[0093] Preferably, the control module is further configured to:

[0094] The opening speed of the bypass valve is dynamically adjusted based on the real-time distance between the current operating point and the surge line; wherein, the closer the current operating point is to the surge line, the faster the bypass valve opens.

[0095] Preferably, when the current operating point returns to the normal operating range defined by the valve opening line, an output command is given to close the bypass valve and switch to PID control mode.

[0096] In this embodiment, the control module can be an industrial PLC, DCS controller, or dedicated control cabinet. The data acquisition module includes a pressure transmitter, flow meter, and speed sensor, etc. In the actuator, the frequency converter adopts vector control type, and the bypass valve is an equal percentage characteristic regulating valve.

[0097] Since the gas volume regulation and anti-surge control system for centrifugal compressors provided by this invention belongs to the same inventive concept as the gas volume regulation and anti-surge control method for centrifugal compressors described above, the gas volume regulation and anti-surge control system for centrifugal compressors provided by this invention has all the advantages of the gas volume regulation and anti-surge control method for centrifugal compressors described above. Therefore, the beneficial effects of the gas volume regulation and anti-surge control system for centrifugal compressors provided by this invention will not be described in detail here.

[0098] Based on the same inventive concept, this invention also proposes a readable storage medium storing a computer program that, when executed, can realize the gas volume regulation and anti-surge control method of the centrifugal compressor as described above.

[0099] A readable storage medium can be a tangible device capable of holding and storing instructions for use by an instruction execution device, such as, but not limited to, electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof. The computer programs described herein can be downloaded from the readable storage medium to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. Networks can include copper transmission cables, fiber optic transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. Each computing / processing device's network adapter card or network interface receives and forwards a computer program from the network for storage on a readable storage medium within the respective computing / processing device. The computer program used to perform the operations of this invention can be execution instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as "C" or similar languages. The computer program can execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuits, such as programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), are personalized by utilizing state information from a computer program. These electronic circuits can execute computer-readable program instructions, thereby realizing various aspects of the present invention.

[0100] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, systems, and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by a computer program. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. These computer programs can also be stored in a readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the readable storage medium storing the computer program comprises an article of manufacture including instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams.

[0101] A computer program may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the computer program executing on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0102] Since the readable storage medium provided by this invention belongs to the same inventive concept as the gas volume regulation and anti-surge control method of the centrifugal compressor described above, the readable storage medium provided by this invention has all the advantages of the gas volume regulation and anti-surge control method of the centrifugal compressor described above. Therefore, the beneficial effects of the readable storage medium provided by this invention will not be described in detail here.

[0103] In summary, this invention provides a method and system for regulating gas volume and preventing surge in a centrifugal compressor. By dynamically generating an opening valve line to establish the control boundary, and employing a cascaded control strategy of "speed reduction first, valve opening later," the system prioritizes the most energy-efficient speed regulation to address load changes. Only when the speed drops to the safety lower limit and still fails to meet requirements is the more energy-intensive bypass control activated. This strategy minimizes the opening time and degree of the bypass valve, significantly reducing energy loss compared to the traditional method of drastically opening the valve near the anti-surge line. Compared to traditional methods that can only operate stably at 70%-100% load, this invention, by dynamically generating an opening valve line independent of the surge line as the control benchmark, successfully expands the stable gas volume regulation range to 10%-100% while ensuring pure oil-free compression quality and absolute safety, overcoming the long-standing technical bottleneck of the trade-off between "wide range" and "high stability."

[0104] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure are within the protection scope of the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method of flow rate adjustment and anti-surge control of a centrifugal compressor, characterized by, The method comprises: a preset target volume flow rate and a target pressure are taken as control targets, and a valve opening line independent of a surge line is dynamically generated based on performance characteristics of a centrifugal compressor, the valve opening line being a control boundary line on a performance curve diagram of the centrifugal compressor; actual operating parameters of the centrifugal compressor, including an actual volume flow rate, an actual pressure and an actual rotating speed, are acquired in real time to determine a current operating point; the current operating point is compared with the valve opening line in position, and the target pressure is maintained by reducing the actual rotating speed when the current operating point approaches the valve opening line in a direction of reducing volume flow rate due to a decrease in a demand volume flow rate; if the actual rotating speed is reduced to a preset safe rotating speed and the current operating point is located in an anti-surge control area defined by the valve opening line, the current rotating speed of the centrifugal compressor is locked, and a bypass valve is controlled to open so that the current operating point returns to a normal operating range defined by the valve opening line.

2. The control method of claim 1, wherein The valve opening line is calculated and generated based on the target volume flow rate and the target pressure and according to a pressure ratio-volume flow rate relationship of the centrifugal compressor as a curve similar in shape to the surge line.

3. The control method of claim 1, wherein The control of the opening of the bypass valve comprises: a speed of opening of the bypass valve is dynamically adjusted according to a real-time distance between the current operating point and the surge line, wherein the closer the current operating point is to the surge line, the faster the speed of opening of the bypass valve.

4. The control method of claim 1, wherein After the current operating point returns to the normal operating range defined by the valve opening line, the method further comprises: the bypass valve is closed, and a PID control mode is switched to for controlling an outlet pressure of the centrifugal compressor.

5. The control method of claim 4, wherein The PID control mode is a variable percentage PID control, and control parameters thereof are automatically adjusted according to a real-time operating state of the centrifugal compressor.

6. The control method of surge prevention and capacity regulation of a centrifugal compressor according to claim 1, wherein The anti-surge control area is an area defined by the valve opening line and the surge line.

7. A flow rate regulating and anti-surge control system for a centrifugal compressor, characterized by, The method comprises: a data acquisition module configured to acquire actual operating parameters of a centrifugal compressor in real time, including an actual volume flow rate, an actual pressure and an actual rotating speed; a control module in communication connection with the data acquisition module, the control module being configured to: take a preset target volume flow rate and a target pressure as control targets, and dynamically generate a valve opening line independent of a surge line based on performance characteristics of the centrifugal compressor; determine a current operating point according to the actual operating parameters, and compare the current operating point with the valve opening line in position; maintain the target pressure by outputting an instruction to reduce the actual rotating speed when the current operating point approaches the valve opening line in a direction of reducing volume flow rate due to a decrease in a demand volume flow rate; if the actual rotating speed is reduced to a preset safe rotating speed and the current operating point is located in an anti-surge control area defined by the valve opening line, output an instruction to lock the current rotating speed of the centrifugal compressor and control a bypass valve to open; an execution mechanism including a frequency converter driving the centrifugal compressor and the bypass valve, the execution mechanism being in communication connection with the control module and executing instructions thereof.

8. The flow rate regulating and anti-surge control system of a centrifugal compressor according to claim 7, wherein The control module is further configured to: According to a real-time distance between the current operating point and the surge line, an opening speed of the bypass valve is dynamically adjusted; wherein the closer the current operating point is to the surge line, the faster the opening speed of the bypass valve.

9. The capacity control and anti-surge control system of a centrifugal compressor according to claim 7, wherein, When the current operating point returns to a normal operating range defined by the valve opening line, an instruction is output to close the bypass valve and switch to a PID control mode.

10. A readable storage medium, having stored thereon a computer program, characterized in that, The computer program, when executed, can implement the gas volume regulation and anti-surge control method of the centrifugal compressor according to any one of claims 1-6.

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