A hybrid fully superconducting magnetic levitation bearing and its control method

Abstract

This invention discloses a hybrid fully superconducting magnetic levitation bearing and its control method, belonging to the technical field of high-temperature superconducting magnetic levitation bearings. The hybrid fully superconducting magnetic levitation bearing includes a rotor assembly, a stator assembly disposed below the rotor, a cryogenic cooling assembly for maintaining the superconducting state, and a control assembly. The rotor assembly includes a permanent magnet rotor with a central rotating shaft in the middle. The stator assembly includes a high-temperature superconducting bulk material and a superconducting adjustment coil arranged sequentially from the inside out. A magnetic yoke is disposed on the outer and bottom sides of the superconducting adjustment coil. The cryogenic cooling assembly includes a cold-conducting component disposed at the bottom end of the high-temperature superconducting bulk material. The control assembly is used to control the current and magnetic field to adjust the axial balance position of the rotor. This invention solves the problems of non-adjustable stiffness and easy position drift in existing high-temperature superconducting magnetic levitation bearings, while reducing the heat generation and high AC loss risks associated with traditional active control.

Description

Technical Field

[0001] This invention relates to the field of high-temperature superconducting magnetic levitation bearing technology, and in particular to a hybrid fully superconducting magnetic levitation bearing and its control method. Background Technology

[0002] High-temperature superconducting magnetic levitation bearings are increasingly being used in various fields such as flywheel energy storage, high-speed motors, and aerospace due to their unique self-stabilizing levitation characteristics. However, current superconducting magnetic levitation bearings are mainly divided into passive and active types: passive types achieve levitation by utilizing the magnetic flux pinning effect of high-temperature superconducting bulk materials, but their stiffness is not adjustable, and after long-term operation, the equilibrium position will drift due to magnetic flux creep; active or hybrid types introduce coils for control, but usually use conventional copper coils, which will generate a large amount of Joule heat in low-temperature environments, significantly increasing the burden on the cooling system; while if superconducting coils are used directly for high-frequency control, the superconducting material will lose its superconductivity due to AC losses, resulting in low reliability. Summary of the Invention

[0003] The purpose of this invention is to provide a hybrid fully superconducting magnetic levitation bearing and its control method, which solves the problems of non-adjustable stiffness and easy position drift of existing high-temperature superconducting magnetic levitation bearings, while reducing the risks of heat generation and high AC loss caused by traditional active control.

[0004] To achieve the above objectives, the present invention provides a hybrid fully superconducting magnetic levitation bearing, comprising a rotor assembly, a stator assembly disposed below the rotor assembly, a cryogenic cooling assembly for maintaining the superconducting state, and a control assembly. The rotor assembly includes a permanent magnet rotor with a central rotating shaft disposed in the middle. The stator assembly includes a high-temperature superconducting bulk material and a superconducting adjustment coil arranged sequentially from the inside to the outside. A magnetic yoke is disposed on the outer side and bottom side of the superconducting adjustment coil. The cryogenic cooling assembly includes a cold-conducting component disposed at the bottom end of the high-temperature superconducting bulk material. The control assembly is used to control the current and magnetic field to adjust the axial balance position of the permanent magnet rotor.

[0005] Preferably, the permanent magnet rotor is coaxial with the central rotating shaft.

[0006] Preferably, the high-temperature superconducting bulk material is located directly below the permanent magnet rotor, using the magnetic flux pinning effect to provide axial levitation force.

[0007] Preferably, the superconducting adjustment coil is disposed around the high-temperature superconducting bulk material and coaxially disposed with the high-temperature superconducting bulk material, and a physical gap is left between the superconducting adjustment coil and the high-temperature superconducting bulk material. The superconducting adjustment coil uses the magnetic field generated by energizing to modulate the background magnetic field of the working air gap.

[0008] Preferably, the magnetic yoke is an L-shaped cross-section magnetic yoke, which wraps around the outside and bottom of the superconducting adjustment coil.

[0009] Preferably, the magnetic yoke is used to constrain the leakage magnetic field of the superconducting regulating coil, guide the regulating magnetic field to the working air gap and the high-temperature superconducting bulk material region, and at the same time play a magnetic shielding role.

[0010] Preferably, the cryogenic cooling component is used to maintain the low temperature of the high-temperature superconducting bulk material and the superconducting regulating coil.

[0011] Preferably, the bottom of the high-temperature superconducting block is connected to the cold head of the refrigerator through a cooling component to maintain the superconducting state.

[0012] Preferably, the control components include a displacement sensor, a low-pass filter, a controller, and a bipolar power supply. The displacement sensor is fixedly mounted on the stator assembly, with its probe facing the axial end face of the permanent magnet rotor. The displacement sensor is used to acquire the axial displacement signal of the permanent magnet rotor in real time. The output of the displacement sensor is connected to the input of the low-pass filter. The axial displacement signal of the permanent magnet rotor is filtered out by the low-pass filter to remove high-frequency vibration components and retain quasi-static or low-frequency displacement signals. The output of the low-pass filter is connected to the controller, the output of the controller is connected to the control terminal of the bipolar power supply, the output of the bipolar power supply is connected to the superconducting regulating coil, and the controller drives the bipolar power supply to output regulating current to the superconducting regulating coil.

[0013] This invention also provides a control method for a hybrid fully superconducting magnetic levitation bearing, comprising the following steps: Step 1: The axial displacement signal of the permanent magnet rotor is acquired in real time by a displacement sensor. The acquired axial displacement signal is filtered out by a low-pass filter to remove high-frequency vibration components and retain quasi-static or low-frequency displacement signals. Step 2: The quasi-static or low-frequency displacement signal filtered in Step 1 is compared with the ideal axial suspension balance position setpoint of the permanent magnet rotor by the controller to obtain the position deviation. The position deviation is then calculated using a PID control algorithm or a fuzzy control algorithm to generate a control quantity representing the magnitude and direction of the required compensation current. Step 3: The controller drives the bipolar power supply to output a regulating current to the superconducting regulating coil; Step four: Based on the hybrid mechanism of high-temperature superconducting bulk material providing main load-bearing capacity and superconducting adjustment coil providing fine-tuning force, the magnetic field generated by the superconducting adjustment coil is superimposed with the main magnetic field of the permanent magnet rotor at the working air gap. The magnitude and direction of the superconducting adjustment coil current are changed by the controller to enhance or weaken the magnetic flux density at the working air gap, thereby realizing low-frequency non-contact active adjustment of the axial balance position of the permanent magnet rotor.

[0014] The advantages and positive effects of the hybrid fully superconducting magnetic levitation bearing and its control method described in this invention are as follows: 1. High load-bearing capacity and controllability coexist: Combining the advantages of passive suspension and active control, high-temperature superconducting bulk material is used to provide the main load-bearing capacity, and superconducting adjustment coils are used in conjunction with control components to achieve precise position adjustment; 2. Improve control efficiency: Introduce a magnetic yoke to reduce leakage magnetic flux of the peripheral superconducting regulating coil, so that the regulating magnetic field acts on the working air gap, thereby reducing the required control current; 3. Reduced AC losses: By adopting a low-frequency modulation strategy, the current of the superconducting regulating coil is in a quasi-static state, which greatly reduces the AC losses of the superconducting coil and ensures the safety of the cryogenic cooling components.

[0015] 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

[0016] Figure 1 This is a cross-sectional view of the overall structure of an embodiment of a hybrid fully superconducting magnetic levitation bearing according to the present invention; Figure 2 This is a top view of the stator assembly of an embodiment of a hybrid fully superconducting magnetic levitation bearing according to the present invention; Figure 3 This is a control framework diagram of an embodiment of the control method for a hybrid fully superconducting magnetic levitation bearing of the present invention.

[0017] Figure label: 1. Permanent magnet rotor; 2. High-temperature superconducting bulk material; 3. Superconducting regulating coil; 4. Magnetic yoke; 5. Cooling component; 6. Central shaft. Detailed Implementation

[0018] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0019] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] Example: Considering the extremely high load-bearing capacity of the high-temperature superconducting bulk material 2 and the flexible magnetic field adjustment capability of the superconducting adjustment coil 3, this invention proposes a hybrid fully superconducting magnetic levitation bearing and its control method. The high-temperature superconducting bulk material 2 bears the main axial levitation force, while the superconducting adjustment coil 3, coaxially arranged on the periphery, generates a fine-tuning magnetic field to "modulate" the background magnetic field of the working air gap. This combines the high stability of passive levitation with the adjustability of active control, achieving stable levitation with no heat loss, controllable stiffness, and the ability to compensate for positional drift.

[0022] like Figure 1 , Figure 2 As shown, the hybrid fully superconducting magnetic levitation bearing of the present invention includes a rotor assembly, a stator assembly disposed below the rotor assembly, a cryogenic cooling assembly for maintaining the superconducting state, and a control assembly.

[0023] The rotor assembly includes a permanent magnet rotor 1, with a central rotating shaft 6 disposed in the middle of the permanent magnet rotor 1. The permanent magnet rotor 1 and the central rotating shaft 6 are coaxially arranged, and the permanent magnet rotor 1 is fixed on the central rotating shaft 6.

[0024] like Figure 2 As shown, the stator assembly includes a high-temperature superconducting bulk material 2 and a superconducting regulating coil 3 arranged sequentially from the inside out. A magnetic yoke 4 is disposed on the outer and bottom sides of the superconducting regulating coil 3. The high-temperature superconducting bulk material 2 is located directly below the permanent magnet rotor 1, providing axial levitation force using the flux pinning effect. The superconducting regulating coil 3 is disposed around the high-temperature superconducting bulk material 2 and coaxially with it, with a physical gap between them. The superconducting regulating coil 3 uses the magnetic field generated by energizing to modulate the background magnetic field in the working air gap (the gap between the permanent magnet rotor 1 and the high-temperature superconducting bulk material 2). The magnetic yoke 4 is an L-shaped cross-section magnetic yoke 4, which wraps around the outer and bottom sides of the superconducting regulating coil 3. The magnetic yoke 4 is used to constrain the leakage magnetic field of the superconducting regulating coil 3, guide the regulating magnetic field to the area between the working air gap and the high-temperature superconducting bulk material 2, and also serves as magnetic shielding.

[0025] The cryogenic cooling assembly is used to maintain the low temperature of the high-temperature superconducting bulk material 2 and the superconducting regulating coil 3. The cryogenic cooling assembly includes a cold-conducting component 5, and the bottom of the high-temperature superconducting bulk material 2 is connected to the cold head of the refrigerator through the cold-conducting component 5 to maintain the superconducting state.

[0026] The control component is used to adjust the axial balance position of the permanent magnet rotor 1 by controlling the current and magnetic field. The control component includes a displacement sensor, a low-pass filter, a controller, and a bipolar power supply. The displacement sensor is fixedly mounted on the stator assembly, with its probe facing the axial end face of the permanent magnet rotor 1. The displacement sensor is used to acquire the axial displacement signal of the permanent magnet rotor 1 in real time. The output terminal of the displacement sensor is connected to the input terminal of the low-pass filter. The axial displacement signal of the permanent magnet rotor 1 is filtered by the low-pass filter to remove high-frequency vibration components, retaining only the quasi-static or low-frequency displacement signal. The output terminal of the low-pass filter is connected to the controller, the output terminal of the controller is connected to the control terminal of the bipolar power supply, and the output terminal of the bipolar power supply is connected to the superconducting adjustment coil 3. The controller drives the bipolar power supply to output an adjustment current to the superconducting adjustment coil 3.

[0027] like Figure 3 As shown, the control method for a hybrid fully superconducting magnetic levitation bearing of the present invention includes the following steps: Step 1: The axial displacement signal of the permanent magnet rotor 1 is acquired in real time by a displacement sensor. The acquired axial displacement signal is first filtered by a low-pass filter to remove high-frequency vibration components, and only quasi-static or low-frequency displacement signals are retained.

[0028] Step two: Then, the quasi-static or low-frequency displacement signal filtered in step one is compared with the set value by the controller and the control quantity is calculated. The setpoint is the ideal axial suspension equilibrium position of the permanent magnet rotor 1. The controller compares the displacement signal with the preset ideal axial equilibrium position setpoint of the permanent magnet rotor 1 to obtain the position deviation, and uses a PID control algorithm or fuzzy control algorithm to calculate the position deviation, generating a control quantity representing the magnitude and direction of the required compensation current. The control quantity is essentially a current command signal, which instructs the bipolar power supply to output a current of corresponding magnitude and direction to the superconducting regulating coil 3, thereby generating a magnetic field of a specific direction around the superconducting regulating coil 3, changing the total magnetic flux in the air gap, and thus causing the permanent magnet rotor 1 to return to the setpoint position.

[0029] The controller incorporates an existing PI (proportional-integral) control algorithm module, and its specific signal processing and physical processes are as follows: 1. Input (deviation generation): The controller receives the quasi-static displacement signal from the low-pass filter, compares it with the preset equilibrium position, and calculates the position deviation in real time.

[0030] 2. Processing logic (proportional and integral effects): Proportional (P) step: Multiply the positional deviation by a proportionality coefficient. When a slight change in load causes the permanent magnet rotor 1 to deviate from its equilibrium position, the proportional element immediately calculates a transient compensation amount proportional to the deviation, which is used to provide basic electromagnetic restoring stiffness.

[0031] Integration (I) stage: Multiply the position deviation by the integration coefficient. And it accumulates over time. Due to the inherent "magnetic flux creep" phenomenon of the high-temperature superconducting bulk material 2 during long-term operation (which causes the permanent magnet rotor 1 to slowly sink, generating a steady-state static error that is difficult to eliminate), the integral element will continuously accumulate this small sinking error over time, gradually increasing the compensation amount until the permanent magnet rotor 1 is completely pushed back to the ideal position, achieving zero static error.

[0032] Since the high-frequency vibration noise of the permanent magnet rotor 1 has been filtered out by the low-pass filter, the controller does not need to introduce a differential (D) stage that is extremely sensitive to high-frequency noise, thus ensuring the smoothness of the output signal at the algorithm level.

[0033] 3. Output (Drive Command): The final control quantity is generated by adding the calculation results of the proportional and integral components. This control quantity is sent as a command signal to the bipolar power supply, which linearly amplifies it into the actual physical drive current. And inject into the regulating coil 3.

[0034] Step 3: Then the controller drives the bipolar power supply to output a regulating current to the superconducting regulating coil 3; Step four: Based on the hybrid mechanism of the high-temperature superconducting block 2 providing the main load-bearing force and the superconducting adjustment coil 3 providing the fine-tuning force, the magnetic field generated by the superconducting adjustment coil 3 is superimposed with the main magnetic field of the permanent magnet rotor 1 at the working air gap. By changing the magnitude and direction of the current of the superconducting adjustment coil 3 through the controller, the magnetic flux density at the working air gap is enhanced or weakened, thereby changing the levitation force on the permanent magnet rotor 1 and realizing low-frequency non-contact active adjustment of the axial balance position of the permanent magnet rotor 1.

[0035] This invention employs a decoupled layout with the bulk material in the center and the coil on the side. The magnetic yoke 4 on the periphery can precisely guide the regulating magnetic field of the superconducting regulating coil 3 to the working air gap, avoiding leakage magnetic interference. Therefore, this invention does not require the complex constant-conducting magnet assembly or independent cooling circuit found in traditional hybrid bearings, resulting in a more compact structure, lower energy consumption, and effectively avoiding the AC loss risk caused by high-frequency regulation of the superconducting coil.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A hybrid fully superconducting magnetic levitation bearing, characterized in that: The device includes a rotor assembly, a stator assembly located below the rotor assembly, a cryogenic cooling assembly for maintaining the superconducting state, and a control assembly. The rotor assembly includes a permanent magnet rotor with a central rotating shaft in the middle. The stator assembly includes a high-temperature superconducting bulk material and a superconducting adjustment coil arranged sequentially from the inside to the outside. A magnetic yoke is provided on the outer and bottom sides of the superconducting adjustment coil. The cryogenic cooling assembly includes a cold-conducting component located at the bottom end of the high-temperature superconducting bulk material. The control assembly is used to control the current and magnetic field to adjust the axial balance position of the permanent magnet rotor.

2. The hybrid fully superconducting magnetic levitation bearing according to claim 1, characterized in that, The permanent magnet rotor is coaxially arranged with the central rotating shaft.

3. The hybrid fully superconducting magnetic levitation bearing according to claim 1, characterized in that, The high-temperature superconducting bulk material is located directly below the permanent magnet rotor, and uses the magnetic flux pinning effect to provide axial levitation force.

4. The hybrid fully superconducting magnetic levitation bearing according to claim 1, characterized in that, The superconducting adjustment coil is set around the high-temperature superconducting bulk material and is coaxial with the high-temperature superconducting bulk material. A physical gap is left between the superconducting adjustment coil and the high-temperature superconducting bulk material. The superconducting adjustment coil uses the magnetic field generated by energizing to modulate the background magnetic field of the working air gap.

5. The hybrid fully superconducting magnetic levitation bearing according to claim 1, characterized in that, The magnetic yoke is an L-shaped cross-section magnetic yoke, which wraps around the outside and bottom of the superconducting adjustment coil.

6. The hybrid fully superconducting magnetic levitation bearing according to claim 5, characterized in that, The magnetic yoke is used to constrain the leakage magnetic field of the superconducting regulating coil, guide the regulating magnetic field to the working air gap and the high-temperature superconducting bulk material region, and at the same time play a role in magnetic shielding.

7. The hybrid fully superconducting magnetic levitation bearing according to claim 1, characterized in that, The cryogenic cooling component is used to maintain the low temperature of the high-temperature superconducting bulk material and the superconducting control coil.

8. The hybrid fully superconducting magnetic levitation bearing according to claim 7, characterized in that, The bottom of the high-temperature superconducting bulk material is connected to the cold head of the refrigerator through a cooling component to maintain the superconducting state.

9. The hybrid fully superconducting magnetic levitation bearing according to claim 1, characterized in that, The control components include a displacement sensor, a low-pass filter, a controller, and a bipolar power supply. The displacement sensor is fixedly mounted on the stator assembly, with its probe facing the axial end face of the permanent magnet rotor. The displacement sensor is used to acquire the axial displacement signal of the permanent magnet rotor in real time. The output of the displacement sensor is connected to the input of the low-pass filter. The axial displacement signal of the permanent magnet rotor is filtered out by the low-pass filter to remove high-frequency vibration components and retain quasi-static or low-frequency displacement signals. The output of the low-pass filter is connected to the controller, the output of the controller is connected to the control terminal of the bipolar power supply, the output of the bipolar power supply is connected to the superconducting regulating coil, and the controller drives the bipolar power supply to output regulating current to the superconducting regulating coil.

10. A control method for a hybrid fully superconducting magnetic levitation bearing according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: The axial displacement signal of the permanent magnet rotor is acquired in real time by a displacement sensor. The acquired axial displacement signal is filtered out by a low-pass filter to remove high-frequency vibration components and retain quasi-static or low-frequency displacement signals. Step 2: The quasi-static or low-frequency displacement signal filtered in Step 1 is compared with the ideal axial suspension balance position setpoint of the permanent magnet rotor by the controller to obtain the position deviation. The position deviation is then calculated using a PID control algorithm or a fuzzy control algorithm to generate a control quantity representing the magnitude and direction of the required compensation current. Step 3: The controller drives the bipolar power supply to output a regulating current to the superconducting regulating coil; Step four: Based on the hybrid mechanism of high-temperature superconducting bulk material providing main load-bearing capacity and superconducting adjustment coil providing fine-tuning force, the magnetic field generated by the superconducting adjustment coil is superimposed with the main magnetic field of the permanent magnet rotor at the working air gap. The magnitude and direction of the superconducting adjustment coil current are changed by the controller to enhance or weaken the magnetic flux density at the working air gap, thereby realizing low-frequency non-contact active adjustment of the axial balance position of the permanent magnet rotor.

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