Control method and device of magnetic suspension bearing and magnetic suspension bearing system

Abstract

The invention discloses a control method and device for a magnetic suspension bearing, a magnetic suspension bearing system, a storage medium and a computer program product, and the method comprises the steps: starting a reference displacement self-checking process when the magnetic suspension bearing is started each time, and driving a rotor of the magnetic suspension bearing to float in a preset minimum current active control mode in the self-checking process, acquiring the real-time displacement of the rotor in the minimum current suspension state; controlling the rotor to drop the shaft, and then determining the target reference displacement of the rotor according to the real-time displacement; and a preset fixed reference displacement control mode is adopted, the target reference displacement serves as a control standard, and the magnetic suspension bearing is controlled to operate. According to the scheme, the instability and unpredictability of minimum current active control are solved, the complexity that manual setting is needed for fixed reference displacement control is avoided, and low power consumption and stable operation of the magnetic suspension bearing are both considered.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation bearing control technology, specifically relating to a control method, device, magnetic levitation bearing system, storage medium, and computer program product for a magnetic levitation bearing. Background Technology

[0002] Magnetic levitation bearing systems, with their significant advantages of being frictionless and having low energy consumption, are increasingly in demand in fields such as high-speed rotating machinery and precision equipment, and have become an important technological direction for replacing traditional mechanical bearings. Among them, permanent magnet biased magnetic levitation bearings use a permanent magnet bias magnetic field provided by magnets to replace the bias magnetic field generated by bias current in pure electromagnetic bearings. This not only significantly reduces power consumption during levitation operation, but also reduces the number of winding turns and the overall size of the bearing, providing a key technological path for the miniaturization and low-energy consumption upgrade of magnetic levitation systems.

[0003] In the actual control of magnetic levitation bearings, the core control logic typically adopts a dual closed-loop architecture consisting of an outer displacement loop and an inner current loop. The reference displacement setting of the outer displacement loop directly affects the system's operating performance and power consumption. To achieve low-power operation, the main control methods currently available are minimum current active control and fixed reference displacement control, but both have significant drawbacks and cannot meet the requirements for stable and efficient operation of magnetic levitation devices. Specifically:

[0004] On the one hand, minimum current active control is one of the mainstream control methods for pursuing low power consumption. Theoretically, this method can balance the rotor's gravity and some disturbance forces through permanent magnet force, making the control current approach zero, thereby achieving extremely low power consumption. However, its core problem is that the reference displacement remains constant during the control process, while the actual displacement of the rotor changes in real time with the device's operating state (such as speed changes, load fluctuations, and external disturbances), and the actual displacement cannot follow the fixed reference displacement adjustment. This displacement mismatch problem is particularly prominent under high-speed operation or complex operating conditions. The drastic fluctuations in real-time displacement can lead to great unpredictability in the control logic, making the system prone to oscillations, instability, and other risks, seriously affecting the system's operational reliability.

[0005] On the other hand, while fixed reference displacement control can stably suspend the rotor at a set reference displacement through a dual closed loop, avoiding drastic fluctuations in actual displacement and improving operational stability, this method requires manual adjustment of the reference displacement before each device startup to achieve minimum current suspension and reduce power consumption. Technicians need to repeatedly adjust the reference displacement value to minimize current based on specific operating conditions. This cumbersome and time-consuming process not only reduces the startup efficiency of the device but also places high demands on the professional skills of operators, making it difficult to adapt to automated and large-scale application scenarios.

[0006] In summary, the two existing mainstream control methods suffer from instability and unpredictability, and require cumbersome manual operation for stable control. As a result, the magnetic levitation bearing system cannot simultaneously meet the core requirements of low power consumption, high stability, and convenient operation in practical applications.

[0007] 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

[0008] The purpose of this invention is to provide a control method, device, system, storage medium, and computer program product for magnetic levitation bearings, in order to solve the problems of instability and unpredictability in the control of magnetic levitation bearings in related solutions, and the need for cumbersome manual operation for stable control. The invention achieves the effect of obtaining the real-time displacement of the rotor in the minimum current suspension state by adopting the minimum current active control method, determining the target reference displacement after the shaft is lowered, and using the fixed reference displacement control method to control the operation of the magnetic levitation bearing based on the target displacement, making the control of magnetic levitation bearings simpler, more efficient, and more stable.

[0009] This invention provides a control method for a magnetic levitation bearing, comprising: initiating a reference displacement self-test process each time the magnetic levitation bearing is started; in the self-test process, using a preset minimum current active control mode to drive the rotor of the magnetic levitation bearing to float, and obtaining the real-time displacement of the rotor when it is in the minimum current levitation state; controlling the rotor to lower the shaft; then determining the target reference displacement of the rotor based on the real-time displacement; and using a preset fixed reference displacement control mode, using the target reference displacement as a control benchmark, to control the operation of the magnetic levitation bearing.

[0010] In some implementations, determining the target reference displacement of the rotor based on the real-time displacement includes: determining whether the real-time displacement is within a preset movable range of the magnetic levitation bearing rotor; if the real-time displacement is within the preset movable range, then determining the real-time displacement as the target reference displacement of the rotor.

[0011] In some implementations, if the real-time displacement exceeds the preset movable range, the boundary value of the preset movable range is determined as the target reference displacement of the rotor.

[0012] In some implementations, the preset fixed reference displacement control method adopts a dual closed-loop control architecture, which includes an outer displacement loop and an inner current loop. The outer displacement loop adjusts the feedback value of the rotor deviating from the target reference displacement through a position adjuster and outputs a control current. The inner current loop detects the bearing coil current of the magnetic levitation bearing in real time, adjusts it according to the difference between the detected feedback current and the control current, and outputs a control signal to control the bearing coil current.

[0013] In some implementations, in the preset minimum current active control method, the control logic of the outer displacement loop does not include an integral element, and the inner current loop is provided with an integral positive feedback element, which is used to perform integral calculation on the bearing coil current of the magnetic levitation bearing.

[0014] In conjunction with the above method, another aspect of the present invention provides a control device for a magnetic levitation bearing, comprising: an acquisition unit configured to initiate a reference displacement self-test process each time the magnetic levitation bearing is powered on, wherein the rotor of the magnetic levitation bearing is driven to levitate using a preset minimum current active control method during the self-test process, and the real-time displacement of the rotor when it is in a minimum current levitation state is acquired; a control unit configured to control the rotor to lower itself, and then determine a target reference displacement of the rotor based on the real-time displacement; the control unit is further configured to use a preset fixed reference displacement control method, with the target reference displacement as a control reference, to control the operation of the magnetic levitation bearing.

[0015] In conjunction with the above-mentioned device, the present invention further provides a magnetic levitation bearing system, including: the control device for the magnetic levitation bearing described above.

[0016] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device on which the storage medium is located executes the above-described control method for magnetic levitation bearings.

[0017] In conjunction with the above method, the present invention further provides a computer program product comprising a computer program that, when processed and executed, implements the steps of the above-described magnetic levitation bearing control method.

[0018] The present invention initiates a reference displacement self-check process each time the magnetic levitation bearing is powered on. During this process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to levitate, acquiring the real-time displacement of the rotor when it is in a minimum current levitation state. The rotor is then controlled to lower itself, and a target reference displacement is determined based on the real-time displacement. A preset fixed reference displacement control method is then employed, using the target reference displacement as the control benchmark to control the operation of the magnetic levitation bearing. This solves both the instability and unpredictability of minimum current active control and avoids the cumbersome manual tuning required for fixed reference displacement control, achieving a balance between low power consumption and stable operation of the magnetic levitation bearing.

[0019] 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.

[0020] 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

[0021] Figure 1 This is a flowchart illustrating an embodiment of the control method for magnetic levitation bearings of the present invention;

[0022] Figure 2 This is a schematic diagram of a structure of an embodiment of the control device for the magnetic levitation bearing of the present invention;

[0023] Figure 3 Diagram of a fixed reference displacement control system for a magnetic levitation bearing;

[0024] Figure 4 Response diagram of displacement current controlled by fixed reference displacement of magnetic levitation bearing;

[0025] Figure 5 Diagram of the minimum current control system for a magnetic levitation bearing;

[0026] Figure 6 The displacement current response diagram for the minimum current control of the magnetic levitation bearing;

[0027] Figure 7 This is a flowchart illustrating another embodiment of the control method for magnetic levitation bearings.

[0028] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0029] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0030] 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.

[0031] According to an embodiment of the present invention, a control method for a magnetic levitation bearing is provided, such as... Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. The control method of the magnetic levitation bearing may include steps S110 to S130.

[0032] In step S110, each time the magnetic levitation bearing is powered on, a reference displacement self-test process is initiated. In the self-test process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to float, and the real-time displacement of the rotor when it is in the minimum current suspension state is obtained.

[0033] If a magnetic levitation bearing is started directly using a fixed reference displacement control method, the reference displacement that can achieve minimum current levitation needs to be manually adjusted in advance, which is cumbersome. However, the minimum current active control method can make the rotor levitate in the state of minimum current through magnetic field force balance. The displacement in this state is the key benchmark for achieving low energy consumption operation.

[0034] Specifically, when the magnetic levitation bearing is powered on and started, the system automatically triggers a reference displacement self-check process. In this process, the system calls a pre-set minimum current active control mode, generating magnetic force by adjusting relevant magnetic field parameters to gradually drive the rotor away from the initial support structure to achieve levitation. As the magnetic force is dynamically adjusted, the rotor's levitation current gradually decreases until it reaches the minimum current state. At this point, the system detects and records the rotor's actual levitation position in real time, thus obtaining the real-time displacement of the rotor when it is in the minimum current levitation state. This real-time displacement matches the current operating conditions of the magnetic levitation bearing, preventing reference displacement failure due to changes in operating conditions.

[0035] In some implementations, in the preset minimum current active control method, the control logic of the outer displacement loop does not include an integral element, and the inner current loop is provided with an integral positive feedback element, which is used to perform integral calculation on the bearing coil current of the magnetic levitation bearing.

[0036] In the reference displacement self-test process, after the system calls the preset minimum current active control mode, it first acquires the rotor position signal in real time through the outer displacement loop, generates a preliminary current adjustment command based on the position signal, and transmits it to the inner current loop. After receiving the command, the inner current loop starts the integral positive feedback loop, continuously integrates the actual current of the bearing coil, and incorporates the integration result into the current adjustment process in the form of positive feedback. If the coil current is not zero, the integration result continues to change, and the inner current loop outputs a dynamic adjustment signal to drive the coil current to gradually decrease. During this process, the outer displacement loop, because it has no integral loop, only outputs the appropriate preliminary command based on the current position state, without forcibly correcting the position deviation. The rotor position adjusts naturally as the current decreases. Until the coil current drops to zero (or approaches zero), the integral result of the integral positive feedback loop stabilizes, the output of the inner current loop is fixed, and the system enters a stable state. At this time, the rotor's suspension position is the real-time displacement under the minimum current suspension state. The system completes the acquisition of this displacement, and the minimum current control process of the self-test phase ends.

[0037] The system structure of the minimum current active control method is as follows: Figure 5 As shown, the integral term is removed from the outer-loop PID control of the magnetic bearing variable reference displacement control. Therefore, the rotor's levitation position will deviate from the given reference position to some extent. Simultaneously, an inner-loop integral positive feedback term is added to integrate the current in the magnetic bearing coil. Only when the current in the coil is zero will the output of the integral term reach a fixed value, and the system reach a steady state. Otherwise, the output of the integral term will continuously change, and the system will remain in a dynamic process, unable to reach a steady state. When the system reaches steady state, the output control quantity of the outer-loop displacement control is balanced with the output quantity of the inner-loop integral positive feedback term, and the current in the coil is approximately zero.

[0038] The displacement current response of the minimum current active control method is as follows: Figure 6 As shown, minimum current control is used. Displacement loop adjustment is performed using minimum current control. When the suspension is finally stable, the position feedback value... Feedback current value It can achieve minimum current control.

[0039] By combining the displacement outer loop deintegration stage and the current inner loop with integral positive feedback stage, the coil current is forced to converge to zero. The dynamic characteristics of the integral positive feedback stage determine that "the system is stable only when the current is zero". The displacement outer loop deintegration stage avoids the current from being increased due to position correction. The two work together to ensure that the rotor can be stabilized in the suspension state with the minimum coil current, thereby minimizing the coil current and improving the accuracy of the minimum current displacement.

[0040] In step S120, the rotor is controlled to drop off the shaft, and then the target reference displacement of the rotor is determined based on the real-time displacement.

[0041] While the minimum current active control method can obtain the real-time displacement corresponding to low energy consumption, the actual displacement of the rotor will fluctuate with the operating state under this method, and it cannot be directly used for long-term stable control. Controlling the rotor to fall back to the shaft can temporarily return the rotor to the initial support structure and get rid of the dynamic suspension state, providing static analysis conditions for subsequent determination of the stable target reference displacement. Determining the target reference displacement based on the real-time displacement can ensure that the target reference displacement is based on the low energy consumption requirement and can also adapt to the stable operation requirements of the fixed reference displacement control method, avoiding the tedious operation of manual tuning.

[0042] Specifically, after acquiring the real-time displacement, the system adjusts the relevant magnetic field parameters to reduce the magnetic force, allowing the rotor to gradually fall back to the initial support structure under gravity (i.e., the rotor returning to its original position). After the rotor returns to its original position, the system analyzes and judges the previously acquired real-time displacement, and, combined with the operating characteristics and control requirements of the magnetic levitation bearing rotor, selects position data that meet the requirements of fixed reference displacement control, and determines this as the target reference displacement of the rotor. The target reference displacement is the benchmark position for subsequent fixed reference displacement control, and this displacement must meet the requirements of subsequent stable control.

[0043] In some implementations, step S120, the specific process of determining the target reference displacement of the rotor based on the real-time displacement, includes: determining whether the real-time displacement is within a preset movable range of the magnetic levitation bearing rotor; if the real-time displacement is within the preset movable range, then determining the real-time displacement as the target reference displacement of the rotor.

[0044] The movement of a magnetic levitation bearing rotor has physical and safety boundaries. Presetting the movable range is a key constraint to ensure that the rotor operates safely and controllably. If the real-time displacement exceeding this range is directly used as the target reference displacement, the rotor may touch the structural boundary during subsequent operation, causing equipment damage or control failure. Therefore, it is necessary to first determine whether the real-time displacement is within the preset movable range to provide a prerequisite for determining an effective target reference displacement and avoid operational risks caused by displacement exceeding the safety range.

[0045] Specifically, after the rotor is lowered onto the shaft, the system calls the pre-set preset movable range parameters of the magnetic levitation bearing rotor and compares the real-time rotor displacement obtained in the reference displacement self-check process with the upper and lower limits of the preset movable range. Through numerical comparison or logical judgment, it determines whether the specific value of the real-time displacement falls within the preset movable range. When the system determines that the real-time displacement is within the preset movable range of the magnetic levitation bearing rotor, it directly determines the value of the real-time displacement as the target reference displacement of the rotor; the system records the value of the target reference displacement as the target reference displacement.

[0046] By determining whether the real-time displacement is within the preset movable range, it is possible to avoid using displacements exceeding the safety boundary as the target reference displacement. This prevents the rotor from colliding with other components due to excessive displacement or from causing system instability due to exceeding control capabilities during subsequent operation, thereby improving the safety of magnetic levitation bearing operation. At the same time, it simplifies the process of determining the target reference displacement, eliminating the need for manual intervention and further enhancing the practicality and reliability of the magnetic levitation bearing control method.

[0047] In some implementations, if the real-time displacement exceeds the preset movable range, the boundary value of the preset movable range is determined as the target reference displacement of the rotor.

[0048] Fluctuations in the operating conditions of magnetic levitation bearings may cause real-time displacement to exceed the preset movable range. If this excess real-time displacement is directly used as the target reference displacement, the rotor may face collision risks during subsequent fixed reference displacement control due to the displacement approaching or touching the structural boundary, or it may fail to maintain stable levitation due to exceeding the system's control accuracy range. The boundary value of the preset movable range is a safety critical value verified by structural and control design. Using it as the target reference displacement can maximize the preservation of the low-energy consumption potential of near-minimum current levitation displacement while ensuring the rotor remains within a safe and controllable operating range, avoiding equipment failure or control instability caused by displacement exceeding limits.

[0049] Specifically, after the rotor is lowered onto the shaft, the real-time displacement obtained from the reference displacement self-check process is compared with the preset movable range of the magnetic levitation bearing rotor. When the real-time displacement exceeds the preset movable range, the system automatically extracts the boundary value of the preset movable range. If the real-time displacement is greater than the upper limit, the upper limit of the range is selected as the candidate benchmark; if the real-time displacement is less than the lower limit, the lower limit of the range is selected as the candidate benchmark. Subsequently, the system directly determines the selected boundary value as the target reference displacement of the rotor, thereby ensuring that the magnetic levitation bearing is always in a safe and controllable operating state and reducing the risk of equipment failure. For example, if the movable range is [-3V, 3V], if the real-time displacement is -2V, the target reference displacement is -2V; if the real-time displacement is 4V, the target reference displacement is 3V; if the real-time displacement is -5V, the target reference displacement is -3V.

[0050] In step S130, a preset fixed reference displacement control method is adopted, using the target reference displacement as the control benchmark to control the operation of the magnetic levitation bearing.

[0051] After determining the target reference displacement, the system calls the pre-set fixed reference displacement control mode and sets the target reference displacement as the position reference of the control mode. During the operation of the magnetic levitation bearing, the system detects the actual position of the rotor in real time and compares it with the target reference displacement to calculate the position deviation. Based on the position deviation, the system dynamically adjusts the relevant parameters of the magnetic field and generates corresponding control signals to adjust the magnetic field force, so that the actual position of the rotor is always stable near the target reference displacement, thereby achieving the continuous and stable operation of the magnetic levitation bearing.

[0052] This solution uses a minimum current active control method to determine the reference displacement for the fixed reference displacement control method, eliminating the need for manual adjustment of the reference displacement and effectively simplifying the operation process. This solves the problem of cumbersome manual operation required by the traditional fixed reference displacement control method. At the same time, it leverages the low energy consumption characteristics of the minimum current active control method to lay a solid foundation for energy efficiency, while avoiding displacement fluctuations through the stability advantages of the fixed reference displacement control method. This solves the instability and unpredictability problems of the minimum current active control method, ultimately achieving a balance between low energy consumption and high stability during the operation of the magnetic levitation bearing. Furthermore, it can re-test and adapt to changes in operating conditions each time it is started, improving the adaptability and reliability of the control method.

[0053] In some implementations, the preset fixed reference displacement control method adopts a dual closed-loop control architecture, which includes an outer displacement loop and an inner current loop. The outer displacement loop adjusts the feedback value of the rotor deviating from the target reference displacement through a position adjuster and outputs a control current. The inner current loop detects the bearing coil current of the magnetic levitation bearing in real time, adjusts it according to the difference between the detected feedback current and the control current, and outputs a control signal to control the bearing coil current.

[0054] In the dual closed-loop control architecture, the outer displacement loop focuses on precise positioning, while the inner current loop focuses on rapid current response. The inner loop provides stable current support for the outer loop, and the outer loop provides clear current commands to the inner loop. The two work together to solve the problems of position deviation correction and current response lag, enabling the rotor to accurately track the target reference displacement while avoiding position oscillations caused by current fluctuations, thus meeting the stable operation requirements of the fixed reference displacement control method.

[0055] The outer ring displacement loop works as follows: When the magnetic levitation bearing is in operation, the system detects the actual levitation position of the rotor in real time and compares the position with the target reference displacement to calculate the feedback value of the rotor's deviation from the target reference displacement. This position deviation is input to the position regulator, which calculates the position deviation through a preset adjustment algorithm and outputs the corresponding control current command according to the magnitude and trend of the deviation. This control current command is the target current of the inner ring current loop.

[0056] The inner current loop operates as follows: It continuously monitors the actual current of the bearing coil to obtain a feedback current; it compares this feedback current with the control current output by the outer displacement loop to calculate the current deviation; the inner current loop performs adjustment calculations based on this deviation and outputs a control signal that matches the deviation; this control signal is transmitted to the power amplifier and related equipment, which adjusts the power amplifier's output characteristics to change the actual current of the bearing coil, gradually bringing the feedback current closer to the control current, thus stabilizing the coil current; as the coil current stabilizes near the control current, the magnetic force generated by the coil also stabilizes, thereby gradually pushing the rotor's actual position closer to the target reference displacement, ultimately achieving stable rotor levitation.

[0057] The system structure of the fixed reference displacement control method is as follows: Figure 3 As shown, the displacement sensor of the displacement ring acquires the feedback value of the bearing rotor. The control current is obtained by adjusting the position using a position adjuster (PID control). That is, the output control quantity of the displacement loop. The current sensor in the current loop detects the bearing coil current in real time and returns the feedback current value. and control current value The difference is calculated and used to adjust the current. The real-time duty cycle PWM is output to the power amplifier topology to control the bearing coil current, thereby realizing the position control of the bearing rotor and making the rotor stably suspend at a given reference position.

[0058] The displacement current response of the fixed reference displacement control method is as follows: Figure 4 As shown, a fixed reference displacement is used. PID control is used for displacement loop adjustment, and the position feedback value is obtained when the suspension is stable. Feedback current value .

[0059] Figure 7 A flowchart illustrating another embodiment of the control method for magnetic levitation bearings, as shown below. Figure 7 As shown, the method includes:

[0060] Step 1: After each power-on, the magnetic levitation bearing runs the reference displacement self-test function to levitate the rotor and detect the bearing coil current. If the detected bearing coil current is 0 or close to 0, proceed to step 3; otherwise, call the minimum current active control mode of the displacement loop to obtain the real-time displacement when levitating with the minimum current. Proceed to step 2.

[0061] Step 2: Determine the real-time displacement at the minimum current obtained. Is it within the movable range of the magnetic bearing rotor? )Inside. like Within the movable range ( Within ) then As a reference displacement; if Not within the movable range ( Within ) the movable range ( The boundary value is used as the reference displacement.

[0062] Step 3: Write the modified reference displacement into the EEPROM register of the DSP controller for hardening, and then start the machine using the fixed reference displacement control mode.

[0063] The technical solution of this embodiment initiates a reference displacement self-check process each time the magnetic levitation bearing is powered on. During this process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to levitate, acquiring the real-time displacement of the rotor when it is in a minimum current levitation state. The rotor is then controlled to lower itself, and a target reference displacement is determined based on the real-time displacement. A preset fixed reference displacement control method is then used, with the target reference displacement as the control benchmark, to control the operation of the magnetic levitation bearing. This solves both the instability and unpredictability of minimum current active control and avoids the cumbersome manual tuning required for fixed reference displacement control, achieving a balance between low power consumption and stable operation of the magnetic levitation bearing.

[0064] According to an embodiment of the present invention, a control device for a magnetic levitation bearing, corresponding to a control method for magnetic levitation bearings, is also provided. See also Figure 2 The diagram shows a structural schematic of an embodiment of the device of the present invention. The control device for the magnetic levitation bearing may include: an acquisition unit 102 and a control unit 104.

[0065] The acquisition unit 102 is configured to initiate a reference displacement self-test process each time the magnetic levitation bearing is powered on. During this self-test process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to levitate, acquiring the real-time displacement of the rotor when it is in a minimum current levitation state. The specific functions and processing of this acquisition unit 102 are described in step S110.

[0066] If a magnetic levitation bearing is started directly using a fixed reference displacement control method, the reference displacement that can achieve minimum current levitation needs to be manually adjusted in advance, which is cumbersome. However, the minimum current active control method can make the rotor levitate in the state of minimum current through magnetic field force balance. The displacement in this state is the key benchmark for achieving low energy consumption operation.

[0067] Specifically, when the magnetic levitation bearing is powered on and started, the system automatically triggers a reference displacement self-check process. In this process, the system calls a pre-set minimum current active control mode, generating magnetic force by adjusting relevant magnetic field parameters to gradually drive the rotor away from the initial support structure to achieve levitation. As the magnetic force is dynamically adjusted, the rotor's levitation current gradually decreases until it reaches the minimum current state. At this point, the system detects and records the rotor's actual levitation position in real time, thus obtaining the real-time displacement of the rotor when it is in the minimum current levitation state. This real-time displacement matches the current operating conditions of the magnetic levitation bearing, preventing reference displacement failure due to changes in operating conditions.

[0068] In some implementations, in the preset minimum current active control method, the control logic of the outer displacement loop does not include an integral element, and the inner current loop is provided with an integral positive feedback element, which is used to perform integral calculation on the bearing coil current of the magnetic levitation bearing.

[0069] In the reference displacement self-test process, after the system calls the preset minimum current active control mode, it first acquires the rotor position signal in real time through the outer displacement loop, generates a preliminary current adjustment command based on the position signal, and transmits it to the inner current loop. After receiving the command, the inner current loop starts the integral positive feedback loop, continuously integrates the actual current of the bearing coil, and incorporates the integration result into the current adjustment process in the form of positive feedback. If the coil current is not zero, the integration result continues to change, and the inner current loop outputs a dynamic adjustment signal to drive the coil current to gradually decrease. During this process, the outer displacement loop, because it has no integral loop, only outputs the appropriate preliminary command based on the current position state, without forcibly correcting the position deviation. The rotor position adjusts naturally as the current decreases. Until the coil current drops to zero (or approaches zero), the integral result of the integral positive feedback loop stabilizes, the output of the inner current loop is fixed, and the system enters a stable state. At this time, the rotor's suspension position is the real-time displacement under the minimum current suspension state. The system completes the acquisition of this displacement, and the minimum current control process of the self-test phase ends.

[0070] The system structure of the minimum current active control method is as follows: Figure 5 As shown, the integral term is removed from the outer-loop PID control of the magnetic bearing variable reference displacement control. Therefore, the rotor's levitation position will deviate from the given reference position to some extent. Simultaneously, an inner-loop integral positive feedback term is added to integrate the current in the magnetic bearing coil. Only when the current in the coil is zero will the output of the integral term reach a fixed value, and the system reach a steady state. Otherwise, the output of the integral term will continuously change, and the system will remain in a dynamic process, unable to reach a steady state. When the system reaches steady state, the output control quantity of the outer-loop displacement control is balanced with the output quantity of the inner-loop integral positive feedback term, and the current in the coil is approximately zero.

[0071] The displacement current response of the minimum current active control method is as follows: Figure 6 As shown, minimum current control is used. Displacement loop adjustment is performed using minimum current control. When the suspension is finally stable, the position feedback value... Feedback current value It can achieve minimum current control.

[0072] By combining the displacement outer loop deintegration stage and the current inner loop with integral positive feedback stage, the coil current is forced to converge to zero. The dynamic characteristics of the integral positive feedback stage determine that "the system is stable only when the current is zero". The displacement outer loop deintegration stage avoids the current from being increased due to position correction. The two work together to ensure that the rotor can be stabilized in the suspension state with the minimum coil current, thereby minimizing the coil current and improving the accuracy of the minimum current displacement.

[0073] Control unit 104 is configured to control the rotor to drop off the shaft, and then determine the target reference displacement of the rotor based on the real-time displacement. The specific functions and processing of control unit 104 are described in step S120.

[0074] While the minimum current active control method can obtain the real-time displacement corresponding to low energy consumption, the actual displacement of the rotor will fluctuate with the operating state under this method, and it cannot be directly used for long-term stable control. Controlling the rotor to fall back to the shaft can temporarily return the rotor to the initial support structure and get rid of the dynamic suspension state, providing static analysis conditions for subsequent determination of the stable target reference displacement. Determining the target reference displacement based on the real-time displacement can ensure that the target reference displacement is based on the low energy consumption requirement and can also adapt to the stable operation requirements of the fixed reference displacement control method, avoiding the tedious operation of manual tuning.

[0075] Specifically, after acquiring the real-time displacement, the system adjusts the relevant magnetic field parameters to reduce the magnetic force, allowing the rotor to gradually fall back to the initial support structure under gravity (i.e., the rotor returning to its original position). After the rotor returns to its original position, the system analyzes and judges the previously acquired real-time displacement, and, combined with the operating characteristics and control requirements of the magnetic levitation bearing rotor, selects position data that meet the requirements of fixed reference displacement control, and determines this as the target reference displacement of the rotor. The target reference displacement is the benchmark position for subsequent fixed reference displacement control, and this displacement must meet the requirements of subsequent stable control.

[0076] In some embodiments, the control unit 104 determines the target reference displacement of the rotor based on the real-time displacement, including: determining whether the real-time displacement is within a preset movable range of the magnetic levitation bearing rotor; if the real-time displacement is within the preset movable range, then determining the real-time displacement as the target reference displacement of the rotor.

[0077] The movement of a magnetic levitation bearing rotor has physical and safety boundaries. Presetting the movable range is a key constraint to ensure that the rotor operates safely and controllably. If the real-time displacement exceeding this range is directly used as the target reference displacement, the rotor may touch the structural boundary during subsequent operation, causing equipment damage or control failure. Therefore, it is necessary to first determine whether the real-time displacement is within the preset movable range to provide a prerequisite for determining an effective target reference displacement and avoid operational risks caused by displacement exceeding the safety range.

[0078] Specifically, after the rotor is lowered onto the shaft, the system calls the pre-set preset movable range parameters of the magnetic levitation bearing rotor and compares the real-time rotor displacement obtained in the reference displacement self-check process with the upper and lower limits of the preset movable range. Through numerical comparison or logical judgment, it determines whether the specific value of the real-time displacement falls within the preset movable range. When the system determines that the real-time displacement is within the preset movable range of the magnetic levitation bearing rotor, it directly determines the value of the real-time displacement as the target reference displacement of the rotor; the system records the value of the target reference displacement as the target reference displacement.

[0079] By determining whether the real-time displacement is within the preset movable range, it is possible to avoid using displacements exceeding the safety boundary as the target reference displacement. This prevents the rotor from colliding with other components due to excessive displacement or from causing system instability due to exceeding control capabilities during subsequent operation, thereby improving the safety of magnetic levitation bearing operation. At the same time, it simplifies the process of determining the target reference displacement, eliminating the need for manual intervention and further enhancing the practicality and reliability of the magnetic levitation bearing control method.

[0080] In some implementations, if the real-time displacement exceeds the preset movable range, the boundary value of the preset movable range is determined as the target reference displacement of the rotor.

[0081] Fluctuations in the operating conditions of magnetic levitation bearings may cause real-time displacement to exceed the preset movable range. If this excess real-time displacement is directly used as the target reference displacement, the rotor may face collision risks during subsequent fixed reference displacement control due to the displacement approaching or touching the structural boundary, or it may fail to maintain stable levitation due to exceeding the system's control accuracy range. The boundary value of the preset movable range is a safety critical value verified by structural and control design. Using it as the target reference displacement can maximize the preservation of the low-energy consumption potential of near-minimum current levitation displacement while ensuring the rotor remains within a safe and controllable operating range, avoiding equipment failure or control instability caused by displacement exceeding limits.

[0082] Specifically, after the rotor is lowered onto the shaft, the real-time displacement obtained from the reference displacement self-check process is compared with the preset movable range of the magnetic levitation bearing rotor. When the real-time displacement exceeds the preset movable range, the system automatically extracts the boundary value of the preset movable range. If the real-time displacement is greater than the upper limit, the upper limit of the range is selected as the candidate benchmark; if the real-time displacement is less than the lower limit, the lower limit of the range is selected as the candidate benchmark. Subsequently, the system directly determines the selected boundary value as the target reference displacement of the rotor, thereby ensuring that the magnetic levitation bearing is always in a safe and controllable operating state and reducing the risk of equipment failure. For example, if the movable range is [-3V, 3V], if the real-time displacement is -2V, the target reference displacement is -2V; if the real-time displacement is 4V, the target reference displacement is 3V; if the real-time displacement is -5V, the target reference displacement is -3V.

[0083] The control unit 104 is further configured to use a preset fixed reference displacement control mode, using the target reference displacement as the control benchmark, to control the operation of the magnetic levitation bearing. The specific functions and processing of this control unit 104 are described in step S130.

[0084] After determining the target reference displacement, the system calls the pre-set fixed reference displacement control mode and sets the target reference displacement as the position reference of the control mode. During the operation of the magnetic levitation bearing, the system detects the actual position of the rotor in real time and compares it with the target reference displacement to calculate the position deviation. Based on the position deviation, the system dynamically adjusts the relevant parameters of the magnetic field and generates corresponding control signals to adjust the magnetic field force, so that the actual position of the rotor is always stable near the target reference displacement, thereby achieving the continuous and stable operation of the magnetic levitation bearing.

[0085] This solution uses a minimum current active control method to determine the reference displacement for the fixed reference displacement control method, eliminating the need for manual adjustment of the reference displacement and effectively simplifying the operation process. This solves the problem of cumbersome manual operation required by the traditional fixed reference displacement control method. At the same time, it leverages the low energy consumption characteristics of the minimum current active control method to lay a solid foundation for energy efficiency, while avoiding displacement fluctuations through the stability advantages of the fixed reference displacement control method. This solves the instability and unpredictability problems of the minimum current active control method, ultimately achieving a balance between low energy consumption and high stability during the operation of the magnetic levitation bearing. Furthermore, it can re-test and adapt to changes in operating conditions each time it is started, improving the adaptability and reliability of the control method.

[0086] In some implementations, the preset fixed reference displacement control method adopts a dual closed-loop control architecture, which includes an outer displacement loop and an inner current loop. The outer displacement loop adjusts the feedback value of the rotor deviating from the target reference displacement through a position adjuster and outputs a control current. The inner current loop detects the bearing coil current of the magnetic levitation bearing in real time, adjusts it according to the difference between the detected feedback current and the control current, and outputs a control signal to control the bearing coil current.

[0087] In the dual closed-loop control architecture, the outer displacement loop focuses on precise positioning, while the inner current loop focuses on rapid current response. The inner loop provides stable current support for the outer loop, and the outer loop provides clear current commands to the inner loop. The two work together to solve the problems of position deviation correction and current response lag, enabling the rotor to accurately track the target reference displacement while avoiding position oscillations caused by current fluctuations, thus meeting the stable operation requirements of the fixed reference displacement control method.

[0088] The outer ring displacement loop works as follows: When the magnetic levitation bearing is in operation, the system detects the actual levitation position of the rotor in real time and compares the position with the target reference displacement to calculate the feedback value of the rotor's deviation from the target reference displacement. This position deviation is input to the position regulator, which calculates the position deviation through a preset adjustment algorithm and outputs the corresponding control current command according to the magnitude and trend of the deviation. This control current command is the target current of the inner ring current loop.

[0089] The inner current loop operates as follows: It continuously monitors the actual current of the bearing coil to obtain a feedback current; it compares this feedback current with the control current output by the outer displacement loop to calculate the current deviation; the inner current loop performs adjustment calculations based on this deviation and outputs a control signal that matches the deviation; this control signal is transmitted to the power amplifier and related equipment, which adjusts the power amplifier's output characteristics to change the actual current of the bearing coil, gradually bringing the feedback current closer to the control current, thus stabilizing the coil current; as the coil current stabilizes near the control current, the magnetic force generated by the coil also stabilizes, thereby gradually pushing the rotor's actual position closer to the target reference displacement, ultimately achieving stable rotor levitation.

[0090] The system structure of the fixed reference displacement control method is as follows: Figure 3 As shown, the displacement sensor of the displacement ring acquires the feedback value of the bearing rotor. The control current is obtained by adjusting the position using a position adjuster (PID control). That is, the output control quantity of the displacement loop. The current sensor in the current loop detects the bearing coil current in real time and returns the feedback current value. and control current value The difference is calculated and used to adjust the current. The real-time duty cycle PWM is output to the power amplifier topology to control the bearing coil current, thereby realizing the position control of the bearing rotor and making the rotor stably suspend at a given reference position.

[0091] The displacement current response of the fixed reference displacement control method is as follows: Figure 4 As shown, a fixed reference displacement is used. PID control is used for displacement loop adjustment, and the position feedback value is obtained when the suspension is stable. Feedback current value .

[0092] 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.

[0093] By employing the technical solution of this invention, a reference displacement self-check process is initiated each time the magnetic levitation bearing is powered on. During this process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to levitate, acquiring the real-time displacement of the rotor when it is in a minimum current levitation state. The rotor is then controlled to lower itself, and a target reference displacement is determined based on the real-time displacement. A preset fixed reference displacement control method is then used, with the target reference displacement as the control benchmark, to control the operation of the magnetic levitation bearing. This solves both the instability and unpredictability of minimum current active control and avoids the cumbersome manual tuning required for fixed reference displacement control, achieving a balance between low power consumption and stable operation of the magnetic levitation bearing.

[0094] According to an embodiment of the present invention, a magnetic levitation bearing system corresponding to a control device for a magnetic levitation bearing is also provided. This magnetic levitation bearing system may include the control device for the magnetic levitation bearing described above.

[0095] Since the processing and functions implemented by the magnetic levitation bearing system in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned devices, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0096] By employing the technical solution of this invention, a reference displacement self-check process is initiated each time the magnetic levitation bearing is powered on. During this process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to levitate, acquiring the real-time displacement of the rotor when it is in a minimum current levitation state. The rotor is then controlled to lower itself, and a target reference displacement is determined based on the real-time displacement. A preset fixed reference displacement control method is then used, with the target reference displacement as the control benchmark, to control the operation of the magnetic levitation bearing. This solves both the instability and unpredictability of minimum current active control and avoids the cumbersome manual tuning required for fixed reference displacement control, achieving a balance between low power consumption and stable operation of the magnetic levitation bearing.

[0097] According to an embodiment of the present invention, a storage medium corresponding to a control method for a magnetic levitation bearing is also provided, the storage medium including a stored program, wherein the program controls the device where the storage medium is located to execute the control method for the magnetic levitation bearing described above during runtime.

[0098] Since the processing and functions implemented by the storage medium 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.

[0099] By employing the technical solution of this invention, a reference displacement self-check process is initiated each time the magnetic levitation bearing is powered on. During this process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to levitate, acquiring the real-time displacement of the rotor when it is in a minimum current levitation state. The rotor is then controlled to lower itself, and a target reference displacement is determined based on the real-time displacement. A preset fixed reference displacement control method is then used, with the target reference displacement as the control benchmark, to control the operation of the magnetic levitation bearing. This solves both the instability and unpredictability of minimum current active control and avoids the cumbersome manual tuning required for fixed reference displacement control, achieving a balance between low power consumption and stable operation of the magnetic levitation bearing.

[0100] According to an embodiment of the present invention, a computer program product corresponding to the control method for a magnetic levitation bearing is also provided. The computer program product includes a computer program that, when processed and executed, implements the steps of the control method for the magnetic levitation bearing described above.

[0101] Since the processing and functions implemented by the computer program product in this embodiment are basically corresponding to 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.

[0102] By employing the technical solution of this invention, a reference displacement self-check process is initiated each time the magnetic levitation bearing is powered on. During this process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to levitate, acquiring the real-time displacement of the rotor when it is in a minimum current levitation state. The rotor is then controlled to lower itself, and a target reference displacement is determined based on the real-time displacement. A preset fixed reference displacement control method is then used, with the target reference displacement as the control benchmark, to control the operation of the magnetic levitation bearing. This solves both the instability and unpredictability of minimum current active control and avoids the cumbersome manual tuning required for fixed reference displacement control, achieving a balance between low power consumption and stable operation of the magnetic levitation bearing.

[0103] 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.

[0104] 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 bearing, characterized in that, The method includes: Each time the magnetic levitation bearing is powered on, a reference displacement self-test process is initiated. In the self-test process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to float, and the real-time displacement of the rotor when it is in the minimum current suspension state is obtained. The rotor is controlled to drop onto the shaft, and then the target reference displacement of the rotor is determined based on the real-time displacement. The magnetic levitation bearing is controlled by a preset fixed reference displacement control method, with the target reference displacement as the control benchmark.

2. The control method for a magnetic levitation bearing according to claim 1, characterized in that, Determining the target reference displacement of the rotor based on the real-time displacement includes: Determine whether the real-time displacement is within the preset movable range of the magnetic levitation bearing rotor; If the real-time displacement is within the preset movable range, then the real-time displacement is determined as the target reference displacement of the rotor.

3. The control method for a magnetic levitation bearing according to claim 2, characterized in that, Also includes: If the real-time displacement exceeds the preset movable range, the boundary value of the preset movable range is determined as the target reference displacement of the rotor.

4. The control method for a magnetic levitation bearing according to claim 1, characterized in that, The preset fixed reference displacement control method adopts a dual closed-loop control architecture, which includes an outer displacement loop and an inner current loop. The outer displacement loop adjusts the feedback value of the rotor deviating from the target reference displacement through a position adjuster and outputs a control current. The inner current loop detects the bearing coil current of the magnetic levitation bearing in real time, adjusts it according to the difference between the detected feedback current and the control current, and outputs a control signal to control the bearing coil current.

5. The control method for a magnetic levitation bearing according to claim 1, characterized in that, In the preset minimum current active control mode, the control logic of the outer displacement loop does not include an integral element, and the inner current loop is equipped with an integral positive feedback element, which is used to perform integral calculation on the bearing coil current of the magnetic levitation bearing.

6. A control device for a magnetic levitation bearing, characterized in that, include: The acquisition unit is configured to initiate a reference displacement self-test process each time the magnetic levitation bearing is powered on. In the self-test process, a preset minimum current active control method is used to drive the rotor of the magnetic levitation bearing to float, and the real-time displacement of the rotor when it is in the minimum current suspension state is acquired. The control unit is configured to control the rotor to drop off the shaft, and then determine the target reference displacement of the rotor based on the real-time displacement. The control unit is also configured to use a preset fixed reference displacement control method, using the target reference displacement as the control reference, to control the operation of the magnetic levitation bearing.

7. A magnetic levitation bearing system, characterized in that, include: The control device for the magnetic levitation bearing as described in claim 6.

8. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the control method for the magnetic levitation bearing as described in any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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