Control methods, devices, equipment, media, and procedures for magnetic levitation bearings.

Abstract

This invention discloses a control method, device, equipment, medium, and program product for a magnetic levitation bearing, relating to the field of magnetic levitation technology. The invention includes first acquiring the current levitation position of the rotor detected by a displacement sensor; then, when the target distance difference between the current levitation position and a set reference position meets the position change condition, acquiring the bearing coil current and the unit pressure difference determined by a pressure sensor. Based on the bearing coil current, unit pressure difference, and target distance difference, the reference position of the magnetic levitation bearing is iterated. Finally, when the distance difference between the iterated temporary reference position and the set reference position meets the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position. Thus, by modifying the rotor's levitation reference position, the current gain can be reduced, improving the rotor's operational stability and accuracy.

Description

Technical Field

[0001] This invention relates to the field of magnetic levitation technology, and in particular to control methods, devices, equipment, media, and program products for magnetic levitation bearings. Background Technology

[0002] In existing magnetic levitation control systems, the main objective is to maintain the rotor's levitation position at a set reference position. The control methods primarily employ displacement loops and current loops. The displacement loop mainly utilizes displacement signals collected by displacement sensors, which are then transmitted to the controller for calculations. The current loop, on the other hand, uses pulse width modulation (PWM) technology to control the current output, thereby meeting the requirements for stable rotor levitation.

[0003] However, under the impact force, the compressor's rotor suspension position shifts to a position far from the reference position. To stabilize the rotor suspension position back to the set reference position, the current output value of the displacement loop will be much greater than the current coil current, leading to overcurrent problems. Alternatively, increasing the output current using a current loop also requires a certain response time, which may cause rotor suspension instability or poor operating accuracy due to an excessively long response time. Summary of the Invention

[0004] This invention addresses the technical problems of rotor levitation position moving far from the set reference position due to impact force, resulting in large instantaneous current gain demand and untimely response, or easy overcurrent in bearing coils. It provides a control method, device, equipment, medium, and program product for magnetic levitation bearings that overcomes or at least partially solves these problems.

[0005] Based on a first aspect of the present invention, a control method for a magnetic levitation bearing is provided, the control method comprising:

[0006] Obtain the current levitation position of the rotor as detected by the displacement sensor;

[0007] When the target distance difference between the current suspension position and the set reference position meets the position change condition, the bearing coil current and the unit pressure difference determined by the pressure sensor are obtained, wherein the unit pressure difference refers to the pressure difference between the exhaust pressure value and the intake pressure value of the compressor unit.

[0008] Based on the bearing coil current, unit pressure difference, and target distance difference, the reference position of the magnetic levitation bearing is iterated. The temporary reference position after iteration is located between the rotor suspension position and the set reference position, and gradually approaches the set reference position.

[0009] If the distance difference between the temporary reference position and the set reference position satisfies the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position.

[0010] Based on a second aspect of the present invention, a control device for a magnetic levitation bearing is also provided, the control device comprising:

[0011] The position acquisition module is used to acquire the current suspension position of the rotor detected by the displacement sensor;

[0012] The data acquisition module is used to acquire the bearing coil current and the unit pressure difference determined by the pressure sensor when the target distance difference between the current suspension position and the set reference position meets the position change condition. The unit pressure difference refers to the pressure difference between the exhaust pressure value and the intake pressure value of the compressor unit.

[0013] The position iteration module is used to iterate the reference position of the magnetic levitation bearing based on the bearing coil current, unit pressure difference and target distance difference. The iterated temporary reference position is located between the rotor suspension position and the set reference position, and gradually moves closer to the set reference position.

[0014] The position reset module is used to end the reference position iteration process and update the temporary reference position to the set reference position when the distance difference between the temporary reference position and the set reference position meets the position recovery condition.

[0015] An optional aspect of the invention, wherein the iterative calculation of the reference position of the magnetic levitation bearing based on the bearing coil current, the unit pressure difference, and the target distance difference includes:

[0016] Calculate the pressure difference ratio between the unit pressure difference and the preset maximum pressure difference;

[0017] The reference position of the magnetic levitation bearing is iterated based on the pressure difference ratio, bearing coil current, and target distance difference.

[0018] An optional aspect of the invention, wherein the iterative calculation of the reference position of the magnetic levitation bearing based on the differential pressure ratio, the bearing coil current, and the target distance difference includes:

[0019] Based on the ratio of bearing coil current to voltage difference, the distance weighting coefficient is determined;

[0020] The reference position of the magnetic levitation bearing is iterated based on the distance weighting coefficient and the target distance difference.

[0021] An optional aspect of the invention, wherein determining the distance weighting coefficient based on the ratio of the bearing coil current to the voltage difference includes:

[0022] When the bearing coil current reaches the coil saturation current, if the differential pressure ratio is between the first ratio and the second ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the second ratio is less than the first ratio.

[0023] If the pressure difference ratio is greater than the first ratio, the first ratio will be used as the distance weighting coefficient;

[0024] If the pressure difference ratio is less than the second ratio, the second ratio is used as the distance weighting coefficient.

[0025] An optional aspect of the invention, wherein determining the distance weighting coefficient based on the ratio of the bearing coil current to the voltage difference includes:

[0026] When the bearing coil current is greater than or equal to the first current value and less than the coil saturation current, if the differential pressure ratio is between the third ratio and the second ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the third ratio is less than the second ratio.

[0027] If the pressure difference ratio is greater than the second ratio, the second ratio will be used as the distance weighting coefficient;

[0028] If the pressure difference ratio is less than the third ratio, the third ratio is used as the distance weighting coefficient.

[0029] An optional aspect of the invention, wherein determining the distance weighting coefficient based on the ratio of the bearing coil current to the voltage difference includes:

[0030] If the bearing coil current is less than the first current value, and the differential pressure ratio is between the fourth ratio and the third ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the fourth ratio is less than the third ratio.

[0031] An optional aspect of the invention, wherein the iterative calculation of the reference position of the magnetic levitation bearing based on the distance weighting coefficient and the target distance difference includes:

[0032] The product of the distance weighting coefficient and the target distance difference is calculated to obtain the iterative distance interval, wherein the iterative distance interval refers to the distance interval between the temporary reference position and the set reference position;

[0033] Based on the iterative distance interval, determine the temporary reference position after the first update;

[0034] If the current suspension position of the rotor is detected to have reached the temporary reference position after the first update, and it is determined that the distance difference between the temporary reference position and the set reference position does not meet the position recovery condition, the iterative distance interval is updated based on the updated bearing coil current, unit pressure difference and target distance difference.

[0035] Based on the updated iterative distance interval, determine the temporary reference position after the second update.

[0036] In one optional embodiment, the method further includes:

[0037] If the current suspension position of the rotor is detected to have reached the temporary reference position after the second update, and it is determined that the distance difference between the temporary reference position and the set reference position does not meet the position recovery condition, the iterative distance interval is updated based on the updated bearing coil current, unit pressure difference and target distance difference.

[0038] Based on the updated iterative distance interval, the temporary reference position after the third update is determined.

[0039] Based on a third aspect of the present invention, an electronic device is also provided, the device comprising:

[0040] One or more processors;

[0041] Memory;

[0042] One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs being configured to perform any of the methods described in the foregoing invention.

[0043] Based on a fourth aspect of the invention, a computer-readable storage medium is also provided for storing a computer program for use in conjunction with an electronic device, the computer program being executable by a processor to perform any of the methods described in the invention.

[0044] Based on a fifth aspect of the present invention, a computer program product is also provided, comprising a computer program / computer executable instructions, wherein the computer program / computer executable instructions, when executed by a processor in an electronic device, implement the method described in any one of the above-described inventions.

[0045] Compared with existing technologies, this invention first acquires the current suspension position of the rotor detected by a displacement sensor. Then, when the target distance difference between the current suspension position and a set reference position meets the position change condition, it acquires the bearing coil current and the unit pressure difference determined by a pressure sensor, where the unit pressure difference refers to the pressure difference between the exhaust pressure and intake pressure of the compressor unit. Based on the bearing coil current, unit pressure difference, and target distance difference, the reference position of the magnetic levitation bearing is iterated. The iterated temporary reference position is located between the rotor suspension position and the set reference position, gradually approaching the set reference position. Finally, when the distance difference between the temporary reference position and the set reference position meets the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position. This allows for modification of the rotor's suspension reference position to reduce current gain, avoid overcurrent problems in the bearing coil current, and improve the rotor's operational stability and accuracy.

[0046] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0047] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0048] In the attached diagram:

[0049] Figure 1 This is a flowchart illustrating the steps of a control method for a magnetic levitation bearing provided in an embodiment of the present invention;

[0050] Figure 2 This is a flowchart illustrating the steps of another magnetic levitation bearing control method provided in an embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of a rotor suspended at a set reference position according to an embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of a rotor undergoing positional displacement due to an impact, provided by an embodiment of the present invention;

[0053] Figure 5This is a schematic diagram of a structure for controlling the rotor to suspend at a temporary reference position after the first update, provided by an embodiment of the present invention;

[0054] Figure 6 This is a schematic diagram of a structure provided by an embodiment of the present invention, in which a temporary reference position gradually approaches a set reference position after multiple updates;

[0055] Figure 7 This is a schematic diagram of the structure of a control device for a magnetic levitation bearing provided in an embodiment of the present invention. Detailed Implementation

[0056] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0057] In existing magnetic levitation control systems, the main purpose of the control system is to control the rotor's levitation position at a set reference position. Figure 3 As shown, the control method mainly employs a displacement loop and a current loop. The displacement loop is primarily implemented by transmitting displacement signals collected by displacement sensors to the controller for computation, while the current loop uses pulse width modulation (PWM) technology to control the current output to meet the requirements for stable rotor levitation.

[0058] However, under the impact force, the compressor's rotor suspension position shifted to a location relatively far from the reference position. Figure 4 As shown, to stabilize the rotor's levitation position at the set reference position, the current output value of the displacement loop will be much greater than the current coil current, leading to overcurrent problems. Alternatively, increasing the output current using a current loop will also require a certain response time, which may cause rotor levitation instability or poor operating accuracy due to excessively long response time.

[0059] To address the aforementioned technical problems, this invention proposes an embodiment. This embodiment may include first acquiring the current suspension position of the rotor detected by a displacement sensor; then, if the target distance difference between the current suspension position and a set reference position satisfies the position change condition, acquiring the bearing coil current and the unit pressure difference determined by a pressure sensor, where the unit pressure difference refers to the pressure difference between the exhaust pressure and intake pressure of the compressor unit. Based on the bearing coil current, unit pressure difference, and target distance difference, the reference position of the magnetic levitation bearing is iterated. The iterated temporary reference position is located between the rotor suspension position and the set reference position, gradually approaching the set reference position. Finally, if the distance difference between the temporary reference position and the set reference position satisfies the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position. This allows for modification of the rotor's suspension reference position to reduce current gain, avoid overcurrent problems in the bearing coil current, and improve the rotor's operational stability and accuracy.

[0060] Reference Figure 1 This invention illustrates a control method for a magnetic levitation bearing, applied in a controller. The method may include:

[0061] S101. Obtain the current suspension position of the rotor detected by the displacement sensor.

[0062] S102, if the target distance difference between the current suspension position and the set reference position meets the position change condition, obtain the bearing coil current and the unit pressure difference determined by the pressure sensor.

[0063] In this embodiment of the invention, the current suspension position of the rotor can be detected by a displacement sensor, and the sensing signal related to the current suspension position is transmitted to the controller. After receiving the current suspension position of the rotor, the controller calculates the target distance difference between the current suspension position and a set reference position. The target distance difference can be represented in units of 1 μm (micrometers). The position change condition is used to determine whether the current suspension position of the rotor is too far from the set reference position. If it is determined that the current suspension position of the rotor is too far from the set reference position, it may cause a large instantaneous current gain demand, resulting in a slow response, or it may easily cause overcurrent in the bearing coil.

[0064] In some optional implementations, the position change condition may be a target distance difference greater than or equal to a first distance threshold. For example, the first distance threshold may be 50 units. Thus, when it is determined that the target distance difference satisfies the position change condition, the bearing coil current and the unit pressure difference determined by the pressure sensor can be obtained. The current bearing coil current may be the control current of the controller's last output, and the unit pressure difference refers to the pressure difference between the compressor unit's discharge pressure and suction pressure. Therefore, the pressure sensor may include a suction pressure sensor and a discharge pressure sensor. The suction pressure sensor is installed at the compressor unit's suction port to detect the compressor unit's suction pressure, and the discharge pressure sensor is installed at the compressor unit's discharge port to detect the compressor unit's discharge pressure. Thus, the unit pressure difference can be obtained by subtracting the suction pressure from the discharge pressure.

[0065] In some implementations, the first distance threshold can be determined based on the actual operating results of the compressor unit. For example, a first distance threshold can be preset, and during the operation of the compressor unit, the current suspension position of the rotor can be detected by a displacement sensor. If the target distance difference between the current suspension position and the set reference position is less than the first distance threshold, and an operational abnormality occurs due to large current gain and untimely response, the first distance threshold is updated to make the updated first distance threshold smaller. This can be repeated to ensure that when the target distance difference between the current suspension position and the set reference position is less than the first distance threshold, operational abnormalities due to large current gain and untimely response will not occur.

[0066] S103. Based on the bearing coil current, unit pressure difference and target distance difference, the reference position of the magnetic levitation bearing is iterated. The temporary reference position after iteration is located between the rotor suspension position and the set reference position, and gradually approaches the set reference position.

[0067] In this embodiment of the invention, the set reference position refers to a state where the attractive force generated by the bearing coil current on the rotor is balanced with the rotor's own gravity, resulting in a suspended equilibrium position for the rotor. Excessive pressure differential in the unit may affect the flow rate of the compressor unit, causing surge in the compressor and resulting in vibration. This vibration exerts an impact force on the rotor of the magnetic levitation bearing, causing the rotor's current suspension position to be far from the set reference position. Therefore, the reference position of the magnetic levitation bearing can be iteratively adjusted based on the bearing coil current, the unit pressure differential, and the target distance difference. This iteration can be understood as repeatedly updating the temporary reference position of the rotor suspension between the current suspension position and the set reference position. Furthermore, each time the rotor moves to the iterated temporary reference position, the next iteration is performed. The distance interval between the temporary reference positions obtained from two adjacent iterations can be determined based on a comprehensive analysis of the bearing coil current, the unit pressure differential, and the target distance difference.

[0068] The temporary reference position obtained in the current iteration becomes the rotor's levitation position in the next iteration. This ensures that the temporary reference position obtained in the current iteration is closer to the predetermined reference position than the temporary reference position obtained in the previous iteration.

[0069] By using a temporary reference position, it can be assumed that the displacement between the rotor's current suspension position and the temporary reference position that needs to be controlled for recovery is small. Therefore, the controller can output a smaller bearing coil current to meet the current position offset recovery requirements. This avoids the potential for large instantaneous current gain demands and delayed response, or bearing coil overcurrent problems, when the rotor's current suspension position is too far from the set reference position. It also improves the rotor's operational stability and accuracy.

[0070] S104. If the distance difference between the temporary reference position and the set reference position satisfies the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position.

[0071] In this embodiment of the invention, the position recovery condition refers to determining whether the temporary reference position of the rotor (which can also be understood as the current suspension position of the rotor after multiple control operations) is too close to the set reference position. During each iteration, the distance difference between the temporary reference position and the set reference position is determined. If it is determined that the distance is too close to the set reference position, the control gain required for the rotor to directly adjust to the set reference position is small, and no overcurrent problem will occur, thereby ending the reference position iteration process. For example, the position recovery condition may include: the distance difference between the temporary reference position and the set reference position is less than or equal to a second distance threshold. For example, the second distance threshold may include 10 units, 15 units, etc. This can end the iteration and update the current temporary reference position to the set reference position. This avoids problems such as a large gap between the rotor's suspension position after an impact and the set suspension position, leading to untimely response, rotor suspension instability, or poor operating accuracy.

[0072] Reference Figure 2 This invention illustrates another control method for a magnetic levitation bearing provided by an embodiment of the present invention, the method comprising:

[0073] S201. Obtain the current suspension position of the rotor detected by the displacement sensor.

[0074] S202, if the target distance difference between the current suspension position and the set reference position meets the position change condition, obtain the bearing coil current and the unit pressure difference determined by the pressure sensor.

[0075] In this embodiment of the invention, the description of steps S201-S202 refers to the description of steps S101-S102 described above.

[0076] S203. Calculate the pressure difference ratio between the unit pressure difference and the preset maximum pressure difference.

[0077] S204. Based on the pressure difference ratio, bearing coil current, and target distance difference, iterate the reference position of the magnetic levitation bearing.

[0078] Based on the bearing coil current, unit pressure difference, and target distance difference, the present invention iterates the reference position of the magnetic levitation bearing. The temporary reference position after iteration is located between the rotor suspension position and the set reference position, and gradually approaches the set reference position.

[0079] In this embodiment of the invention, the preset maximum pressure difference refers to the maximum pressure difference between the discharge pressure and suction pressure of the compressor during stable operation of the compressor unit. The unit pressure difference can also be understood as the real-time pressure difference of the compressor unit. Therefore, the pressure difference situation of the compressor currently in operation can be characterized by the ratio of the unit pressure difference to the preset maximum pressure difference. A larger pressure difference ratio indicates a larger unit pressure difference for the compressor, which may lead to frequent surge phenomena during operation, causing vibration. This generates a large impact force on the rotor of the magnetic levitation bearing, causing it to deviate from the set reference position. Furthermore, the magnitude of the bearing coil current determines the current gain that the controller can output when responding promptly, and also determines the distance the controller needs to restore the rotor's reference position in a single operation.

[0080] The reference position of the magnetic levitation bearing can be iteratively determined based on the bearing coil current, unit pressure difference, and target distance difference. Iteration can be understood as repeatedly updating the temporary reference position of the rotor suspension between the current rotor suspension position and the set reference position. Furthermore, each time the rotor moves to the iterated temporary reference position, the next iteration is performed. The distance interval between the temporary reference positions obtained from two adjacent iterations can be determined based on a comprehensive analysis of the bearing coil current, unit pressure difference, and target distance difference.

[0081] The temporary reference position obtained in the current iteration becomes the rotor's levitation position in the next iteration. This ensures that the temporary reference position obtained in the current iteration is closer to the predetermined reference position than the temporary reference position obtained in the previous iteration. For example, in the first iteration, a temporary reference position A is determined, and the controller outputs a control current to suspend the rotor's current levitation position at temporary reference position A. In the second iteration, temporary reference position A is used as the rotor's current levitation position, and a further temporary reference position B is determined. Temporary reference position B is located between temporary reference position A and the predetermined reference position. Thus, through multiple adjustments by the controller, the rotor gradually approaches the predetermined reference position.

[0082] By using a temporary reference position, it can be assumed that the displacement between the rotor's current suspension position and the temporary reference position that needs to be controlled for recovery is small. Therefore, the controller can output a smaller bearing coil current to meet the current position offset recovery requirements. This avoids the potential for large instantaneous current gain demands and delayed response, or bearing coil overcurrent problems, when the rotor's current suspension position is too far from the set reference position. It also improves the rotor's operational stability and accuracy.

[0083] In one optional embodiment of the invention, the iterative process of determining the reference position of the magnetic levitation bearing based on the pressure difference ratio, the bearing coil current, and the target distance difference includes:

[0084] Based on the bearing coil current, the distance weighting coefficient associated with the differential pressure ratio is determined.

[0085] The reference position of the magnetic levitation bearing is iterated based on the distance weighting coefficient and the target distance difference.

[0086] In this embodiment of the invention, the distance weighting coefficient refers to the coefficient referenced in each iteration of the magnetic levitation bearing's reference position, used to determine the iteration distance interval for each iteration. It can be determined comprehensively by the bearing coil current and the voltage difference ratio. The voltage difference ratio is positively correlated to a certain extent with the degree of rotor levitation position deviation; that is, the larger the voltage difference ratio, the greater the potential impact force on the rotor, thus causing the rotor levitation position to deviate further from the set reference position. The coil current corresponding to when the voltage influence of the bearing coil begins to show significant changes or saturation can be called the coil saturation current of the bearing coil. If the current in the bearing coil has reached the coil saturation current, and if the iteration distance interval is too large, the controller needs to output a higher control gain, i.e., a larger control current, which may cause overcurrent problems in the bearing coil, reducing the operational stability of the magnetic levitation bearing.

[0087] Therefore, under different operating conditions of the compressor unit, different iterative distance intervals can be selected based on the distance weighting coefficient and the target distance difference, so as to improve the response rate and operational stability of the position control of the magnetic levitation bearing.

[0088] In some implementations, if the differential pressure ratio is between a first ratio and a second ratio when the bearing coil current reaches the coil saturation current, directly restoring the magnetic bearing's levitation position to the set reference position would result in a current output value much greater than the coil saturation current, leading to coil overcurrent. Therefore, by setting a larger iteration distance interval—that is, a larger distance interval between the temporary reference position and the set reference position—the distance between the temporary reference position and the rotor's current levitation position is smaller. This allows the rotor to be stably levitated to the temporary reference position with less current gain and a shorter response time. This improves the rotor's levitation stability and response rate. For example, the first ratio could be 0.8, and the second ratio could be 0.6, etc.

[0089] If the pressure difference ratio is between the first ratio and the second ratio (inclusive), the pressure difference ratio can be directly used as the distance weighting coefficient. If the pressure difference ratio is greater than the first ratio, it is determined that the current unit pressure difference is large, which may lead to an excessive offset of the rotor's current suspension position relative to the rotor's set reference position. In this case, the first ratio is selected directly as the distance weighting coefficient. The first ratio can also be considered as the upper limit of the distance weighting coefficient, thus the maximum iteration distance interval can be obtained by multiplying the distance weighting coefficient and the target distance difference. (Refer to...) Figure 5 As shown, since the iteration distance interval refers to the distance interval between the temporary reference position and the set reference position, the temporary reference position after the first update can be obtained by adding the iteration distance interval to the set reference position. This results in a small distance gap between the temporary reference position after the first update and the current suspension position of the rotor, which facilitates the controller to output a smaller current gain and control the rotor's current suspension position to quickly adjust to the temporary reference position after the first update.

[0090] In other embodiments, when the bearing coil current is greater than or equal to a first current value and less than the coil saturation current, if the differential pressure ratio is between the third and second ratios (inclusive), it is determined that the offset of the rotor's current suspension position will not be excessive when the compressor unit operates according to the current unit differential pressure. Therefore, the differential pressure ratio is used as a distance weighting coefficient, and the iterative distance interval is obtained by calculating the product of the distance weighting coefficient and the target distance difference. In this case, it can be determined that when the current bearing coil carries a certain current gain, reducing the iterative distance interval will not cause overcurrent in the bearing coil. Therefore, when reducing the iterative distance interval, the temporary reference position after the first update is closer to the set reference position. This reduces the number of updates to the temporary reference position, allowing the rotor's current suspension position to be quickly reset to the set reference position.

[0091] If the second ratio is greater than the third ratio, and the differential pressure ratio is greater than the second ratio, it is determined that the current unit differential pressure is too large, which may cause a large offset in the current suspension position of the rotor during actual operation. In this case, the second ratio is used as the distance weighting coefficient, and the iterative distance interval is obtained by calculating the product of the distance weighting coefficient and the target distance difference. The second ratio can be considered as the upper limit of the associated distance weighting coefficient when the bearing coil current is greater than or equal to the first current value and less than the coil saturation current. This appropriately increases the iterative distance interval, reducing the number of temporary reference position updates while ensuring that the rotor does not lose suspension stability and that the output current does not cause coil overcurrent.

[0092] If the differential pressure ratio is less than the third ratio, it is determined that the current unit differential pressure is moderate, and the offset of the rotor's current suspension position during actual operation will not be too large. Therefore, the third ratio is used as the distance weighting coefficient, and the iterative distance interval is obtained by calculating the product of the distance weighting coefficient and the target distance difference. The third ratio can be considered as the lower limit of the associated distance weighting coefficient when the bearing coil current is greater than or equal to the first current value and less than the coil saturation current. This reduces the number of temporary reference position updates by narrowing the iterative distance interval, ensuring that the output current does not cause coil overcurrent. For example, the third ratio could be 0.4.

[0093] In some alternative embodiments, if the bearing coil current is less than the first current value, and the differential pressure ratio is between the fourth and third ratios, it is determined that the rotor's displacement due to the impact force is typically small under the current differential pressure ratio operating condition. Furthermore, the bearing coil current is small. Therefore, by reducing the iteration distance interval—that is, by reducing the distance interval between the temporary reference position and the set reference position—the distance interval between the temporary reference position and the rotor's current suspension position becomes larger. This allows for a greater current gain and a shorter response time, reducing the number of temporary reference position updates and controlling the rotor's current suspension position to reset to the set reference position. For example, the fourth ratio is less than the third ratio, and the fourth ratio can be a value such as 0.2.

[0094] If the differential pressure ratio is greater than the third ratio, it is determined that the current unit differential pressure is too large, which may cause a large offset in the rotor's current suspension position during actual operation. In this case, the second ratio is used as the distance weighting coefficient, and the iterative distance interval is obtained by calculating the product of the distance weighting coefficient and the target distance difference. The second ratio can be considered as the upper limit of the associated distance weighting coefficient when the bearing coil current is less than the first current value, thereby appropriately increasing the iterative distance interval. This reduces the number of temporary reference position updates while ensuring that the rotor does not lose suspension stability and that the output current does not cause coil overcurrent.

[0095] If the pressure difference ratio is less than the fourth ratio, it is determined that the current unit pressure difference is small, and the offset of the rotor's current suspension position during actual operation is usually small. Therefore, the fourth ratio is used as the distance weighting coefficient, and the iterative distance interval is obtained by calculating the product of the distance weighting coefficient and the target distance difference. The fourth ratio can be considered as the lower limit of the associated distance weighting coefficient when the bearing coil current is less than the first current value. By reducing the iterative distance interval, the temporary reference position after the first update is made closer to the set reference position while ensuring that the output current does not cause coil overcurrent, thereby reducing the number of updates to the temporary reference position.

[0096] In this embodiment of the invention, the first ratio, the second ratio, the third ratio, and the fourth ratio can be determined based on actual test results. No further limitations are imposed here. Furthermore, the first current value can be half, one-third, or equivalent to the coil saturation current; no further limitations are imposed here.

[0097] If the position sensor detects that the current suspension position of the rotor has reached the temporary reference position after the first update, it is determined whether the distance difference between the temporary reference position and the set reference position value satisfies the position recovery condition. If the position recovery condition is satisfied, step S205 is executed. If the position recovery condition is not satisfied, the above method steps are repeated, that is, the iterative distance interval is updated based on the updated bearing coil current, unit differential pressure, and target distance difference, and the temporary reference position after the second update is determined based on the updated iterative distance interval.

[0098] If the position sensor detects that the rotor's current suspension position has reached the temporary reference position updated after the second time, it is determined whether the distance difference between the temporary reference position and the set reference position value satisfies the position recovery condition. If the position recovery condition is met, step S205 is executed. If the position recovery condition is not met, the above method steps are repeated, that is, the iterative distance interval is updated based on the updated bearing coil current, unit pressure difference, and target distance difference, and the temporary reference position updated after the third time is determined based on the updated iterative distance interval. This process continues until the target reference position is reached. Figure 6 As shown, after updating the temporary reference position multiple times, the rotor can be driven to levitate to the set reference position with a small current gain.

[0099] S205. If the distance difference between the temporary reference position and the set reference position satisfies the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position.

[0100] In this embodiment of the invention, the position recovery condition refers to determining whether the temporary reference position of the rotor (which can also be understood as the current suspension position of the rotor after multiple control operations) is too close to the set reference position. During each iteration, the distance difference between the temporary reference position and the set reference position is determined. If it is determined that the distance is too close to the set reference position, the control gain required for the rotor to directly adjust to the set reference position is small, and no overcurrent problem will occur, thereby ending the reference position iteration process. For example, the position recovery condition may include: the distance difference between the temporary reference position and the set reference position is less than or equal to a second distance threshold. For example, the second distance threshold may include 10 units, 15 units, etc. This can end the iteration and update the current temporary reference position to the set reference position. This avoids problems such as a large gap between the rotor's suspension position after an impact and the set suspension position, leading to untimely response, rotor suspension instability, or poor operating accuracy.

[0101] In summary, this invention discloses a control method for a magnetic levitation bearing. The method includes first acquiring the current levitation position of the rotor detected by a displacement sensor. Then, if the target distance difference between the current levitation position and a set reference position satisfies a position change condition, acquiring the bearing coil current and the unit pressure difference determined by a pressure sensor, where the unit pressure difference refers to the pressure difference between the exhaust pressure and intake pressure of the compressor unit. Based on the bearing coil current, unit pressure difference, and target distance difference, the reference position of the magnetic levitation bearing is iterated. The iterated temporary reference position is located between the rotor levitation position and the set reference position, gradually approaching the set reference position. Finally, if the distance difference between the temporary reference position and the set reference position satisfies a position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position. This allows for the reduction of current gain by modifying the rotor's levitation reference position, avoiding overcurrent problems in the bearing coil current, and improving the rotor's operational stability and accuracy.

[0102] It should be noted that, for the sake of simplicity, the method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments of this application are not limited to the described order of actions, because according to the embodiments of this application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of this application.

[0103] Reference Figure 7 The present invention illustrates a control device for a magnetic levitation bearing provided in an embodiment of the invention. The device may include:

[0104] The position acquisition module 701 is used to acquire the current suspension position of the rotor detected by the displacement sensor.

[0105] The data acquisition module 702 is used to acquire the bearing coil current and the unit pressure difference determined by the pressure sensor when the target distance difference between the current suspension position and the set reference position meets the position change condition. The unit pressure difference refers to the pressure difference between the exhaust pressure value and the intake pressure value of the compressor unit.

[0106] The position iteration module 703 is used to iterate the reference position of the magnetic levitation bearing based on the bearing coil current, the unit pressure difference and the target distance difference. The iterated temporary reference position is located between the rotor suspension position and the set reference position, and gradually approaches the set reference position.

[0107] The position reset module 704 is used to end the reference position iteration process and update the temporary reference position to the set reference position when the distance difference between the temporary reference position and the set reference position meets the position recovery condition.

[0108] In an optional embodiment of the invention, the position iteration module 703 includes:

[0109] The differential pressure ratio calculation submodule is used to calculate the differential pressure ratio between the unit's differential pressure and the preset maximum differential pressure.

[0110] The position iteration submodule is used to iterate the reference position of the magnetic levitation bearing based on the pressure difference ratio, the bearing coil current, and the target distance difference.

[0111] In an optional embodiment of the invention, the position iteration submodule may include:

[0112] The coefficient determination unit is used to determine the distance weighting coefficient based on the ratio of the bearing coil current to the voltage difference.

[0113] The position iteration unit is used to iterate the reference position of the magnetic levitation bearing based on the distance weighting coefficient and the target distance difference.

[0114] In an optional embodiment of the invention, the coefficient determining unit is further configured to:

[0115] When the bearing coil current reaches the coil saturation current, if the differential pressure ratio is between the first ratio and the second ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the second ratio is less than the first ratio.

[0116] If the pressure difference ratio is greater than the first ratio, the first ratio is used as the distance weighting coefficient.

[0117] If the pressure difference ratio is less than the second ratio, the second ratio is used as the distance weighting coefficient.

[0118] In an optional embodiment of the invention, the coefficient determining unit is further configured to:

[0119] When the bearing coil current is greater than or equal to the first current value and less than the coil saturation current, if the differential pressure ratio is between the third ratio and the second ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the third ratio is less than the second ratio.

[0120] If the pressure difference ratio is greater than the second ratio, the second ratio is used as the distance weighting coefficient.

[0121] If the pressure difference ratio is less than the third ratio, the third ratio is used as the distance weighting coefficient.

[0122] In an optional embodiment of the invention, the coefficient determining unit is further configured to:

[0123] If the bearing coil current is less than the first current value, and the differential pressure ratio is between the fourth ratio and the third ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the fourth ratio is less than the third ratio.

[0124] In an optional embodiment of the invention, the position iteration unit is further configured to:

[0125] The product of the distance weighting coefficient and the target distance difference is calculated to obtain the iterative distance interval.

[0126] Based on the iterative distance interval, determine the temporary reference position after the first update.

[0127] If the current suspension position of the rotor is detected to have reached the temporary reference position after the first update, and it is determined that the distance difference between the temporary reference position and the set reference position does not meet the position recovery condition, the iterative distance interval is updated based on the updated bearing coil current, unit pressure difference and target distance difference.

[0128] Based on the updated iterative distance interval, determine the temporary reference position after the second update.

[0129] In an optional embodiment of the invention, the position iteration unit is further configured to:

[0130] If the current suspension position of the rotor is detected to have reached the temporary reference position after the second update, and it is determined that the distance difference between the temporary reference position and the set reference position does not meet the position recovery condition, the iterative distance interval is updated based on the updated bearing coil current, unit differential pressure and target distance difference.

[0131] Based on the updated iterative distance interval, the temporary reference position after the third update is determined.

[0132] In summary, this invention discloses a control device for a magnetic levitation bearing. The control device may first acquire the current levitation position of the rotor detected by a displacement sensor. Then, when the target distance difference between the current levitation position and a set reference position meets the position change condition, it acquires the bearing coil current and the unit pressure difference determined by a pressure sensor, where the unit pressure difference refers to the pressure difference between the exhaust pressure and intake pressure of the compressor unit. Based on the bearing coil current, unit pressure difference, and target distance difference, the reference position of the magnetic levitation bearing is iterated. The iterated temporary reference position is located between the rotor levitation position and the set reference position, gradually approaching the set reference position. Finally, when the distance difference between the temporary reference position and the set reference position meets the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position. Therefore, by modifying the rotor's levitation reference position, the current gain can be reduced, avoiding overcurrent problems in the bearing coil current, and improving the rotor's operational stability and accuracy.

[0133] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0134] It will be readily apparent to those skilled in the art that any combination of the above embodiments is feasible, and therefore any combination of the above embodiments is an implementation scheme of the present invention. However, due to space limitations, this specification will not describe them in detail here.

[0135] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0136] Similarly, it should be understood that, in order to simplify the invention and aid in understanding one or more of the various inventive aspects, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all features of the single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0137] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0138] An electronic device, comprising:

[0139] One or more processors;

[0140] Memory;

[0141] One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs being configured to perform the methods described in the above embodiments.

[0142] A computer-readable storage medium stores a computer program for use in conjunction with an electronic device, the computer program being executable by a processor to perform the methods described in the embodiments above.

[0143] A computer program product includes a computer program / computer executable instructions, which, when executed by a processor in an electronic device, implement the method described in any of the above embodiments of the invention.

[0144] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, embodiments of the present invention can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of the present invention can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0145] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0146] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0147] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal equipment, causing a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0148] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0149] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0150] The control method and control device for a magnetic levitation bearing provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A control method for a magnetic levitation bearing, characterized in that, The method includes: Obtain the current levitation position of the rotor as detected by the displacement sensor; When the target distance difference between the current suspension position and the set reference position meets the position change condition, the bearing coil current and the unit pressure difference determined by the pressure sensor are obtained, wherein the unit pressure difference refers to the pressure difference between the exhaust pressure value and the intake pressure value of the compressor unit. Calculate the pressure difference ratio between the unit pressure difference and the preset maximum pressure difference; Based on the ratio of bearing coil current to voltage difference, the distance weighting coefficient is determined; The product of the distance weighting coefficient and the target distance difference is calculated to obtain the iterative distance interval, wherein the iterative distance interval refers to the distance interval between the temporary reference position and the set reference position; Based on the iterative distance interval, determine the temporary reference position after the first update; If the current suspension position of the rotor is detected to have reached the temporary reference position after the first update, and it is determined that the distance difference between the temporary reference position and the set reference position does not meet the position recovery condition, the iterative distance interval is updated based on the updated bearing coil current, unit pressure difference and target distance difference. Based on the updated iteration distance interval, the temporary reference position after the second update is determined. The iterative temporary reference position is located between the rotor suspension position and the set reference position, and gradually approaches the set reference position. If the distance difference between the temporary reference position and the set reference position satisfies the position recovery condition, the iteration process of the reference position ends, and the temporary reference position is updated to the set reference position.

2. The control method for a magnetic levitation bearing according to claim 1, characterized in that, The distance weighting coefficient is determined based on the ratio of the bearing coil current to the voltage difference, including: When the bearing coil current reaches the coil saturation current, if the differential pressure ratio is between the first ratio and the second ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the second ratio is less than the first ratio. If the pressure difference ratio is greater than the first ratio, the first ratio will be used as the distance weighting coefficient; If the pressure difference ratio is less than the second ratio, the second ratio is used as the distance weighting coefficient.

3. The control method for a magnetic levitation bearing according to claim 1, characterized in that, The distance weighting coefficient is determined based on the ratio of the bearing coil current to the voltage difference, including: When the bearing coil current is greater than or equal to the first current value and less than the coil saturation current, if the differential pressure ratio is between the third ratio and the second ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the third ratio is less than the second ratio. If the pressure difference ratio is greater than the second ratio, the second ratio will be used as the distance weighting coefficient; If the pressure difference ratio is less than the third ratio, the third ratio is used as the distance weighting coefficient.

4. The control method for a magnetic levitation bearing according to claim 1, characterized in that, The distance weighting coefficient is determined based on the ratio of the bearing coil current to the voltage difference, including: If the bearing coil current is less than the first current value, and the differential pressure ratio is between the fourth ratio and the third ratio, the differential pressure ratio is used as the distance weighting coefficient, wherein the fourth ratio is less than the third ratio.

5. The control method for a magnetic levitation bearing according to claim 1, characterized in that, The method further includes: If the current suspension position of the rotor is detected to have reached the temporary reference position after the second update, and it is determined that the distance difference between the temporary reference position and the set reference position does not meet the position recovery condition, the iterative distance interval is updated based on the updated bearing coil current, unit pressure difference and target distance difference. Based on the updated iterative distance interval, the temporary reference position after the third update is determined.

6. A control device for a magnetic levitation bearing, characterized in that, The device includes: The position acquisition module is used to acquire the current suspension position of the rotor detected by the displacement sensor; The data acquisition module is used to acquire the bearing coil current and the unit pressure difference determined by the pressure sensor when the target distance difference between the current suspension position and the set reference position meets the position change condition. The unit pressure difference refers to the pressure difference between the exhaust pressure value and the intake pressure value of the compressor unit. The position iteration module is used to calculate the pressure difference ratio between the unit pressure difference and the preset maximum pressure difference; determine the distance weighting coefficient based on the bearing coil current and the pressure difference ratio; calculate the product of the distance weighting coefficient and the target distance difference to obtain the iteration distance interval, wherein the iteration distance interval refers to the distance interval between the temporary reference position and the set reference position; determine the temporary reference position after the first update based on the iteration distance interval; if it is detected that the current suspension position of the rotor has reached the temporary reference position after the first update, and it is determined that the distance difference between the temporary reference position and the set reference position does not meet the position recovery condition, update the iteration distance interval based on the updated bearing coil current, unit pressure difference, and target distance difference; determine the temporary reference position after the second update based on the updated iteration distance interval, wherein the iterated temporary reference position is located between the rotor suspension position and the set reference position, and gradually approaches the set reference position; The position reset module is used to end the reference position iteration process and update the temporary reference position to the set reference position when the distance difference between the temporary reference position and the set reference position meets the position recovery condition.

7. An electronic device, characterized in that, include: One or more processors; Memory; One or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs being configured to perform the method of any one of claims 1-5.

8. A computer-readable storage medium for storing a computer program used in conjunction with an electronic device, characterized in that, The computer program can be executed by a processor to perform the method described in any one of claims 1-5.

9. A computer program product comprising a computer program / computer executable instructions, characterized in that, When the computer program / computer-executable instructions are executed by a processor in an electronic device, they implement the method described in any one of claims 1-5.

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