Method, device, medium, controller and product for stopping a magnetic levitation compressor

Abstract

The application provides a kind of magnetic suspension compressor shutdown control method, device, medium, controller and product, the method comprises: when receiving magnetic suspension compressor shutdown instruction, control the operating frequency of the magnetic suspension compressor rises according to preset frequency increasing rate;When the operating frequency of the magnetic suspension compressor rises to preset frequency, control the magnetic suspension compressor stops;Or, after receiving magnetic suspension compressor shutdown instruction, control the magnetic suspension compressor carries out segmented frequency reduction, then control the magnetic suspension compressor stops;Wherein, control the magnetic suspension compressor carries out segmented frequency reduction, comprising: control the magnetic suspension compressor first frequency reduction reaches critical speed and then frequency increasing twice.The scheme provided by the application can avoid surge caused by rotor coasting speed being faster than pressure difference change speed during shutdown process, and ensure the stability of unit during shutdown process.

Description

TECHNICAL FIELD

[0001] The present application relates to the control field, and particularly to a magnetic suspension compressor shutdown control method, device, medium, controller and product. BACKGROUND

[0002] For a magnetic suspension system (for example, a magnetic suspension refrigeration system), its operation process mainly includes three steps of equipment power-on, equipment accepting an instruction to start operation and equipment shutdown, and for a magnetic suspension rotor, its main action is in the running and shutdown processes. The movement process of the magnetic suspension rotor mainly includes static suspension, rotation and stopping rotation. In the shutdown process of the magnetic suspension system, due to the pressure difference existing in the system itself, after the rotor freewheels, the speed of the rotor freewheeling to static suspension is higher than the speed of pressure change, and the system will generate a large airflow impact, which will have a great disturbance to the operation of the rotor, resulting in poor running accuracy of the rotor, and even the rotor cannot stop normally. SUMMARY

[0003] The main purpose of the present application is to overcome the defects of the above-mentioned related technologies, and provide a magnetic suspension compressor shutdown control method, device, medium, controller and product, so as to solve the problem of poor running accuracy of the rotor caused by the large airflow impact of the system in the shutdown process of the magnetic suspension system in the related technologies.

[0004] The present application provides a magnetic suspension compressor shutdown control method, comprising: when receiving a magnetic suspension compressor shutdown instruction, controlling the running frequency of the magnetic suspension compressor to rise at a preset frequency rising rate; when the running frequency of the magnetic suspension compressor rises to a preset frequency, controlling the magnetic suspension compressor to stop; or, after receiving a magnetic suspension compressor shutdown instruction, controlling the magnetic suspension compressor to perform segmented frequency reduction, and then controlling the magnetic suspension compressor to stop; wherein, controlling the magnetic suspension compressor to perform segmented frequency reduction comprises: controlling the magnetic suspension compressor to first reduce the frequency to a critical rotating speed and then increase the frequency twice.

[0005] Optionally, the second control unit controls the magnetic suspension compressor to first decrease frequency to reach a critical rotating speed and then increase frequency in two times, including: when receiving a magnetic suspension compressor shutdown instruction, controlling the operating frequency of the magnetic suspension compressor to decrease at a preset frequency decreasing rate; when the operating frequency of the magnetic suspension compressor decreases to a first critical frequency, controlling the operating frequency of the magnetic suspension compressor to increase at a preset frequency increasing rate for a first preset time; after controlling the operating frequency of the magnetic suspension compressor to increase at the preset frequency increasing rate for the first preset time, controlling the operating frequency of the magnetic suspension compressor to decrease at the preset frequency decreasing rate; when the operating frequency of the magnetic suspension compressor decreases to a second critical frequency, controlling the operating frequency of the magnetic suspension compressor to increase at the preset frequency increasing rate for a second preset time; wherein, after controlling the operating frequency of the magnetic suspension compressor to increase at the preset frequency increasing rate for the second preset time, controlling the magnetic suspension compressor to shutdown.

[0006] Another aspect of the present application provides a magnetic suspension compressor shutdown control device, including: a first control unit, configured to, when receiving a magnetic suspension compressor shutdown instruction, control the operating frequency of the magnetic suspension compressor to increase at a preset frequency increasing rate; and when the operating frequency of the magnetic suspension compressor increases to a preset frequency, control the magnetic suspension compressor to shutdown; or, a second control unit, configured to, when receiving a magnetic suspension compressor shutdown instruction, control the magnetic suspension compressor to perform segmented frequency decreasing, and then control the magnetic suspension compressor to shutdown; wherein, the control of the magnetic suspension compressor to perform segmented frequency decreasing includes: controlling the magnetic suspension compressor to first decrease frequency to reach a critical rotating speed and then increase frequency in two times.

[0007] Optionally, the second control unit controls the magnetic suspension compressor to first decrease frequency to reach a critical rotating speed and then increase frequency in two times, including: when receiving a magnetic suspension compressor shutdown instruction, controlling the operating frequency of the magnetic suspension compressor to decrease at a preset frequency decreasing rate; when the operating frequency of the magnetic suspension compressor decreases to a first critical frequency, controlling the operating frequency of the magnetic suspension compressor to increase at a preset frequency increasing rate for a first preset time; after controlling the operating frequency of the magnetic suspension compressor to increase at the preset frequency increasing rate for the first preset time, controlling the operating frequency of the magnetic suspension compressor to decrease at the preset frequency decreasing rate; when the operating frequency of the magnetic suspension compressor decreases to a second critical frequency, controlling the operating frequency of the magnetic suspension compressor to increase at the preset frequency increasing rate for a second preset time; wherein, after controlling the operating frequency of the magnetic suspension compressor to increase at the preset frequency increasing rate for the second preset time, controlling the magnetic suspension compressor to shutdown.

[0008] Still another aspect of the present application provides a storage medium having a computer program stored thereon, the program being executed by a processor to implement the steps of any of the aforementioned methods.

[0009] In still another aspect the present application provides a controller for a magnetic levitation compressor comprising a processor, a memory and a computer program stored on the memory and executable on the processor, the processor implementing the steps of any of the above described methods when executing the program.

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

[0011] In still another aspect the present application provides a computer program product comprising a computer program, the computer program implementing the steps of any of the above described methods when executed by a processor.

[0012] According to the technical solution of the present application, the magnetic levitation compressor is first increased in frequency and then stopped or is decreased in frequency in sections during shutdown, so as to avoid surge caused by the fact that the rotor idle speed is faster than the differential pressure change speed during shutdown, and to ensure the stability of the unit during shutdown.

[0013] According to the technical solution of the present application, the influence of airflow on the magnetic levitation rotor during shutdown is effectively reduced, the stability of the rotor in passing through the modal section during shutdown is improved, and surge caused by airflow impact during shutdown of the unit is effectively avoided. BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and together with the description serve to explain the present application. In the drawings:

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

[0016] Figure 2 shows the magnetic levitation compressor shutdown and frequency reduction operation curve in the related art;

[0017] Figure 3 shows the magnetic levitation compressor first increased in frequency and then stopped operation curve according to the present application;

[0018] Figure 4 shows the magnetic levitation compressor segmented frequency reduction shutdown operation curve according to the present application;

[0019] Figure 5 shows the comparison between the shutdown curve and the surge line under different shutdown schemes according to the present application;

[0020] Figure 6 shows the step flowchart of controlling the magnetic levitation compressor to first decrease in frequency to reach the critical speed and then increase in frequency according to the present application.

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

[0022] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below in combination with specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0023] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, 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 "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0024] The surge of the magnetic suspension centrifugal compressor is essentially because the refrigerant vapor flow entering the compressor is insufficient to make the compressor generate sufficient pressure, so that the condensing pressure of the condenser is greater than the internal pressure of the compressor. In the actual application of the magnetic suspension refrigeration unit, the rotor idle speed changes faster than the pressure difference between the evaporation pressure and the condensing pressure during shutdown, thus causing surge.

[0025] Figure 2 The magnetic suspension compressor shutdown and frequency reduction operation curve in the related art is shown. As Figure 2 After the magnetic suspension compressor is normally shut down in the related art, the speed of the compressor during shutdown is higher than the change speed of the system pressure difference, and when the speed line (the curve of the compressor speed changing with time) intersects with the pressure difference line (the curve of the pressure difference between the evaporation pressure and the condensing pressure changing with time), i.e. Figure 2 A point in the related art (the critical frequency at which the compressor surges, i.e. the critical speed), surge occurs, causing the rotor to be unstable during shutdown.

[0026] The present application provides a magnetic suspension compressor shutdown control method. The method is mainly applicable to a magnetic suspension centrifugal compressor.

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

[0028] As shown in Figure 1 , according to an embodiment of the present application, the magnetic suspension compressor shutdown control method comprises steps S110 and S120, or step S130.

[0029] Step S110, after receiving the magnetic suspension compressor shutdown instruction, control the operating frequency of the magnetic suspension compressor to rise at a preset frequency rising rate.

[0030] Step S120, when the operating frequency of the magnetic suspension compressor rises to a preset frequency, control the magnetic suspension compressor to shut down.

[0031] Specifically, after the shutdown instruction is issued, first increase the operating frequency of the magnetic suspension compressor (for example, increase the operating frequency of the magnetic suspension compressor at a speed of 6 Hz / s), at this time, the pressure ratio of the evaporating pressure and the condensing pressure of the unit and the operating frequency will rise at the same time, but the rising amplitude of the operating frequency is much higher than that of the pressure ratio. When rising to a certain frequency (preset frequency), control the magnetic suspension compressor to shut down.

[0032] Figure 3 The magnetic suspension compressor first rising frequency and then shutdown operation curve according to the present application is shown. As shown in Figure 3 , the horizontal axis represents time, and the vertical axis represents pressure difference and rotating speed. When rising to a certain frequency (preset frequency), i.e. point m, the unit shuts down. Since the frequency change speed is higher than the pressure difference change speed, the rotating speed line of the unit will not intersect with the pressure difference line, and surge will not occur, which ensures the stability of the rotor during shutdown.

[0033] During the operation of the unit, the frequency change speed is higher than the pressure difference change speed, which is a common phenomenon. The frequency change is directly controlled by the frequency converter, and the pressure difference change is changed after the frequency change. The rising amplitude is determined by time, which can be obtained through multiple tests to obtain the rising frequency time and rising frequency amplitude suitable for shutdown.

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

[0035] Specifically, after receiving the magnetic suspension compressor shutdown instruction, control the magnetic suspension compressor to first reduce the frequency to the critical rotating speed and then increase the frequency twice, i.e. control the magnetic suspension compressor to first reduce the frequency to the critical rotating speed and then increase the frequency twice.

[0036] Figure 6A flow chart of the step of controlling the magnetic suspension compressor to first reduce frequency to reach critical speed and then increase frequency according to the present application is shown. As shown in Figure 6 In one embodiment, the step of controlling the magnetic suspension compressor to first reduce frequency to reach critical speed and then increase frequency can include steps S131-S134.

[0037] Step S131, after receiving a shutdown instruction of the magnetic suspension compressor, control the operating frequency of the magnetic suspension compressor to decrease at a preset frequency reduction rate.

[0038] Step S132, when the operating frequency of the magnetic suspension compressor decreases to a first critical frequency, control the operating frequency of the magnetic suspension compressor to increase at a preset frequency increase rate for a first preset time.

[0039] Specifically, after the shutdown instruction is issued, the magnetic suspension compressor does not immediately perform shutdown coasting, but performs frequency reduction, which can control the operating frequency of the magnetic suspension compressor to decrease at a preset frequency reduction rate. Figure 4 A magnetic suspension compressor segmented frequency reduction shutdown operation curve according to the present application is shown. As shown in Figure 4 The horizontal axis represents time, and the vertical axis represents pressure difference and speed. When the compressor reduces frequency and is about to reach the critical speed, i.e. point a, the unit increases the operating frequency, and the pressure ratio and operating frequency of the unit will increase at the same time. Since the increase in the operating frequency of the unit is much higher than the increase in the pressure ratio, surge of the unit can be avoided. Curve 1 represents the curve of the shutdown speed changing with time in the related art, curve 2 represents the curve of the shutdown pressure difference changing with time in the related art, curve 3 represents the curve of the segmented frequency reduction speed changing with time, and curve 4 represents the curve of the segmented frequency reduction pressure difference changing with time.

[0040] The first critical frequency can be the critical frequency at which the magnetic suspension compressor surges, i.e. the critical speed. The critical frequency at which the magnetic suspension compressor surges can be obtained by experimental testing, for example, by testing the magnetic suspension compressor when it normally shuts down, the unit starts to surge at a certain frequency, and then the operating frequency of the compressor at which the surge occurs is recorded, i.e. the critical speed.

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

[0042] Step S134, when the operating frequency of the magnetic suspension compressor decreases to a second critical frequency, control the operating frequency of the magnetic suspension compressor to increase at a preset frequency increase rate for a second preset time. That is, after controlling the operating frequency of the magnetic suspension compressor to increase at a preset frequency increase rate for a second preset time, control the magnetic suspension compressor to shut down.

[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, ensuring the stability of the rotor during the shutdown process.

[0044] The second critical frequency may specifically be a critical frequency, i.e., a critical speed, 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. This critical frequency can be obtained through experimental testing. For example, through experimental testing, upon 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. When the operating frequency of the magnetic levitation compressor decreases 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, and then the compressor is directly shut down. If the unit begins to surge at a certain frequency, the frequency at which surge occurs is recorded, which is the second critical speed.

[0045] Figure 5 Comparison of shutdown curves and surge lines under different shutdown plans. Figure 5 As shown, the horizontal axis represents the surge frequency, and the vertical axis represents the pressure ratio of evaporating pressure to condensing pressure. The area above the surge line is the non-operable region, and the area below the surge line is the operable region. Points I and II are the critical surge speeds, i.e., the minimum speeds required for the pressure differential to reach the critical surge state. Compared with the shutdown control schemes in related technologies, the two shutdown schemes of staged frequency reduction and first frequency increase followed by frequency reduction can effectively avoid surge caused by the rotor idling speed being faster than the pressure differential change speed during shutdown, ensuring the stability of the unit during shutdown. ① is the shutdown curve of first frequency increase followed by frequency reduction; ② is the shutdown curve of staged frequency reduction; ③ represents the frequency reduction curve of related technologies; and 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 This is a structural block diagram of an embodiment of the magnetic suspension compressor shutdown control device provided by the present invention. Figure 7 As shown, the magnetic levitation compressor shutdown control device 100 includes: a first control unit 110 or a second control unit 120.

[0048] The first control unit 110 is configured to control the operating frequency of the magnetic levitation compressor to increase according to a preset frequency increase rate upon receiving a magnetic levitation compressor shutdown instruction; and control the magnetic levitation compressor to shut down when the operating frequency of the magnetic levitation compressor reaches 0.

[0049] Specifically, when the shutdown instruction 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 evaporating pressure and the condensing pressure of the unit and the operating frequency will increase simultaneously, but the increase amplitude of the operating frequency is much higher than that of the pressure ratio. When the operating frequency increases to a certain frequency (preset frequency), the magnetic suspension compressor is controlled to be shut down.

[0050] Figure 3 The operating curve of the magnetic suspension compressor according to the present application is shown. As shown in the figure, the horizontal axis represents time, and the vertical axis represents pressure difference and rotating speed. When the operating frequency increases to a certain frequency (preset frequency), that is, point m, the unit is shut down. Since the speed of the frequency change is higher than that of the pressure difference change, the rotating speed line of the unit will not intersect with the pressure difference line, and therefore, the surge will not occur, and the stability of the rotor during the shutdown process is ensured. Figure 3

[0051] During the operation of the unit, the speed of the frequency change is higher than that of the pressure difference change. The frequency change is directly controlled by the frequency converter, and the pressure difference change is changed after the frequency change. The increase amplitude is determined by time, and the increase time and the increase amplitude suitable for shutdown can be obtained through multiple tests.

[0052] The second control unit 120 is configured to control the magnetic suspension compressor to be shut down after the magnetic suspension compressor is controlled to be reduced in frequency in a segmented manner when the magnetic suspension compressor shutdown instruction is received.

[0053] The magnetic suspension compressor is controlled to be reduced in frequency in a segmented manner, including controlling the magnetic suspension compressor to be first reduced in frequency to a critical rotating speed and then increased in frequency. Specifically, when the magnetic suspension compressor shutdown instruction is received, the operating frequency of the magnetic suspension compressor is controlled to be reduced at a preset frequency reduction rate. When the operating frequency of the magnetic suspension compressor is reduced to a first critical frequency, the operating frequency of the magnetic suspension compressor is controlled to be increased at a preset frequency increase rate for a first preset time. After the operating frequency of the magnetic suspension compressor is controlled to be increased at the preset frequency increase rate for the first preset time, the operating frequency of the magnetic suspension compressor is controlled to be reduced at the preset frequency reduction rate. When the operating frequency of the magnetic suspension compressor is reduced to a second critical frequency, the operating frequency of the magnetic suspension compressor is controlled to be increased at the preset frequency increase rate for a second preset time. After the operating frequency of the magnetic suspension compressor is controlled to be increased at the preset frequency increase rate for the second preset time, the magnetic suspension compressor is controlled to be shut down.

[0054] Specifically, when the shutdown instruction is issued, the magnetic suspension compressor will not be immediately shut down and idled, but will be reduced in frequency. The operating frequency of the magnetic suspension compressor can be controlled to be reduced at a preset frequency reduction rate. Figure 4 ​A magnetic suspension compressor segmented frequency reduction shutdown operation curve according to the present application is shown. As shown in Figure 4 the horizontal axis represents time, and the vertical axis represents pressure difference and rotating speed, when the compressor reduces frequency and is about to reach the critical rotating speed, i.e. point a, the unit increases the operating frequency, and the pressure ratio of the unit and the operating frequency will rise at the same time, and since the rising amplitude of the operating frequency of the unit is much higher than that of the pressure ratio, the unit can be prevented from surging. Curve 1 represents a curve of the shutdown rotating speed changing with time in the related art, curve 2 represents a curve of the shutdown pressure difference changing with time in the related art, curve 3 represents a curve of the segmented frequency reduction rotating speed changing with time, and curve 4 represents a curve of the segmented frequency reduction pressure difference changing with time.

[0055] The first critical frequency can be specifically a critical frequency at which the magnetic suspension compressor surges, i.e. a critical rotating speed. The critical frequency at which the magnetic suspension compressor surges can be obtained through experimental testing, for example, by testing the magnetic suspension compressor when it normally shuts down, the unit starts to surge at a certain frequency, and then the rotating speed of the compressor at which the surge occurs is recorded, i.e. the critical rotating speed.

[0056] Specifically, after the magnetic suspension compressor is frequency-increased for a period of time (first preset time) and then frequency-reduced again, if the critical rotating speed (second critical frequency) is reached again, i.e. point b, the frequency is increased again, and the unit is shut down after the frequency is increased for a period of time (second preset time), at this time, the unit will not surge, and the stability of the rotor during shutdown is ensured.

[0057] The second critical frequency can be specifically a critical frequency at which the unit surges when the operating frequency of the magnetic suspension compressor is directly shut down after being controlled to increase according to a preset frequency-increase rate. The critical frequency can be obtained through experimental testing, for example, by testing the magnetic suspension compressor when a shutdown instruction is received, controlling the operating frequency of the magnetic suspension compressor to decrease according to a preset frequency-reduction rate, controlling the operating frequency of the magnetic suspension compressor to increase according to a preset frequency-increase rate for a first preset time when the operating frequency of the magnetic suspension compressor decreases to the first critical frequency, and then directly shutting down, the unit starts to surge at a certain frequency, and then the frequency at which the surge occurs is recorded, i.e. the second critical rotating speed.

[0058] Figure 5 Comparison of shutdown curves and surge lines under different shutdown schemes. As shown in Figure 5As shown, the horizontal axis represents the surge frequency, and the vertical axis represents the pressure ratio of the evaporation pressure and the condensation pressure; the area above the surge line is the non-operable area, the area below the surge line is the operable area, points I and II are the critical rotating speed of the surge, that is, the minimum rotating speed required for the pressure difference when reaching the critical surge state; ① is the first frequency rising and then frequency falling shutdown curve; ② is the segmented frequency falling shutdown curve; ③ represents the frequency falling curve of the related technology; and ④ is the surge line. Compared with the shutdown control scheme in the related technology, the two shutdown schemes of the segmented frequency falling and the first frequency rising and then frequency falling can effectively avoid the surge caused by the fact that the rotor inertia speed is faster than the pressure difference changing speed in the shutdown process, and ensure the stability of the unit in the shutdown process.

[0059] The application further provides a storage medium corresponding to the magnetic suspension compressor shutdown control method, which has a computer program stored thereon, and the computer program realizes the steps of any of the foregoing methods when executed by a processor.

[0060] The application further provides a controller of a magnetic suspension compressor corresponding to the magnetic suspension compressor shutdown control method, which comprises a processor, a memory and a computer program stored on the memory and executable on the processor, and the processor realizes the steps of any of the foregoing methods when executing the computer program.

[0061] The application further provides a controller of a magnetic suspension compressor corresponding to the magnetic suspension compressor shutdown control device, which comprises the magnetic suspension compressor shutdown control device of any of the foregoing.

[0062] The application further provides a computer program product corresponding to the magnetic suspension compressor shutdown control method, which comprises a computer program, and the computer program realizes the steps of any of the foregoing methods when executed by a processor.

[0063] Accordingly, the scheme provided by the application avoids the surge caused by the fact that the rotor inertia speed is faster than the pressure difference changing speed in the shutdown process by first rising the frequency and then shutting down or by segmented frequency falling, and ensures the stability of the unit in the shutdown process.

[0064] According to the technical scheme of the application, the influence of airflow on the magnetic suspension rotor in the shutdown process is effectively reduced, the stability of the rotor in the shutdown process is improved, the surge of the unit in the shutdown process caused by airflow impact is effectively avoided, and the operation stability and reliability of the rotor in the shutdown process of different types of refrigeration systems and different situations are improved.

[0065] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on or transferred over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions can also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, "or" as used in a list of items prefaced by "comprising" to indicate a disjunctive list means each single item in the list has been recited before "or" one or more additional disjunctive items also have been recited. However, "or" in such a phrase does not mean that the list is inclusive of at least one of the items. Further, as used herein, "comprising" is to be interpreted as including the more restrictive terms "consisting of" and "consisting essentially of."

[0066] In several embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. Among them, the above-mentioned device embodiments are only schematic, for example, the division of the units can be a logical function division, and other division manners can be used in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, units or modules, which can be electrical or other forms.

[0067] The units described as separate components can or can not be physically separated, and the components of the control device can or can not be physical units, i.e. can be located in one place or can be distributed on a plurality of units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0068] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the related art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server or a network device, etc.) execute all or part of the steps of the method described in various embodiments of the present application. The aforementioned storage medium includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0069] The above merely illustrates the embodiments of the present application but should not be taken as limitations. Various changes and modifications can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A magnetic levitation compressor shutdown control method, characterized in that: include: When receiving a 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; The step of controlling the magnetic levitation compressor to perform segmented frequency reduction includes: controlling the magnetic levitation compressor to reduce the frequency to a critical speed and then increase the frequency twice; controlling the magnetic levitation compressor to reduce the frequency to a critical speed and then increase the frequency twice includes: When receiving a magnetic levitation compressor shutdown instruction, 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 decreases 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 decreases 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 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.

2. A magnetic levitation compressor shutdown control device, characterized in that: include: a second control unit, configured to, upon receiving a magnetic levitation compressor shutdown instruction, control the magnetic levitation compressor to perform a stepwise frequency reduction and then control the magnetic levitation 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, including: When receiving a magnetic levitation compressor shutdown instruction, 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 decreases 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 decreases 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 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.

3. A storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the steps of the method according to claim 1 are implemented.

4. 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 claim 1 are implemented when the processor executes the program.

5. A controller for a magnetic levitation compressor, characterized in that: Comprising the control device as claimed in claim 2.

6. A computer program product, characterized in that The invention comprises a computer program, which implements the steps of the method according to claim 1 when the computer program is executed by a processor.

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