A magnetic levitation compressor and a control method and device thereof

Abstract

The application discloses a kind of control method, device and magnetic suspension compressor of magnetic suspension compressor, the method comprises: after the stable operation of magnetic suspension compressor, according to the displacement accuracy of magnetic bearing rotor, determine whether the suspension state of magnetic bearing rotor is in unstable state;If the suspension state of magnetic bearing rotor is in unstable state, according to the fluctuation value of compressor's working parameter, determine whether the suspension state of magnetic bearing rotor is in unstable state is caused by the fluctuation of magnetic suspension compressor internal cavity pressure;If the suspension state of magnetic bearing rotor is in unstable state is caused by the fluctuation of magnetic suspension compressor internal cavity pressure, then adjust the control parameter of magnetic bearing, obtain the new control parameter of magnetic bearing, control magnetic bearing runs according to new control parameter.The scheme, by using the frequency converter current of magnetic suspension compressor or the fluctuation of magnetic suspension compressor exhaust pressure, analyzes the running state of magnetic bearing rotor, and then controls magnetic bearing rotor stable operation.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation technology, specifically relating to a control method, device, and magnetic levitation compressor for a magnetic levitation compressor, and more particularly to a control method, device, and magnetic levitation compressor for a magnetic levitation bearing in a magnetic levitation compressor. Background Technology

[0002] A magnetic levitation bearing (i.e., a magnetic bearing) is an intelligent bearing system (i.e., a magnetic levitation bearing control system) that uses controllable electromagnetic force to keep the rotor of the magnetic levitation bearing (i.e., the magnetic bearing rotor) in a non-contact levitation state. Magnetic levitation bearings not only feature wear-free operation, high speed, and low power consumption, but also, when combined with a bearing control system, can achieve intelligent control of the magnetic bearing rotor with operating precision down to the micrometer level.

[0003] In the relevant solutions, the magnetic bearing control system adjusts the electromagnetic force of the magnetic bearing rotor by real-time detection of its displacement accuracy, thereby achieving stable levitation of the rotor. For magnetic levitation compressors, magnetic bearings are used. A high-speed rotating magnetic bearing rotor drives an impeller to generate centrifugal force, drawing in low-pressure refrigerant and discharging high-pressure refrigerant. Because the impeller is embedded in the magnetic bearing rotor, when the compressor cavity pressure fluctuates drastically, such as during surge, the airflow impacts the impeller, causing a decrease in the displacement accuracy of the magnetic bearing rotor. At this time, the bearing coil current fluctuation is not significant, typically within 0.5A. Simultaneously, the instability of the magnetic bearing rotor causes changes in its driving torque, resulting in significant fluctuations in the inverter current flowing through the motor stator, exceeding 2A. Therefore, relying solely on the magnetic bearing coil current cannot accurately reflect the rotor's operating characteristics, affecting the operational stability of the magnetic bearing rotor in the magnetic levitation compressor.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a control method, device, and compressor for a magnetic levitation compressor. This addresses the problem that traditional magnetic bearing control methods, which rely on real-time detection of the magnetic bearing rotor's displacement accuracy to adjust the electromagnetic force of the magnetic bearing for stable levitation, fail to accurately reflect the rotor's operating characteristics and thus its displacement accuracy. Consequently, adjusting the electromagnetic force based on the rotor's displacement accuracy cannot guarantee stable rotor operation. The invention aims to analyze the rotor's operating state by utilizing fluctuations in the compressor's inverter current or exhaust pressure, thereby controlling its stable operation and ensuring the stability of the magnetic bearing rotor's operation.

[0006] This invention provides a control method for a magnetic levitation compressor, wherein the magnetic levitation compressor has a magnetic bearing and a magnetic bearing rotor; the control method for the magnetic levitation compressor includes: controlling the operation of the magnetic levitation compressor after it is started; when the stability of the operation of the magnetic levitation compressor reaches a set stability level, acquiring the displacement accuracy of the magnetic bearing rotor; determining whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor; the unstable state refers to the state in which the levitation position of the magnetic bearing rotor deviates from a set reference position; when it is determined that the levitation state of the magnetic bearing rotor is in the unstable state, acquiring the fluctuation value of the compressor's operating parameters; determining whether the levitation state of the magnetic bearing rotor in the unstable state is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor based on the fluctuation value of the compressor's operating parameters; when it is determined that the levitation state of the magnetic bearing rotor in the unstable state is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, adjusting the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing.

[0007] In some embodiments, the magnetic levitation compressor further includes a frequency converter; the operating parameter fluctuation values ​​of the compressor include: the current fluctuation value of the frequency converter current of the compressor within a set detection time, and / or the discharge pressure fluctuation value of the compressor within a set detection time.

[0008] In some implementations, determining whether the magnetic bearing rotor's levitation state is unstable based on its displacement accuracy includes: determining whether the magnetic bearing rotor's displacement accuracy is greater than a set displacement accuracy threshold; if the magnetic bearing rotor's displacement accuracy is greater than the set displacement accuracy threshold, then determining that the magnetic bearing rotor's levitation state is unstable and initiating a notification message indicating that the magnetic bearing rotor's levitation state is unstable; if the magnetic bearing rotor's displacement accuracy is less than or equal to the set displacement accuracy threshold, then determining that the magnetic bearing rotor's levitation state is stable, returning to the previous state, and continuing to determine whether the magnetic bearing rotor's displacement accuracy is greater than the set displacement accuracy threshold; the stable state refers to the state where the magnetic bearing rotor's levitation position has not deviated from a set reference position.

[0009] In some embodiments, determining whether the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, based on the fluctuation values ​​of the compressor's operating parameters, includes: determining whether the fluctuation value of the compressor's operating parameters is greater than a set threshold value; if the fluctuation value of the compressor's operating parameters is greater than the set threshold value, then determining that the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor; if the fluctuation value of the compressor's operating parameters is less than or equal to the set threshold value, then determining that the unstable state of the magnetic bearing rotor is not caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, controlling the magnetic bearing to maintain the operation of the magnetic bearing's control parameters, and returning to continue determining whether the fluctuation value of the compressor's operating parameters is greater than the set threshold value.

[0010] In some embodiments, the method further includes: after controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing, determining whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold; if it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the levitation state of the magnetic bearing rotor is still in an unstable state, returning to the previous state to continue adjusting the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and continuing to control the magnetic bearing to operate according to the new control parameters of the magnetic bearing; if it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold, then it is determined that the levitation state of the magnetic bearing rotor has returned to a stable state, the reminder message that the levitation state of the magnetic bearing rotor is in an unstable state is released, the magnetic bearing is controlled to maintain the operation of the control parameters of the magnetic bearing, returning to the previous state to re-determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor.

[0011] In conjunction with the above method, another aspect of the present invention provides a control device for a magnetic levitation compressor, wherein the magnetic levitation compressor has a magnetic bearing and a magnetic bearing rotor; the control device for the magnetic levitation compressor includes: a control unit configured to control the operation of the magnetic levitation compressor after it is started; an acquisition unit configured to acquire the displacement accuracy of the magnetic bearing rotor when the stability of the magnetic levitation compressor operation reaches a set stability level; the control unit is further configured to determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor; the unstable state refers to the state in which the levitation position of the magnetic bearing rotor deviates from a set reference position. The acquisition unit is further configured to acquire the operating parameter fluctuation value of the compressor when it is determined that the suspension state of the magnetic bearing rotor is in the unstable state; the control unit is further configured to determine, based on the operating parameter fluctuation value of the compressor, whether the suspension state of the magnetic bearing rotor in the unstable state is caused by pressure fluctuation in the internal cavity of the magnetic levitation compressor; the control unit is further configured to adjust the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing when it is determined that the suspension state of the magnetic bearing rotor in the unstable state is caused by pressure fluctuation in the internal cavity of the magnetic levitation compressor; and control the magnetic bearing to operate according to the new control parameters of the magnetic bearing.

[0012] In some embodiments, the magnetic levitation compressor further includes a frequency converter; the operating parameter fluctuation values ​​of the compressor include: the current fluctuation value of the frequency converter current of the compressor within a set detection time, and / or the discharge pressure fluctuation value of the compressor within a set detection time.

[0013] In some embodiments, the control unit determines whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor, including: determining whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold; if the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then the control unit determines that the levitation state of the magnetic bearing rotor is in an unstable state and initiates an alert message indicating that the levitation state of the magnetic bearing rotor is in an unstable state; if the displacement accuracy of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold, then the control unit determines that the levitation state of the magnetic bearing rotor is in a stable state, returns, and continues to determine whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold; the stable state refers to the state in which the levitation position of the magnetic bearing rotor does not deviate from the set reference position.

[0014] In some embodiments, the control unit determines whether the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor based on the fluctuation values ​​of the compressor's operating parameters. This includes: determining whether the fluctuation value of the compressor's operating parameters is greater than a set threshold value; if the fluctuation value is greater than the threshold value, then the unstable state of the magnetic bearing rotor is determined to be caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor; if the fluctuation value is less than or equal to the threshold value, then the unstable state of the magnetic bearing rotor is determined not to be caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, and the control unit controls the magnetic bearing to maintain its control parameters and returns to continue determining whether the fluctuation value of the compressor's operating parameters is greater than the threshold value.

[0015] In some embodiments, the control unit is further configured to: after controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing, determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold; the control unit is further configured to: if it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, determine that the levitation state of the magnetic bearing rotor is still in an unstable state, return to continue adjusting the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and continue to control the magnetic bearing to operate according to the new control parameters of the magnetic bearing; the control unit is further configured to: if it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold, determine that the levitation state of the magnetic bearing rotor has returned to a stable state, remove the reminder message that the levitation state of the magnetic bearing rotor is in an unstable state, control the magnetic bearing to maintain the operation of the control parameters of the magnetic bearing, return to re-determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor.

[0016] In conjunction with the above-mentioned device, the present invention further provides a magnetic levitation compressor, comprising: the control device for the magnetic levitation compressor described above.

[0017] Therefore, the solution of this invention, for the magnetic levitation compressor, sets a current fluctuation threshold for the inverter of the magnetic levitation compressor, and determines the operating state of the magnetic bearing rotor by detecting the current fluctuation value of the inverter within a unit time; or, sets a discharge pressure fluctuation threshold for the magnetic levitation compressor, and determines the operating state of the magnetic bearing rotor by detecting the discharge pressure fluctuation value of the magnetic levitation compressor within a unit time; based on the operating state of the magnetic bearing rotor, when the magnetic bearing rotor becomes unstable, the control parameters of the magnetic bearing are dynamically adjusted to achieve adaptive and stable control of the magnetic bearing rotor. Thus, by utilizing the current fluctuation of the inverter of the magnetic levitation compressor or the discharge pressure fluctuation of the magnetic levitation compressor, the operating state of the magnetic bearing rotor is analyzed, and the stable operation of the magnetic bearing rotor is controlled to ensure the operational stability of the magnetic bearing rotor of the magnetic levitation compressor.

[0018] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 A schematic diagram of the unstable state of the magnetic bearing rotor of a magnetic levitation compressor;

[0021] Figure 2 This is a flowchart illustrating an embodiment of the control method for the magnetic levitation compressor of the present invention;

[0022] Figure 3 This is a flowchart illustrating an embodiment of the method of the present invention for determining whether the levitation state of the magnetic bearing rotor is in an unstable state;

[0023] Figure 4 This is a flowchart illustrating an embodiment of the method of the present invention for determining whether the levitation state of the magnetic bearing rotor is in the unstable state is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor;

[0024] Figure 5 This is a flowchart illustrating an embodiment of the method of the present invention for dynamically adjusting the control parameters of the magnetic levitation bearing in a loop.

[0025] Figure 6 This is a schematic diagram of the structure of an embodiment of the control device for the magnetic levitation compressor of the present invention;

[0026] Figure 7 This is a schematic diagram of the displacement accuracy curve of the magnetic bearing rotor of a magnetic levitation compressor.

[0027] Figure 8This is a schematic diagram of the inverter current fluctuation of a magnetic levitation compressor.

[0028] Figure 9 This is a flowchart illustrating the control strategy of the magnetic bearing for a magnetic levitation compressor.

[0029] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0030] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] Figure 1 This is a schematic diagram of the structure of a magnetic bearing rotor in an unstable state in a magnetic levitation compressor. (Example:) Figure 1 As shown, when the magnetic bearing rotor of the magnetic levitation compressor is running stably, it fluctuates slightly near the stable position A0. At this time, the distance between the magnetic bearing rotor and the motor stator is the stable distance S0. When the magnetic bearing rotor is in an unstable state, it fluctuates significantly to the first fluctuation position A1 and the second fluctuation position A2. At this time, the distance between the magnetic bearing rotor and the motor stator is the first fluctuation distance S1 and the second fluctuation distance S2. During this period, the inverter current of the magnetic levitation compressor will fluctuate significantly, and the discharge pressure of the magnetic levitation compressor will also fluctuate significantly. The implementation process of the present invention will be illustrated below using the example of significant fluctuations in the inverter current of the magnetic levitation compressor.

[0033] In this design, the magnetic levitation compressor requires the rotor to be suspended in a stable center position, with the stable position A0 being the set reference center position. The first fluctuation position A1 and the second fluctuation position A2 refer to the approximate positions of the magnetic bearing rotor when the inverter current fluctuates significantly after rotor instability. The stable distance S0, the first fluctuation distance S1, and the second fluctuation distance S2 are used to represent the relationship between data values; for example, the stable distance S0 is approximately 2000µm, the first fluctuation distance S1 is approximately 1000µm, and the second fluctuation distance S2 is approximately 3000µm.

[0034] Considering, see Figure 1In the example shown, for a magnetic levitation compressor, the magnetic bearing coil current is only used to levitate the rotor shaft, typically only a few amperes (A). After the compressor starts running, as the magnetic bearing rotor rotates, the magnetic bearing coil current will exhibit normal, small fluctuations. Furthermore, even if the compressor experiences surge, the magnetic bearing coil current fluctuations will almost never exceed 0.5A. Therefore, relying solely on the magnetic bearing coil current fluctuations is insufficient to determine the levitation state of the magnetic bearing rotor, and thus, to control its stable operation. However, the current fluctuations of the inverter and the discharge pressure fluctuations of the magnetic levitation compressor can accurately reflect the surge state of the compressor system. Therefore, in order to solve... Figure 1 The present invention addresses the problem of unstable magnetic bearing rotor in a magnetic levitation compressor affecting its operational stability. Specifically, it provides a control method for a magnetic levitation compressor, specifically a control method for the magnetic bearing in the compressor. This method utilizes fluctuations in the inverter current or exhaust pressure of the magnetic levitation compressor to analyze the operating state of the magnetic bearing rotor, thereby controlling its stable operation and ensuring the operational stability of the magnetic bearing rotor in the magnetic levitation compressor.

[0035] According to an embodiment of the present invention, a control method for a magnetic levitation compressor is provided, such as... Figure 2 The diagram shows a flowchart of an embodiment of the method of the present invention. The magnetic levitation compressor has a magnetic bearing and a magnetic bearing rotor. The control method of the magnetic levitation compressor includes steps S110 to S160.

[0036] In step S110, after the magnetic levitation compressor is turned on, the operation of the magnetic levitation compressor is controlled.

[0037] In step S120, when the stability of the magnetic levitation compressor reaches a set stability level, the displacement accuracy of the magnetic bearing rotor is obtained, such as the real-time detected displacement accuracy X of the magnetic bearing rotor.

[0038] In step S130, based on the displacement accuracy of the magnetic bearing rotor, it is determined whether the suspension state of the magnetic bearing rotor is in an unstable state. The unstable state refers to the state in which the suspension position of the magnetic bearing rotor deviates from the set reference position.

[0039] In some embodiments, the specific process of determining whether the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor in step S130 is illustrated in the following exemplary description.

[0040] The following is combined with Figure 3The schematic diagram shown is a flowchart of an embodiment of the method of the present invention for determining whether the levitation state of the magnetic bearing rotor is in an unstable state. It further illustrates the specific process of determining whether the levitation state of the magnetic bearing rotor is in an unstable state in step S130, including steps S210 to S230.

[0041] Step S210: Determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold. The set displacement accuracy threshold is, for example, a set magnetic bearing rotor displacement accuracy threshold X. θ .

[0042] Step S220: If it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is in an unstable state, and a reminder message that the suspension state of the magnetic bearing rotor is in an unstable state is initiated.

[0043] Step S230: If it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is in a stable state, i.e., in a non-instable state. The process returns to continue determining whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold. The stable state refers to the state where the suspension position of the magnetic bearing rotor does not deviate from the set reference position.

[0044] Specifically, Figure 9 This is a flowchart illustrating the control strategy for the magnetic levitation bearing in a magnetic levitation compressor. Figure 9 As shown, the present invention proposes a magnetic levitation bearing control strategy for a magnetic levitation compressor, comprising:

[0045] Step 1: After the unit containing the magnetic levitation compressor is started, control the operation of the magnetic levitation compressor until the magnetic levitation compressor is running stably.

[0046] Step 2: Under stable operation of the magnetic levitation compressor, once the compressor reaches a stable operating state after a set time, the displacement accuracy of the magnetic bearing rotor is detected in real time and recorded as the real-time detected displacement accuracy X of the magnetic bearing rotor. Specifically, the magnetic levitation bearing uses a displacement sensor to detect the rotor's displacement voltage value. The control system considers the difference between the real-time measured displacement voltage value and the target voltage value as the displacement accuracy.

[0047] Step 3: Set the displacement accuracy threshold of the magnetic bearing rotor to X. θ Determine whether the real-time detected displacement accuracy X of the magnetic bearing rotor is greater than the set displacement accuracy threshold X of the magnetic bearing rotor. θIf so, the magnetic bearing rotor is considered to be in an unstable state, and step 4 is executed to analyze the instability state of the magnetic bearing rotor and adjust the control strategy of the magnetic bearing. Otherwise, the magnetic bearing rotor is considered to be operating stably (i.e., running stably), and the magnetic bearing rotor is controlled to continue to operate stably. The process returns to step 3 to continue judging whether the real-time detected displacement accuracy X of the magnetic bearing rotor is greater than the set displacement accuracy threshold X. θ .

[0048] Figure 7 This is a schematic diagram of the displacement accuracy curve of the magnetic bearing rotor of a magnetic levitation compressor, as shown below. Figure 7 As shown, when the real-time detected displacement accuracy X of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold X of the magnetic bearing rotor... θ At this time, the magnetic bearing rotor is operating stably. When the real-time detected displacement accuracy X of the magnetic bearing rotor exceeds the set displacement accuracy threshold X... θ If the magnetic bearing rotor is in an unstable state, an alarm will be sent to the unit (i.e., the unit where the magnetic levitation compressor is located). It is necessary to analyze the unstable state of the magnetic bearing rotor and adjust the control strategy of the magnetic bearing.

[0049] In step S140, if it is determined that the magnetic bearing rotor is in the unstable state, the fluctuation value of the compressor's operating parameters is obtained.

[0050] The magnetic levitation compressor also includes a frequency converter. The operating parameter fluctuation values ​​of the compressor include: the current fluctuation value of the compressor's frequency converter current within a set detection time, and / or the discharge pressure fluctuation value of the compressor within a set detection time.

[0051] In step S150, based on the fluctuation value of the compressor's operating parameters, it is determined whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor.

[0052] In some embodiments, the specific process of determining whether the suspension state of the magnetic bearing rotor in the unstable state is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor based on the fluctuation value of the compressor's operating parameters in step S150 is illustrated in the following exemplary description.

[0053] The following is combined with Figure 4The schematic diagram of an embodiment of the method of the present invention, which shows whether the suspension state of the magnetic bearing rotor is in the unstable state due to pressure fluctuations in the internal cavity of the magnetic levitation compressor, further illustrates the specific process of determining whether the suspension state of the magnetic bearing rotor is in the unstable state due to pressure fluctuations in the internal cavity of the magnetic levitation compressor in step S150, including steps S310 to S330.

[0054] Step S310: Determine whether the fluctuation value of the compressor's operating parameters exceeds a set operating parameter fluctuation threshold. The set operating parameter fluctuation threshold is a set parameter threshold corresponding to the operating parameter fluctuation value. For example, if the operating parameter fluctuation value is the inverter's current fluctuation value, the set operating parameter fluctuation threshold is the inverter's standard current fluctuation value ΔI. θ When the fluctuation value of the operating parameter is the fluctuation value of the compressor's discharge pressure, the set threshold value of the operating parameter fluctuation value is the standard fluctuation value of the compressor's set discharge pressure.

[0055] Step S320: If it is determined that the fluctuation value of the operating parameter of the compressor is greater than the set threshold value of the operating parameter fluctuation value, then it is determined that the suspension state of the magnetic bearing rotor is in the unstable state due to the pressure fluctuation of the internal cavity of the magnetic levitation compressor.

[0056] Step S330: If it is determined that the fluctuation value of the operating parameter of the compressor is less than or equal to the set operating parameter fluctuation value threshold, then it is determined that the suspension state of the magnetic bearing rotor in the unstable state is not caused by the pressure fluctuation of the internal cavity of the magnetic levitation compressor. The magnetic bearing is controlled to maintain the operation of the control parameters of the magnetic bearing, and then the process is returned to continue to determine whether the fluctuation value of the operating parameter of the compressor is greater than the set operating parameter fluctuation value threshold.

[0057] Specifically, such as Figure 9 As shown, the magnetic bearing control strategy for a magnetic levitation compressor proposed in this invention further includes:

[0058] Step 4: Analyze the operating status of the magnetic bearing rotor by real-time detection of the inverter current fluctuation value ΔI per unit time.

[0059] Specifically, in step 4, the standard fluctuation value of the inverter current per unit time is set to ΔI. θ The real-time fluctuation value of the compressor's inverter current per unit time is detected and recorded as the real-time detected inverter current fluctuation value of the compressor per unit time, ΔI. Then, it is determined whether the real-time detected inverter current fluctuation value ΔI of the compressor per unit time is greater than the set standard current fluctuation value of the inverter per unit time, ΔI. θIf yes, proceed to step 5 to adjust the control parameters of the magnetic bearing. Otherwise, keep the control parameters of the magnetic bearing unchanged, allowing the magnetic bearing to operate at those control parameters.

[0060] Figure 8 This is a schematic diagram of the inverter current fluctuation of a magnetic levitation compressor, as shown below. Figure 8 As shown, the standard current fluctuation value of the inverter per unit time is set to ΔI. θ When the real-time detected inverter current fluctuation value ΔI of the compressor per unit time is less than or equal to the set standard current fluctuation value ΔI of the inverter per unit time. θ At this point, the rotor instability of the magnetic bearing is not caused by pressure fluctuations in the magnetic levitation compressor. Therefore, the bearing control parameters are not modified, and the system continues to run and the data is observed. The process then returns to the step of measuring rotor displacement accuracy. Reaching this point indicates that the rotor instability is not caused by compressor pressure fluctuations; therefore, the magnetic bearing control parameters are not modified, and the rotor status is continuously observed. When the real-time detected inverter current fluctuation value ΔI of the compressor per unit time is greater than the set standard inverter current fluctuation value ΔI per unit time... θ When the instability of the magnetic bearing rotor is determined, it is caused by a large fluctuation in the internal cavity pressure of the magnetic levitation compressor, such as surge of the magnetic levitation compressor, which causes the magnetic bearing rotor to be disturbed, resulting in a decrease in the real-time detected displacement accuracy X of the magnetic bearing rotor. At this time, step 5 is executed.

[0061] In step S160, if it is determined that the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, the control parameters of the magnetic bearing are adjusted to obtain new control parameters. The magnetic bearing is then controlled to operate according to these new control parameters.

[0062] This invention proposes a control method for magnetic bearings in a magnetic levitation compressor. By analyzing the fluctuations in the inverter current or the exhaust pressure of the magnetic levitation compressor, the operating state of the magnetic bearing rotor is analyzed, and then the rotor is controlled to operate stably, ensuring the operational stability of the magnetic bearing rotor in the magnetic levitation compressor. This solves the problem in related solutions where the magnetic bearing control system adjusts the electromagnetic force of the magnetic bearing to achieve stable levitation by real-time detection of the rotor's displacement accuracy. However, this method is insufficient for quickly and accurately detecting the rotor's operating state and rapidly adjusting for rotor instability in magnetic levitation compressors.

[0063] Specifically, in the solution of this invention, by setting a threshold for inverter current fluctuation, the current fluctuation value of the inverter within a unit time is detected to analyze the operating state of the magnetic bearing rotor. Alternatively, when the compressor is running stably, the operating state of the magnetic bearing rotor is determined by detecting the magnitude of the discharge pressure fluctuation of the magnetic levitation compressor within a unit time. Specifically, this means setting a discharge pressure fluctuation threshold; if the threshold is exceeded, it is determined that the rotor instability is caused by internal pressure fluctuations in the compressor. The logic is the same as the method for judging inverter current fluctuation values, but it is more accurate based on inverter current fluctuation values. For example, under high-load operation of the compressor, the discharge pressure will also fluctuate significantly, but the magnetic bearing rotor will operate stably. The inverter current fluctuation more directly reflects the internal pressure changes of the compressor, thus providing feedback on the rotor's operating state. Furthermore, in the case of magnetic bearing rotor instability, an alarm is sent to the magnetic bearing control system, and the bearing control parameters are dynamically adjusted to improve the self-disruption resistance of the magnetic bearing control system, achieving adaptive control of the magnetic bearing rotor. This ensures stable operation of the magnetic bearing rotor in the magnetic levitation compressor.

[0064] In some embodiments, the control method for the magnetic levitation compressor described in the present invention further includes: a process of cyclically adjusting the control parameters of the magnetic levitation bearing.

[0065] The following is combined with Figure 5 The flowchart shown is a schematic diagram of an embodiment of the method of the present invention for dynamically adjusting the control parameters of the magnetic levitation bearing in a loop. The specific process of dynamically adjusting the control parameters of the magnetic levitation bearing in a loop is further explained, including steps S410 to S430.

[0066] Step S410: After controlling the magnetic bearing to operate according to the new control parameters, determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold. The set displacement accuracy threshold is, for example, a set magnetic bearing rotor displacement accuracy threshold X. θ .

[0067] Step S420: If it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is still in an unstable state. Return to the previous step to continue adjusting the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and continue to control the magnetic bearing to operate according to the new control parameters of the magnetic bearing.

[0068] Step S430: If it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor has recovered to a stable state, i.e., it is in an unstable state. The reminder message that the suspension state of the magnetic bearing rotor is in an unstable state is released. The magnetic bearing is controlled to maintain the operation of the control parameters of the magnetic bearing. Then, the process returns to determine whether the suspension state of the magnetic bearing rotor is in an unstable state again based on the displacement accuracy of the magnetic bearing rotor.

[0069] like Figure 9 As shown, the magnetic bearing control strategy for a magnetic levitation compressor proposed in this invention further includes:

[0070] Step 5: Dynamically adjust the control parameters of the magnetic bearing using the magnetic bearing control system, then proceed to step 6. The magnetic bearing control system parameters include bearing stiffness and damping, which are common to the magnetic bearing development industry. Dynamic adjustment refers to the magnetic bearing control system's ability to analyze the collected real-time displacement voltage values, interpret their changing trends, and adjust the stiffness and damping parameters until the rotor operates stably.

[0071] Step 6: During the dynamic adjustment of the control parameters of the magnetic bearing, the displacement accuracy of the magnetic bearing rotor is detected in real time to obtain the real-time detected displacement accuracy X of the magnetic bearing rotor. It is then determined whether the real-time detected displacement accuracy X of the magnetic bearing rotor is greater than the set displacement accuracy threshold X of the magnetic bearing rotor. θ If yes, return to step 5 and continue to dynamically adjust the control parameters of the magnetic bearing using the magnetic bearing control system. Otherwise, assume the magnetic bearing rotor is levitated and stable, and return to step 2 for cyclic control.

[0072] In this way, during the dynamic adjustment of the magnetic bearing control parameters, the displacement accuracy of the magnetic bearing rotor is detected in real time to obtain the real-time detected displacement accuracy X of the magnetic bearing rotor, until the optimal magnetic bearing control parameters are matched so that the real-time detected displacement accuracy X of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold X of the magnetic bearing rotor. θ This ensures stable operation of the magnetic bearing rotor, clears alarms, and enables adaptive adjustment of the magnetic bearing's control parameters.

[0073] The present invention utilizes the fluctuation of the inverter current or the fluctuation of the exhaust pressure of the magnetic levitation compressor to analyze the operating state of the magnetic bearing rotor. This enables real-time detection of the operating state of the magnetic bearing rotor, achieving rapid response and adjustment of the magnetic bearing control system, enhancing the anti-interference capability of the magnetic bearing control system, and improving the reliability of the magnetic bearing control system, thereby ensuring the safe and stable operation of the magnetic levitation compressor.

[0074] The technical solution of this embodiment involves setting a current fluctuation threshold for the inverter of the magnetic levitation compressor. By detecting the current fluctuation value of the inverter within a unit of time, the operating state of the magnetic bearing rotor is determined. Alternatively, a discharge pressure fluctuation threshold for the magnetic levitation compressor is set, and the operating state of the magnetic bearing rotor is determined by detecting the discharge pressure fluctuation value of the magnetic levitation compressor within a unit of time. Based on the operating state of the magnetic bearing rotor, when instability is detected, the control parameters of the magnetic bearing are dynamically adjusted to achieve adaptive and stable control of the magnetic bearing rotor. Therefore, by analyzing the current fluctuation of the inverter or the discharge pressure fluctuation of the magnetic levitation compressor, the operating state of the magnetic bearing rotor is analyzed, and the stable operation of the magnetic bearing rotor is controlled to ensure the operational stability of the magnetic bearing rotor of the magnetic levitation compressor.

[0075] According to an embodiment of the present invention, a control device for a magnetic levitation compressor corresponding to the control method for the magnetic levitation compressor is also provided. See also Figure 6 The diagram shows a structural schematic of an embodiment of the device of the present invention. The magnetic levitation compressor has a magnetic bearing and a magnetic bearing rotor. The control device of the magnetic levitation compressor includes: an acquisition unit 102 and a control unit 104.

[0076] The control unit 104 is configured to control the operation of the magnetic levitation compressor after it is started. The specific functions and processing of the control unit 104 are described in step S110.

[0077] The acquisition unit 102 is configured to acquire the displacement accuracy of the magnetic bearing rotor, such as the real-time detected displacement accuracy X of the magnetic bearing rotor, when the stability of the magnetic levitation compressor operation reaches a set stability level. The specific functions and processing of this acquisition unit 102 are described in step S120.

[0078] The control unit 104 is further configured to determine whether the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor. The unstable state refers to the state where the suspension position of the magnetic bearing rotor deviates from a set reference position. The specific functions and processing of this control unit 104 are further described in step S130.

[0079] In some embodiments, the control unit 104 determines whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor, including:

[0080] The control unit 104 is further configured to determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold. The set displacement accuracy threshold is, for example, a set displacement accuracy threshold X for the magnetic bearing rotor. θFor details on the specific functions and processing of the control unit 104, please refer to step S210.

[0081] The control unit 104 is further configured to determine that the magnetic bearing rotor is in an unstable levitation state if the displacement accuracy of the magnetic bearing rotor is determined to be greater than a set displacement accuracy threshold, and to initiate a reminder message indicating that the magnetic bearing rotor is in an unstable levitation state. The specific functions and processing of this control unit 104 are further described in step S220.

[0082] The control unit 104 is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to a set displacement accuracy threshold, determine that the suspension state of the magnetic bearing rotor is in a stable state, i.e., in a non-instable state, and return to continue determining whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold. The stable state refers to the state in which the suspension position of the magnetic bearing rotor does not deviate from the set reference position. The specific functions and processing of this control unit 104 are further described in step S230.

[0083] Specifically, Figure 9 This is a flowchart illustrating the control strategy for the magnetic levitation bearing in a magnetic levitation compressor. Figure 9 As shown, the present invention proposes a magnetic levitation bearing control strategy for a magnetic levitation compressor, comprising:

[0084] Step 1: After the unit containing the magnetic levitation compressor is started, control the operation of the magnetic levitation compressor until the magnetic levitation compressor is running stably.

[0085] Step 2: Under the condition that the magnetic levitation compressor is running stably, such as after the magnetic levitation compressor reaches a stable operating state after running for a set time, the displacement accuracy of the magnetic bearing rotor is detected in real time and recorded as the real-time detected displacement accuracy of the magnetic bearing rotor X.

[0086] Step 3: Set the displacement accuracy threshold of the magnetic bearing rotor to X. θ Determine whether the real-time detected displacement accuracy X of the magnetic bearing rotor is greater than the set displacement accuracy threshold X of the magnetic bearing rotor. θ If so, the magnetic bearing rotor is considered to be in an unstable state, and step 4 is executed to analyze the instability state of the magnetic bearing rotor and adjust the control strategy of the magnetic bearing. Otherwise, the magnetic bearing rotor is considered to be operating stably (i.e., running stably), and the magnetic bearing rotor is controlled to continue to operate stably. The process returns to step 3 to continue judging whether the real-time detected displacement accuracy X of the magnetic bearing rotor is greater than the set displacement accuracy threshold X. θ .

[0087] Figure 7 This is a schematic diagram of the displacement accuracy curve of the magnetic bearing rotor of a magnetic levitation compressor, as shown below. Figure 7As shown, when the real-time detected displacement accuracy X of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold X of the magnetic bearing rotor... θ At this time, the magnetic bearing rotor is operating stably. When the real-time detected displacement accuracy X of the magnetic bearing rotor exceeds the set displacement accuracy threshold X... θ If the magnetic bearing rotor is in an unstable state, an alarm will be sent to the unit (i.e., the unit where the magnetic levitation compressor is located). It is necessary to analyze the unstable state of the magnetic bearing rotor and adjust the control strategy of the magnetic bearing.

[0088] The acquisition unit 102 is further configured to acquire the operating parameter fluctuation value of the compressor when it is determined that the suspension state of the magnetic bearing rotor is in the unstable state. The specific function and processing of this acquisition unit 102 are further described in step S140.

[0089] The magnetic levitation compressor also includes a frequency converter. The operating parameter fluctuation values ​​of the compressor include: the current fluctuation value of the compressor's frequency converter current within a set detection time, and / or the discharge pressure fluctuation value of the compressor within a set detection time.

[0090] The control unit 104 is further configured to determine, based on the fluctuation values ​​of the compressor's operating parameters, whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations within the internal cavity of the magnetic levitation compressor. The specific functions and processing of this control unit 104 are further described in step S150.

[0091] In some embodiments, the control unit 104 determines, based on the fluctuation values ​​of the compressor's operating parameters, whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations within the internal cavity of the magnetic levitation compressor, including:

[0092] The control unit 104 is further configured to determine whether the fluctuation value of the compressor's operating parameters exceeds a set operating parameter fluctuation value threshold. The set operating parameter fluctuation value threshold is a set parameter threshold corresponding to the operating parameter fluctuation value. For example, when the operating parameter fluctuation value is the inverter's current fluctuation value, the set operating parameter fluctuation value threshold is the inverter's standard current fluctuation value ΔI. θ When the fluctuation value of the operating parameter is the same as the fluctuation value of the compressor's discharge pressure, the set threshold value for the operating parameter fluctuation value is the standard fluctuation value of the compressor's set discharge pressure. For the specific functions and processing of this control unit 104, please refer to step S310.

[0093] The control unit 104 is further configured to determine, if it is determined that the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, if the fluctuation value of the compressor's operating parameters is greater than a set threshold value for the operating parameters. The specific functions and processing of this control unit 104 are further described in step S320.

[0094] The control unit 104 is further configured to, if it is determined that the fluctuation value of the compressor's operating parameters is less than or equal to a set operating parameter fluctuation value threshold, determine that the instability of the magnetic bearing rotor's levitation state is not caused by pressure fluctuations within the magnetic levitation compressor's internal cavity, control the magnetic bearing to maintain the operation of its control parameters, and return to continue determining whether the compressor's operating parameter fluctuation value is greater than the set operating parameter fluctuation value threshold. The specific functions and processing of this control unit 104 are further described in step S330.

[0095] Specifically, such as Figure 9 As shown, the magnetic bearing control strategy for a magnetic levitation compressor proposed in this invention further includes:

[0096] Step 4: Analyze the operating status of the magnetic bearing rotor by real-time detection of the inverter current fluctuation value ΔI per unit time.

[0097] Specifically, in step 4, the standard fluctuation value of the inverter current per unit time is set to ΔI. θ The real-time fluctuation value of the compressor's inverter current per unit time is detected and recorded as the real-time detected inverter current fluctuation value of the compressor per unit time, ΔI. Then, it is determined whether the real-time detected inverter current fluctuation value ΔI of the compressor per unit time is greater than the set standard current fluctuation value of the inverter per unit time, ΔI. θ If yes, proceed to step 5 to adjust the control parameters of the magnetic bearing. Otherwise, keep the control parameters of the magnetic bearing unchanged, allowing the magnetic bearing to operate at those control parameters.

[0098] Figure 8 This is a schematic diagram of the inverter current fluctuation of a magnetic levitation compressor, as shown below. Figure 8 As shown, the standard current fluctuation value of the inverter per unit time is set to ΔI. θ When the real-time detected inverter current fluctuation value ΔI of the compressor per unit time is less than or equal to the set standard current fluctuation value ΔI of the inverter per unit time. θ At this point, the instability of the magnetic bearing rotor is not caused by pressure fluctuations in the magnetic levitation compressor. Therefore, the bearing control parameters are not modified, and the compressor continues to run while data is monitored. When the real-time detected inverter current fluctuation value ΔI of the compressor per unit time is greater than the set standard current fluctuation value ΔI of the inverter per unit time... θWhen the instability of the magnetic bearing rotor is determined, it is caused by a large fluctuation in the internal cavity pressure of the magnetic levitation compressor, such as surge of the magnetic levitation compressor, which causes the magnetic bearing rotor to be disturbed, resulting in a decrease in the real-time detected displacement accuracy X of the magnetic bearing rotor. At this time, step 5 is executed.

[0099] The control unit 104 is further configured to, when it is determined that the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, adjust the control parameters of the magnetic bearing to obtain new control parameters for the magnetic bearing, and control the magnetic bearing to operate according to the new control parameters. The specific functions and processing of this control unit 104 are further described in step S160.

[0100] This invention proposes a control device for the magnetic bearing in a magnetic levitation compressor. It analyzes the operating state of the magnetic bearing rotor by monitoring fluctuations in the inverter current or exhaust pressure of the magnetic levitation compressor, thereby controlling the rotor to operate stably and ensuring its stability. This solves the problem in related solutions where the magnetic bearing control system adjusts the electromagnetic force of the magnetic bearing to achieve stable levitation by real-time detection of rotor displacement accuracy. However, this method is insufficient for quickly and accurately detecting the rotor's operating state and rapidly adjusting for rotor instability in magnetic levitation compressors.

[0101] Specifically, in the solution of this invention, by setting a current fluctuation threshold for the frequency converter, the current fluctuation value of the frequency converter within a unit time is detected, and the operating state of the magnetic bearing rotor at this time is analyzed. Alternatively, when the compressor is running stably, the operating state of the magnetic bearing rotor is determined by detecting the magnitude of the exhaust pressure fluctuation of the magnetic levitation compressor within a unit time. Furthermore, in the case of magnetic bearing rotor instability, an alarm is sent to the magnetic bearing control system, and the bearing control parameters are dynamically adjusted to improve the self-disruption resistance capability of the magnetic bearing control system, realize adaptive control of the magnetic bearing rotor, and ensure the stable operation of the magnetic bearing rotor of the magnetic levitation compressor.

[0102] In some embodiments, the control device for the magnetic levitation compressor described in the present invention further includes: a process of cyclically and dynamically adjusting the control parameters of the magnetic levitation bearing, as detailed below:

[0103] The control unit 104 is further configured to, after controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing, determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold. The set displacement accuracy threshold is, for example, a set magnetic bearing rotor displacement accuracy threshold X. θFor details on the specific functions and processing of the control unit 104, please refer to step S410.

[0104] The control unit 104 is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold, determine that the levitation state of the magnetic bearing rotor is still unstable, return, and continue to adjust the control parameters of the magnetic bearing to obtain new control parameters; and continue to control the magnetic bearing to operate according to the new control parameters. The specific functions and processing of this control unit 104 are further described in step S420.

[0105] The control unit 104 is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to a set displacement accuracy threshold, then determine that the levitation state of the magnetic bearing rotor has returned to a stable state, i.e., it is in a non-instable state; then, cancel the reminder message that the levitation state of the magnetic bearing rotor is in an unstable state; control the magnetic bearing to maintain the operation of the control parameters of the magnetic bearing; and return to re-determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor. The specific functions and processing of this control unit 104 are further described in step S430.

[0106] like Figure 9 As shown, the magnetic bearing control strategy for a magnetic levitation compressor proposed in this invention further includes:

[0107] Step 5: Dynamically adjust the control parameters of the magnetic bearing by the magnetic bearing control system, and then proceed to step 6.

[0108] Step 6: During the dynamic adjustment of the control parameters of the magnetic bearing, the displacement accuracy of the magnetic bearing rotor is detected in real time to obtain the real-time detected displacement accuracy X of the magnetic bearing rotor. It is then determined whether the real-time detected displacement accuracy X of the magnetic bearing rotor is greater than the set displacement accuracy threshold X of the magnetic bearing rotor. θ If yes, return to step 5 and continue to dynamically adjust the control parameters of the magnetic bearing using the magnetic bearing control system. Otherwise, assume the magnetic bearing rotor is levitated and stable, and return to step 2 for cyclic control.

[0109] In this way, during the dynamic adjustment of the magnetic bearing control parameters, the displacement accuracy of the magnetic bearing rotor is detected in real time to obtain the real-time detected displacement accuracy X of the magnetic bearing rotor, until the optimal magnetic bearing control parameters are matched so that the real-time detected displacement accuracy X of the magnetic bearing rotor is less than or equal to the set displacement accuracy threshold X of the magnetic bearing rotor. θ This ensures stable operation of the magnetic bearing rotor, clears alarms, and enables adaptive adjustment of the magnetic bearing's control parameters.

[0110] The present invention utilizes the fluctuation of the inverter current or the fluctuation of the exhaust pressure of the magnetic levitation compressor to analyze the operating state of the magnetic bearing rotor. This enables real-time detection of the operating state of the magnetic bearing rotor, achieving rapid response and adjustment of the magnetic bearing control system, enhancing the anti-interference capability of the magnetic bearing control system, and improving the reliability of the magnetic bearing control system, thereby ensuring the safe and stable operation of the magnetic levitation compressor.

[0111] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0112] By employing the technical solution of this invention, for the magnetic levitation compressor, a current fluctuation threshold for the inverter of the magnetic levitation compressor is set, and the operating state of the magnetic bearing rotor is determined by detecting the current fluctuation value of the inverter within a unit time; or, a discharge pressure fluctuation threshold for the magnetic levitation compressor is set, and the operating state of the magnetic bearing rotor is determined by detecting the discharge pressure fluctuation value of the magnetic levitation compressor within a unit time; based on the operating state of the magnetic bearing rotor, when the magnetic bearing rotor becomes unstable, the control parameters of the magnetic bearing are dynamically adjusted to achieve adaptive and stable control of the magnetic bearing rotor, which can enhance the anti-interference capability of the magnetic bearing control system and enable the magnetic levitation compressor to operate safely and stably.

[0113] According to an embodiment of the present invention, a magnetic levitation compressor corresponding to a control device for a magnetic levitation compressor is also provided. This magnetic levitation compressor may include the control device for a magnetic levitation compressor described above.

[0114] Since the processing and functions implemented by the magnetic levitation compressor in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned device, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0115] The technical solution of this invention sets a current fluctuation threshold for the inverter of the magnetic levitation compressor and determines the operating state of the magnetic bearing rotor by detecting the current fluctuation value of the inverter within a unit time. Alternatively, it sets a discharge pressure fluctuation threshold for the magnetic levitation compressor and determines the operating state of the magnetic bearing rotor by detecting the discharge pressure fluctuation value of the magnetic levitation compressor within a unit time. Based on the operating state of the magnetic bearing rotor, when the magnetic bearing rotor becomes unstable, the control parameters of the magnetic bearing are dynamically adjusted to achieve adaptive and stable control of the magnetic bearing rotor. This method can quickly and accurately detect the operating state of the magnetic bearing rotor and quickly adjust the unstable state of the magnetic bearing rotor, thereby improving the self-disruption resistance capability of the magnetic bearing control system and ensuring the stable operation of the magnetic bearing rotor.

[0116] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0117] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A control method for a magnetic levitation compressor, characterized in that, The magnetic levitation compressor has a magnetic bearing and a magnetic bearing rotor; the control method of the magnetic levitation compressor includes: After the magnetic levitation compressor is turned on, control the operation of the magnetic levitation compressor; When the stability of the magnetic levitation compressor reaches a set stability level, the displacement accuracy of the magnetic bearing rotor is obtained; Based on the displacement accuracy of the magnetic bearing rotor, determine whether the suspension state of the magnetic bearing rotor is in an unstable state; the unstable state refers to the state in which the suspension position of the magnetic bearing rotor deviates from the set reference position. When it is determined that the magnetic bearing rotor is in the unstable state, the fluctuation value of the compressor's operating parameters is obtained; Based on the fluctuation values ​​of the compressor's operating parameters, determine whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations within the magnetic levitation compressor's internal cavity. If it is determined that the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, the control parameters of the magnetic bearing are adjusted to obtain new control parameters; and the magnetic bearing is controlled to operate according to the new control parameters.

2. The control method for the magnetic levitation compressor according to claim 1, characterized in that, in, The magnetic levitation compressor also has a frequency converter; the operating parameter fluctuation values ​​of the compressor include: the current fluctuation value of the frequency converter current of the compressor within a set detection time, and / or the discharge pressure fluctuation value of the compressor within a set detection time.

3. The control method for the magnetic levitation compressor according to claim 1 or 2, characterized in that, Based on the displacement accuracy of the magnetic bearing rotor, determining whether the suspension state of the magnetic bearing rotor is in an unstable state includes: Determine whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold. If it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is in an unstable state, and an alert message indicating that the suspension state of the magnetic bearing rotor is in an unstable state is initiated. If the displacement accuracy of the magnetic bearing rotor is determined to be less than or equal to the set displacement accuracy threshold, then the suspension state of the magnetic bearing rotor is determined to be in a stable state, and the process returns to continue determining whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold; the stable state refers to the state in which the suspension position of the magnetic bearing rotor has not deviated from the set reference position.

4. The control method for a magnetic levitation compressor according to claim 1 or 2, characterized in that, Based on the fluctuation values ​​of the compressor's operating parameters, determine whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations within the internal cavity of the magnetic levitation compressor, including: Determine whether the fluctuation value of the compressor's operating parameters is greater than the set threshold value for operating parameter fluctuation; If it is determined that the fluctuation value of the operating parameters of the compressor is greater than the set threshold value of the operating parameter fluctuation value, then it is determined that the levitation state of the magnetic bearing rotor is in the unstable state due to the pressure fluctuation of the internal cavity of the magnetic levitation compressor. If it is determined that the fluctuation value of the compressor's operating parameters is less than or equal to the set operating parameter fluctuation value threshold, then it is determined that the instability of the magnetic bearing rotor's suspension state is not caused by the pressure fluctuation inside the magnetic levitation compressor's cavity. The magnetic bearing is then controlled to maintain the operation of the magnetic bearing's control parameters and returned to continue determining whether the fluctuation value of the compressor's operating parameters is greater than the set operating parameter fluctuation value threshold.

5. The control method for the magnetic levitation compressor according to claim 3, characterized in that, Based on the fluctuation values ​​of the compressor's operating parameters, determine whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations within the internal cavity of the magnetic levitation compressor, including: Determine whether the fluctuation value of the compressor's operating parameters is greater than the set threshold value for operating parameter fluctuation; If it is determined that the fluctuation value of the operating parameters of the compressor is greater than the set threshold value of the operating parameter fluctuation value, then it is determined that the levitation state of the magnetic bearing rotor is in the unstable state due to the pressure fluctuation of the internal cavity of the magnetic levitation compressor. If it is determined that the fluctuation value of the compressor's operating parameters is less than or equal to the set operating parameter fluctuation value threshold, then it is determined that the instability of the magnetic bearing rotor's suspension state is not caused by the pressure fluctuation inside the magnetic levitation compressor's cavity. The magnetic bearing is then controlled to maintain the operation of the magnetic bearing's control parameters and returned to continue determining whether the fluctuation value of the compressor's operating parameters is greater than the set operating parameter fluctuation value threshold.

6. The control method for the magnetic levitation compressor according to any one of claims 1, 2, and 5, characterized in that, Also includes: After controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing, determine whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold. If it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is still in an unstable state, and the process returns to continue adjusting the control parameters of the magnetic bearing to obtain new control parameters; and the magnetic bearing continues to be controlled to operate according to the new control parameters. If the displacement accuracy of the magnetic bearing rotor is determined to be less than or equal to the set displacement accuracy threshold, then the suspension state of the magnetic bearing rotor is determined to have returned to a stable state. The reminder message that the suspension state of the magnetic bearing rotor is in an unstable state is released, and the magnetic bearing is controlled to maintain the operation of the control parameters of the magnetic bearing. Then, the process returns to determine whether the suspension state of the magnetic bearing rotor is in an unstable state again based on the displacement accuracy of the magnetic bearing rotor.

7. The control method for the magnetic levitation compressor according to claim 3, characterized in that, Also includes: After controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing, determine whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold. If it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is still in an unstable state, and the process returns to continue adjusting the control parameters of the magnetic bearing to obtain new control parameters; and the magnetic bearing continues to be controlled to operate according to the new control parameters. If the displacement accuracy of the magnetic bearing rotor is determined to be less than or equal to the set displacement accuracy threshold, then the suspension state of the magnetic bearing rotor is determined to have returned to a stable state. The reminder message that the suspension state of the magnetic bearing rotor is in an unstable state is released, and the magnetic bearing is controlled to maintain the operation of the control parameters of the magnetic bearing. Then, the process returns to determine whether the suspension state of the magnetic bearing rotor is in an unstable state again based on the displacement accuracy of the magnetic bearing rotor.

8. The control method for the magnetic levitation compressor according to claim 4, characterized in that, Also includes: After controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing, determine whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold. If it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is still in an unstable state, and the process returns to continue adjusting the control parameters of the magnetic bearing to obtain new control parameters; and the magnetic bearing continues to be controlled to operate according to the new control parameters. If the displacement accuracy of the magnetic bearing rotor is determined to be less than or equal to the set displacement accuracy threshold, then the suspension state of the magnetic bearing rotor is determined to have returned to a stable state. The reminder message that the suspension state of the magnetic bearing rotor is in an unstable state is released, and the magnetic bearing is controlled to maintain the operation of the control parameters of the magnetic bearing. Then, the process returns to determine whether the suspension state of the magnetic bearing rotor is in an unstable state again based on the displacement accuracy of the magnetic bearing rotor.

9. A control device for a magnetic levitation compressor, characterized in that, The magnetic levitation compressor has a magnetic bearing and a magnetic bearing rotor; the control device of the magnetic levitation compressor includes: The control unit is configured to control the operation of the magnetic levitation compressor after the magnetic levitation compressor is turned on; The acquisition unit is configured to acquire the displacement accuracy of the magnetic bearing rotor when the stability of the magnetic levitation compressor operation reaches a set stability level. The control unit is further configured to determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor; the unstable state refers to the state in which the levitation position of the magnetic bearing rotor deviates from the set reference position. The acquisition unit is further configured to acquire the operating parameter fluctuation value of the compressor when it is determined that the suspension state of the magnetic bearing rotor is in the unstable state; The control unit is further configured to determine, based on the fluctuation value of the compressor's operating parameters, whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor. The control unit is further configured to, when it is determined that the unstable state of the magnetic bearing rotor is caused by pressure fluctuations in the internal cavity of the magnetic levitation compressor, adjust the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and control the magnetic bearing to operate according to the new control parameters of the magnetic bearing.

10. The control device for the magnetic levitation compressor according to claim 9, characterized in that, in, The magnetic levitation compressor also has a frequency converter; the operating parameter fluctuation values ​​of the compressor include: the current fluctuation value of the frequency converter current of the compressor within a set detection time, and / or the discharge pressure fluctuation value of the compressor within a set detection time.

11. The control device for the magnetic levitation compressor according to claim 9 or 10, characterized in that, The control unit determines whether the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor, including: Determine whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold. If it is determined that the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold, then it is determined that the suspension state of the magnetic bearing rotor is in an unstable state, and an alert message indicating that the suspension state of the magnetic bearing rotor is in an unstable state is initiated. If the displacement accuracy of the magnetic bearing rotor is determined to be less than or equal to the set displacement accuracy threshold, then the suspension state of the magnetic bearing rotor is determined to be in a stable state, and the process returns to continue determining whether the displacement accuracy of the magnetic bearing rotor is greater than the set displacement accuracy threshold; the stable state refers to the state in which the suspension position of the magnetic bearing rotor has not deviated from the set reference position.

12. The control device for the magnetic levitation compressor according to claim 9 or 10, characterized in that, The control unit determines, based on the fluctuation values ​​of the compressor's operating parameters, whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations within the internal cavity of the magnetic levitation compressor, including: Determine whether the fluctuation value of the compressor's operating parameters is greater than the set threshold value for operating parameter fluctuation; If it is determined that the fluctuation value of the operating parameters of the compressor is greater than the set threshold value of the operating parameter fluctuation value, then it is determined that the levitation state of the magnetic bearing rotor is in the unstable state due to the pressure fluctuation of the internal cavity of the magnetic levitation compressor. If it is determined that the fluctuation value of the compressor's operating parameters is less than or equal to the set operating parameter fluctuation value threshold, then it is determined that the instability of the magnetic bearing rotor's suspension state is not caused by the pressure fluctuation inside the magnetic levitation compressor's cavity. The magnetic bearing is then controlled to maintain the operation of the magnetic bearing's control parameters and returned to continue determining whether the fluctuation value of the compressor's operating parameters is greater than the set operating parameter fluctuation value threshold.

13. The control device for the magnetic levitation compressor according to claim 11, characterized in that, The control unit determines, based on the fluctuation values ​​of the compressor's operating parameters, whether the unstable state of the magnetic bearing rotor's suspension is caused by pressure fluctuations within the internal cavity of the magnetic levitation compressor, including: Determine whether the fluctuation value of the compressor's operating parameters is greater than the set threshold value for operating parameter fluctuation; If it is determined that the fluctuation value of the operating parameters of the compressor is greater than the set threshold value of the operating parameter fluctuation value, then it is determined that the levitation state of the magnetic bearing rotor is in the unstable state due to the pressure fluctuation of the internal cavity of the magnetic levitation compressor. If it is determined that the fluctuation value of the compressor's operating parameters is less than or equal to the set operating parameter fluctuation value threshold, then it is determined that the instability of the magnetic bearing rotor's suspension state is not caused by the pressure fluctuation inside the magnetic levitation compressor's cavity. The magnetic bearing is then controlled to maintain the operation of the magnetic bearing's control parameters and returned to continue determining whether the fluctuation value of the compressor's operating parameters is greater than the set operating parameter fluctuation value threshold.

14. The control device for the magnetic levitation compressor according to any one of claims 9, 10, and 13, characterized in that, Also includes: The control unit is further configured to determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold after controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing. The control unit is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold, determine that the suspension state of the magnetic bearing rotor is still in an unstable state, return, and continue to adjust the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and continue to control the magnetic bearing to operate according to the new control parameters of the magnetic bearing. The control unit is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to a set displacement accuracy threshold, determine that the levitation state of the magnetic bearing rotor has returned to a stable state, remove the reminder message that the levitation state of the magnetic bearing rotor is in an unstable state, control the magnetic bearing to maintain the operation of the control parameters of the magnetic bearing, and return to re-determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor.

15. The control device for the magnetic levitation compressor according to claim 11, characterized in that, Also includes: The control unit is further configured to determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold after controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing. The control unit is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold, determine that the suspension state of the magnetic bearing rotor is still in an unstable state, return, and continue to adjust the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and continue to control the magnetic bearing to operate according to the new control parameters of the magnetic bearing. The control unit is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to a set displacement accuracy threshold, determine that the levitation state of the magnetic bearing rotor has returned to a stable state, remove the reminder message that the levitation state of the magnetic bearing rotor is in an unstable state, control the magnetic bearing to maintain the operation of the control parameters of the magnetic bearing, and return to re-determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor.

16. The control device for the magnetic levitation compressor according to claim 12, characterized in that, Also includes: The control unit is further configured to determine whether the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold after controlling the magnetic bearing to operate according to the new control parameters of the magnetic bearing. The control unit is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is greater than a set displacement accuracy threshold, determine that the suspension state of the magnetic bearing rotor is still in an unstable state, return, and continue to adjust the control parameters of the magnetic bearing to obtain new control parameters of the magnetic bearing; and continue to control the magnetic bearing to operate according to the new control parameters of the magnetic bearing. The control unit is further configured to, if it is determined that the displacement accuracy of the magnetic bearing rotor is less than or equal to a set displacement accuracy threshold, determine that the levitation state of the magnetic bearing rotor has returned to a stable state, remove the reminder message that the levitation state of the magnetic bearing rotor is in an unstable state, control the magnetic bearing to maintain the operation of the control parameters of the magnetic bearing, and return to re-determine whether the levitation state of the magnetic bearing rotor is in an unstable state based on the displacement accuracy of the magnetic bearing rotor.

17. A magnetic levitation compressor, characterized in that, include: The control device for the magnetic levitation compressor as described in any one of claims 9 to 16.

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