A control method for a magnetic suspension centrifugal compressor unit system

Abstract

The present application relates to the field of compressor unit, especially to a control method for a magnetic suspension centrifugal compressor unit system, which comprises a compressor, a controller, a frequency converter and a unit control cabinet, and the controller is integrally arranged on the compressor; the method specifically comprises the following steps: S1, the frequency converter integrates and sends current state and rotating speed information to the controller; S2, the controller transmits information data reflected by the frequency converter to the unit control cabinet; S3, the unit control cabinet sets working conditions according to the information data and sends them to the controller; S4, the controller controls the opening of the valve of the compressor according to the working conditions and issues rotating speed command to the frequency converter; S5, after the system is adjusted, the whole system maintains the set working conditions to operate until an external shutdown instruction is received, and the system is shut down. By integrally arranging the controller on the compressor, the compressor is highly integrated and independently controlled, and the control method can reduce the overall adjustment period of the system.

Description

Technical Field

[0001] This invention relates to the field of compressor units, and more particularly to a control method for a magnetic levitation centrifugal compressor unit system. Background Technology

[0002] Magnetic levitation centrifugal water chiller systems are highly efficient and low-noise cooling devices widely used in many fields. The system comprises a frequency converter, compressor, controller, and chiller unit. Its compressor utilizes magnetic levitation technology, applying electromagnetic force to control the position and speed of the impeller. When the motor starts, the compressor's magnetic bearing attracts the impeller, creating centrifugal motion. At this time, the magnetic field in the air generates friction, causing the impeller to rotate at high speed, thus achieving the cooling effect of the chiller unit.

[0003] Magnetic levitation centrifugal compressors are frequently used in refrigeration and heating equipment such as refrigerators and air conditioners. A magnetic levitation centrifugal compressor consists of a magnetic levitation motor and a centrifugal compressor. The magnetic levitation motor mainly includes a housing, a stator housed within and fixedly connected to the housing, a rotor housed within the stator, radial magnetic levitation bearings to support the rotor's rotation, and an axial thrust bearing to maintain the rotor's axial position. The magnetic levitation motor also includes a protective bearing housed within the housing. This protective bearing supports the stationary rotor, preventing contact between the rotor and the radial magnetic levitation bearings, thus protecting the radial magnetic levitation bearings. When the magnetic levitation motor is operating, energizing the radial magnetic levitation bearings causes the rotor to separate from the protective bearings and levitate.

[0004] Currently, the compressor and controller of the unit system are two separate devices, which requires a long adjustment period in terms of overall commissioning and is also large in size and difficult to arrange. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a control method for a magnetic levitation centrifugal compressor unit system. By integrating the controller onto the compressor, the compressor can be highly integrated while also being controlled independently. Furthermore, the control method in this patent can reduce the overall system adjustment cycle.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A control method for a magnetic levitation centrifugal compressor unit system, the system comprising a compressor, a controller, a frequency converter, and a unit control cabinet connected to each other, wherein the frequency converter is equipped with a communication module and a detection module, and the controller is integrated on the compressor;

[0008] The method specifically includes the following steps:

[0009] S1. The inverter integrates the current status and speed information through the communication module and the detection module and sends it to the controller.

[0010] S2. The controller transmits the information data reflected by the frequency converter to the unit control cabinet;

[0011] S3. The unit control cabinet sets the operating conditions based on this information data and sends it to the controller.

[0012] S4. The controller controls the opening degree of the compressor valve according to the operating conditions and sends speed commands to the frequency converter.

[0013] S5. After the system adjustment is completed, the system will maintain the set operating conditions until an external shutdown command is received, at which point the system will shut down.

[0014] As a preferred option, the compressor, controller, frequency converter, and unit control cabinet should be powered on and tested before step S1 to ensure they can operate normally; if the self-test fails, the unit should be stopped for inspection to identify the fault point.

[0015] As a preferred option, the frequency converter needs to undergo an independent power-on test, and after the test, the test status should be fed back to the controller, and a power-on test should be performed synchronously with the compressor; the unit control cabinet should undergo an independent power-on test.

[0016] Preferably, in step S4, the controller calculates the required valve opening based on the operating conditions and sends it to the unit control cabinet, which then adjusts the valve opening.

[0017] Preferably, in step S4, after the inverter and controller complete the execution of the operating commands, they transmit their current information to the next level, until it is transmitted to the unit control cabinet.

[0018] Preferably, in step S5, after the system adjustment is completed, the unit control cabinet makes a judgment based on the received shutdown command: if no shutdown command is received, steps S3 and S4 are repeated to make the water-cooled unit system operate under the target conditions; if a shutdown command is received, the system performs shutdown processing.

[0019] Preferably, the compressor has a first aviation plug connector and a controller on its outer side. The controller includes a control housing, a magnetic levitation bearing control component, a bracket, and a PLC control component. The control housing covers the outer surface of the first aviation plug connector. The magnetic levitation bearing control component is located inside the control housing and fixed to the surface of the outer housing. The bracket is installed above the magnetic levitation bearing control component, and the PLC control component is installed above the bracket. The control housing has a second aviation plug connector that connects to the outside of the control housing. The second aviation plug connector connects the compressor's intake end and exhaust end via a wiring harness.

[0020] In summary, the advantages of this invention are as follows:

[0021] This invention significantly shortens the development and debugging cycle of compressor control. For customers, compared to the original separate debugging of compressors, independently controlled compressors reduce many intermediate steps, allowing the controller to be used as a black box; simply sending the required operating conditions to the compressor enables direct control. For manufacturers, highly integrated independently controlled compressors are more stable and help maintain technology confidentiality. Attached Figure Description

[0022] Figure 1 The flowchart shows the control method for the unit system.

[0023] Figure 2 A simplified flowchart of the control method for the unit system;

[0024] Figure 3 This is a schematic diagram of the compressor structure of this patent. Figure 1 ;

[0025] Figure 4 This is a schematic diagram of the compressor structure of this patent. Figure 2 ;

[0026] Figure 5 This is a schematic diagram of the compressor structure of this patent. Figure 3 ;

[0027] Figure 6 This is a schematic diagram of the internal structure of the controller;

[0028] Figure 7 This is a cross-sectional view of the compressor in this patent.

[0029] Reference numerals: 1. First aviation connector; 2. Controller; 3. Cooling channel; 11. Motor housing; 12. Motor stator; 13. Motor rotor; 14. Magnetic levitation bearing; 15. First-stage impeller; 16. Second-stage impeller; 17. First-stage volute; 18. Second-stage volute; 19. Gas transmission channel; 21. Control housing; 22. Magnetic levitation bearing control component; 23. Bracket; 24. PLC control component; 25. Second aviation connector. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not 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 application.

[0032] It should also be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] like Figures 1 to 7 As shown, the magnetic levitation compressor described in this patent includes a motor housing 11, a motor stator 12, a motor rotor 13, and magnetic levitation bearings 14. Specifically, the motor stator 12 is arranged around the inner wall of the motor housing 11 and connected to the motor housing 11, while the motor rotor 13 is adapted to the motor stator 12 and is rotatably disposed within the motor housing 11 along the axial direction of the motor housing 11. Two sets of magnetic levitation bearings 14 are provided and are radially disposed at the left and right ends of the motor rotor 13, respectively.

[0035] A primary impeller 15 and a secondary impeller 16 are respectively installed on both ends of the motor rotor 13. A primary volute 17, which is fixedly connected to the motor barrel 11, is fitted around the primary impeller 15. A secondary volute 18, which is fixedly connected to the motor barrel 11, is fitted around the secondary impeller 16. The secondary volute 18 and the primary volute 17 are located on the left and right ends of the motor barrel 11, respectively. The compressor is also provided with a gas transmission channel 19, the two ends of which are connected to the primary volute 17 and the secondary volute 18, respectively.

[0036] The compressor has a cooling channel 3 inside, which is used to cool and reduce the temperature of the compressor interior.

[0037] Since the above structures are basically existing technologies, they will not be described in detail. For specific structures, please refer to the utility model patent with application number CN202320922950.4.

[0038] like Figures 3 to 6As shown, the compressor has a first aviation plug connector 1 and a controller 2 covering the first aviation plug connector 1 on its outer side. Through the first aviation plug connector 1, the internal wiring harness of the compressor, such as the bearing control line, sensor harness, and IGV guide vane, can be led out to the controller 2 and connected to the internal module of the controller 2, so that the controller 2 can directly control the compressor.

[0039] Specifically, the controller 2 includes a control housing 21 and a magnetic levitation bearing control component 22, a bracket 23, and a PLC control component 24 disposed inside the control housing 21. The control housing 21 covers the outer surface of the first aviation plug connector 1, while the magnetic levitation bearing control component 22 is fixedly mounted on the outer surface of the compressor while connecting to the aforementioned inner wiring harness. The bracket 23 is mounted above the magnetic levitation bearing control component 22, and the PLC control component 24 is mounted above the bracket 23. This structure allows for efficient data transmission / processing and effective heat dissipation for the controller 2.

[0040] The control housing 21 is provided with a second aviation plug connector 25 (which can be connected to the structural module inside the controller 2) that connects to the outside of the control housing 21. The entire controller 2 is connected to the outside through the second aviation plug connector 25.

[0041] The second aviation plug connector 25 connects the compressor's intake end and exhaust end via a wire harness, enabling the controller 2 to obtain the compressor's intake pressure, intake temperature, exhaust pressure, and exhaust temperature.

[0042] The second aviation plug connector 25 can be reserved for wiring harnesses to the unit control cabinet and frequency converter. During operation, the compressor controller 2 receives control signals from the control cabinet and controls the compressor speed and valve opening based on sensor data monitoring on the suction and exhaust sides, thereby achieving the effect of independent compressor control.

[0043] like Figures 1 to 2 As shown, the frequency converter and unit control cabinet described above constitute a magnetic levitation centrifugal compressor unit system. This system typically includes interconnected compressors, controller 2, frequency converters, and unit control cabinets. However, in this patent, the compressor and controller 2 are integrated into a single unit, significantly shortening the development and debugging cycle of compressor control. For customers, compared to the original separate compressor debugging, the independently controlled compressor reduces many intermediate steps, allowing controller 2 to be used as a black box; it only needs to send the required operating conditions to the compressor for direct control. For manufacturers, highly integrated independently controlled compressors are more stable and help maintain technology confidentiality.

[0044] Specifically, the inverter is equipped with a communication module for sending data and a detection module for detecting its own status, while the aforementioned controller 2 is integrated into the compressor.

[0045] The specific control methods for this system include the following steps:

[0046] S1. Perform power-on testing on the compressor, controller 2, frequency converter, and unit control cabinet to ensure normal operation; if the self-test fails, stop the machine for inspection to identify the fault point; then the frequency converter integrates the current status and speed information through the communication module and detection module and sends it to controller 2.

[0047] S2 and controller 2 transmit the information data reflected by the frequency converter to the unit control cabinet;

[0048] S3. The unit control cabinet sets the operating conditions based on this information data and sends it to controller 2.

[0049] S4. Controller 2 calculates the required valve opening based on the operating conditions and sends it to the unit control cabinet. The unit control cabinet adjusts the valve opening and sends speed commands to the frequency converter. After the frequency converter and controller 2 have completed executing the operating condition commands, they transmit their current information to the next level, until it is transmitted to the unit control cabinet.

[0050] S5. In step S5, after the system adjustment is completed, the unit control cabinet makes a judgment based on the received shutdown command: if no shutdown command is received, S3 and S4 are repeated to make the water-cooled unit system operate according to the target operating condition; if a shutdown command is received, the system performs shutdown processing.

[0051] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A control method for a magnetic levitation centrifugal compressor unit system, the system comprising a compressor, a controller (2), a frequency converter, and a unit control cabinet interconnected, wherein the frequency converter is internally equipped with a communication module and a detection module, characterized in that, The controller (2) is integrated into the compressor; The method specifically includes the following steps: S1. The inverter integrates the current status and speed information through the communication module and the detection module and sends it to the controller (2); S2, the controller (2) transmits the information data reflected by the frequency converter to the unit control cabinet; S3. The unit control cabinet sets the operating conditions based on this information data and sends it to the controller (2); S4. The controller (2) controls the opening degree of the compressor valve according to the working conditions and sends speed commands to the frequency converter. The controller (2) calculates the required valve opening based on the operating conditions and sends it to the unit control cabinet, which then adjusts the valve opening. After the inverter and controller (2) complete the execution of the operating condition command, the inverter transmits its current information to the next level until it is transmitted to the unit control cabinet. S5. After the system adjustment is completed, the unit control cabinet makes a judgment based on the received shutdown command: if no shutdown command is received, S3 and S4 are repeated to make the water-cooled unit system operate under the target conditions; if a shutdown command is received, the system performs shutdown processing.

2. The control method for a magnetic levitation centrifugal compressor unit system according to claim 1, characterized in that, Before step S1, the compressor, controller (2), frequency converter and unit control cabinet need to be powered on and tested to ensure that they can operate normally; if the self-test fails, the machine should be stopped for inspection to identify the fault point.

3. The control method for a magnetic levitation centrifugal compressor unit system according to claim 2, characterized in that, The inverter needs to be tested independently once, and the test status is fed back to the controller (2) after the test, and a power-on test is performed synchronously with the compressor; the unit control cabinet is tested independently once.

4. The control method for a magnetic levitation centrifugal compressor unit system according to claim 1, characterized in that, The compressor is provided with a first aviation plug connector (1) and a controller (2) on its outer side. The controller (2) includes a control housing (21), a magnetic levitation bearing control component (22), a bracket (23), and a PLC control component (24). The control housing (21) covers the outer surface of the first aviation plug connector (1). The magnetic levitation bearing control component (22) is located inside the control housing (21) and fixed to the surface of the outer shell. The bracket (23) is installed above the magnetic levitation bearing control component (22). The PLC control component (24) is installed above the bracket (23). The control housing (21) is provided with a second aviation plug connector (25) that connects to the outside of the control housing (21). The second aviation plug connector (25) connects the compressor's intake end and exhaust end through a wire harness.

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