Centrifugal air compressor joint control method and device

Abstract

The present invention discloses a centrifugal air compressor joint control method and device, the method comprising: connecting a controller to a centrifugal air compressor and a monitoring device through a bus; using a monitoring device to measure the exhaust pressure and pipe network pressure of the centrifugal air compressor, using a controller to calculate the pressure difference between the exhaust pressure and the pipe network pressure of the centrifugal air compressor, and calculating the actual exhaust pressure of the centrifugal air compressor; setting the set pressure of the centrifugal air compressor according to the actual exhaust pressure, reading the full load specific power of the centrifugal air compressor under the actual exhaust pressure; reading the pipe network status information in real time, judging the fault state of the centrifugal air compressor, eliminating the centrifugal air compressor with a fault, and then starting the centrifugal air compressor and performing joint control according to the pipe network information; repeatedly controlling the centrifugal air compressor and releasing the valve to discharge the compressed air into the pipe network. The present invention optimizes the overall specific power when multiple centrifuges are connected to the grid and run, thereby improving the operating efficiency of the entire compressed air system.

Description

Technical Field

[0001] The present invention belongs to the technical field of air compressor stations, and in particular relates to a centrifugal air compressor joint control method and device. Background Art

[0002] Compressed air plays an important role in the industrial field. It is not only one of the three major driving forces in industrial production and the second largest power energy source after electricity, but is also widely used in equipment manufacturing, automobiles, metallurgy, electricity, electronics, medical treatment, textiles and other industrial fields. Although compressed air has high energy consumption, its importance in the industrial field cannot be ignored. In order to reduce energy consumption and improve efficiency, a series of measures need to be taken, including optimizing system design, using advanced energy-saving technologies, and improving equipment efficiency.

[0003] In large compressed air systems, centrifugal air compressors are widely used due to their oil-free, large flow, high efficiency, and high reliability. In actual applications, an air compression station will use multiple centrifugal air compressors with different flow rates to cope with different operating conditions. However, the flow and power characteristics of the centrifugal air compressor will be affected by the exhaust pressure, the opening of the intake valve, and the opening of the vent valve. If different types of centrifugal air compressors are used together and improperly operated, the compressed air will be vented, greatly reducing the working efficiency of the compressed air system. Summary of the invention

[0004] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a centrifugal air compressor joint control method and device, which controls the operation mode, inlet guide vane opening and release valve opening of the centrifugal air compressor according to the centrifugal air compressor performance curve, thereby realizing the joint control of the operation quantity, set pressure and pipeline parameters of the centrifugal air compressor, so as to optimize the overall specific power, thereby greatly improving the operating efficiency of the entire compressed air system.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a centrifugal air compressor joint control method, comprising the following steps:

[0007] S1. Connecting a controller to a centrifugal air compressor and a monitoring device through a bus, wherein the controller stores operating data of each centrifugal air compressor at different flow rates and pressures, and the monitoring device is used to monitor flow rates and pressures;

[0008] S2. Use monitoring equipment to measure the exhaust pressure and pipe network pressure of the centrifugal air compressor, use a controller to calculate the pressure difference between the exhaust pressure of the centrifugal air compressor and the pipe network pressure, and calculate the actual exhaust pressure of the centrifugal air compressor; set the set pressure of the centrifugal air compressor according to the actual exhaust pressure, and read the full load specific power of the centrifugal air compressor under the actual exhaust pressure;

[0009] S3, read the pipeline network status information in real time, determine the fault status of the centrifugal air compressor, eliminate the faulty centrifugal air compressor, and give priority to starting a centrifugal air compressor with the best full-load specific power and the shortest running time. After a delay, the centrifugal air compressors are jointly controlled according to the pipeline network status information and the number of centrifugal air compressors; the pipeline network status information includes the fault status of the centrifugal air compressor, the opening of the inlet guide vane, and the opening of the vent valve;

[0010] The joint control comprises the following steps:

[0011] S31. If there is only one centrifugal air compressor in operation, the vent valve is controlled according to the difference between the exhaust pressure and the set pressure; when the read inlet guide vane opening and the vent valve opening meet the requirements, the centrifugal air compressor is controlled to continue to operate; otherwise, a suitable centrifugal air compressor is started according to the flow and pressure of the pipeline network, and the current centrifugal air compressor is stopped;

[0012] S32. If there are multiple centrifugal air compressors in operation, the drain valve is controlled by comparing the pipe network flow rate with the total flow rate of the multiple centrifugal air compressors; when the drain valve opening read meets the requirements, the centrifugal air compressor is controlled to continue to operate, otherwise the set pressure of the centrifugal air compressor is adjusted or the centrifugal air compressor is started and stopped according to the pipe network status information;

[0013] S4, repeating step S3, and discharging the compressed air into the compressed air pipe network by jointly controlling the centrifugal air compressor.

[0014] As a preferred technical solution, the operating condition data include flow, power and specific power at different inlet guide vane openings of each centrifugal air compressor under different exhaust pressures when the exhaust valve is not opened.

[0015] As a preferred technical solution, step S31 includes the following steps:

[0016] If the difference between the exhaust pressure and the set pressure falls within the set range and the vent valve opening is not zero, start the appropriate centrifugal air compressor according to the flow and pressure of the pipeline network, and stop the current centrifugal air compressor after a delay;

[0017] If the difference between the exhaust pressure and the set pressure falls within the set interval and the vent valve opening is zero, the read vent valve opening meets the requirements and the centrifugal air compressor is controlled to continue running.

[0018] As a preferred technical solution, step S31 includes the following steps: if the difference between the exhaust pressure and the set pressure is less than the set threshold, the vent valve opening is zero and the inlet guide vane opening is greater than the set threshold, the centrifugal air compressor is controlled to continue running, and an additional centrifugal air compressor is added to run; if other situations occur, return to step S3.

[0019] As a preferred technical solution, step S32 includes the following steps:

[0020] If the network flow is in the range of 70% to 100% of the total flow of multiple centrifugal air compressors under the current operating conditions, the openings of all vent valves are read; when the openings of all the vent valves read are zero, the centrifugal air compressors are controlled to continue running, otherwise, the set pressure of the centrifugal air compressors whose vent valves are not opened is lowered, and the set pressure of the centrifugal air compressors whose vent valves are opened is increased, with a delay for a period of time.

[0021] As a preferred technical solution, step S32 includes the following steps: if the pipe network flow exceeds the total flow of multiple centrifugal air compressors under the current operating conditions, a centrifugal air compressor with the best full-load power ratio and the shortest operating time is started first.

[0022] As a preferred technical solution, step S32 includes the following steps:

[0023] If the network flow does not exceed the total flow of multiple centrifugal air compressors in the current working condition, but the difference between the full load flow of multiple centrifugal air compressors in the current working condition and the network flow exceeds the full load flow of one of the centrifugal air compressors, then one of the centrifugal compressors that meets the flow difference will be stopped;

[0024] If the network flow does not exceed the total flow of multiple centrifugal air compressors under the current operating conditions, and the difference between the full load flow of multiple centrifugal air compressors under the current operating conditions and the network flow is lower than the full load flow of one of the centrifugal air compressors, then the set pressure of the other centrifugal air compressors except the centrifugal air compressor with the worst specific power under the current operating conditions is adjusted at intervals of y seconds so that the flow of the centrifugal air compressor reaches 70% of its full load flow. At the same time, the set pressure of the centrifugal air compressor with the worst specific power under the current operating conditions is adjusted so that the opening of its vent valve is not in a fully open state.

[0025] In a second aspect, the present invention further provides a centrifugal air compressor control system, which is applied to the centrifugal air compressor joint control method, comprising a controller, a centrifugal air compressor, a post-processing device and a monitoring device; the centrifugal air compressor comprises a motor, a current transformer, a compressor, an intake guide vane, a vent valve, a check valve, an auxiliary oil pump, an oil heater, a contactor and a relay, the post-processing device comprises a dryer and a filter, and the monitoring device comprises a pressure sensor and a flow meter;

[0026] The controller is connected to the centrifugal air compressor, post-processing equipment and monitoring device through a bus, and is used to control equipment operation, parameter collection and analysis, performance adjustment, and fault diagnosis and protection; the monitoring device is installed at the exhaust end of the centrifugal air compressor and the air inlet end of the compressed air network, and is used to collect the exhaust pressure and air flow of the system.

[0027] As a preferred technical solution, the control device operates, specifically: controlling the oil heater, auxiliary oil pump and drive motor to ensure the start, operation and stop of the unit under safe conditions;

[0028] The parameter collection and analysis includes the following steps:

[0029] Read the exhaust pressure and pipe network pressure data of the centrifugal air compressor in real time;

[0030] Calculate the pressure difference between the exhaust pressure of the centrifugal air compressor and the pipe network pressure, and calculate the actual exhaust pressure of the centrifugal air compressor;

[0031] Read the pipe network status information in real time, the pipe network status information includes the fault status of the centrifugal air compressor, the opening of the inlet guide vane and the opening of the vent valve;

[0032] The performance adjustment is specifically: adjusting the inlet guide vane and the vent valve by detecting the pipe network pressure to change the compressor operating conditions to meet the constant pressure requirement;

[0033] The fault diagnosis and protection include fault diagnosis, anti-surge protection, overcurrent protection and alarm interlock protection;

[0034] The fault diagnosis is specifically: making corresponding emergency treatment when the centrifugal air compressor, post-processing equipment and monitoring device fail;

[0035] The anti-surge protection is specifically: judging whether the compressor is about to surge by detecting the inlet pressure difference, motor current and exhaust pressure, and then achieving anti-surge by adjusting the vent valve and inlet guide vane;

[0036] The overcurrent protection is specifically: adjusting the inlet guide vanes to make the motor run below the safe current;

[0037] The alarm interlock protection is specifically: when the system parameters exceed the normal range, the unit is protected by alarm and tripping.

[0038] In a third aspect, the present invention further provides a controller for joint control of a centrifugal air compressor, the controller comprising:

[0039] at least one processor; and,

[0040] a memory communicatively connected to the at least one processor; wherein,

[0041] The memory stores computer program instructions that can be executed by the at least one processor, and the computer program instructions are executed by the at least one processor so that the at least one processor can execute the centrifugal air compressor joint control method.

[0042] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0043] (1) The present invention controls the operation mode, inlet guide vane opening and release valve opening of the centrifugal air compressor according to the centrifugal air compressor performance curve, realizes the joint control of the operation quantity, set pressure and pipe network parameters of the centrifugal air compressor, makes the overall specific power optimal when multiple centrifugal compressors are connected to the grid and run, and improves the operation efficiency of the entire compressed air system;

[0044] (2) The present invention can match the number of centrifuges and adjust the set pressure of the centrifuges under different pipeline network pressures and flow rates by jointly controlling multiple centrifugal air compressors, thereby improving the adaptability of the centrifugal air compressor control system to the pipeline network and enhancing the operating efficiency of the compressed air system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 This is a flow chart of a centrifugal air compressor joint control method according to an embodiment of the present invention;

[0047] Figure 2 This is a first structural schematic diagram of a centrifugal air compressor control system according to an embodiment of the present invention;

[0048] Figure 3 It is a second structural schematic diagram of a centrifugal air compressor control system according to an embodiment of the present invention;

[0049] Figure 4 This is a control curve of a centrifugal air compressor according to an embodiment of the present invention;

[0050] Figure 5 It is a structural diagram of a controller for joint control of a centrifugal air compressor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0052] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0053] See also Figure 1 The present embodiment provides a centrifugal air compressor joint control method, comprising the following steps:

[0054] S1. Connecting a controller to a centrifugal air compressor and a monitoring device through a bus, wherein the controller stores operating data of each centrifugal air compressor at different flow rates and pressures, and the monitoring device is used to monitor flow rates and pressures;

[0055] In this embodiment, the controller can communicate with each active device of the centrifugal air compressor control system through the bus, especially with the centrifugal air compressor and the monitoring device. In order to monitor the flow and pressure, a pipe network pressure sensor and a pipe network flow meter are provided at the air inlet end of the pipe network, and a pressure sensor and a flow meter are provided at the exhaust end of the centrifugal air compressor. In addition, in order to further protect the system, this embodiment can set sensors for measuring temperature and vibration in appropriate places of the centrifugal air compressor control system. Specifically, for system protection, please refer to the embodiment "Centrifugal Air Compressor Control System".

[0056] Since the centrifugal air compressor is installed in a pipeline network, the compressed air pressure and compressed air flow in different areas of the pipeline network are uneven. Therefore, before analyzing and calculating the parameters of the centrifugal air compressor, this embodiment stores the operating data of the centrifugal air compressor at different flow rates and pressures in the controller, where the operating data includes the flow rate, power and specific power at different inlet guide vane openings of each centrifugal air compressor under different exhaust pressures when the exhaust valve is not opened.

[0057] S2. Use monitoring equipment to measure the exhaust pressure and pipe network pressure of the centrifugal air compressor, use a controller to calculate the pressure difference between the exhaust pressure of the centrifugal air compressor and the pipe network pressure, and calculate the actual exhaust pressure of the centrifugal air compressor; set the set pressure of the centrifugal air compressor according to the actual exhaust pressure, and read the full load specific power of the centrifugal air compressor under the actual exhaust pressure;

[0058] See also Figure 2 If the centrifugal air compressor enters the post-processing equipment first and then enters the compressed air network, the pressure loss of each post-processing equipment is inconsistent, so it is necessary to calculate the difference between the exhaust pressure of each centrifugal air compressor and the network pressure. Completing the difference calculation can compensate for the pressure loss in the exhaust pressure measurement value of the centrifugal air compressor, so that the actual exhaust pressure of the centrifugal air compressor can be calculated relatively accurately.

[0059] It is worth noting that before calculating the full-load specific power, it is necessary to read the maximum flow rate and maximum current under the actual exhaust pressure, so as to further calculate the full-load specific power of the centrifugal air compressor.

[0060] S3, read the pipeline network status information in real time, determine the fault status of the centrifugal air compressor, eliminate the faulty centrifugal air compressor, and give priority to starting a centrifugal air compressor with the best full-load specific power and the shortest running time. After a delay, the centrifugal air compressors are jointly controlled according to the pipeline network status information and the number of centrifugal air compressors; the pipeline network status information includes the fault status of the centrifugal air compressor, the opening of the inlet guide vane, and the opening of the vent valve;

[0061] The following part needs to focus on joint control.

[0062] S31. If there is only one centrifugal air compressor in operation in the current centrifugal air compressor control system, the processing method is as follows:

[0063] (1) Condition 1: The difference between the exhaust pressure and the set pressure is less than ±0.1 bar, and the vent valve opening is greater than 0%, which means that the actual flow rate of the current pipe network is far less than the efficient operating condition of the centrifuge. Under this condition, the controller needs to stop the centrifuge that is not suitable for the current operating condition after the newly put into operation centrifuge has been running stably for x seconds according to the centrifuge that does not open the vent valve under the current pressure and flow; if the specific power of other centrifuges under the current operating condition is not better than that of the currently running centrifuge, the current centrifuge will continue to run.

[0064] (2) Operating condition 2: The difference between the exhaust pressure and the set pressure is less than ±0.1 bar, the vent valve opening is equal to 0%, and the actual flow rate is in the range of 70% to 95% of the centrifuge in the current operating condition, indicating that the centrifuge matches the network flow rate, and the controller allows the current centrifuge to continue to operate.

[0065] (3) Operating condition 3: the difference between the exhaust pressure and the set pressure is less than ±0.1 bar, the vent valve opening is equal to 0%, and the inlet guide vane opening is greater than 95%, indicating that the full load flow of the centrifuge is less than the required flow of the pipeline network. The controller adds one more centrifuge according to step S3.

[0066] S32. If there are multiple centrifugal air compressors running in the current centrifugal air compressor control system, the processing method is as follows:

[0067] (4) Operating condition 4: The difference between the exhaust pressure of each centrifuge and its set pressure is less than ±0.1 bar, the vent valve opening is equal to 0%, and the pipeline flow rate is in the range of 70% to 95% of the total flow rate of multiple centrifuges in the current operating condition, which means that the current centrifuge operating condition matches the pipeline flow rate. The controller allows the current centrifuge to maintain the same operating condition and continue to operate.

[0068] (5) Operating condition 5: The network flow is between 70% and 100% of the total flow of multiple centrifuges in the current operating condition, but the vent valve opening of one or more centrifuges is greater than 0%, which means that the set pressure of the centrifuge with the vent valve open is not optimized. The controller lowers the set pressure of the centrifuge with the vent valve not open by 0.05 bar every y seconds, and increases the set pressure of the centrifuge with the vent valve open by 0.05 bar at the same time, until all centrifuges have their vent valves open.

[0069] (6) Operating condition 6: The conditions of operating condition 5 are not met, and the network flow is greater than or equal to 100% of the total flow of the multiple centrifuges in the current operating condition, which means that the full load flow of the current centrifuge is less than the network flow requirement. Then the controller adds one more centrifuge according to step S3.

[0070] (7) Operating Condition 7: The conditions of Operating Condition 6 are not met, where the vent valve opening of one or more centrifuges is greater than 0%, and the difference between the total full load flow of multiple centrifuges in the current operating condition and the network flow exceeds the full load flow of one of the centrifuges in operation. The controller selects the startup combination with the best power ratio among the currently operating centrifuges based on the network flow, and stops one of the centrifuges that meets the flow difference.

[0071] (8) Operating Condition 8: The conditions of Operating Condition 7 are not met, and the vent valve opening of one or more centrifuges is greater than 0%, and the difference between the total full load flow of the multiple centrifuges in the current operating condition and the pipe network flow is lower than the full load flow of one of the centrifuges in operation. The controller adjusts the set pressure of the centrifuges except the centrifuge with the worst specific power by ±0.05 bar every y seconds to make the flow of these centrifuges reach 70% of their full load flow, that is, to make the load as low as possible without opening the vent valve; at the same time, the set pressure of the centrifuge with the worst specific power in the current operating condition is adjusted so that the vent valve opening is not in a fully open state.

[0072] S4, repeating step S3, and discharging the compressed air into the compressed air pipe network by jointly controlling the centrifugal air compressor.

[0073] The performance of centrifugal air compressor is affected by many factors such as exhaust pressure, intake guide vane opening, vent valve opening, motor, etc. The basic exhaust pressure regulation is completed by adjusting the intake guide vane opening and vent valve opening. The flow and power of centrifugal air compressor are jointly affected by exhaust pressure, intake guide vane, and vent valve. The basic centrifugal air compressor control curve is as follows: Figure 4 As shown, this control curve is generally provided by the centrifugal air compressor manufacturer.

[0074] It should be noted that, for the sake of convenience, the aforementioned method embodiments are all expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited to the described order of actions, because according to the present invention, certain steps can be performed in other orders or simultaneously.

[0075] Based on the same idea as the centrifugal air compressor joint control method in the above embodiment, the present invention also provides a centrifugal air compressor control system, which can be used to execute the above centrifugal air compressor joint control method. For ease of explanation, the structural schematic diagram of the centrifugal air compressor control system embodiment only shows the parts related to the embodiment of the present invention. Those skilled in the art can understand that the illustrated structure does not constitute a limitation on the device, and may include more or fewer components than shown in the diagram, or combine certain components, or arrange the components differently.

[0076] See also Figure 2 and Figure 3 In another embodiment of the present application, a centrifugal air compressor control system 10 is provided, which includes a controller 11, a centrifugal air compressor 12, a post-processing device 13, a monitoring device 14, and connected pipes and lines; the centrifugal air compressor 12 includes a motor, a current transformer, a compressor, an intake guide vane, a vent valve, a check valve, an auxiliary oil pump, an oil heater, a contactor, and a relay; the post-processing device 13 includes a dryer and a filter; and the monitoring device 14 includes a pressure sensor and a flow meter;

[0077] The controller 11 is connected to the centrifugal air compressor 12, the post-processing equipment 13 and the monitoring device 14 through a bus, and is used to control equipment operation, parameter collection and analysis, performance adjustment, and fault diagnosis and protection; the monitoring device 14 is installed at the exhaust end of the centrifugal air compressor 12 and the air inlet end of the compressed air network, and is used to collect the exhaust pressure and air flow of the system.

[0078] The control equipment operation is specifically: controlling the oil heater, auxiliary oil pump and drive motor to ensure the unit starts, runs and stops under safe conditions;

[0079] The parameter collection and analysis includes the following steps:

[0080] Read the exhaust pressure and pipe network pressure data of the centrifugal air compressor 12 in real time;

[0081] Calculate the pressure difference between the exhaust pressure of the centrifugal air compressor 12 and the pipe network pressure, and calculate the actual exhaust pressure of the centrifugal air compressor 12;

[0082] Reading the pipe network status information in real time, wherein the pipe network status information includes the fault status of the centrifugal air compressor 12, the opening of the inlet guide vane and the opening of the vent valve;

[0083] The performance adjustment is specifically: adjusting the inlet guide vane and the vent valve by detecting the pipe network pressure to change the compressor operating conditions to meet the constant pressure requirement;

[0084] The fault diagnosis and protection include fault diagnosis, anti-surge protection, overcurrent protection and alarm interlock protection;

[0085] The fault diagnosis is specifically: making corresponding emergency treatment when the centrifugal air compressor 12, the post-processing equipment 13 and the monitoring device 14 fail;

[0086] The anti-surge protection is specifically: judging whether the compressor is about to surge by detecting the inlet pressure difference, motor current and exhaust pressure, and then achieving anti-surge by adjusting the vent valve and inlet guide vane;

[0087] The overcurrent protection is specifically: adjusting the inlet guide vanes to make the motor run below the safe current;

[0088] The alarm interlock protection is specifically: when the system parameters exceed the normal range, the unit is protected by alarm and tripping.

[0089] It should be noted that the centrifugal air compressor control system of the present invention corresponds one-to-one to the centrifugal air compressor joint control method of the present invention. The technical features and beneficial effects described in the above-mentioned embodiment of the centrifugal air compressor joint control method are all applicable to the embodiment of the centrifugal air compressor joint control method. For specific contents, please refer to the description in the embodiment of the method of the present invention. It will not be repeated here. This is hereby declared.

[0090] In addition, in the implementation of the centrifugal air compressor control system in the above-mentioned embodiment, the logical division of each program module is only an example. In actual application, the above-mentioned functions can be assigned to different program modules as needed, for example, for the configuration requirements of the corresponding hardware or the convenience of software implementation. That is, the internal structure of the centrifugal air compressor control system is divided into different program modules to complete all or part of the functions described above.

[0091] See also Figure 5 In one embodiment, a controller for implementing a centrifugal air compressor linkage control method is provided. The controller 20 may include a first processor 21, a first memory 22 and a bus, and may also include a computer program stored in the first memory 22 and executable on the first processor 21, such as a centrifugal air compressor linkage control program 23.

[0092] The first memory 22 includes at least one type of readable storage medium, and the readable storage medium includes flash memory, mobile hard disk, multimedia card, card-type memory (for example: SD or DX memory, etc.), magnetic memory, disk, optical disk, etc. In some embodiments, the first memory 22 can be an internal storage unit of the controller 20, such as a mobile hard disk of the controller 20. In other embodiments, the first memory 22 can also be an external storage device of the controller 20, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the controller 20. Further, the first memory 22 can also include both an internal storage unit of the controller 20 and an external storage device. The first memory 22 can not only be used to store application software and various types of data installed in the controller 20, such as the code of the centrifugal air compressor joint control program 23, but also can be used to temporarily store data that has been output or is to be output.

[0093] In some embodiments, the first processor 21 may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips. The first processor 21 is the control core (ControlUnit) of the controller, and uses various interfaces and lines to connect various components of the entire controller, and executes various functions and processes data of the controller 20 by running or executing programs or modules stored in the first memory 22, and calling data stored in the first memory 22.

[0094] Figure 5 Only a controller of a centrifugal air compressor joint control having components is shown, and those skilled in the art can understand that Figure 5 The illustrated structure does not constitute a limitation on the controller 20 , and may include fewer or more components than illustrated, or a combination of certain components, or a different arrangement of components.

[0095] The centrifugal air compressor joint control program 23 stored in the first memory 22 of the controller 20 is a combination of multiple instructions. When running in the first processor 21, it can achieve:

[0096] S1. Connecting a controller to a centrifugal air compressor and a monitoring device through a bus, wherein the controller stores operating data of each centrifugal air compressor at different flow rates and pressures, and the monitoring device is used to monitor flow rates and pressures;

[0097] S2. Use monitoring equipment to measure the exhaust pressure and pipe network pressure of the centrifugal air compressor, use a controller to calculate the pressure difference between the exhaust pressure of the centrifugal air compressor and the pipe network pressure, and calculate the actual exhaust pressure of the centrifugal air compressor; set the set pressure of the centrifugal air compressor according to the actual exhaust pressure, and read the full load specific power of the centrifugal air compressor under the actual exhaust pressure;

[0098] S3, read the pipeline network status information in real time, determine the fault status of the centrifugal air compressor, eliminate the faulty centrifugal air compressor, and give priority to starting a centrifugal air compressor with the best full-load specific power and the shortest running time. After a delay, the centrifugal air compressors are jointly controlled according to the pipeline network status information and the number of centrifugal air compressors; the pipeline network status information includes the fault status of the centrifugal air compressor, the opening of the inlet guide vane, and the opening of the vent valve;

[0099] The joint control comprises the following steps:

[0100] S31. If there is only one centrifugal air compressor in operation, the vent valve is controlled according to the difference between the exhaust pressure and the set pressure; when the read inlet guide vane opening and the vent valve opening meet the requirements, the centrifugal air compressor is controlled to continue to operate; otherwise, a suitable centrifugal air compressor is started according to the flow and pressure of the pipeline network, and the current centrifugal air compressor is stopped;

[0101] S32. If there are multiple centrifugal air compressors in operation, the drain valve is controlled by comparing the pipe network flow rate with the total flow rate of the multiple centrifugal air compressors; when the drain valve opening read meets the requirements, the centrifugal air compressor is controlled to continue to operate, otherwise the set pressure of the centrifugal air compressor is adjusted or the centrifugal air compressor is started and stopped according to the pipe network status information;

[0102] S4, repeat step S3, and discharge the compressed air into the compressed air network by jointly controlling the centrifugal air compressor. Furthermore, if the module / unit integrated in the controller 20 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium. The computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0103] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0104] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A centrifugal air compressor joint control method, characterized in that: The steps include: S1. Connecting a controller to a centrifugal air compressor and a monitoring device through a bus, wherein the controller stores operating data of each centrifugal air compressor at different flow rates and pressures, and the monitoring device is used to monitor flow rates and pressures; S2. Using a monitoring device to measure the exhaust pressure and the pipe network pressure of the centrifugal air compressor, using a controller to calculate the pressure difference between the exhaust pressure of the centrifugal air compressor and the pipe network pressure, and calculating the actual exhaust pressure of the centrifugal air compressor; Set the set pressure of the centrifugal air compressor according to the actual exhaust pressure, and read the full load specific power of the centrifugal air compressor at the actual exhaust pressure; S3, read the pipeline network status information in real time, determine the fault status of the centrifugal air compressor, eliminate the faulty centrifugal air compressor, and give priority to starting a centrifugal air compressor with the best full-load specific power and the shortest running time. After a delay, the centrifugal air compressors are jointly controlled according to the pipeline network status information and the number of centrifugal air compressors; the pipeline network status information includes the fault status of the centrifugal air compressor, the opening of the inlet guide vane, and the opening of the vent valve; The joint control comprises the following steps: S31. If there is only one centrifugal air compressor in operation, the vent valve is controlled according to the difference between the exhaust pressure and the set pressure; when the read inlet guide vane opening and the vent valve opening meet the requirements, the centrifugal air compressor is controlled to continue to operate; otherwise, a suitable centrifugal air compressor is started according to the flow and pressure of the pipeline network, and the current centrifugal air compressor is stopped; S32. If there are multiple centrifugal air compressors in operation, the drain valve is controlled by comparing the pipe network flow rate with the total flow rate of the multiple centrifugal air compressors; when the drain valve opening read meets the requirements, the centrifugal air compressor is controlled to continue to operate, otherwise the set pressure of the centrifugal air compressor is adjusted or the centrifugal air compressor is started and stopped according to the pipe network status information; S4, repeating step S3, and discharging the compressed air into the compressed air network by jointly controlling the centrifugal air compressor; Wherein step S31 includes the following steps: if the difference between the exhaust pressure and the set pressure is less than the set threshold, the vent valve opening is zero and the inlet guide vane opening is greater than the set threshold, the centrifugal air compressor is controlled to continue to operate, and an additional centrifugal air compressor is added to operate.

2. The centrifugal air compressor joint control method according to claim 1, characterized in that: The operating condition data include flow, power and specific power at different inlet guide vane openings of each centrifugal air compressor under different exhaust pressures when the exhaust valve is not opened.

3. The centrifugal air compressor joint control method according to claim 1, characterized in that: The step S31 comprises the following steps: If the difference between the exhaust pressure and the set pressure falls within the set range and the vent valve opening is not zero, start the appropriate centrifugal air compressor according to the flow and pressure of the pipeline network, and stop the current centrifugal air compressor after a delay; If the difference between the exhaust pressure and the set pressure falls within the set interval and the vent valve opening is zero, the read vent valve opening meets the requirements and the centrifugal air compressor is controlled to continue running.

4. The centrifugal air compressor joint control method according to claim 1, characterized in that: The step S32 comprises the following steps: If the network flow is in the range of 70% to 100% of the total flow of multiple centrifugal air compressors under the current operating conditions, the openings of all vent valves are read; when the openings of all the vent valves read are zero, the centrifugal air compressors are controlled to continue running, otherwise, the set pressure of the centrifugal air compressors whose vent valves are not opened is lowered, and the set pressure of the centrifugal air compressors whose vent valves are opened is increased, with a delay for a period of time.

5. The centrifugal air compressor joint control method according to claim 1, characterized in that: The step S32 comprises the following steps: if the pipe network flow exceeds the total flow of the multiple centrifugal air compressors under the current working condition, a centrifugal air compressor with the best full load power ratio and the shortest operating time is started preferentially.

6. The centrifugal air compressor joint control method according to claim 1, characterized in that: The step S32 comprises the following steps: If the network flow does not exceed the total flow of multiple centrifugal air compressors in the current working condition, but the difference between the full load flow of multiple centrifugal air compressors in the current working condition and the network flow exceeds the full load flow of one of the centrifugal air compressors, then one of the centrifugal compressors that meets the flow difference will be stopped; If the network flow does not exceed the total flow of multiple centrifugal air compressors under the current operating conditions, and the difference between the full load flow of multiple centrifugal air compressors under the current operating conditions and the network flow is lower than the full load flow of one of the centrifugal air compressors, then the set pressure of the other centrifugal air compressors except the centrifugal air compressor with the worst specific power under the current operating conditions is adjusted at intervals of y seconds so that the flow of the centrifugal air compressor reaches 70% of its full load flow. At the same time, the set pressure of the centrifugal air compressor with the worst specific power under the current operating conditions is adjusted so that the opening of its vent valve is not in a fully open state.

7. Centrifugal air compressor control system, characterized in that: A centrifugal air compressor joint control method applied to any one of claims 1 to 6, comprising a controller, a centrifugal air compressor, a post-processing device and a monitoring device; the centrifugal air compressor comprises a motor, a current transformer, a compressor, an intake guide vane, a vent valve, a check valve, an auxiliary oil pump, an oil heater, a contactor and a relay; the post-processing device comprises a dryer and a filter; and the monitoring device comprises a pressure sensor and a flow meter; The controller is connected to the centrifugal air compressor, post-processing equipment and monitoring device through a bus, and is used to control equipment operation, parameter collection and analysis, performance adjustment, and fault diagnosis and protection; the monitoring device is installed at the exhaust end of the centrifugal air compressor and the air inlet end of the compressed air network, and is used to collect the exhaust pressure and air flow of the system.

8. The centrifugal air compressor control system according to claim 7, characterized in that: The control equipment operation is specifically: controlling the oil heater, auxiliary oil pump and drive motor to ensure the unit starts, runs and stops under safe conditions; The parameter collection and analysis includes the following steps: Read the exhaust pressure and pipe network pressure data of the centrifugal air compressor in real time; Calculate the pressure difference between the exhaust pressure of the centrifugal air compressor and the pipe network pressure, and calculate the actual exhaust pressure of the centrifugal air compressor; Read the pipe network status information in real time, the pipe network status information includes the fault status of the centrifugal air compressor, the opening of the inlet guide vane and the opening of the vent valve; The performance adjustment is specifically: adjusting the inlet guide vane and the vent valve by detecting the pipe network pressure to change the compressor operating conditions to meet the constant pressure requirement; The fault diagnosis and protection include fault diagnosis, anti-surge protection, overcurrent protection and alarm interlock protection; The fault diagnosis is specifically: making corresponding emergency treatment when the centrifugal air compressor, post-processing equipment and monitoring device fail; The anti-surge protection is specifically: judging whether the compressor is about to surge by detecting the inlet pressure difference, motor current and exhaust pressure, and then achieving anti-surge by adjusting the vent valve and inlet guide vane; The over-current protection, specifically: by adjusting the inlet guide vanes so that the motor runs below the safe current; The alarm interlock protection is specifically: when the system parameters exceed the normal range, the unit is protected by alarm and tripping.

9. A controller for joint control of a centrifugal air compressor, characterized in that: The controller comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores computer program instructions that can be executed by the at least one processor, and the computer program instructions are executed by the at least one processor so that the at least one processor can execute the centrifugal air compressor joint control method as described in any one of claims 1-6.

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