A test device for a magnetic levitation bearing flexible rotor system

Abstract

This invention relates to a test device for a magnetic levitation bearing flexible rotor system, comprising a base, a drive motor, a stator assembly, a bearing assembly, an eddy current displacement measurement assembly, a flexible coupling, a flexible rotor, and a programmable control system. The drive motor, stator assembly, and bearing assembly are sequentially fixedly connected to one side of the upper surface of the base. The eddy current displacement measurement assembly is slidably connected to the upper surface of the base. The output shaft of the drive motor is fixedly connected to one end of the flexible coupling. The other end of the flexible coupling is fixedly connected to the flexible rotor. This invention's test device for a magnetic levitation bearing flexible rotor system uses a cantilever structure to simulate the asymmetric dynamic behavior of the flexible rotor, providing a more uniform air gap magnetic field. The base has guide grooves for translating the eddy current displacement measurement assembly and also has a locking function.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation technology and relates to a test device for a magnetic levitation bearing flexible rotor system. Background Technology

[0002] In rotating machinery systems such as aero-engines, centrifugal compressors, and turbine generators, rotor dynamics are a key factor affecting equipment stability and reliability. In high-speed, high-precision applications, flexible rotors, due to their light weight and low critical speed, are prone to vibration instability. The contact friction and lubrication limitations of traditional mechanical bearings are insufficient to meet the high-speed, long-life operational requirements. Magnetic levitation bearings achieve contactless rotor support through electromagnetic force, offering advantages such as frictionless operation and actively controllable damping. However, the development of their control algorithms and the verification of their dynamic characteristics require high-precision testing equipment.

[0003] Existing magnetic levitation bearing testing devices mostly employ a double-supported symmetrical rotor structure, which cannot simulate the asymmetric dynamic characteristics of asymmetric cantilever rotors. Furthermore, the fixed displacement sensor layout of existing devices fails to fully reflect modal information when the flexible rotor bends, and is difficult to adapt to the air gap measurement requirements of different rotor configurations. Regarding the stator design of magnetic levitation bearings, the magnetic field uniformity and control accuracy of the traditional 8-pole layout still have room for optimization, and there is a lack of targeted optimization and verification work for accurate modeling of the nonlinear electromagnetic forces of magnetic levitation bearings.

[0004] To address the aforementioned issues, there is an urgent need for an experimental device capable of simulating the asymmetric dynamics of flexible rotors, possessing adjustable measurement and protection functions, and optimizing the accurate modeling of nonlinear electromagnetic forces in magnetic levitation bearings. This device would provide a reliable testing platform for the development of active control strategies for high-speed rotating magnetic levitation bearing rotor equipment. Summary of the Invention

[0005] To address the technical problems existing in the above-mentioned technologies, this invention provides a test device for a magnetic levitation bearing flexible rotor system. The specific technical solution of this invention is as follows:

[0006] A test device for a magnetic levitation bearing flexible rotor system includes a base 1, a drive motor 2, a stator assembly 3, a bearing assembly 4, an eddy current displacement measurement assembly 5, a flexible coupling 6, a flexible rotor 7, and a programmable control system 8.

[0007] A drive motor 2, a stator assembly 3, and a bearing assembly 4 are sequentially fixedly connected to one side of the upper surface of the base 1; an eddy current displacement measuring assembly 5 is slidably connected to the upper surface of the base 1; one end of a flexible coupling 6 is fixedly connected to the output shaft of the drive motor 2; and a flexible rotor 7 is fixedly connected to the other end of the flexible coupling 6.

[0008] Furthermore, the stator assembly 3 includes a near-end magnetic levitation bearing stator assembly 31 and a far-end magnetic levitation bearing stator assembly 32, the bearing assembly 4 includes a near-end protection bearing assembly 41 and a far-end protection bearing assembly 42, and the eddy current displacement measurement assembly 5 includes a near-end eddy current displacement measurement assembly 51 and a far-end eddy current displacement measurement assembly 52.

[0009] The flexible rotor 7 passes concentrically through the near-end protection bearing assembly 41, the near-end magnetic levitation bearing stator assembly 31, the near-end eddy current displacement measurement assembly 51, the far-end eddy current displacement measurement assembly 52, the far-end magnetic levitation bearing stator assembly 32, and the far-end protection bearing assembly 42 in sequence.

[0010] Furthermore, the base 1 includes a guide groove 101, which has a locking mechanism; the position and adjustable range of the guide groove 101 are specially adapted to the measurement requirements of the programmable control system 8 for the bending mode vibration of the flexible rotor 7, so that the near-end eddy current displacement measurement assembly 51 and the far-end eddy current displacement measurement assembly 52 can flexibly set the measurement section position according to the control program written in the programmable control system 8.

[0011] Furthermore, the stator assembly 3 also includes a stator outer ring 302 fixedly connected above a stator support frame 301. A stator magnetic pole 303 is fixedly connected inside the stator outer ring 302, and a stator coil 304 is wound and fixedly connected to each stator magnetic pole 303. The stator coil 304 is optimized for current ripple measurement. When the bias current set by the controller assembly 801 and the chopping frequency of the power amplifier 802 are constant, the number of coil turns, wire diameter, and winding direction are adjusted to ensure the coil has the lowest possible inductive reactance while maintaining load-bearing capacity, thus supporting self-sensing control by the programmable control system 8. The stator coil 304 is arranged in the following magnetic pole polarization sequence:

[0012] They are arranged in an NSSNNSSNNSSNNSSN pattern, with each group of four connected electrically.

[0013] Furthermore, the stator outer ring 302 is made of silicon steel sheets insulated and laminated, and the stator magnetic poles 303 are made of 16 sets of silicon steel sheets insulated and laminated evenly distributed along the circumference.

[0014] Furthermore, the bearing assembly 4 also includes a protective bearing support frame 401, the surface of which is provided with reinforcing ribs and a deep groove ball protective bearing 402 is fixed at the opening; the near-end protective bearing assembly 41 is installed close to the near-end magnetic levitation bearing stator assembly 31; the far-end protective bearing assembly 42 is installed close to the far-end magnetic levitation bearing stator assembly 32.

[0015] Furthermore, the eddy current displacement measurement assembly 5 includes an eddy current displacement sensor support frame 501. The surface of the eddy current displacement sensor support frame 501 is provided with reinforcing ribs and can be translated or locked along the guide groove 101. The eddy current displacement sensor support frame 501 is fixedly connected to four eddy current displacement sensors 502 respectively arranged in the horizontal and vertical directions to support the realization of sensing control by the programmable control system 8.

[0016] Furthermore, the flexible rotor 7 includes a main shaft 701; a proximal journal 702, a proximal counterweight turntable 703, a mid-position counterweight turntable 704, a distal journal 705, and a cantilever counterweight turntable 706 are concentrically fixedly connected to the main shaft 701 in sequence; a gap d exists between the main shaft 701 and the inner ring of the deep groove ball bearing 402. p There is a gap d between the main shaft 701 and the measuring end face of the eddy current displacement sensor 502. m The proximal journal 702, distal journal 705, and stator pole 303 have an air gap s, and the three satisfy the following relationship:

[0017] d m >s>d p (1)

[0018] The near-end journal 702 and the far-end journal 703 are made of silicon steel sheets insulated and laminated; the end face of the center counterweight turntable 704 is provided with 8 unbalanced counterweight mounting holes 7041 evenly distributed along the circumference.

[0019] Furthermore, the programmable control system 8 includes a controller assembly 801 and a power amplifier 802; the controller assembly 801 is electrically connected to the eddy current displacement sensor 502; and the power amplifier 802 is electrically connected to the controller assembly 801 and the stator coil 304.

[0020] Beneficial effects

[0021] The experimental device for a magnetic levitation bearing flexible rotor system of the present invention uses a cantilever structure to simulate the asymmetric dynamic behavior of a flexible rotor. The stator section of the active magnetic bearing uses 16 magnetic poles to provide a more uniform air gap magnetic field. The base has guide slots for translating the eddy current displacement measurement assembly and has a locking function. The programmable control system is highly integrated with the hardware and has a drive signal ripple feedback function, enabling self-sensing control of the magnetic levitation bearing. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the test device for the magnetic levitation bearing flexible rotor system of the present invention.

[0023] Figure 2 This is a schematic diagram of the magnetic levitation bearing stator assembly of the test device for the magnetic levitation bearing flexible rotor system of the present invention.

[0024] Figure 3 This is a schematic diagram of the protective bearing assembly structure of the test device for the magnetic levitation bearing flexible rotor system of the present invention.

[0025] Figure 4 This is a schematic diagram of the eddy current displacement measurement assembly of the magnetic levitation bearing flexible rotor system test device of the present invention.

[0026] Figure 5 This is a schematic diagram of the flexible cantilever rotor structure of the test device for the magnetic levitation bearing flexible rotor system of the present invention.

[0027] Figure 6 This is a schematic diagram of the working principle of the programmable controller of the magnetic levitation bearing flexible rotor system test device of the present invention.

[0028] Attached icon number

[0029] 1-Base, 101-Guide groove, 2-Drive motor, 31-Near-end magnetic levitation bearing stator assembly, 32-Distant-end magnetic levitation bearing stator assembly, 301-Stator support frame, 302-Stator outer ring, 303-Stator magnetic pole, 304-Stator coil, 41-Near-end protection bearing assembly, 42-Distant-end protection bearing assembly, 401-Protective bearing bracket, 402-Deep groove ball bearing protection, 51-Near-end eddy current displacement measurement assembly, 52-Distant-end... Eddy current displacement measurement assembly, 501-Eddy current displacement sensor bracket, 502-Eddy current displacement sensor, 6-Flexible coupling, 7-Flexible rotor, 701-Main shaft, 702-Proximal journal, 703-Proximal counterweight turntable, 704-Mid-position counterweight turntable, 7041-Unbalanced counterweight mounting hole, 705-Far-end journal, 706-Cantilever counterweight turntable, 8-Programmable control system, 801-Controller assembly, 802-Power amplifier. Detailed Implementation

[0030] The following is in conjunction with the appendix Figures 1 to 6 The following detailed embodiments of the experimental device for a magnetic levitation bearing flexible rotor system of the present invention are further described with specific examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] like Figure 1 As shown, in the magnetic levitation bearing flexible rotor system test device of the present invention, the base 1 serves as the mounting carrier for the drive motor 2, stator assembly 3, bearing assembly 4, and eddy current displacement measurement assembly 5, and has a flat upper surface for mounting these components. The guide groove 101 on the base can guide the eddy current displacement measurement assembly 51 / 52 to translate within a certain range and can be fixed by a locking mechanism, specifically adapted to the measurement requirements of the programmable control system 8 for the bending mode vibration of the flexible rotor 7, and flexibly setting the measurement section position.

[0032] The drive motor 2 provides rotational driving torque to the flexible rotor 7, and can perform program speed regulation and constant speed dwell within the working speed range, adjusting the speed of the flexible rotor 7 to the speed range specified by the programmable control system 8.

[0033] The near-end magnetic levitation bearing stator assembly 31 and the far-end magnetic levitation bearing stator assembly 32 are driven by the programmable control system 8, providing controlled electromagnetic force support for the flexible rotor 7.

[0034] like Figure 2 As shown, the stator support frame 301 is fixedly connected to the base 1, and simultaneously fixedly connected to the stator outer ring 302 above, providing stable support for the stator assembly 3. The stator outer ring 302 and the 16 stator magnetic poles 303 evenly distributed and fixedly connected along the circumference are all made of laminated silicon steel sheets, forming part of the stator magnetic circuit, minimizing eddy current losses on the stator during the operation of the magnetic levitation bearing. Each stator magnetic pole 303 is wound and fixedly connected with a stator coil 304. All 16 stator coils are arranged in the manner of "NSSNNSSNNSSNNSSN", and are electrically connected in groups of four, driven by current, providing support to the flexible rotor 7 in the form of electromagnetic force.

[0035] The stator coil 304 is optimized for current ripple measurement. When the bias current set by the controller assembly 801 and the chopping frequency of the power amplifier 802 are constant, the coil needs to have as little inductive reactance as possible while ensuring load capacity, so as to support the realization of self-sensing control by the programmable control system 8.

[0036] The near-end protection bearing assembly 41 and the far-end protection bearing assembly 42 provide protection for the magnetic levitation bearing stator assembly and the flexible rotor 7.

[0037] like Figure 3 As shown, the surface of the protective bearing support frame 401 is provided with reinforcing ribs and is fixedly connected to the base 1. At the same time, the upper opening is fixedly connected to the outer ring of the deep groove ball protective bearing 402, providing stable support for the protective bearing assembly.

[0038] When the magnetic levitation bearing operates under normal controlled conditions, the flexible rotor 7 has no mechanical contact with any structure other than the flexible coupling 6. When the magnetic levitation bearing does not operate or operates abnormally, the inner ring of the deep groove ball bearing 402 will preferentially contact and support the main shaft 701 before the proximal journal 702, distal journal 705, and stator pole 303 collide and rub against each other, thus ensuring protection for the magnetic levitation bearing stator assembly and the flexible rotor 7. Let d be the gap between the main shaft 701 and the inner ring of the deep groove ball bearing 402. p An air gap s exists between the near-end journal 702, the far-end journal 705, and the stator pole 303, which should satisfy the following:

[0039] s>d p (3)

[0040] Considering that the flexible rotor 7 may induce bending modes at high speeds, to ensure the effectiveness of the protection function, the bearing assembly 41 must be installed as close as possible to the stator assembly 3 without affecting the normal rotation of the flexible rotor 7. In the event of a failure of the programmable control system 8, if the flexible rotor 7 is in a state of significant bending or torsion, this installation method minimizes the rubbing damage between the flexible rotor 7 and the magnetic levitation bearing stator assembly 31 / 32.

[0041] The near-end eddy current displacement measurement assembly 51 and the far-end eddy current displacement measurement assembly 52 measure the radial displacement of the flexible rotor 7 at their respective installation positions.

[0042] like Figure 4 As shown, the eddy current displacement sensor support frame 501 has reinforcing ribs on its surface, allowing it to be translated or locked along the guide groove 101. It is also fixedly connected to four eddy current displacement sensors 502 arranged horizontally and vertically, providing stable support for the eddy current displacement measurement assembly 5 to support the programmable control system 8 in implementing sensor-based control. To ensure accurate measurement of the possible radial displacement of the flexible rotor 7 within the air gap s, a gap d is defined between the main shaft 701 and the measuring end face of the eddy current displacement sensor 502. m It should satisfy:

[0043] d m >s (4)

[0044] Considering that the flexible rotor 7 may induce bending modes at high speeds, if it is desired to accurately reflect the radial displacement at the rotor journal for the sensor-controlled implementation of the programmable control system 8, the eddy current displacement measurement assembly must be locked as close as possible to the magnetic levitation bearing stator assembly on the guide groove 101 without affecting the normal rotation of the flexible rotor 7. If it is desired to measure the radial displacement of the rotor at a certain distance away from the near-end journal 702 and the far-end journal 705 for the sensor-controlled implementation of the programmable control system 8, the near-end eddy current displacement measurement assembly 51 and the far-end eddy current displacement measurement assembly 52 must be locked at a designated position on the guide groove 101. By accurately modeling the magnetic levitation bearing flexible rotor system constructed by this invention, a state observer is obtained, thereby indirectly calculating the radial displacement at the near-end journal 702 and the far-end journal 705 of the rotor.

[0045] The flexible coupling 6 is fixedly connected to the drive motor 2 and the flexible rotor 7 at both ends, respectively. While transmitting the torque from the drive motor 2 to the flexible rotor 7, it does not provide additional support stiffness for the flexible rotor 7 at the connection point, so as to minimize the impact on the mechanical characteristics of the flexible rotor 7 and reduce the structural disturbance and control error when the programmable control system 8 is executed.

[0046] The flexible rotor 7 is the rotating mechanism in the experimental device of this invention. The main shaft 701 is concentrically fixed with the following components in sequence: a proximal journal 702, a proximal counterweight turntable 703, a mid-position counterweight turntable 704, a distal journal 705, and a cantilever counterweight turntable 706. The proximal journal 702 and the distal journal 705 are made of laminated silicon steel sheets, forming part of the rotor's magnetic circuit to minimize eddy current losses on the rotor during magnetic levitation bearing operation. The arrangement of the proximal counterweight turntable 703, the mid-position counterweight turntable 704, and the cantilever counterweight turntable 706 on the rotor simulates the characteristics of a turbine generator rotor in actual operation. The mid-position counterweight turntable 704 has eight circumferentially distributed unbalanced counterweight mounting holes 7041 on its end face for conducting dynamic balancing tests on the mid-position counterweight turntable 704 or the flexible rotor 7 as a whole.

[0047] The programmable control system 8 obtains feedback from the eddy current displacement measurement system and performs control on the magnetic levitation bearing stator assembly to levitate the flexible rotor 7 and control its vibration. Figure 6 As shown, the programmable control system 8 includes a controller assembly 801 and a power amplifier 802. The controller assembly 801 has data acquisition, control program writing and execution functions, and is electrically connected to the eddy current displacement sensor 502 of the eddy current displacement measurement assembly for displacement signal acquisition. The power amplifier 802 has current drive and drive signal feedback functions, and is electrically connected to the controller assembly 801 to acquire control signals and feed back drive current, voltage, ripple, and other signals. It is also electrically connected to the stator coil 304 of the magnetic levitation bearing stator assembly for current drive. Depending on the control implementation requirements, the controller assembly 801 can be programmed with a sensing control algorithm using the displacement signal fed back from the eddy current displacement measurement assembly, or it can be programmed with a self-sensing control algorithm using the coil ripple signal fed back from the power amplifier 802, providing rich experimental conditions for hardware-in-the-loop control algorithm programming.

[0048] The specific method of using the device of the present invention is as follows:

[0049] Step 1: Correctly install and debug the test device for the magnetic levitation bearing flexible rotor system of the present invention.

[0050] Step 2: Select the control implementation method and write the control program on the programmable control system 8.

[0051] Step 3: Determine and lock the installation positions of the near-end eddy current displacement measurement assembly 51 and the far-end eddy current displacement measurement assembly 52 according to the requirements of the selected control implementation method.

[0052] Step 4: With the drive motor 2 off, start the programmable control system 8 to power on the near-end magnetic levitation bearing stator assembly 31 and the far-end magnetic levitation bearing stator assembly 32, and attempt a pre-vibration test of the flexible rotor 7.

[0053] Step 5: After confirming that the pre-vibration in Step 6 is normal, start the drive motor 2 and conduct the formal test.

[0054] Step 6: End the experiment and clean up the test site.

[0055] The above description of the present invention is only a preferred embodiment of the present invention and is not intended to limit the implementation of the present invention. Those skilled in the art can easily make corresponding modifications or alterations based on the main concept and spirit of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection claimed in the claims.

Claims

1. A test device for a magnetic levitation bearing flexible rotor system, characterized in that, It includes a base (1), a drive motor (2), a stator assembly (3), a bearing assembly (4), an eddy current displacement measurement assembly (5), a flexible coupling (6), a flexible rotor (7), and a programmable control system (8); A drive motor (2), a stator assembly (3), and a bearing assembly (4) are sequentially fixedly connected to one side of the upper surface of the base (1); an eddy current displacement measuring assembly (5) is slidably connected to the upper surface of the base (1); one end of a flexible coupling (6) is fixedly connected to the output shaft of the drive motor (2); and a flexible rotor (7) is fixedly connected to the other end of the flexible coupling (6). The stator assembly (3) includes a near-end magnetic levitation bearing stator assembly (31) and a far-end magnetic levitation bearing stator assembly (32); the bearing assembly (4) includes a near-end protection bearing assembly (41) and a far-end protection bearing assembly (42); and the eddy current displacement measurement assembly (5) includes a near-end eddy current displacement measurement assembly (51) and a far-end eddy current displacement measurement assembly (52). The flexible rotor (7) passes concentrically through the near-end protection bearing assembly (41), the near-end magnetic levitation bearing stator assembly (31), the near-end eddy current displacement measurement assembly (51), the far-end eddy current displacement measurement assembly (52), the far-end magnetic levitation bearing stator assembly (32), and the far-end protection bearing assembly (42) in sequence. The stator assembly (3) also includes a stator outer ring (302) fixedly connected above a stator support frame (301). A stator magnetic pole (303) is fixedly connected inside the stator outer ring (302). A stator coil (304) is wound and fixedly connected on each of the stator magnetic poles (303). The number of turns, wire diameter, and winding direction of the stator coil (304) are matched according to the bias current set by the controller assembly (801) and the chopping frequency of the power amplifier (802) to support the programmable control system (8) to perform self-sensing control. The stator coils (304) are arranged in the order of magnetic pole polarization as NSSNNSS NNSSNNSSN, and are electrically connected in groups of four. The flexible rotor (7) includes a main shaft (701); a proximal journal (702), a proximal counterweight turntable (703), a mid-position counterweight turntable (704), a distal journal (705), and a cantilever counterweight turntable (706) are concentrically fixedly connected on the main shaft (701); there is a gap between the main shaft (701) and the inner ring of the deep groove ball bearing (402). There is a gap between the main shaft (701) and the measuring end face of the eddy current displacement sensor (502). An air gap exists between the proximal journal (702), the distal journal (705), and the stator pole (303). The three satisfy the following relation: The near-end journal (702) and the far-end journal (703) are made of silicon steel sheets insulated and laminated; the end face of the center counterweight turntable (704) is provided with 8 unbalanced counterweight mounting holes (7041) evenly distributed along the circumference.

2. The test device for a magnetic levitation bearing flexible rotor system according to claim 1, characterized in that, The base (1) includes a guide groove (101) with a locking mechanism; the position and adjustable range of the guide groove (101) are specially adapted to the measurement requirements of the programmable control system (8) for the bending mode vibration of the flexible rotor (7), so that the near-end eddy current displacement measurement assembly (51) and the far-end eddy current displacement measurement assembly (52) can flexibly set the measurement section position according to the control program written in the programmable control system (8).

3. The test device for a magnetic levitation bearing flexible rotor system according to claim 1, characterized in that, The stator outer ring (302) is made of silicon steel sheets insulated and laminated, and the stator magnetic poles (303) are made of 16 sets of silicon steel sheets insulated and laminated evenly distributed along the circumference.

4. The test device for a magnetic levitation bearing flexible rotor system according to claim 1, characterized in that, The bearing assembly (4) also includes a protective bearing support frame (401), the surface of which is provided with reinforcing ribs and a deep groove ball protective bearing (402) is fixed at the opening; the near-end protective bearing assembly (41) is installed close to the near-end magnetic levitation bearing stator assembly (31); the far-end protective bearing assembly (42) is installed close to the far-end magnetic levitation bearing stator assembly (32).

5. The test device for a magnetic levitation bearing flexible rotor system according to claim 1, characterized in that, The eddy current displacement measurement assembly (5) includes an eddy current displacement sensor support frame (501). The eddy current displacement sensor support frame (501) has reinforcing ribs on its surface and can be translated or locked along the guide groove (101). The eddy current displacement sensor support frame (501) is fixedly connected to four eddy current displacement sensors (502) arranged in the horizontal and vertical directions respectively, so as to support the realization of sensing control by the programmable control system (8).

6. The test device for a magnetic levitation bearing flexible rotor system according to claim 1, characterized in that, The programmable control system (8) includes a controller assembly (801) and a power amplifier (802); the controller assembly (801) is electrically connected to an eddy current displacement sensor (502); the power amplifier (802) is electrically connected to the controller assembly (801) and the stator coil (304).

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