Magnetic suspension compressor shutdown control method and device, medium, controller and product

Abstract

The invention provides a magnetic suspension compressor shutdown control method and device, a medium, a controller and a product, and the method comprises the steps: controlling the operation frequency of a magnetic suspension compressor to rise according to a preset frequency rising rate after a magnetic suspension compressor shutdown instruction is received; when the operation frequency of the magnetic suspension compressor rises to a preset frequency, the magnetic suspension compressor is controlled to stop; or after a magnetic suspension compressor shutdown instruction is received, the magnetic suspension compressor is controlled to carry out sectional frequency reduction, and then the magnetic suspension compressor is controlled to be shut down; wherein the step of controlling the magnetic suspension compressor to carry out sectional frequency reduction comprises the following substeps: controlling the magnetic suspension compressor to carry out frequency reduction at first and then to carry out frequency increase after reaching a critical rotating speed in two times. According to the scheme, surge caused by the fact that the running-down speed of the rotor is higher than the differential pressure change speed in the shutdown process can be avoided, and the stability of the unit in the shutdown process is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of control, and in particular to a magnetic suspension compressor shutdown control method, device, medium, controller and product. Background Art

[0002] For magnetic levitation systems (such as magnetic levitation refrigeration systems), the operation process mainly includes three steps: powering on the equipment, receiving instructions to start running, and shutting down the equipment. For magnetic levitation rotors, they mainly act in the two processes of operation and shutdown. The movement process of magnetic levitation rotors mainly includes static suspension, rotation, and stopping. During the shutdown process of the magnetic levitation system, due to the pressure difference in the system itself, after the rotor idles, the speed of the rotor idling to static suspension is higher than the speed of pressure change, and the system will produce a large airflow impact, which will greatly interfere with the operation of the rotor, resulting in poor rotor operation accuracy and even failure to shut down normally. Summary of the invention

[0003] The main purpose of the present invention is to overcome the defects of the above-mentioned related technologies and to provide a magnetic levitation compressor shutdown control method, device, medium, controller and product to solve the problem in the related technology that during the shutdown process of the magnetic levitation system, the system will generate a large airflow impact, resulting in poor rotor operation accuracy.

[0004] On one hand, the present invention provides a magnetic levitation compressor shutdown control method, comprising: after receiving a magnetic levitation compressor shutdown command, controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate; when the operating frequency of the magnetic levitation compressor increases to a preset frequency, controlling the magnetic levitation compressor to shut down; or, after receiving a magnetic levitation compressor shutdown command, controlling the magnetic levitation compressor to perform segmented frequency reduction, and then controlling the magnetic levitation compressor to shut down; wherein, controlling the magnetic levitation compressor to perform segmented frequency reduction includes: controlling the magnetic levitation compressor to reduce the frequency twice to first reduce the frequency to reach a critical speed and then increase the frequency.

[0005] Optionally, the magnetic levitation compressor is controlled twice to first reduce the frequency to reach a critical speed and then increase the frequency, including: after receiving a magnetic levitation compressor shutdown command, controlling the operating frequency of the magnetic levitation compressor to reduce according to a preset frequency reduction rate; when the operating frequency of the magnetic levitation compressor is reduced to a first critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate for a first preset time; after controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate for a first preset time, controlling the operating frequency of the magnetic levitation compressor to reduce according to a preset frequency reduction rate; when the operating frequency of the magnetic levitation compressor is reduced to a second critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate for a second preset time; wherein, after controlling the operating frequency of the magnetic levitation compressor to increase according to the preset frequency increase rate for a second preset time, controlling the magnetic levitation compressor to stop.

[0006] On the other hand, the present invention provides a magnetic levitation compressor shutdown control device, comprising: a first control unit, for controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate after receiving a magnetic levitation compressor shutdown command; when the operating frequency of the magnetic levitation compressor rises to a preset frequency, controlling the magnetic levitation compressor to shut down; or, a second control unit, for controlling the magnetic levitation compressor to perform segmented frequency reduction after receiving a magnetic levitation compressor shutdown command, and then controlling the magnetic levitation compressor to shut down; wherein, controlling the magnetic levitation compressor to perform segmented frequency reduction includes: controlling the magnetic levitation compressor to reduce the frequency twice to first reduce the frequency to reach a critical speed and then increase the frequency.

[0007] Optionally, the second control unit controls the magnetic levitation compressor in two steps to first reduce the frequency to reach a critical speed and then increase the frequency, including: after receiving a magnetic levitation compressor shutdown command, controlling the operating frequency of the magnetic levitation compressor to reduce according to a preset frequency reduction rate; when the operating frequency of the magnetic levitation compressor is reduced to a first critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate for a first preset time; after controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate for a first preset time, controlling the operating frequency of the magnetic levitation compressor to reduce according to a preset frequency reduction rate; when the operating frequency of the magnetic levitation compressor is reduced to a second critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate for a second preset time; wherein, after controlling the operating frequency of the magnetic levitation compressor to increase according to the preset frequency increase rate for a second preset time, controlling the magnetic levitation compressor to stop.

[0008] Another aspect of the present invention provides a storage medium having a computer program stored thereon, wherein the program implements the steps of any of the aforementioned methods when executed by a processor.

[0009] In another aspect, the present invention provides a controller for a magnetic levitation compressor, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned methods when executing the program.

[0010] In another aspect, the present invention provides a controller for a magnetic levitation compressor, comprising any of the control devices described above.

[0011] In yet another aspect, the present invention provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the steps of any of the aforementioned methods are implemented.

[0012] According to the technical solution of the present invention, during the shutdown process of the magnetic levitation compressor, the frequency is first increased and then shut down or the frequency is reduced in stages to avoid surge caused by the rotor idling speed being faster than the pressure difference change speed during the shutdown process, thereby ensuring the stability of the unit during the shutdown process.

[0013] According to the technical solution of the present invention, the influence of airflow on the magnetic suspension rotor during the shutdown process is effectively reduced, and the stability of the rotor crossing the modal segment during the shutdown process is improved; the surge caused by airflow impact during the shutdown process of the unit is effectively avoided; and the operating stability and reliability of the rotor during the shutdown process in different types of refrigeration systems and under different circumstances can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0015] Figure 1 1 is a schematic diagram of an embodiment of a method for controlling shutdown of a magnetic levitation compressor provided by the present invention;

[0016] Figure 2 The shutdown and frequency reduction operation curve of the magnetic suspension compressor in the related art is shown;

[0017] Figure 3 The operation curve of the magnetic suspension compressor according to the present invention, which first increases the frequency and then stops, is shown;

[0018] Figure 4 The segmented frequency reduction and shutdown operation curve according to the present invention is shown;

[0019] Figure 5 The comparison between the shutdown curve and the surge line under different shutdown schemes according to the present invention is shown;

[0020] Figure 6 A flowchart showing the steps of controlling the magnetic suspension compressor twice according to the present invention, first reducing the frequency to reach the critical speed and then increasing the frequency;

[0021] Figure 7 It is a structural block diagram of an embodiment of a magnetic suspension compressor shutdown control device provided by the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention 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 interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof 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.

[0024] The surge of magnetic suspension centrifugal compressor is essentially because the refrigerant vapor flow entering the compressor is not enough to generate enough pressure in the compressor, so that the condensing pressure of the condenser is greater than the internal pressure of the compressor. In the actual application of magnetic suspension refrigeration units, during the shutdown process, the rotor idling speed will change faster than the pressure difference between the evaporation pressure and the condensing pressure, thus causing surge.

[0025] Figure 2 FIG. 2 shows the shutdown and frequency reduction operation curve of the magnetic suspension compressor in the related art. Figure 2 In the related art shown in the figure, after the magnetic suspension compressor stops normally, the speed of the compressor stopping and idling is higher than the speed of change of the system pressure difference. When the speed line (the curve of the compressor speed changing with time) and the pressure difference line (the curve of the pressure difference between the evaporation pressure and the condensation pressure changing with time) intersect, that is, Figure 2 At point A in the diagram (the critical frequency at which the compressor surges, i.e., the critical speed), surge will occur, causing the rotor to be unstable during shutdown.

[0026] The present invention provides a magnetic suspension compressor shutdown control method, which is mainly applicable to magnetic suspension centrifugal compressors.

[0027] Figure 1 It is a method schematic diagram of an embodiment of a magnetic suspension compressor shutdown control method provided by the present invention.

[0028] like Figure 1 As shown, according to one embodiment of the present invention, the magnetic levitation compressor shutdown control method includes step S110 and step S120, or includes step S130.

[0029] Step S110, when a shutdown instruction of the magnetic levitation compressor is received, the operating frequency of the magnetic levitation compressor is controlled to increase according to a preset frequency increase rate.

[0030] Step S120: When the operating frequency of the magnetic levitation compressor rises to a preset frequency, the magnetic levitation compressor is controlled to stop.

[0031] Specifically, when the shutdown command is issued, the operating frequency of the magnetic suspension compressor is first increased (for example, the operating frequency of the magnetic suspension compressor is increased at a speed of 6 Hz / s). At this time, the pressure ratio of the evaporation pressure to the condensation pressure of the unit and the operating frequency will increase at the same time, but the increase in the operating frequency is much higher than the increase in the pressure ratio. When it rises to a certain frequency (preset frequency), the magnetic suspension compressor is controlled to shut down.

[0032] Figure 3 The operation curve of the magnetic suspension compressor according to the present invention is shown as follows: Figure 3 As shown, the horizontal axis represents time, and the vertical axis represents the pressure difference and speed. When it rises to a certain frequency (preset frequency), that is, point m, the unit shuts down. Since the frequency changes faster than the pressure difference, the speed line of the unit will not intersect with the pressure difference line, and surge will not occur, thus ensuring the stability of the rotor during the shutdown process.

[0033] During the operation of the unit, it is a common phenomenon that the frequency change speed is higher than the pressure difference change speed. The frequency change is directly controlled by the inverter, while the pressure difference changes after the frequency change. The amplitude of the increase is determined by time. Through multiple tests, the frequency increase time and frequency increase amplitude suitable for shutdown can be obtained.

[0034] Step S130, after receiving the magnetic levitation compressor shutdown instruction, controlling the magnetic levitation compressor to perform segmented frequency reduction, and then controlling the magnetic levitation compressor to shut down.

[0035] Specifically, when a shutdown instruction of the magnetic levitation compressor is received, the magnetic levitation compressor is controlled twice to first reduce the frequency to reach a critical speed and then increase the frequency, that is, the magnetic levitation compressor is controlled twice to first reduce the frequency to reach a critical speed and then increase the frequency.

[0036] Figure 6The flowchart shows the steps of controlling the magnetic suspension compressor twice according to the present invention, first reducing the frequency to reach the critical speed and then increasing the frequency. Figure 6 As shown, in a specific implementation, the step of controlling the magnetic levitation compressor twice to first reduce the frequency to reach the critical speed and then increase the frequency may specifically include steps S131 to S134.

[0037] Step S131, when receiving the magnetic levitation compressor shutdown instruction, controlling the operating frequency of the magnetic levitation compressor to decrease according to a preset frequency reduction rate.

[0038] Step S132: When the operating frequency of the magnetic levitation compressor is reduced to a first critical frequency, the operating frequency of the magnetic levitation compressor is controlled to increase at a preset frequency increase rate for a first preset time.

[0039] Specifically, when a shutdown command is issued, the magnetic levitation compressor does not immediately stop and idle, but instead performs frequency reduction. The operating frequency of the magnetic levitation compressor can be controlled to decrease according to a preset frequency reduction rate. Figure 4 The following is a diagram showing the operation curve of the magnetic suspension compressor according to the present invention in a segmented frequency reduction and shutdown manner. Figure 4 As shown, the horizontal axis represents time, and the vertical axis represents pressure difference and speed. When the compressor frequency is reduced and is about to reach the critical speed, that is, point a, the unit increases the operating frequency, and the unit's pressure ratio and operating frequency will increase at the same time. Since the increase in the unit's operating frequency is much higher than the increase in the pressure ratio, unit surge can be avoided. Curve 1 represents the curve of shutdown speed changing with time in the related art, curve 2 represents the curve of shutdown pressure difference changing with time in the related art, curve 3 represents the curve of segmented frequency reduction speed changing with time, and curve 4 represents the curve of segmented frequency reduction pressure difference changing with time.

[0040] The first critical frequency may be a critical frequency at which the magnetic levitation compressor surges, that is, a critical speed. The critical frequency at which the magnetic levitation compressor surges may be obtained through experimental testing. For example, when the magnetic levitation compressor is shut down normally, the unit begins to surge at a certain frequency, and the compressor operating frequency at which the surge occurs is recorded, which is the critical speed.

[0041] Step S133, after controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a first preset time, controlling the operating frequency of the magnetic levitation compressor to decrease at a preset frequency reduction rate.

[0042] Step S134, when the operating frequency of the magnetic levitation compressor is reduced to the second critical frequency, the operating frequency of the magnetic levitation compressor is controlled to increase at a preset frequency increase rate for a second preset time. That is, after the operating frequency of the magnetic levitation compressor is controlled to increase at a preset frequency increase rate for a second preset time, the magnetic levitation compressor is controlled to stop.

[0043] Specifically, after the magnetic levitation compressor increases the frequency for a period of time (the first preset time), it reduces the frequency again. If it reaches the critical speed (the second critical frequency), that is, point b, it increases the frequency again and shuts down after a period of frequency increase. At this time, the unit will not surge, thus ensuring the stability of the rotor during the shutdown process.

[0044] The second critical frequency may specifically be a critical frequency at which surge occurs when the operating frequency of the magnetic levitation compressor is directly shut down after being controlled to increase at a preset frequency increase rate, that is, a critical speed. The critical frequency may be obtained through experimental testing, for example, through experimental testing, after receiving a magnetic levitation compressor shutdown command, the operating frequency of the magnetic levitation compressor is controlled to decrease at a preset frequency reduction rate, and when the operating frequency of the magnetic levitation compressor is reduced to the first critical frequency, the operating frequency of the magnetic levitation compressor is controlled to increase at a preset frequency increase rate for a first preset time, and then directly shut down, and the unit starts to surge at a certain frequency, then the frequency at which surge occurs is recorded, which is the second critical speed.

[0045] Figure 5 Comparison of shutdown curve and surge line under different shutdown schemes. Figure 5 As shown, the horizontal axis represents the surge frequency, and the vertical axis represents the pressure ratio of evaporation pressure to condensation pressure; the area above the surge line is the non-operational area, and the area below the surge line is the operable area. Points Ⅰ and Ⅱ are the critical speeds of surge, that is, the minimum speed required for the pressure difference to reach the critical surge state; compared with the shutdown control schemes in related technologies, the two shutdown schemes of segmented frequency reduction and first frequency increase and then frequency reduction can effectively avoid surge caused by the rotor idling speed being faster than the pressure difference change speed during the shutdown process, and ensure the stability of the unit during the shutdown process. ① is the shutdown curve of first frequency increase and then frequency reduction; ② is the shutdown curve of segmented frequency reduction; ③ represents the frequency reduction curve of related technologies; ④ is the surge line.

[0046] The present invention also provides a magnetic suspension compressor shutdown control device, which is mainly applicable to magnetic suspension centrifugal compressors.

[0047] Figure 7 FIG. 1 is a structural block diagram of an embodiment of a magnetic suspension compressor shutdown control device provided by the present invention. Figure 7 As shown, the magnetic suspension compressor shutdown control device 100 includes: a first control unit 110 or a second control unit 120.

[0048] The first control unit 110 is used for controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate after receiving a shutdown instruction of the magnetic levitation compressor; when the operating frequency of the magnetic levitation compressor reaches , controlling the magnetic levitation compressor to shut down.

[0049] Specifically, when the shutdown command is issued, the operating frequency of the magnetic suspension compressor is first increased (for example, the operating frequency of the magnetic suspension compressor is increased at a speed of 6 Hz / s). At this time, the pressure ratio of the evaporation pressure to the condensation pressure of the unit and the operating frequency will increase at the same time, but the increase in the operating frequency is much higher than the increase in the pressure ratio. When it rises to a certain frequency (preset frequency), the magnetic suspension compressor is controlled to shut down.

[0050] Figure 3 The operation curve of the magnetic suspension compressor according to the present invention is shown as follows: Figure 3 As shown, the horizontal axis represents time, and the vertical axis represents the pressure difference and speed. When it rises to a certain frequency (preset frequency), that is, point m, the unit shuts down. Since the frequency changes faster than the pressure difference, the speed line of the unit will not intersect with the pressure difference line, and surge will not occur, thus ensuring the stability of the rotor during the shutdown process.

[0051] During the operation of the unit, it is a common phenomenon that the frequency change speed is higher than the pressure difference change speed. The frequency change is directly controlled by the inverter, while the pressure difference changes after the frequency change. The amplitude of the increase is determined by time. Through multiple tests, the frequency increase time and frequency increase amplitude suitable for shutdown can be obtained.

[0052] The second control unit 120 is used for controlling the magnetic levitation compressor to perform segmented frequency reduction and then stop the magnetic levitation compressor after receiving a magnetic levitation compressor stop instruction.

[0053] Wherein, controlling the magnetic levitation compressor to perform segmented frequency reduction includes: controlling the magnetic levitation compressor to reduce the frequency first to reach the critical speed and then increase the frequency twice. Specifically, after receiving the magnetic levitation compressor shutdown command, the operating frequency of the magnetic levitation compressor is controlled to be reduced according to the preset frequency reduction rate; when the operating frequency of the magnetic levitation compressor is reduced to the first critical frequency, the operating frequency of the magnetic levitation compressor is controlled to increase according to the preset frequency increase rate for the first preset time; after the operating frequency of the magnetic levitation compressor is controlled to increase according to the preset frequency increase rate for the first preset time, the operating frequency of the magnetic levitation compressor is controlled to be reduced according to the preset frequency reduction rate; when the operating frequency of the magnetic levitation compressor is reduced to the second critical frequency, the operating frequency of the magnetic levitation compressor is controlled to increase according to the preset frequency increase rate for the second preset time; wherein, after the operating frequency of the magnetic levitation compressor is controlled to increase according to the preset frequency increase rate for the second preset time, the magnetic levitation compressor is controlled to stop.

[0054] Specifically, when a shutdown command is issued, the magnetic levitation compressor does not immediately stop and idle, but instead performs frequency reduction. The operating frequency of the magnetic levitation compressor can be controlled to decrease according to a preset frequency reduction rate. Figure 4The following is a diagram showing the operation curve of the magnetic suspension compressor according to the present invention in a segmented frequency reduction and shutdown manner. Figure 4 As shown, the horizontal axis represents time, and the vertical axis represents pressure difference and speed. When the compressor frequency is reduced and is about to reach the critical speed, that is, point a, the unit increases the operating frequency, and the unit's pressure ratio and operating frequency will increase at the same time. Since the increase in the unit's operating frequency is much higher than the increase in the pressure ratio, unit surge can be avoided. Curve 1 represents the curve of shutdown speed changing with time in the related art, curve 2 represents the curve of shutdown pressure difference changing with time in the related art, curve 3 represents the curve of segmented frequency reduction speed changing with time, and curve 4 represents the curve of segmented frequency reduction pressure difference changing with time.

[0055] The first critical frequency may be a critical frequency at which the magnetic levitation compressor surges, that is, a critical speed. The critical frequency at which the magnetic levitation compressor surges may be obtained through experimental testing. For example, when the magnetic levitation compressor is shut down normally, the unit begins to surge at a certain frequency, and the compressor operating frequency at which the surge occurs is recorded, which is the critical speed.

[0056] Specifically, after the magnetic levitation compressor increases the frequency for a period of time (the first preset time), it reduces the frequency again. If it reaches the critical speed (the second critical frequency), that is, point b, it increases the frequency again and shuts down after a period of time (the second preset time). At this time, the unit will not surge, thus ensuring the stability of the rotor during the shutdown process.

[0057] The second critical frequency may specifically be a critical frequency at which surge occurs when the operating frequency of the magnetic levitation compressor is directly shut down after being controlled to increase at a preset frequency increase rate, that is, a critical speed. The critical frequency may be obtained through experimental testing, for example, through experimental testing, after receiving a magnetic levitation compressor shutdown command, the operating frequency of the magnetic levitation compressor is controlled to decrease at a preset frequency reduction rate, and when the operating frequency of the magnetic levitation compressor is reduced to the first critical frequency, the operating frequency of the magnetic levitation compressor is controlled to increase at a preset frequency increase rate for a first preset time, and then directly shut down, and the unit starts to surge at a certain frequency, then the frequency at which surge occurs is recorded, which is the second critical speed.

[0058] Figure 5 Comparison of shutdown curve and surge line under different shutdown schemes. Figure 5As shown, the horizontal axis represents the surge frequency, and the vertical axis represents the pressure ratio of evaporation pressure to condensation pressure; the area above the surge line is the non-operational area, and the area below the surge line is the operable area. Points Ⅰ and Ⅱ are the critical speeds of surge, that is, the minimum speed required for the pressure difference to reach the critical surge state; ① is the shutdown curve of first increasing the frequency and then decreasing the frequency; ② is the shutdown curve of segmented frequency reduction; ③ represents the frequency reduction curve of related technologies; ④ is the surge line. Compared with the shutdown control scheme in the related technology, the two shutdown schemes of segmented frequency reduction and first increasing the frequency and then decreasing the frequency can effectively avoid the surge caused by the rotor idling speed being faster than the pressure difference change speed during the shutdown process, and ensure the stability of the unit during the shutdown process.

[0059] The present invention also provides a storage medium corresponding to the magnetic levitation compressor shutdown control method, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the above methods are implemented.

[0060] The present invention also provides a controller of a magnetic levitation compressor corresponding to the magnetic levitation compressor shutdown control method, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the aforementioned methods when executing the computer program.

[0061] The present invention also provides a controller of a magnetic levitation compressor corresponding to the magnetic levitation compressor shutdown control device, comprising any of the magnetic levitation compressor shutdown control devices described above.

[0062] The present invention also provides a computer program product corresponding to the magnetic levitation compressor shutdown control method, including a computer program, and when the computer program is executed by a processor, the steps of any of the aforementioned methods are implemented.

[0063] Accordingly, the solution provided by the present invention avoids surge caused by the rotor idling speed being faster than the pressure difference change speed during the shutdown process of the magnetic levitation compressor by first increasing the frequency and then shutting down or by reducing the frequency in stages, thereby ensuring the stability of the unit during the shutdown process.

[0064] According to the technical solution of the present invention, the influence of airflow on the magnetic suspension rotor during the shutdown process is effectively reduced, and the stability of the rotor crossing the modal segment during the shutdown process is improved; the surge caused by airflow impact during the shutdown process of the unit is effectively avoided; and the operating stability and reliability of the rotor during the shutdown process in different types of refrigeration systems and under different circumstances can be improved.

[0065] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present invention and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these. In addition, each functional unit may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit.

[0066] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0067] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed in multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0068] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the relevant technology or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk and other media that can store program codes.

[0069] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A magnetic suspension compressor shutdown control method, characterized in that: include: When receiving a shutdown instruction of the magnetic levitation compressor, controlling the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate; When the operating frequency of the magnetic levitation compressor rises to a preset frequency, controlling the magnetic levitation compressor to stop; or, After receiving the magnetic suspension compressor shutdown instruction, controlling the magnetic suspension compressor to perform segmented frequency reduction, and then controlling the magnetic suspension compressor to shut down; The step of controlling the magnetic levitation compressor to perform segmented frequency reduction includes: controlling the magnetic levitation compressor twice to first reduce the frequency to reach a critical speed and then increase the frequency.

2. The method according to claim 1, characterized in that: The magnetic suspension compressor is controlled twice to first reduce the frequency to reach a critical speed and then increase the frequency, including: When receiving a shutdown instruction of the magnetic levitation compressor, controlling the operating frequency of the magnetic levitation compressor to decrease according to a preset frequency reduction rate; When the operating frequency of the magnetic levitation compressor is reduced to a first critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a first preset time; After controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a first preset time, controlling the operating frequency of the magnetic levitation compressor to decrease at a preset frequency reduction rate; When the operating frequency of the magnetic levitation compressor is reduced to a second critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a second preset time; Wherein, after controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a second preset time, the magnetic levitation compressor is controlled to stop.

3. A magnetic suspension compressor shutdown control device, characterized in that: include: A first control unit is used to control the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate after receiving a shutdown instruction of the magnetic levitation compressor; When the operating frequency of the magnetic levitation compressor rises to a preset frequency, controlling the magnetic levitation compressor to stop; or, A second control unit is used for controlling the magnetic suspension compressor to perform segmented frequency reduction and then stop the magnetic suspension compressor after receiving a magnetic suspension compressor stop instruction; The step of controlling the magnetic levitation compressor to perform segmented frequency reduction includes: controlling the magnetic levitation compressor twice to first reduce the frequency to reach a critical speed and then increase the frequency.

4. The device according to claim 3, characterized in that The second control unit controls the magnetic suspension compressor twice to first reduce the frequency to reach a critical speed and then increase the frequency, including: When receiving a shutdown instruction of the magnetic levitation compressor, controlling the operating frequency of the magnetic levitation compressor to decrease according to a preset frequency reduction rate; When the operating frequency of the magnetic levitation compressor is reduced to a first critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a first preset time; After controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a first preset time, controlling the operating frequency of the magnetic levitation compressor to decrease at a preset frequency reduction rate; When the operating frequency of the magnetic levitation compressor is reduced to a second critical frequency, controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a second preset time; Wherein, after controlling the operating frequency of the magnetic levitation compressor to increase at a preset frequency increase rate for a second preset time, the magnetic levitation compressor is controlled to stop.

5. A storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the steps of any method described in claims 1-2 are implemented.

6. A controller for a magnetic levitation compressor, characterized in that: The method comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein the steps of the method according to any one of claims 1 to 2 are implemented when the processor executes the program.

7. A controller for a magnetic levitation compressor, characterized in that: Comprising a control device as described in any one of claims 3-4.

8. A computer program product, characterized in that The invention comprises a computer program, which implements the steps of the method according to any one of claims 1 to 2 when being executed by a processor.

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