Compressor and control method

Abstract

The invention provides a compressor and a control method, the compressor comprises a compressor body, a driving device, a magnetofluid sealing device and a control device, the compressor body is provided with a first shell and an input shaft, and the input end of the input shaft is located on the outer side of the first shell; the driving end of the driving device is connected with the input end of the input shaft, and the driving device is used for driving the input shaft to rotate; the magnetic fluid sealing device is arranged on the input shaft in a sleeving mode, at least part of the magnetic fluid sealing device is located in the first shell, and the magnetic fluid sealing device is relatively and fixedly connected with the first shell; the driving device is located on the side, away from the first shell, of the magnetofluid sealing device. The magnetofluid sealing device is filled with magnetofluid, and the magnetofluid is located on the outer wall of the input shaft so that the input shaft can be sealed through the magnetofluid. According to the compressor, the technical problem that in the prior art, the sealing performance of an input shaft of an open-type screw compressor is poor, and refrigerant leakage is possibly caused is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a compressor and a control method thereof. Background Art

[0002] In the prior art, commonly used refrigeration screw compressors generally adopt a fully enclosed structure. In this structure, the motor and the compressor are coaxial and all enclosed in a metal shell, and the stator and rotor of the motor are surrounded by refrigerant. The advantage of this design is that the whole machine is small in size and the refrigerant will not leak out. However, the disadvantages are also obvious: when the compressor is working, the heat emitted by the motor needs to be taken away by the refrigeration cycle system, and in a high temperature environment, this heat load is large, resulting in poor heat dissipation of the motor, which is easy to cause overheating and burning. In addition, the heat dissipation of the motor consumes part of the cooling capacity. At the same time, the fully enclosed structure also increases the difficulty of repair and maintenance. In addition, the stator and rotor windings of the motor are soaked in gaseous or liquid refrigerants, which have high requirements on the insulation and chemical corrosion resistance of the windings, so special motors need to be used.

[0003] In order to solve the above problems, open screw compressors have emerged. Compared with fully enclosed compressors, the power part (such as motor, etc.) and the compressor part of the open screw compressor are two independent components. The power part drives the compressor through the power shaft to drive the pulley, coupling or gear and other structures. The advantage of this structure is that the heat generated by the motor is cooled by the fan itself and has nothing to do with the refrigeration cycle. No matter how large the heat load of the refrigeration system is, it will not affect the heat dissipation and normal operation of the motor, and the heat dissipation of the motor will not consume the energy of the refrigeration system. At the same time, the motor can use a mature ordinary standard motor. The split structure of the open compressor is also more convenient for maintenance.

[0004] However, open screw compressors also have obvious disadvantages, namely, the size of the whole machine is larger, and if the sealing performance of the compressor input shaft is not good, it may cause refrigerant leakage. In addition, the sealing shaft ring needs to be replaced regularly, and its sealing performance may be unstable. Therefore, when the refrigerant leaks too much, it will have a serious impact on the operation and maintenance of the entire system and the compressor.

[0005] Therefore, the prior art needs to be further developed. Summary of the invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies and provide a compressor and a control method to solve the technical problem that the sealing performance of the input shaft of the open screw compressor in the prior art is poor and may cause refrigerant leakage.

[0007] To achieve the above technical objectives, according to one aspect of the present invention: a compressor is provided, comprising: a compressor body and a driving device, the compressor body having a first shell and an input shaft, the input end of the input shaft being located on the outside of the first shell; the driving end of the driving device is connected to the input end of the input shaft, and the driving device is used to drive the input shaft to rotate; a magnetic fluid sealing device, which is sleeved on the input shaft, and at least part of the magnetic fluid sealing device is located in the first shell, and the magnetic fluid sealing device is relatively fixedly connected to the first shell; the driving device is located on the side of the magnetic fluid sealing device away from the first shell; the magnetic fluid sealing device is filled with magnetic fluid, and the magnetic fluid is located on the outer wall of the input shaft, so as to seal the input shaft through the magnetic fluid; a control device, the control device is used to obtain a current first pressure value in the first shell, and a current second pressure value outside the first shell, so as to adaptively adjust the magnetic field strength of the magnetic fluid according to the current first pressure value and the current second pressure value.

[0008] Furthermore, the magnetic fluid sealing device includes: a second shell, the second shell is inserted on the first shell, and at least part of the second shell is located in the first shell, the second shell is relatively fixedly connected to the first shell, a first placement cavity and a second placement cavity are provided in the second shell, the first placement cavity and the second placement cavity both extend along the axial direction of the input shaft; the first placement cavity is nested in the second placement cavity; the first placement cavity is filled with magnetic fluid: an electromagnet assembly, the electromagnet assembly is arranged in the second placement cavity, so as to adjust the magnetic field strength of the magnetic fluid by turning on and off the power of the electromagnet assembly; the electromagnet assembly is connected to the control device, and the control device adaptively controls the power on and off state of the electromagnet assembly according to the current first pressure value and the current second pressure value.

[0009] Furthermore, the second placement cavity is an annular cavity, and the electromagnet assembly includes: at least two electromagnets, each of which is sequentially arranged on the outer wall of the first placement cavity along the extension direction of the second placement cavity; wherein the control device adaptively controls the on and off states of each electromagnet according to the current first pressure value and the current second pressure value.

[0010] Furthermore, the magnetic fluid sealing device also includes: a permanent magnet assembly, which is arranged in the second placement cavity and sleeved on the outer wall of the first placement cavity; and an electromagnet assembly is nested in the permanent magnet assembly.

[0011] Furthermore, the permanent magnet assembly includes: at least two permanent magnet rings, each permanent magnet ring is arranged in sequence along the extension direction of the second placement cavity; the magnetic poles of two adjacent permanent magnet rings in each permanent magnet ring are arranged in different directions; the electromagnet assembly is nested in at least one permanent magnet ring in each permanent magnet ring.

[0012] Furthermore, the compressor also includes: a first pressure detection device, which is arranged on the magnetic fluid sealing device and is located in the first shell; the first pressure detection device is used to detect a first pressure value in the first shell; the first pressure detection device is connected to the control device, and the first pressure detection device sends the detected first pressure value in the first shell to the control device.

[0013] Furthermore, the compressor also includes: a second pressure detection device, which is arranged on the magnetic fluid sealing device and is located outside the first shell; the second pressure detection device is used to detect a second pressure value outside the first shell; the second pressure detection device is connected to the control device, and the second pressure detection device sends the detected second pressure value outside the first shell to the control device.

[0014] Furthermore, the magnetic fluid sealing device includes: a second shell, the second shell is provided with a first placement cavity, a circulation cavity, and an inlet and an outlet respectively connected to the circulation cavity; the first placement cavity is nested in the circulation cavity, and the first placement cavity and the circulation cavity both extend along the axial direction of the input shaft; the first placement cavity is filled with magnetic fluid; the circulation cavity is used for the circulation of refrigerant, and the refrigerant enters the circulation cavity through the inlet to exchange heat with the magnetic fluid; the refrigerant after absorbing heat flows out from the outlet.

[0015] Furthermore, the compressor body has a first air intake port and a second air intake port; the compressor also includes: a circulating pump, the input end of the circulating pump is connected to the first air intake port of the compressor body, and the output end of the circulating pump is connected to the inlet; the circulating pump is used to extract the refrigerant at the first air intake port of the compressor body; the extracted refrigerant enters the circulation cavity through the output end and the inlet of the circulating pump.

[0016] Furthermore, the compressor also includes: an electromagnetic expansion valve, which is arranged between the circulating pump and the inlet, and the output end of the circulating pump is connected to the inlet through the electromagnetic expansion valve; the electromagnetic expansion valve is used to adjust the flow rate and flow rate of the refrigerant; and / or, a first pipeline, which is respectively connected to the outlet and the second air intake port, and the refrigerant flowing out of the outlet passes through the first pipeline and the second air intake port in sequence and enters the compressor body.

[0017] According to another aspect of the present invention: a control method is provided, which is applied to the above-mentioned compressor, and the control method includes: obtaining a current first pressure value inside the first shell and a current second pressure value outside the first shell; and adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device according to the current first pressure value and the current second pressure value.

[0018] Furthermore, the control method is applied to the above-mentioned compressor; the method for adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device according to the current first pressure value and the current second pressure value includes: calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the on and off state of the electromagnet assembly according to the pressure difference; if the pressure difference is less than a first preset value, controlling the electromagnet assembly to be in a power-off state to maintain the current magnetic field strength of the magnetic fluid; if the pressure difference is greater than or equal to the first preset value, controlling at least a portion of the electromagnet assembly to switch to a power-on state, so as to adjust the magnetization intensity of the magnetic fluid through at least a portion of the electromagnet assembly in the power-on state.

[0019] Further, if the electromagnet assembly has N electromagnets, N≥2; the electromagnets are arranged in sequence along the axial direction of the input shaft; if the pressure difference is greater than a first preset value, at least a portion of the electromagnet assembly is controlled to switch to a powered state, so as to adjust the magnetization intensity of the magnetic fluid through at least a portion of the electromagnet assembly in the powered state, the method includes: if the pressure difference is greater than or equal to the first preset value, the number of electromagnets powered on is adaptively controlled according to the pressure difference; wherein the number of electromagnets powered on is controlled to be proportional to the pressure difference.

[0020] Furthermore, the method for adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device according to the current first pressure value and the current second pressure value also includes: within a first preset time, if the pressure difference changes frequently, controlling the electromagnet assembly to switch to a power-on state, so as to adjust the magnetization strength of the magnetic fluid through the electromagnet assembly in the power-on state.

[0021] Furthermore, the control method is applied to the above-mentioned compressor, and the control method also includes: calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the electromagnetic expansion valve according to the pressure difference; if the pressure difference is less than the first preset value, controlling the opening of the electromagnetic expansion valve to maintain at the preset opening; if the pressure difference is greater than or equal to the first preset value, increasing the opening of the electromagnetic expansion valve according to the pressure difference; wherein, the opening of the electromagnetic expansion valve is controlled to be proportional to the pressure difference.

[0022] Beneficial effects:

[0023] The technical solution of the present invention is applied, and the compressor provided by the present invention includes: a compressor body, a driving device, a magnetic fluid sealing device and a control device, wherein the compressor body has a first housing and an input shaft, wherein the input end of the input shaft is located outside the first housing, the driving device is located on one side of the compressor body, and the driving end of the driving device is connected to the input end of the input shaft, thereby driving the rotation of the input shaft to complete the compression work of the compressor on the refrigerant. At the same time, a magnetic fluid sealing device is arranged on one side of the first housing close to the driving device, the magnetic fluid sealing device is sleeved on the input shaft, and the magnetic fluid sealing device is inserted on the first housing so that part of the magnetic fluid sealing device is located in the first housing. The magnetic fluid sealing device is relatively fixedly connected to the first housing, and the driving device is located on the side of the magnetic fluid sealing device away from the first housing. The magnetic fluid sealing device is filled with a magnetic fluid that forms a dynamic seal, and the magnetic fluid is located on the outer wall of the input shaft, that is, the magnetic fluid wraps the part of the input shaft located in the magnetic fluid sealing device, ensuring that the input shaft is sealed by the magnetic fluid, thereby preventing the refrigerant from leaking along the outer wall of the input shaft. In addition, the control device is connected to the magnetic fluid sealing device, and the control device is used to obtain the current first pressure value in the first shell, and the current second pressure value outside the first shell, so as to adaptively adjust the magnetic field strength of the magnetic fluid according to the current first pressure value and the current second pressure value. It can be seen that the magnetic fluid sealing device ensures the tight sealing between the input shaft and the first shell through the dynamic sealing mechanism, effectively prevents the leakage of refrigerant, and avoids the leakage of lubricating oil in the compressor body when the driving device rotates at high speed, thereby improving the reliability of the system. In addition, the position design of the magnetic fluid sealing device effectively closes the interface between the input shaft and the first shell. In addition, a contact seal is formed between the magnetic fluid as a liquid seal and the input shaft, which avoids direct friction between the input shaft and the seal and reduces the additional load. At the same time, the current first pressure value in the first shell and the current second pressure value outside the first shell are obtained by the control device, and the magnetic field strength of the magnetic fluid is adaptively adjusted according to the current first pressure value and the current second pressure value. This process can effectively control the magnetic field strength of the magnetic fluid motion space, ensure the stability and reliability of the dynamic seal, and ensure that the sealing layer is always in the best state to meet the needs of different working conditions. In addition, by arranging a magnetic fluid sealing device on the side of the first housing close to the driving device, the problem of frequent replacement of the sealing shaft ring is avoided, the maintenance cost is reduced, and the energy efficiency of the compressor and the service life of the equipment are improved. The compressor of the present invention effectively solves the technical problem that the sealing performance of the input shaft of the open screw compressor in the prior art is poor, which may cause refrigerant leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic structural diagram of a compressor according to an embodiment of the present invention from a first viewing angle is shown;

[0025] Figure 2 A second perspective structural schematic diagram of an embodiment of a compressor of the present invention is shown;

[0026] Figure 3 A schematic structural diagram of a magnetic fluid sealing device in an embodiment of a compressor of the present invention is shown;

[0027] Figure 4 A flow chart showing an embodiment of the control method of the present invention is shown.

[0028] The above drawings include the following reference numerals:

[0029] 1. Compressor body; 11. First shell; 12. Input shaft; 13. First air intake port; 14. Second air intake port; 15. Compression component; 2. Driving device; 21. Driving body; 22. Driving shaft; 3. Magnetic fluid sealing device; 31. Second shell; 311. First placement cavity; 312. Second placement cavity; 313. Circulation cavity; 314. Inlet; 315. Outlet; 33. Electromagnet assembly; 331. Electromagnet; 34. Permanent magnet assembly; 341. Permanent magnet ring; 4. First pressure detection device; 5. Second pressure detection device; 6. Circulation pump; 7. Electromagnetic expansion valve; 8. First pipeline; 9. Coupling. DETAILED DESCRIPTION

[0030] 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 described clearly and completely 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, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0031] See also Figures 1 to 3As shown, according to an embodiment of the present invention, the present invention provides a compressor, comprising: a compressor body 1, a driving device 2, a magnetic fluid sealing device 3 and a control device, the compressor body 1 has a first shell 11 and an input shaft 12, the input end of the input shaft 12 is located outside the first shell 11; the driving end of the driving device 2 is connected to the input end of the input shaft 12, and the driving device 2 is used to drive the input shaft 12 to rotate; the magnetic fluid sealing device 3 is sleeved on the input shaft 12, and at least part of the magnetic fluid sealing device 3 is located in the first shell 11, and the magnetic fluid sealing device 3 is relatively fixedly connected to the first shell 11; the driving device 2 is located on the side of the magnetic fluid sealing device 3 away from the first shell 11; the magnetic fluid sealing device 3 is filled with a magnetic fluid, and the magnetic fluid is located on the outer wall of the input shaft 12, so as to seal the input shaft 12 through the magnetic fluid; the control device is used to obtain the current first pressure value in the first shell 11, and the current second pressure value outside the first shell 11, so as to adaptively adjust the magnetic field strength of the magnetic fluid according to the current first pressure value and the current second pressure value.

[0032] It can be seen that the compressor provided by the present invention includes: a compressor body 1, a driving device 2, a magnetic fluid sealing device 3 and a control device, the compressor body 1 has a first shell 11 and an input shaft 12, wherein the input end of the input shaft 12 is located outside the first shell 11, the driving device 2 is located on one side of the compressor body 1, and the driving end of the driving device 2 is connected to the input end of the input shaft 12, thereby driving the rotation of the input shaft 12 to complete the compression of the refrigerant by the compressor. At the same time, a magnetic fluid sealing device 3 is arranged on one side of the first shell 11 close to the driving device 2, the magnetic fluid sealing device 3 is sleeved on the input shaft 12, and the magnetic fluid sealing device 3 is inserted on the first shell 11, so that part of the magnetic fluid sealing device 3 is located in the first shell 11. The magnetic fluid sealing device 3 is relatively fixedly connected to the first shell 11, and the driving device 2 is located on the side of the magnetic fluid sealing device 3 away from the first shell 11. The magnetic fluid sealing device 3 is filled with a magnetic fluid that forms a dynamic seal, and the magnetic fluid is located on the outer wall of the input shaft 12 (that is, the magnetic fluid wraps the portion of the input shaft 12 located in the magnetic fluid sealing device 3), ensuring that the input shaft 12 is sealed by the magnetic fluid, thereby preventing the refrigerant from leaking along the outer wall of the input shaft 12. In addition, the control device is connected to the magnetic fluid sealing device 3, and the control device is used to obtain the current first pressure value in the first shell 11 and the current second pressure value outside the first shell 11, so as to adaptively adjust the magnetic field strength of the magnetic fluid according to the current first pressure value and the current second pressure value.

[0033] It can be seen that the magnetic fluid sealing device 3 ensures a tight seal between the input shaft 12 and the first housing 11 through a dynamic sealing mechanism, effectively prevents refrigerant leakage, and avoids leakage of lubricating oil in the compressor body 1 when the driving device 2 rotates at high speed, thereby improving the reliability of the system. In addition, the position design of the magnetic fluid sealing device 3 effectively closes the interface between the input shaft 12 and the first housing 11. In addition, a contact seal is formed between the magnetic fluid as a liquid seal and the input shaft 12, avoiding direct friction between the input shaft and the seal, and reducing the additional load. At the same time, the current first pressure value in the first housing 11 and the current second pressure value outside the first housing 11 are obtained by the control device. According to the current first pressure value and the current second pressure value, the magnetic field strength of the magnetic fluid is adaptively adjusted. This process can effectively control the magnetic field strength of the magnetic fluid motion space, ensure the stability and reliability of the dynamic seal, and ensure that the sealing layer is always in the best state to meet the needs of different working conditions. In addition, by arranging the magnetic fluid sealing device 3 on the side of the first housing 11 close to the driving device, the problem of frequent replacement of the sealing shaft ring is avoided, the maintenance cost is reduced, and the energy efficiency of the compressor and the service life of the equipment are improved. The compressor of the present invention effectively solves the technical problem that the sealing performance of the input shaft of the open screw compressor in the prior art is poor, which may cause refrigerant leakage.

[0034] Optionally, the compressor is an open screw compressor.

[0035] Optionally, the magnetic fluid seal utilizes the principle of dynamic sealing and can actively adjust the sealing strength according to the operating state of the system. This dynamic characteristic enables the magnetic fluid seal device 3 to maintain a stable sealing effect under different conditions during operation, and adapt to working conditions such as high-speed rotation of the compressor.

[0036] Among them, magnetic fluid is a liquid material. Under the action of an external magnetic field, it forms a liquid sealing layer between the input shaft and the shell. This sealing layer can not only effectively prevent the leakage of refrigerant, but also prevent the escape of lubricating oil. Because of the fluidity and adjustability of magnetic fluid, it can simultaneously surround and isolate two fluids in liquid sealing mode.

[0037] Furthermore, the driving device 2 includes a driving body 21 and a driving shaft 22 , both ends of the driving shaft 22 are respectively connected to the driving body 21 and the input end of the input shaft 12 , and one end of the driving shaft 22 is close to the input shaft 12 to form the driving end of the driving device 2 .

[0038] Optionally, the axis of the drive shaft 22 is arranged to coincide with the axis of the input shaft 12 (ie, the drive shaft 22 is coaxial and collinear with the input shaft 12). This design ensures precise transmission between the drive device 2 and the compressor body 1, reduces mechanical vibration and wear, and improves the stability and efficiency of the system.

[0039] Optionally, the driving device 2 is a motor.

[0040] Furthermore, the compressor further comprises: a coupling 9 , and the driving end of the driving device 2 is connected to the input end of the input shaft 12 through the coupling 9 .

[0041] Furthermore, the compressor body 1 further includes: a compression component 15, the compression component 15 is located in the first housing 11, and the compression component 15 is used to compress the refrigerant. The input end of the input shaft 12 is connected to the compression component 15. When the driving device 2 drives the input shaft 12 to rotate, the compression component 15 is driven to move by the rotation of the input shaft 12, thereby realizing the compression of the refrigerant.

[0042] Specifically, Figure 1 and Figure 3 As shown, the magnetic fluid sealing device 3 includes: a second housing 31 and an electromagnet assembly 33, the second housing 31 is inserted on the first housing 11, and at least part of the second housing 31 is located in the first housing 11, the second housing 31 is relatively fixedly connected to the first housing 11, a first placement cavity 311 and a second placement cavity 312 are provided in the second housing 31, and the first placement cavity 311 and the second placement cavity 312 both extend along the axial direction of the input shaft 12; the first placement cavity 311 is nested in the second placement cavity 312; the first placement cavity 311 is filled with magnetic fluid: the electromagnet assembly 33 is arranged in the second placement cavity 312, so as to adjust the magnetic field strength of the magnetic fluid by turning the electromagnet assembly 33 on and off; the electromagnet assembly 33 is connected to the control device, and the control device adaptively controls the on and off state of the electromagnet assembly 33 according to the current first pressure value and the current second pressure value. With such a structural setting, the second housing 31 is provided with a first placement cavity 311 and a second placement cavity 312, wherein the first placement cavity 311 is nested in the second placement cavity 312. This design facilitates effective isolation of the magnetic fluid from the electromagnet assembly 33. In addition, by arranging the electromagnet assembly 33 in the second placement cavity 312, the magnetic field strength of the magnetic fluid can be enhanced when the electromagnet assembly 33 is partially powered, thereby increasing the saturation magnetization strength of the magnetic fluid, thereby ensuring that the sealing performance of the magnetic fluid sealing device 3 is more stable.

[0043] Among them, the electromagnet generates a magnetic field through a current-carrying conductor. When current flows through the electromagnet coil, a magnetic field is formed around it, and the strength of the magnetic field is proportional to the current and the number of turns of the coil. Magnetic fluid is a liquid containing ferromagnetic particles that can exhibit magnetism under the action of an external magnetic field. Its saturation magnetization intensity represents the maximum magnetic effect that the magnetic fluid can achieve under a strong magnetic field. The enhanced external magnetic field can make the magnetic particles in the magnetic fluid more effectively arranged, thereby improving its magnetic field-based performance. Under the action of the magnetic field strength, the magnetic fluid will circulate, thereby forming a physical seal isolation.

[0044] Therefore, when the electromagnet assembly 33 is powered, even if it is partially powered, the magnetic field generated is sufficient to enhance the arrangement of particles inside the magnetic fluid, thereby increasing its saturation magnetization. This means that the ability of the magnetic fluid to resist external influences is enhanced under the action of the external magnetic field, thereby improving the sealing effect.

[0045] At the same time, the magnetic fluid sealing device 3 relies on the magnetism of the magnetic fluid to form a reliable seal. Under the action of a stronger magnetic field, the retention capacity and pressure bearing capacity of the magnetic fluid are enhanced, effectively preventing the leakage of liquid or gas. In addition, the increase in saturation magnetization can ensure that the sealing performance remains stable under different working conditions (such as temperature and pressure changes) and is not easily affected by external conditions.

[0046] Optionally, the second shell 31 is a cylindrical annular shell, the first placement cavity 311 and the second placement cavity 312 are both annular cavities, and the first placement cavity 311 is nested in the second placement cavity 312 .

[0047] Optionally, the second shell 31 is made of non-magnetic bronze material.

[0048] Optionally, when the magnetic fluid sealing device 3 is sleeved on the input shaft 12 , part of the input shaft 12 is located in the first placement cavity 311 .

[0049] Specifically, Figure 3As shown, the second placement cavity 312 is an annular cavity, and the electromagnet assembly 33 includes: at least two electromagnets 331, each electromagnet 331 is sequentially sleeved on the outer wall of the first placement cavity 311 along the extension direction of the second placement cavity 312; wherein the control device adaptively controls the on-off state of each electromagnet 331 according to the current first pressure value and the current second pressure value. With such a structural setting, the control device automatically adjusts the on-off state of each electromagnet 331 according to the current first pressure value and the current second pressure value, thereby ensuring that the magnetic field strength of the magnetic fluid is always in the best state, so that the magnetic fluid sealing device 3 can adapt to different working conditions. And it can also control the number of electromagnets powered on according to actual conditions, thereby reducing unnecessary energy consumption and improving the energy efficiency of the system. In addition, dynamically adjusting the number of electromagnets powered on reduces excessive loads on mechanical components, reduces the risk of wear, and extends the service life of the equipment. And it can achieve more precise magnetic field strength regulation to ensure the stability and reliability of the sealing layer.

[0050] Optionally, the control device may select to control all the electromagnets 331 to be in an energized state or an energized state according to the current first pressure value and the current second pressure value, or may select to control some of the electromagnets 331 to be in an energized state. That is, the control device may control the number of electromagnets 331 energized according to actual conditions.

[0051] Specifically, Figure 2 As shown, the magnetic fluid sealing device 3 also includes: a permanent magnet assembly 34, which is arranged in the second placement cavity 312, and the permanent magnet assembly 34 is sleeved on the outer wall of the first placement cavity 311; the electromagnet assembly 33 is nested in the permanent magnet assembly 34. With such a structural setting, by setting the permanent magnet assembly 34, a constant magnetic field can be provided for the magnetic fluid, which helps to maintain the optimal working state of the magnetic fluid when the electromagnet assembly 33 is not energized, thereby ensuring the stability of the sealing effect. The permanent magnet assembly 34 and the electromagnet assembly 33 are nested to design the overall structure to be more compact, which helps to reduce the volume of the device and improve the reliability and maintenance convenience of the system. At the same time, when it is necessary to quickly restore or change the state of the magnetic fluid, the permanent magnet assembly 34 can respond immediately, combined with the rapid change of the electromagnet assembly 33, to provide support for the system to quickly adjust the sealing effect of the magnetic fluid. In addition, the permanent magnet assembly 34 reduces the demand for current input, saves energy, and improves the energy efficiency of the system by effectively utilizing the static magnetic field. Furthermore, the combination of the permanent magnet assembly 34 and the electromagnet assembly 33 can enhance the magnetic field effect of the magnetic fluid when the electromagnet assembly 33 is powered on. This synergistic effect increases the saturation magnetization intensity of the magnetic fluid, further enhances the sealing effect, and reduces the risk of liquid or gas leakage.

[0052] Specifically, Figure 2 As shown, the permanent magnet assembly 34 includes: at least two permanent magnet rings 341, each permanent magnet ring 341 is arranged in sequence along the extension direction of the second placement cavity 312; the magnetic poles of two adjacent permanent magnet rings 341 in each permanent magnet ring 341 are arranged in different directions; the electromagnet assembly 33 is nested in at least one permanent magnet ring 341 in each permanent magnet ring 341. Each permanent magnet ring 341 is sleeved on the outer wall of the first placement cavity 311. With such a structural setting, the different directions of the arrangement of adjacent permanent magnet rings 341 can effectively enhance the density and uniformity of the magnetic field and form a stronger comprehensive magnetic field, which is very important for improving the saturation magnetization intensity and sealing performance of the magnetic fluid. By setting a plurality of permanent magnet rings 341, the influence of magnetic field changes on the performance of the equipment can be effectively dispersed, and the stability of the magnetic fluid sealing device 3 in harsh environments such as high temperature and high pressure can be enhanced. In addition, the nested design of the electromagnet assembly 33 enables it to respond quickly to external signals with the assistance of the permanent magnetic field, thereby adjusting the sealing effect in time and adapting to the ever-changing working environment.

[0053] Optionally, each permanent magnet ring 341 is made of permanent magnet material, and each extreme end is adsorbed with a magnetic pole made of 45# steel, and such a combination forms a "magnetic source" of a pole segment. Each group of "magnetic sources" adopts axial series connection in NN and SS directions.

[0054] Specifically, Figure 1 As shown, the compressor also includes: a first pressure detection device 4, which is arranged on the magnetic fluid sealing device 3, and the first pressure detection device 4 is located in the first shell 11; the first pressure detection device 4 is used to detect the first pressure value in the first shell 11; the first pressure detection device 4 is connected to the control device, and the first pressure detection device 4 sends the detected first pressure value in the first shell 11 to the control device. With such a structural setting, the first pressure detection device 4 can monitor the pressure change in the first shell 11 in real time, and feed back the data to the control device in time, ensuring that the control system always has the latest working condition information. The control device accurately adjusts the on and off state of the electromagnet assembly 33 according to the accurate data provided by the first pressure detection device 4, ensuring that the magnetic field strength of the magnetic fluid is always in the best state and improving the sealing performance.

[0055] Specifically, Figure 1As shown, the compressor also includes: a second pressure detection device 5, which is arranged on the magnetic fluid sealing device 3, and the second pressure detection device 5 is located outside the first shell 11; the second pressure detection device 5 is used to detect the second pressure value outside the first shell 11; the second pressure detection device 5 is connected to the control device, and the second pressure detection device 5 sends the detected second pressure value outside the first shell 11 to the control device. With such a structural setting, the pressure change outside the first shell 11 can be monitored in real time by setting the second pressure detection device 5, and the data can be fed back to the control device in time to ensure that the control system always has the latest working condition information. The control device accurately adjusts the on and off state of the electromagnet assembly 33 according to the data of the internal and external pressure difference, ensures that the magnetic field strength of the magnetic fluid is always in the best state, and improves the sealing performance. And through the data of the internal and external pressure difference, the control system can dynamically adjust the number of electromagnets powered on according to actual needs, realize intelligent adjustment, and adapt to different working conditions.

[0056] Optionally, the first pressure detection device 4 and the second pressure detection device 5 are arranged on the magnetic fluid sealing device 3 at intervals along the axial direction of the input shaft 12 .

[0057] Further, when the control device obtains the first pressure value and the second pressure value, it determines whether to power on based on the pressure difference between the first pressure value and the second pressure value, so that at least part of the electromagnet assembly 33 is in a powered state.

[0058] Optionally, since the internal pressure of the compressor body 1 (i.e., the first pressure inside the first shell 11) is much greater than the external pressure (i.e., the second pressure outside the first shell 11), the liquid in the compressor body 1 will be easily thrown out during the rotation of the input shaft 12. Therefore, it is necessary to control at least part of the electromagnet assembly 33 to be in an energized state, thereby further enhancing the magnetic field strength of the magnetic fluid. The magnetic fluid is subjected to greater force in the magnetic field, and its movement speed is faster, so the liquid seal formed will be more stable.

[0059] Optionally, the outer wall of each permanent magnet ring 341 abuts against the inner wall of the second placement cavity 312 , so that each permanent magnet ring 341 is fixed in the second placement cavity 312 .

[0060] Specifically, Figure 3As shown, the magnetic fluid sealing device 3 includes: a second shell 31, the second shell 31 is provided with a first placement cavity 311, a circulation cavity 313, and an inlet 314 and an outlet 315 respectively connected to the circulation cavity 313; the first placement cavity 311 is nested in the circulation cavity 313, and the first placement cavity 311 and the circulation cavity 313 both extend along the axial direction of the input shaft 12; the first placement cavity 311 is filled with magnetic fluid; the circulation cavity 313 is used for the circulation of refrigerant, and the refrigerant enters the circulation cavity 313 through the inlet 314 to exchange heat with the magnetic fluid; the refrigerant after absorbing heat flows out from the outlet 315. With such a structural setting, by setting the circulation cavity 313, the circulation of the refrigerant can be facilitated, the heat exchange between the refrigerant and the magnetic fluid is realized, and the temperature of the magnetic fluid is reduced, and the magnetic field fluctuations that may be caused by the temperature increase are reduced, thereby improving the stability of the magnetic field of the magnetic fluid. The magnetic fluid sealing device 3 has a simple structure, is easy to install and replace, and reduces the assembly time of the compressor and improves the work efficiency. The magnetic fluid sealing device 3 is more suitable for large commercial units such as open screw compressors.

[0061] Optionally, the magnetic fluid generates heat when it moves, and the heat will affect the stability of the magnetic field. Therefore, by introducing a refrigerant into the circulation cavity 313, the refrigerant circulates to remove the heat generated by the magnetic fluid when it moves, thereby maintaining the stability of the magnetic field of the magnetic fluid.

[0062] Optionally, the first placement cavity 311 is nested in the second placement cavity 312, and the second placement cavity 312 is nested in the circulation cavity 313. The refrigerant flows into the circulation cavity 313 to exchange heat with the permanent magnet assembly 34 and the electromagnet assembly 33. In addition, when the electromagnet is energized, the heat generated by it can also be effectively absorbed.

[0063] Optionally, the second shell 31 is a cylindrical annular shell and adopts a double-layer hollow design, wherein the middle hollow portion forms a flow cavity 313 .

[0064] Specifically, Figure 2As shown, the compressor has a first air inlet 13 and a second air inlet 14; the compressor also includes: a circulating pump 6, the input end of the circulating pump 6 is connected to the first air inlet 13 of the compressor body 1, and the output end of the circulating pump 6 is connected to the inlet 314; the circulating pump 6 is used to extract the refrigerant at the first air inlet 13 of the compressor body 1; the extracted refrigerant enters the circulation cavity 313 through the output end and the inlet 314 of the circulating pump 6. With such a structural arrangement, by setting the circulating pump 6, the refrigerant can be introduced into the circulation cavity 313, the working environment stability of the magnetic fluid sealing device 3 is enhanced, the magnetic fluid is ensured to work in the best state, and the sealing effect is improved. The introduction of the circulating pump 6 enables the refrigerant to circulate effectively in the system, and by accurately controlling the flow path of the refrigerant, the coordinated work between the various components is ensured, and the performance and reliability of the entire compressor system are optimized. In addition, by connecting the circulating pump 6 to the first air inlet 13, it is convenient to introduce the refrigerant at a low temperature (the refrigerant that is not compressed) into the circulation cavity 313, so that the temperature of the magnetic fluid can be effectively reduced.

[0065] Specifically, Figure 2 As shown, the compressor also includes: an electromagnetic expansion valve 7, which is arranged between the circulation pump 6 and the inlet 314, and the output end of the circulation pump 6 is connected to the inlet 314 through the electromagnetic expansion valve 7; the electromagnetic expansion valve 7 is used to adjust the flow rate and flow rate of the refrigerant. With such a structural arrangement, the flow rate and flow rate of the refrigerant can be accurately adjusted according to actual needs by setting the electromagnetic expansion valve 7, ensuring that the system is always in the best working state, and improving the stability and reliability of the system. By accurately controlling the flow rate and flow rate of the refrigerant, it is ensured that the refrigerant in the magnetic fluid sealing device 3 flows smoothly, the sealing effect is enhanced, and the risk of leakage is reduced. In addition, accurately adjusting the refrigerant flow rate and flow rate helps to optimize the working efficiency of the system, reduce unnecessary energy consumption, and improve the energy efficiency of the system. In addition, the electromagnetic expansion valve 7 can flexibly adjust the flow rate and flow rate of the refrigerant according to different working conditions, so that the system can better adapt to various operating conditions, and improve the flexibility and applicability of the system.

[0066] Furthermore, the electromagnetic expansion valve 7 is connected to a control device, and the control device adaptively adjusts the opening of the electromagnetic expansion valve 7 according to the current first pressure value and the current second pressure value.

[0067] Optionally, if the pressure difference between the current first pressure value and the current second pressure value is too large, the heat generated by the magnetic fluid will increase significantly. In order to effectively dissipate heat and maintain the stable operation of the system, the control device controls the electromagnetic expansion valve 7 to increase its opening, thereby increasing the flow rate and flow of the refrigerant. In this way, more refrigerant is introduced into the circulation cavity 313, quickly taking away the heat generated by the magnetic fluid and the electromagnet 331 after power is turned on, thereby maintaining the stable operation of the magnetic field.

[0068] Specifically, Figure 2 As shown, the compressor further includes: a first pipeline 8, the first pipeline 8 is connected to the outlet 315 and the second air inlet 14 respectively, and the refrigerant flowing out of the outlet 315 passes through the first pipeline 8 and the second air inlet 14 in sequence and enters the compressor body 1. With such a structural arrangement, the design of the first pipeline 8 ensures that the refrigerant can circulate efficiently in the system, avoids the refrigerant from being retained in the magnetic fluid sealing device 3, and improves the refrigeration efficiency of the system.

[0069] The present invention provides a control method, which is applied to the compressor of the above embodiment. Figure 4 As shown, the control method includes:

[0070] S11, obtaining a current first pressure value inside the first shell 11 and a current second pressure value outside the first shell 11;

[0071] S12, adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device 3 according to the current first pressure value and the current second pressure value.

[0072] By adopting such a control method, the magnetic field strength of the magnetic fluid can be adaptively adjusted according to the current first pressure value and the current second pressure value. This process can effectively control the magnetic field strength of the magnetic fluid movement space, ensure the stability and reliability of dynamic sealing, and ensure that the sealing layer is always in the best state to meet the needs of different working conditions.

[0073] Specifically, the method for adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device 3 according to the current first pressure value and the current second pressure value includes: calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the on-off state of the electromagnet assembly 33 according to the pressure difference; if the pressure difference is less than the first preset value, controlling the electromagnet assembly 33 to be in a power-off state to maintain the current magnetic field strength of the magnetic fluid; if the pressure difference is greater than or equal to the first preset value, controlling at least part of the electromagnet assembly 33 to switch to a power-on state, so as to adjust the magnetization intensity of the magnetic fluid through at least part of the electromagnet assembly 33 in the power-on state. With such a control method, the magnetic field strength of the magnetic fluid is dynamically adjusted according to the actual pressure difference, ensuring that the best sealing effect is always maintained under different working conditions, and effectively preventing refrigerant leakage. And by real-time monitoring and automatically adjusting the on-off state of the electromagnet assembly according to the pressure difference, it is ensured that the magnetic field strength of the magnetic fluid is always in the best state, which improves the reliability and response speed of the system. At the same time, when the pressure difference is small, the electromagnet assembly remains in a power-off state, reducing unnecessary energy consumption and improving the energy efficiency of the system.

[0074] The first preset value refers to a preset pressure difference threshold value, which is used to determine whether the on / off state of the electromagnet assembly needs to be adjusted.

[0075] Optionally, when the pressure difference is less than the first preset value, it means that the pressure inside the compressor body 1 is not much different from the pressure outside the compressor body 1, and the liquid inside the compressor body 1 is not easy to leak out, and at this time, the magnetic field strength of the permanent magnet can be maintained. When the pressure difference is greater than or equal to the first preset value, it means that the pressure inside the compressor body 1 is too different from the pressure outside the compressor body 1, and the liquid inside the compressor body 1 is easy to be thrown out. Therefore, it is necessary to control at least part of the electromagnet assembly 33 to be in an energized state, thereby further enhancing the magnetic field strength of the magnetic fluid. The magnetic fluid is subjected to greater force in the magnetic field, and its movement speed is faster, and the formed liquid seal will be more stable.

[0076] Specifically, if the electromagnet assembly 33 has N electromagnets 331, N≥2; each electromagnet 331 is arranged in sequence along the axial direction of the input shaft 12; if the pressure difference is greater than or equal to the first preset value, at least part of the electromagnet assembly 33 is controlled to switch to the energized state, so as to adjust the magnetization intensity of the magnetic fluid through at least part of the electromagnet assembly 33 in the energized state, including: if the pressure difference is greater than or equal to the first preset value, the number of electromagnets 331 energized is adaptively controlled according to the pressure difference; wherein the number of electromagnets 331 energized is controlled to be proportional to the pressure difference. With such a control method, when the pressure difference is greater than or equal to the first preset value, the number of energized electromagnet assemblies is automatically adjusted according to the actual pressure difference, thereby ensuring that the magnetic field intensity of the magnetic fluid is always in the best state, thereby improving the reliability and response speed of the system. In addition, the number of electromagnets energized is dynamically adjusted, which reduces unnecessary energy consumption and improves the energy efficiency of the system. And, a more refined magnetic field intensity adjustment is achieved to ensure the stability and reliability of the sealing layer. Through effective pressure difference monitoring and magnetic field strength adjustment mechanism, the overall safety of the system is improved, and the system can flexibly adjust the magnetic field strength according to different working conditions, which improves the applicability and flexibility of the system.

[0077] Furthermore, if the pressure difference is greater than or equal to the first preset value, as the pressure difference increases, the number of electromagnets 331 that are energized also increases.

[0078] For example, there are three electromagnets 331. When the pressure difference is greater than or equal to the first preset value, if the pressure difference is less than the second preset value, one electromagnet 331 is controlled to be energized, so that the electromagnet 331 is in a powered state. If the pressure difference is greater than or equal to the second preset value and less than the third preset value, two electromagnets 331 are controlled to be in a powered state. If the pressure value is greater than or equal to the third preset value, all electromagnets 331 are controlled to be in a powered state. When the pressure difference is less than the first preset value, all electromagnets 331 are controlled to be in a powered state. Among them, the first preset value is less than the second preset value, and the second preset value is less than the third preset value.

[0079] Specifically, according to the current first pressure value and the current second pressure value, the method for adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device 3 also includes: within the first preset time, if the pressure difference changes frequently, the control electromagnet assembly 33 is switched to the power-on state, so as to adjust the magnetization of the magnetic fluid by the electromagnet assembly 33 in the power-on state. Adopting such a control method, when the pressure difference changes frequently, by timely adjusting the power-on state of the electromagnet assembly 33, the stable magnetic field strength is effectively maintained, and the overall stability of the system is improved. And it is also possible to quickly respond to the pressure difference that changes frequently, ensure that the magnetization of the magnetic fluid is always maintained in the best state, and prevent the sealing failure caused by pressure fluctuations. At the same time, by real-time monitoring and automatically adjusting the power-on state of the electromagnet assembly 33 according to the change of the pressure difference, ensure that the magnetic field strength of the magnetic fluid is always in the best state, and improve the reliability and response speed of the system.

[0080] Furthermore, within the first preset time, if the pressure difference changes frequently, all the electromagnets 331 are controlled to be in an energized state to adjust the magnetic field strength of the magnetic fluid to the maximum, thereby ensuring that the sealing is optimal.

[0081] Specifically, the control method further includes: calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the electromagnetic expansion valve 7 according to the pressure difference; if the pressure difference is less than the first preset value, controlling the opening of the electromagnetic expansion valve 7 to maintain the preset opening; if the pressure difference is greater than or equal to the first preset value, increasing the opening of the electromagnetic expansion valve 7 according to the pressure difference; wherein the opening of the electromagnetic expansion valve 7 is controlled to be proportional to the pressure difference. By adopting such a control method, the opening of the electromagnetic expansion valve 7 is dynamically adjusted according to the actual pressure difference, ensuring that the refrigerant flow rate and flow velocity are always in the best state, thereby improving the stability and reliability of the system. When the pressure difference is less than the first preset value, by maintaining the electromagnetic expansion valve 7 at the preset opening, unnecessary energy consumption is reduced and the energy efficiency of the system is improved. When the pressure difference is greater than or equal to the first preset value, by increasing the opening of the electromagnetic expansion valve 7, the flow velocity and flow of the refrigerant can be increased, thereby allowing more refrigerant to be introduced into the circulation cavity 313, and quickly taking away the heat generated by the magnetic fluid and the electromagnet 331 after being energized, thereby effectively dissipating heat and maintaining the stable operation of the system and the stable operation of the magnetic field.

[0082] Furthermore, if the pressure difference is greater than or equal to the first preset value, the opening of the electromagnetic expansion valve 7 is gradually increased as the pressure difference increases.

[0083] Optionally, the control process of the compressor is:

[0084] The magnetic fluid sealing device includes a plurality of permanent magnet rings 341 and a plurality of electromagnets 331 .

[0085] Step 1, when the compressor is working, the driving device 2 drives the input shaft 12 to rotate, thereby driving the compression component of the compressor body 1 to move to achieve refrigerant compression. At the same time, when the compressor is working, the first pressure detection device 4 and the second pressure detection device 5 respectively detect the first pressure value inside the first shell 11 and the second pressure value outside the first shell 11 in real time, and send the detected first pressure value and second pressure value to the control device.

[0086] Step 2, after the control device obtains the first pressure value and the second pressure value, it calculates the pressure difference between the first pressure value and the second pressure value, and compares the calculated pressure difference with the first preset value. If the pressure difference is less than the first preset value, a stable magnetic field is provided for the magnetic fluid through the permanent magnet assembly 34, and all the electromagnets 331 are in a power-off state. If the pressure difference is greater than or equal to the first preset value, the number of electromagnets 331 to be energized is determined by the calculated pressure difference, and then the corresponding number of electromagnets 331 are controlled to be in a power-on state. Among them, as the pressure difference increases, the number of electromagnets 331 that are energized increases accordingly.

[0087] Step 3: within the first preset time, if the pressure difference changes frequently, each electromagnet 331 is controlled to be in an energized state, so as to increase the magnetic field strength of the magnetic fluid to the maximum.

[0088] Step 4, after the compressor is turned on, the circulating pump 6 is turned on, and the opening of the electromagnetic expansion valve 7 is adjusted to a preset opening. The low-temperature refrigerant at the first air intake port 13 passes through the circulating pump 6, the electromagnetic expansion valve 7, and the inlet 314 in sequence into the circulation chamber 313, and then the refrigerant exchanges heat with the magnetic fluid, and the refrigerant absorbs the heat generated by the magnetic fluid. The refrigerant after absorbing the heat flows out through the outlet 315, and then enters the compressor body 1 (i.e., the compression component 15) through the first pipeline 8 and the second air intake port 14.

[0089] Step 5: During operation, if the pressure difference is less than the first preset value, the opening of the electromagnetic expansion valve 7 is controlled to be maintained at the preset opening; if the pressure difference is greater than or equal to the first preset value, the opening of the electromagnetic expansion valve 7 is determined by the calculated pressure difference. Then, the opening of the electromagnetic expansion valve 7 is adjusted. As the pressure difference increases, the opening of the electromagnetic expansion valve 7 is gradually increased.

[0090] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable when appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0091] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0092] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0093] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0094] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A compressor, characterized in that: include: A compressor body (1) and a driving device (2), wherein the compressor body (1) comprises a first housing (11) and an input shaft (12), wherein the input end of the input shaft (12) is located outside the first housing (11); the driving end of the driving device (2) is connected to the input end of the input shaft (12), and the driving device (2) is used to drive the input shaft (12) to rotate; A magnetic fluid sealing device (3) is sleeved on the input shaft (12), and at least a portion of the magnetic fluid sealing device (3) is located in the first housing (11), and the magnetic fluid sealing device (3) is relatively fixedly connected to the first housing (11); the driving device (2) is located on a side of the magnetic fluid sealing device (3) away from the first housing (11); the magnetic fluid sealing device (3) is filled with a magnetic fluid, and the magnetic fluid is located on the outer wall of the input shaft (12), so that the input shaft (12) is sealed by the magnetic fluid; A control device, the control device is used to obtain a current first pressure value inside the first shell (11) and a current second pressure value outside the first shell (11), so as to adaptively adjust the magnetic field strength of the magnetic fluid according to the current first pressure value and the current second pressure value.

2. The compressor according to claim 1, characterized in that The magnetic fluid sealing device (3) comprises: A second shell (31), wherein the second shell (31) is inserted into the first shell (11), and at least a portion of the second shell (31) is located inside the first shell (11); the second shell (31) is relatively fixedly connected to the first shell (11); a first placement cavity (311) and a second placement cavity (312) are provided inside the second shell (31); the first placement cavity (311) and the second placement cavity (312) both extend along the axial direction of the input shaft (12); the first placement cavity (311) is nested inside the second placement cavity (312); the first placement cavity (311) is filled with the magnetic fluid: An electromagnet assembly (33), wherein the electromagnet assembly (33) is arranged in the second placement cavity (312) so as to adjust the magnetic field strength of the magnetic fluid by turning the electromagnet assembly (33) on and off; the electromagnet assembly (33) is connected to the control device, and the control device adaptively controls the on and off state of the electromagnet assembly (33) according to the current first pressure value and the current second pressure value.

3. The compressor according to claim 2, characterized in that The second placement cavity (312) is an annular cavity, and the electromagnet assembly (33) comprises: At least two electromagnets (331), each of the electromagnets (331) being sequentially sleeved on the outer wall of the first placement cavity (311) along the extension direction of the second placement cavity (312); Wherein, the control device adaptively controls the on / off state of each electromagnet (331) according to the current first pressure value and the current second pressure value.

4. The compressor according to claim 2, characterized in that The magnetic fluid sealing device (3) further comprises: a permanent magnet assembly (34), wherein the permanent magnet assembly (34) is arranged in the second placement cavity (312), and the permanent magnet assembly (34) is sleeved on the outer wall of the first placement cavity (311); and the electromagnet assembly (33) is nested in the permanent magnet assembly (34).

5. The compressor according to claim 4, characterized in that The permanent magnet assembly (34) comprises: at least two permanent magnet rings (341), each of the permanent magnet rings (341) being arranged in sequence along the extension direction of the second placement cavity (312); the magnetic poles of two adjacent permanent magnet rings (341) in each of the permanent magnet rings (341) are arranged in different directions; and the electromagnet assembly (33) is nested in at least one of the permanent magnet rings (341) in each of the permanent magnet rings (341).

6. The compressor according to claim 1, characterized in that The compressor further comprises: a first pressure detection device (4), the first pressure detection device (4) being arranged on the magnetic fluid sealing device (3), and the first pressure detection device (4) being located in the first shell (11); the first pressure detection device (4) being used for detecting a first pressure value in the first shell (11); the first pressure detection device (4) being connected to the control device, and the first pressure detection device (4) being used for sending the detected first pressure value in the first shell (11) to the control device.

7. The compressor according to claim 1, characterized in that The compressor also includes: A second pressure detection device (5), wherein the second pressure detection device (5) is arranged on the magnetic fluid sealing device (3), and the second pressure detection device (5) is located outside the first shell (11); the second pressure detection device (5) is used to detect a second pressure value outside the first shell (11); the second pressure detection device (5) is connected to the control device, and the second pressure detection device (5) sends the detected second pressure value outside the first shell (11) to the control device.

8. The compressor according to claim 1, characterized in that The magnetic fluid sealing device (3) comprises: a second shell (31), the second shell (31) being provided with a first placement cavity (311), a circulation cavity (313), and an inlet (314) and an outlet (315) respectively connected to the circulation cavity (313); the first placement cavity (311) is nested in the circulation cavity (313), the first placement cavity (311) and the circulation cavity (313) both extending along the axial direction of the input shaft (12); the first placement cavity (311) is filled with the magnetic fluid; the circulation cavity (313) is used for the circulation of a refrigerant, the refrigerant enters the circulation cavity (313) through the inlet (314) to perform heat exchange with the magnetic fluid; The refrigerant after absorbing heat flows out from the outlet (315).

9. The compressor according to claim 8, characterized in that The compressor unit has a first air intake port (13) and a second air intake port (14); the compressor further comprises: a circulating pump (6), the input end of the circulating pump (6) being connected to the first air intake port (13) of the compressor body (1), and the output end of the circulating pump (6) being connected to the inlet port (314); the circulating pump (6) is used to extract the refrigerant at the first air intake port (13) of the compressor body (1); the extracted refrigerant enters the circulation chamber (313) through the output end of the circulating pump (6) and the inlet port (314).

10. The compressor according to claim 9, characterized in that The compressor also includes: an electromagnetic expansion valve (7), the electromagnetic expansion valve (7) being arranged between the circulation pump (6) and the inlet (314), the output end of the circulation pump (6) being connected to the inlet (314) through the electromagnetic expansion valve (7); the electromagnetic expansion valve (7) being used to adjust the flow rate and flow velocity of the refrigerant; and / or, A first pipeline (8), wherein the first pipeline (8) is connected to the outlet (315) and the second air intake port (14) respectively, and the refrigerant flowing out of the outlet (315) passes through the first pipeline (8) and the second air intake port (14) in sequence and enters the compressor body (1).

11. A control method, characterized in that: The control method is applied to the compressor according to any one of claims 1 to 10, and the control method comprises: Acquiring a current first pressure value inside the first shell (11) and a current second pressure value outside the first shell (11); The magnetic field strength of the magnetic fluid in the magnetic fluid sealing device (3) is adaptively adjusted according to the current first pressure value and the current second pressure value.

12. The control method according to claim 11, characterized in that: The control method is applied to the compressor according to claim 2; the method for adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device (3) according to the current first pressure value and the current second pressure value comprises: Calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the on / off state of the electromagnet assembly (33) according to the pressure difference; If the pressure difference is less than a first preset value, controlling the electromagnet assembly (33) to be in a power-off state to maintain the current magnetic field strength of the magnetic fluid; If the pressure difference is greater than or equal to a first preset value, at least a portion of the electromagnet component (33) is controlled to switch to a powered state, so as to adjust the magnetization intensity of the magnetic fluid through at least a portion of the electromagnet component (33) in the powered state.

13. The control method according to claim 12, characterized in that: If the electromagnet assembly (33) has N electromagnets (331), N≥2; the electromagnets (331) are arranged in sequence along the axial direction of the input shaft (12); if the pressure difference is greater than a first preset value, at least part of the electromagnet assembly (33) is controlled to switch to an energized state, so as to adjust the magnetization intensity of the magnetic fluid through at least part of the electromagnet assembly (33) in the energized state, the method comprising: If the pressure difference is greater than or equal to a first preset value, the amount of power supplied to the electromagnet (331) is adaptively controlled according to the pressure difference; The amount of power supplied to the control electromagnet (331) is proportional to the pressure difference.

14. The control method according to claim 12, characterized in that: The method for adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device (3) according to the current first pressure value and the current second pressure value further includes: If the pressure difference changes frequently within the first preset time, the electromagnet component (33) is controlled to switch to a powered state, so as to adjust the magnetization intensity of the magnetic fluid through the electromagnet component (33) in the powered state.

15. The control method according to claim 12, characterized in that: The control method is applied to the compressor according to claim 10, and the control method further comprises: Calculating a pressure difference between a current first pressure value and a current second pressure value, and controlling an electromagnetic expansion valve (7) according to the pressure difference; If the pressure difference is less than a first preset value, controlling the opening of the electromagnetic expansion valve (7) to maintain a preset opening; If the pressure difference is greater than or equal to a first preset value, the opening of the electromagnetic expansion valve (7) is increased according to the pressure difference; The opening degree of the electromagnetic expansion valve (7) is controlled to be proportional to the pressure difference.

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