A multi-screw compressor main unit and its operation method

Abstract

This invention discloses a multi-screw compressor and its operating method. The multi-screw compressor includes: at least two compression units, each compression unit including a set of screw rotors and a drive motor that independently drives the screw rotors, the drive motors directly driving the corresponding screw rotors; and a control unit, signal-connected to the drive motors, used to independently control the operating parameters of each drive motor to adjust the speed of the corresponding screw rotor; wherein the screw rotors and their drive motors of the at least two compression units are arranged side by side in a horizontal direction, forming a horizontal structure. This invention solves the technical problems of related technologies where two-stage screw compressors use a single motor drive, requiring gears, gearboxes, and couplings to drive the two-stage screw rotors, resulting in complex structure, low transmission efficiency, and non-adjustable inter-stage pressure.

Description

Technical Field

[0001] This invention belongs to the field of air compression technology, and more specifically, relates to a multi-screw compressor host and its operating method. Background Technology

[0002] Screw compressors, as a mature type of positive displacement compressor, are widely used due to their compact structure, stable operation, and high efficiency. To obtain higher discharge pressure, two-stage compression technology has become the preferred solution. It reduces the pressure ratio of a single stage by using two stages in series compression, thereby improving volumetric efficiency and overall machine reliability.

[0003] Most two-stage screw compressor main units on the market currently use a drive gear on the main shaft to drive two driven gears on the first-stage and second-stage screws, arranged in a triangular pattern, and connected to the motor via a coupling. This structure is relatively complex, has high manufacturing costs, and the coupling and gears increase mechanical losses, resulting in significant gear noise at high speeds. In this structure, the speed ratios of the first-stage and second-stage screws can only increase or decrease synchronously, making the interstage pressure of the main unit non-adjustable. The first-stage and second-stage compression chambers cannot be designed with the optimal pressure ratio combination for different operating pressures and gas volumes, thus preventing the main unit from achieving optimal efficiency. Summary of the Invention

[0004] To address the problems of existing two-stage screw compressors using a single motor drive, requiring gears, gearboxes, and couplings to drive the two-stage screw rotors, resulting in complex structures, low transmission efficiency, and unadjustable inter-stage pressure, this invention aims to provide a multi-screw compressor. The multi-screw compressor includes: at least two compression units, each unit comprising a set of screw rotors and an independent drive motor driving each screw rotor; a control unit, signal-connected to the drive motors, for independently controlling the operating parameters of each drive motor to adjust the speed of the corresponding screw rotor; wherein the screw rotors and their drive motors of the at least two compression units are arranged side-by-side in a horizontal direction, forming a horizontal structure.

[0005] Compared with existing technologies, the technical effects achieved by this solution are as follows: Each stage of the multi-screw compressor unit in this application is equipped with an independent drive motor to drive the screw rotor. Each stage of the compressor unit can independently control the speed of its screw rotor through its corresponding drive motor. The interstage pressure can be dynamically adjusted according to different operating conditions. Each stage of the compression chamber can be designed with the optimal pressure ratio combination under different operating pressures and gas volumes to ensure that the screw compressor unit achieves optimal efficiency. By setting the drive motor to directly drive the corresponding screw rotor, that is, setting the drive motor and its corresponding screw rotor to be directly connected as an integral unit, there are no traditional gears, gearboxes, main shafts, couplings, and center brackets, etc., which reduces energy loss in the transmission links, greatly improves transmission efficiency, and has lower cost, more compact structure, and less noise. Compared to the vertical arrangement of compression units with the low-pressure stage above and the high-pressure stage below, the horizontal structure of the compression unit with left and right arrangement results in a low center of gravity, which significantly reduces vibration during unit operation and improves the unit's operational stability. In addition, the horizontal layout is more convenient for installation and maintenance, and the gas flow is more in line with the physical characteristics of hot gas rising, which is conducive to the smooth transport and cooling of gas between stages.

[0006] Furthermore, the multi-screw compressor also includes: a cylinder with at least two compression chambers inside, one for each compression unit; at least two exhaust components, one for each compression unit; wherein the exhaust components are of a split structure, and each exhaust component is detachably connected to the cylinder.

[0007] Compared with existing technologies, the technical advantages of this solution are as follows: Compared to the integrated design of the exhaust component and cylinder, which involves machining the exhaust port on a large machine casing, resulting in a long cycle, high cost, and high machining difficulty, the separate structure of the exhaust component allows for individual machining. The machining accuracy of the exhaust port is easier to guarantee, making machining more convenient and faster. Furthermore, the integrated design of the exhaust component and cylinder necessitates disassembling the drive motor before repairing the screw rotor, which is cumbersome. By detachably connecting the exhaust component and cylinder, the screw rotor can be removed without disassembling the drive motor; simply removing the exhaust component allows for easy removal of the screw rotor, greatly simplifying the maintenance process, making operation more convenient and faster, and improving repair efficiency.

[0008] Furthermore, the multi-screw compressor also includes: a spraying component that extends into the compression chamber for spraying cooling medium into the compression chamber; wherein the spraying direction of the spraying component is parallel or substantially parallel to the axial direction of the screw rotor.

[0009] Compared with existing technologies, the technical effects achieved by this solution are as follows: It should be noted that the nozzles for interstage cooling oil or liquid injection are typically located on the sidewall of the compression chamber, with their injection direction forming an angle with the mainstream gas flow. This easily generates localized eddies and pressure disturbances within the compression chamber, increasing airflow resistance losses. Setting up parallel injection ensures that the injection direction of the cooling medium (cooling oil or liquid) aligns with the direction of the compressed gas, avoiding the problem of jet impact on the sidewall interfering with the main airflow of the compressed gas, forming localized high pressures, or causing eddies. This reduces turbulence, decreases flow losses during compression, and promotes uniform mixing of the cooling medium and compressed gas, improving the cooling effect.

[0010] Furthermore, the multi-screw compressor is a two-stage screw compressor; the multi-screw compressor includes a primary compression unit and a secondary compression unit, and the cylinder is provided with a primary compression chamber and a secondary compression chamber; wherein, the exhaust component includes an interstage exhaust seat and an exhaust seat body, and the interstage exhaust seat integrates an interstage exhaust channel connecting the primary compression chamber and the secondary compression chamber.

[0011] Furthermore, the exhaust seat body is provided with an exhaust port; wherein the exhaust port is arranged perpendicular to the axis of the compression unit.

[0012] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: by setting the exhaust port perpendicular to the axis of the compression unit, it is easier to process and the processing cost is lower. When assembling the whole system, there is no need for an exhaust bend, making the installation of the whole system more convenient and faster.

[0013] Furthermore, the primary compression unit includes a primary drive motor, a primary male screw, and a primary female screw; the primary male screw and the primary female screw mesh with each other, and the primary drive motor can drive the primary female screw to rotate through the primary male screw; wherein, the output shaft of the primary drive motor and the primary male screw are integrally formed rotor shafts.

[0014] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: by setting the output shaft of the primary drive motor and the primary male screw as an integrally formed rotor main shaft, there is no need for intermediate parts such as couplings to connect the primary drive motor and the primary male screw, nor is there a need to set a sealing end cover between the primary drive motor and the primary compression chamber to isolate the cylinder and the primary drive motor. The structure is more compact and the transmission efficiency is 100%.

[0015] Furthermore, the secondary compression unit includes a secondary drive motor, a secondary male screw, and a secondary female screw; the secondary male screw and the secondary female screw mesh with each other, and the secondary drive motor can drive the secondary female screw to rotate through the secondary male screw; wherein, the output shaft of the secondary drive motor and the secondary male screw are integrally formed rotor shafts.

[0016] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: by setting the output shaft of the secondary drive motor and the secondary male screw as an integrally formed rotor main shaft, there is no need for intermediate parts such as couplings to connect the secondary drive motor and the secondary male screw, nor is there a need to set a sealing end cover between the secondary drive motor and the secondary compression chamber to isolate the cylinder and the secondary drive motor. The structure is more compact and the transmission efficiency is 100%.

[0017] Furthermore, a first-stage inlet bearing is provided on the inlet rotor shaft of the first-stage screw rotor; a first-stage outlet bearing is provided on the outlet rotor shaft of the first-stage screw rotor; a second-stage inlet bearing is provided on the inlet rotor shaft of the second-stage screw rotor; and a second-stage outlet bearing is provided on the outlet rotor shaft of the second-stage screw rotor.

[0018] Compared with existing technologies, the technical effects achieved by this solution are as follows: By installing a first-stage feed bearing and a first-stage discharge bearing at both ends of the first-stage screw rotor, the stability and reliability of the first-stage screw rotor during high-speed operation are ensured. Similarly, by installing a second-stage feed bearing and a second-stage discharge bearing at both ends of the second-stage screw rotor, the stability and reliability of the second-stage screw rotor during high-speed operation are also ensured.

[0019] Furthermore, the first-stage exhaust end bearing is located within the interstage exhaust seat; the second-stage exhaust end bearing is located within the exhaust seat body.

[0020] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: by setting the first-stage exhaust end bearing in the interstage exhaust seat and the second-stage exhaust end bearing in the exhaust seat body, that is, integrating the bearings into the exhaust seat, the space of the exhaust seat can be fully utilized, the axial length of the multi-screw compressor host can be shortened, and the structure can be made more compact on the basis of horizontal layout.

[0021] Furthermore, the present invention provides an operating method for a multi-screw compressor, applicable to any of the multi-screw compressors described above. The operating method for the multi-screw compressor includes the following steps: obtaining the target exhaust pressure and target exhaust volume of the multi-screw compressor; the control unit setting an independent speed command for the drive motor of each compression unit according to the target exhaust pressure and target exhaust volume; and controlling the drive motors of each stage to operate at the set speed according to the speed command.

[0022] Compared with existing technologies, the technical effects achieved by adopting this technical solution are: the optimal speed of the primary drive motor and the secondary drive motor can be adjusted according to different operating pressures and exhaust volumes, achieving the optimal pressure ratio combination design and ensuring that the multi-screw compressor host achieves the best efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a multi-screw compressor main unit provided by the present invention; Figure 2 yes Figure 1 A schematic diagram of the structure of a multi-screw compressor host from another perspective; Figure 3 yes Figure 2 A cross-sectional view of a multi-screw compressor main unit (AA section). Figure 4 yes Figure 2 A schematic diagram of the structure of a multi-screw compressor host from another perspective; Figure 5 yes Figure 4 BB cross-sectional view of a multi-screw compressor main unit.

[0024] In the picture: 100. Multi-screw compressor main unit; 10. Cylinder; 11. First-stage compression chamber; 12. Second-stage compression chamber; 13. Air inlet; 20. Interstage exhaust seat; 30. Exhaust seat body; 31. Exhaust port; 41. First-stage drive motor; 42. First-stage male screw; 43. First-stage female screw; 44. First-stage inlet bearing; 45. First-stage outlet bearing; 51. Second-stage drive motor; 52. Second-stage male screw; 53. Second-stage female screw; 54. Second-stage inlet bearing; 55. Second-stage outlet bearing; 60. Cooling medium injection port. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0026] See Figure 1 This is a structural schematic diagram of a multi-screw compressor main unit 100 provided by the present invention. Combined with... Figures 1 to 5 The multi-screw compressor host 100 includes, for example, at least two compression units, each compression unit including a set of screw rotors and a drive motor that independently drives the screw rotors, the drive motors directly driving the corresponding screw rotors; and a control unit, signal-connected to the drive motors, for independently controlling the operating parameters of each drive motor to adjust the speed of the corresponding screw rotor; wherein the screw rotors and their drive motors of the at least two compression units are arranged side by side in the horizontal direction, forming a horizontal structure.

[0027] It is understood that each compression unit of the multi-screw compressor 100 in this application is equipped with an independent drive motor to drive the screw rotor. Each compression unit can independently control the speed of its screw rotor through its corresponding drive motor. The interstage pressure can be dynamically adjusted according to different operating conditions. Each compression chamber can be designed with the optimal pressure ratio combination under different operating pressures and gas volumes to ensure that the screw compressor achieves the best efficiency. By setting the drive motor to directly drive the corresponding screw rotor, that is, setting the drive motor and its corresponding screw rotor to be directly connected as an integral unit, there are no traditional gears, gearboxes, main shafts, couplings and center brackets, etc., which reduces energy loss in the transmission links, greatly improves transmission efficiency, and has lower cost, more compact structure and less noise.

[0028] Compared to the vertical arrangement of compression units with the low-pressure stage above and the high-pressure stage below, the horizontal structure of the compression unit with left and right arrangement results in a low center of gravity, which significantly reduces vibration during unit operation and improves the unit's operational stability. In addition, the horizontal layout is more convenient for installation and maintenance, and the gas flow is more in line with the physical characteristics of hot gas rising, which is conducive to the smooth transport and cooling of gas between stages.

[0029] Furthermore, the multi-screw compressor host 100 also includes: a cylinder 10, which has at least two compression chambers, one for each compression stage; and at least two exhaust components, one for each compression stage. The exhaust components are of a split structure, and each exhaust component is detachably connected to the cylinder 10. For example, the exhaust component includes an interstage exhaust seat 20 and an exhaust seat body 30.

[0030] In one specific embodiment, when repairing the screw rotor, when disassembling the screw rotor in the first-stage compression chamber 11, it is not necessary to disassemble the first-stage drive motor 41; simply removing the interstage exhaust seat 20 is sufficient to remove the corresponding screw rotor. Similarly, when disassembling the screw rotor in the second-stage compression chamber 12, it is not necessary to disassemble the second-stage drive motor 51; simply removing the interstage exhaust seat 20 is sufficient to remove the corresponding screw rotor. This greatly simplifies the maintenance process, making the operation more convenient and faster, and the repair more efficient.

[0031] Understandably, compared to the integrated design of the exhaust component and cylinder 10, machining the exhaust port 31 on the bulky machine housing is time-consuming, costly, and difficult. The separate structure of the exhaust component allows for individual machining, making it easier to ensure the machining accuracy of the exhaust port 31, and resulting in more convenient and faster machining. Furthermore, the integrated design of the exhaust component and cylinder 10 necessitates disassembling the drive motor before repairing the screw rotor, which is cumbersome. By detachably connecting the exhaust component and cylinder 10, the screw rotor can be removed without disassembling the drive motor; simply removing the exhaust component allows for easy removal of the screw rotor, greatly simplifying the maintenance process, making operation more convenient and efficient.

[0032] Furthermore, the multi-screw compressor 100 also includes a spraying component that extends into the compression chamber for spraying cooling medium into the compression chamber; wherein the spraying direction of the spraying component is parallel or substantially parallel to the axial direction of the screw rotor. In one specific embodiment, the compression chamber is provided with multiple cooling medium spray ports 60. Figure 3 The arrow shown indicates the direction of the cooling medium injection port 60.

[0033] It should be noted that the nozzles for interstage cooling oil or liquid injection are usually located on the sidewall of the compression chamber, and their injection direction forms an angle with the mainstream gas direction. This can easily generate local eddies and pressure disturbances within the compression chamber, increasing airflow resistance losses. Setting up parallel injection ensures that the injection direction of the cooling medium (cooling oil or liquid) is consistent with the direction of the compressed gas, avoiding the problem of jet impact on the sidewall interfering with the main airflow of the compressed gas, forming local high pressure or causing eddies. This reduces turbulence, reduces flow losses during compression, and also helps to achieve uniform mixing of the cooling medium and compressed gas, improving the cooling effect.

[0034] Furthermore, the multi-screw compressor host 100 is a two-stage screw compressor host; the multi-screw compressor host 100 includes a primary compression unit and a secondary compression unit, and the cylinder 10 is provided with a primary compression chamber 11 and a secondary compression chamber 12; wherein, the exhaust component includes an interstage exhaust seat 20 and an exhaust seat body 30, and the interstage exhaust seat 20 integrates an interstage exhaust channel connecting the primary compression chamber 11 and the secondary compression chamber 12.

[0035] Furthermore, the exhaust seat body 30 is provided with an exhaust port 31; wherein, the exhaust port 31 is arranged perpendicular to the axial direction of the compression unit.

[0036] Understandably, by setting the exhaust port 31 perpendicular to the axis of the compression unit, it is easier to process and the processing cost is lower. When assembling the whole system, there is no need for an exhaust bend, making the installation of the whole system more convenient and faster.

[0037] Furthermore, the primary compression unit includes a primary drive motor 41, a primary male screw 42, and a primary female screw 43; the primary male screw 42 and the primary female screw 43 mesh with each other, and the primary drive motor 41 can drive the primary female screw 43 to rotate through the primary male screw 42; wherein, the output shaft of the primary drive motor 41 and the primary male screw 42 are integrally formed rotor main shafts.

[0038] It is understandable that by setting the output shaft of the primary drive motor 41 and the primary male screw 42 as an integrally formed rotor main shaft, there is no need for intermediate components such as couplings to connect the primary drive motor 41 and the primary male screw 42, nor is there a need to set a sealing end cover between the primary drive motor 41 and the primary compression chamber 11 to isolate the cylinder 10 and the primary drive motor 41. The structure is more compact and the transmission efficiency is 100%.

[0039] Furthermore, the secondary compression unit includes a secondary drive motor 51, a secondary male screw 52, ​​and a secondary female screw 53; the secondary male screw 52 and the secondary female screw 53 mesh with each other, and the secondary drive motor 51 can drive the secondary female screw 53 to rotate through the secondary male screw 52; wherein, the output shaft of the secondary drive motor 51 and the secondary male screw 52 are integrally formed rotor shafts.

[0040] It is understandable that by setting the output shaft of the secondary drive motor 51 and the secondary male screw 52 as an integrally formed rotor main shaft, there is no need for intermediate components such as couplings to connect the secondary drive motor 51 and the secondary male screw 52, ​​nor is there a need to set a sealing end cover between the secondary drive motor 51 and the secondary compression chamber 12 to isolate the cylinder 10 and the secondary drive motor 51. The structure is more compact and the transmission efficiency is 100%.

[0041] Furthermore, a first-stage inlet bearing 44 is provided on the inlet rotor shaft of the first-stage screw rotor; a first-stage outlet bearing 45 is provided on the outlet rotor shaft of the first-stage screw rotor; a second-stage inlet bearing 54 is provided on the inlet rotor shaft of the second-stage screw rotor; and a second-stage outlet bearing 55 is provided on the outlet rotor shaft of the second-stage screw rotor.

[0042] Understandably, by setting a first-stage feed bearing 44 and a first-stage discharge bearing 45 at both ends of the first-stage screw rotor, the stability and reliability of the first-stage screw rotor during high-speed operation are ensured. Similarly, by setting a second-stage feed bearing 54 and a second-stage discharge bearing 55 at both ends of the second-stage screw rotor, the stability and reliability of the second-stage screw rotor during high-speed operation are ensured.

[0043] Furthermore, the first-stage exhaust end bearing 45 is disposed within the interstage exhaust seat 20; the second-stage exhaust end bearing 55 is disposed within the exhaust seat body 30.

[0044] It is understandable that by placing the first-stage exhaust bearing 45 inside the interstage exhaust seat 20 and the second-stage exhaust bearing 55 inside the exhaust seat body 30, that is, integrating the bearings into the exhaust seat, the space of the exhaust seat can be fully utilized, the axial length of the multi-screw compressor host 100 can be shortened, and the structure can be made more compact on the basis of the horizontal layout.

[0045] Furthermore, the present invention provides an operating method for a multi-screw compressor 100, applicable to any of the multi-screw compressors 100 described above. The operating method for the multi-screw compressor 100 includes the following steps: obtaining the target exhaust pressure and target exhaust volume of the multi-screw compressor 100; the control unit setting an independent speed command for the drive motor of each compression unit according to the target exhaust pressure and target exhaust volume; and controlling the drive motors of each stage to operate at the set speed according to the speed command.

[0046] Understandably, the optimal speeds of the primary drive motor 41 and the secondary drive motor 51 can be adjusted according to different operating pressures and exhaust volumes to achieve the best pressure ratio combination design, ensuring that the multi-screw compressor host 100 achieves optimal efficiency.

[0047] In the description of this invention, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description, and is 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, and therefore should not be construed as a limitation of this invention.

[0048] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A multi-screw compressor main unit, characterized in that, The multi-screw compressor unit (100) includes: At least two compression units, each compression unit includes a set of screw rotors and a drive motor that independently drives the screw rotors, the drive motor directly drives the corresponding screw rotors; The control unit is connected to the drive motor and is used to independently control the operating parameters of each drive motor in order to adjust the speed of the corresponding screw rotor. In this design, the screw rotors and their drive motors of at least two compression units are arranged side by side in the horizontal direction, forming a horizontal structure.

2. The multi-screw compressor main unit according to claim 1, characterized in that, The multi-screw compressor unit (100) also includes: The cylinder (10) has at least two compression chambers inside, with each compression unit corresponding to one compression chamber; There are at least two exhaust components, with one exhaust component corresponding to each compression unit; The exhaust components are of a split structure, and each exhaust component is detachably connected to the cylinder (10).

3. The multi-screw compressor main unit according to claim 2, characterized in that, The multi-screw compressor main unit (100) further includes: a spraying component that extends into the compression chamber for spraying cooling medium into the compression chamber; wherein the spraying direction of the spraying component is parallel or substantially parallel to the axial direction of the screw rotor.

4. The multi-screw compressor main unit according to claim 2, characterized in that, The multi-screw compressor host (100) is a two-stage screw compressor host; the multi-screw compressor host (100) includes a primary compression unit and a secondary compression unit, and the cylinder (10) is provided with a primary compression chamber (11) and a secondary compression chamber (12); wherein, the exhaust component includes an interstage exhaust seat (20) and an exhaust seat body (30), and the interstage exhaust seat (20) integrates an interstage exhaust channel that connects the primary compression chamber (11) and the secondary compression chamber (12).

5. The multi-screw compressor main unit according to claim 4, characterized in that, The exhaust seat body (30) is provided with an exhaust port (31); wherein the exhaust port (31) is arranged perpendicular to the axis of the compression unit.

6. The multi-screw compressor main unit according to claim 4, characterized in that, The primary compression unit includes a primary drive motor (41), a primary male screw (42), and a primary female screw (43); the primary male screw (42) and the primary female screw (43) mesh with each other, and the primary drive motor (41) can drive the primary female screw (43) to rotate through the primary male screw (42); wherein, the output shaft of the primary drive motor (41) and the primary male screw (42) are integrally formed rotor shafts.

7. The multi-screw compressor main unit according to claim 4, characterized in that, The secondary compression unit includes a secondary drive motor (51), a secondary male screw (52), and a secondary female screw (53); the secondary male screw (52) and the secondary female screw (53) mesh with each other, and the secondary drive motor (51) can drive the secondary female screw (53) to rotate through the secondary male screw (52); wherein, the output shaft of the secondary drive motor (51) and the secondary male screw (52) are integrally formed rotor shafts.

8. The multi-screw compressor main unit according to claim 4, characterized in that, A primary screw rotor has a primary inlet bearing (44) on its inlet rotor shaft; a primary outlet bearing (45) is provided on its outlet rotor shaft; a secondary screw rotor has a secondary inlet bearing (54) on its inlet rotor shaft; and a secondary outlet bearing (55) is provided on its outlet rotor shaft.

9. The multi-screw compressor main unit according to claim 8, characterized in that, The first-stage exhaust end bearing (45) is installed inside the interstage exhaust seat (20); the second-stage exhaust end bearing (55) is installed inside the exhaust seat body (30).

10. A method for operating a multi-screw compressor, applied to the multi-screw compressor (100) as described in any one of claims 1-9, characterized in that, The operation method of the multi-screw compressor main unit (100) includes the following steps: Obtain the target exhaust pressure and target exhaust volume of the multi-screw compressor host (100); The control unit sets independent speed commands for the drive motor of each compression unit based on the target exhaust pressure and target exhaust volume; The system controls each stage of the drive motor to operate at the set speed according to the speed command.

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