A magnetic bearing rotor state detection device based on a flexible detection collar

Abstract

The present invention discloses a magnetic bearing rotor state monitoring device based on a flexible detection collar. The rotor motion state detection device comprises a magnetic bearing system, a flexible detection collar, an emitter core, a transmitting coil, a support, and a frequency sweeping device. A flexible detection collar is sleeved on the rotor of the magnetic bearing system. The collar uses a PI flexible material as a base layer and has built-in temperature, acceleration, and strain sensors to collect data and measure the rotor's strain, torsion, amplitude, and temperature. Wireless charging technology is used to charge the collar. Finally, the sensor signal is transmitted at different frequencies through an oscillating circuit in the sensor's supporting circuit and an antenna auxiliary circuit, and then transmitted to a frequency sweeping device for frequency sweeping reception and processing. This device solves the problem of being unable to directly measure important data related to the rotor's modal state in real time. This allows for instantaneous change in the control strategy when the rotor reaches a critical speed, maintaining stable operation of the magnetic bearing system.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic bearing rotor motion state detection, and in particular relates to a magnetic bearing rotor state detection device based on a flexible collar. Background Art

[0002] Magnetic bearings (MBLs) utilize electromagnetic forces to support the rotor's contactless motion. Compared to traditional mechanical bearings, MBLs offer advantages such as zero friction, zero wear, and the need for lubrication. Consequently, they significantly reduce maintenance costs and extend equipment life. However, the stability and reliability of MBLs depend directly on the precise detection and control of the rotor's motion. Therefore, rotor motion detection technology has become a key issue in MBL research.

[0003] In magnetic bearing systems, the rotor's motion typically includes a variety of complex motions, including translation, rotation, vibration, and various disturbances. During high-speed rotation, the rotor may experience multiple critical speeds, corresponding to situations where the rotor's rotational frequency is close to or equal to the natural frequency of a certain mode. Near the critical speed, the rotor's amplitude increases significantly due to resonance, potentially leading to unstable system operation or even damage. To mitigate the effects of resonance on the system, real-time monitoring of rotor strain, torsion, and amplitude data is required to promptly understand the rotor's modal state and adjust the control strategy to maintain stable system operation.

[0004] Existing methods for detecting rotor motion states mainly rely on installing displacement sensors, speed sensors, etc. on the magnetic bearing stators for detection. However, since the rotor is suspended by electromagnetic force, its strain, torsion, and vibration amplitude, which are directly related to the rotor mode, can only be estimated by simulation software. There are inevitable errors compared with the actual operating state of the rotor, resulting in low accuracy and slow response in the acquisition of rotor motion state data, which can easily lead to system instability and urgently needs to be improved. Summary of the Invention

[0005] In response to the above problems, the purpose of the present invention is to provide a magnetic bearing rotor motion state detection device based on flexible detection rings. A total of four flexible rotor rings are used on the two-level stepped shafts of the rotor to measure the rotor strain, torsion, amplitude and temperature data. The rings are made of PI (polyimide) flexible material and have three built-in sensors for temperature, acceleration and strain to collect data. The rings are charged using wireless charging technology of rotating equipment. Finally, different sensor signals are transmitted at different frequencies through an oscillation circuit and transmitted to a sweeping device for sweeping reception and processing, which solves the problem of being unable to directly measure important data related to the rotor mode in real time, so that the control strategy can be changed immediately when the rotor reaches the critical speed to maintain the stable operation of the magnetic bearing system.

[0006] The specific technical solutions are as follows:

[0007] A magnetic bearing rotor condition monitoring device based on a flexible detection collar includes a magnetic bearing rotor, a magnetic bearing stator and a support. The magnetic bearing stator is fixed on a bracket of the support. The inner ring of the magnetic bearing stator is circumferentially distributed with magnetic poles. The two ends of the magnetic bearing rotor respectively pass through the magnetic bearing stator and are magnetically suspended and connected to the magnetic poles.

[0008] The magnetic poles are eight-pole heteropolar magnetic bearing poles. In the structure of the heteropolar magnetic bearing, the polarities of the magnets are arranged alternately in the circumferential direction, that is, the polarities of adjacent poles are opposite. This arrangement enables the magnetic field to generate a stable supporting force, allowing the rotor to rotate in suspension.

[0009] In order to achieve stable suspension, the heteropolar magnetic bearing uses electromagnets to generate a control magnetic field. By adjusting the current of the electromagnets, the system can dynamically adjust the magnitude and direction of the magnetic force to maintain the balance and stability of the rotor.

[0010] The heteropolar magnetic bearing can not only provide radial support force, but also control the axial position and posture of the rotor by adjusting the direction and magnitude of the magnetic force, thereby achieving support and control with multiple degrees of freedom.

[0011] The support described above has a vibration-damping function. While magnetic bearings provide frictionless support, they are sensitive to external vibrations. External vibrations or shocks can be transmitted through the mounting structure to the magnetic bearings and the supported rotor. The vibration-damping support effectively isolates these external vibrations, reducing their impact on the system and suppressing resonance, ensuring stable rotor suspension. The support with a vibration-damping function comprises a rigid isolation base and four spring elastic elements fixed at the bottom corners of the isolation base. These elements provide flexible support, absorb external vibration energy, and reduce the transmission of vibration to the magnetic bearing system.

[0012] The vibration isolation base is the supporting structure of the vibration reduction platform. It connects the entire vibration reduction system with the magnetic bearing body and provides necessary structural support while isolating vibration.

[0013] The stator of the magnetic bearing is covered with an outer cover, which effectively protects the internal components from dust, moisture, and other contaminants, thereby improving the reliability and service life of the magnetic bearing. The cover also secures the stator assembly within the bearing housing, ensuring the stable position of the electromagnetic coils and other internal components, thereby maintaining an appropriate gap between the stator and rotor and reducing noise generated during operation of the magnetic bearing.

[0014] The magnetic bearing rotor is made of high-strength stainless steel to ensure sufficient mechanical strength and rigidity during high-speed rotation. The magnetic bearing rotor has a stepped shaft structure, which includes a first-level stepped shaft, a second-level stepped shaft, and a third-level stepped shaft from the middle to the end. The diameter of the first-level stepped shaft is twice that of the second-level stepped shaft, and the diameter of the second-level stepped shaft is twice that of the third-level stepped shaft. Shaft segments of different diameters are set to accommodate different support positions and load requirements. During the design, ensure that the transition areas between each level of shaft segments are sufficiently smooth to avoid stress concentration and fatigue damage. The rotor geometry should be precise to maintain a uniform air gap between the rotor and the magnetic bearing. The magnetic bearing rotor is strictly dynamically balanced to reduce vibration caused by imbalance. The dynamic balance level of the rotor reaches G2.5, making it suitable for high-speed applications and ensuring long-term stability of the rotor.

[0015] The flexible detection ring includes an insulating ring fixed on the rotor. There are four flexible detection rings in total, two of which are set on both ends of the first-level stepped shaft and two are set on the outer ends of the second-level stepped shafts on both sides.

[0016] The flexible detection collar described above uses PI (polyimide) organic polymer flexible material as the main base material. PI material has good flexibility and bending resistance, and can withstand multiple bending and deformation without damage. It is very suitable for flexible circuit board applications that require flexibility. PI material can be made into a very thin film while maintaining high strength. These advantages allow it to be bent into a circular detection collar and used for a long time. PI material has excellent thermal stability and can be used for a long time at temperatures as high as 300°C or even higher, which gives it a significant advantage in the operating temperature range of 50°C-120°C for magnetic bearings. PI material has little dimensional change under different temperature and humidity conditions and has a low thermal expansion coefficient, which helps the collar maintain circuit stability and reliability in high-precision detection environments.

[0017] The circuit of the flexible detection collar includes three sensors, namely a temperature sensor, an acceleration sensor, and a strain sensor.

[0018] Furthermore, the temperature sensor can detect the temperature of the rotor at this location, which is used to reflect the operating temperature of the rotor in different modes, serving as an auxiliary indicator for switching the control strategy when the rotor reaches a critical state, and monitoring the operating temperature of the rotor in real time.

[0019] Furthermore, the accelerometer can detect the amplitude acceleration of the rotor at that location, reflecting the rotor's vibration amplitude at that location. When the vibration amplitude exceeds a certain threshold, it indicates that the rotor has deviated from normal operating conditions. Failure to identify and address this in a timely manner can lead to a loss of control capability in the magnetic bearings. The vibration amplitude also reflects the rotor's current mode, serving as an important indicator for switching control strategies when the rotor reaches a critical state.

[0020] Furthermore, the strain sensor can detect the stress and torsional force at that location on the rotor. Its function is to reflect the strain and torque at that location on the rotor. Strain and torque, as physical quantities that directly reflect the force state and deformation of the rotor, can provide important measured data for modal characteristic analysis and serve as important indicators for switching control strategies when the rotor reaches a critical state.

[0021] Furthermore, a speed sensor and displacement sensor are mounted directly on the pole tips of the magnetic bearing stator, secured with polyurethane adhesive. Polyurethane adhesive has strong adhesion, elasticity, and impact resistance, making it suitable for applications with high vibrations and ensuring a tight fit between the sensor and the magnetic poles.

[0022] Furthermore, the speed sensor and displacement sensor detect the displacement deformation and speed of the rotor, and their function is to reflect the displacement and speed of the rotor at that location, which serves as an important indicator for switching the control strategy when the rotor reaches a critical state.

[0023] In order to meet the bending and ductility requirements of the flexible ring, the temperature sensor, acceleration sensor and strain sensor all use graphene-based sensors. The graphene sensor has excellent flexibility and can withstand a bending deformation of 270 degrees.

[0024] The graphene strain sensor is a multi-layer structure, and its physical structure is mainly composed of a graphene film layer, a piezoelectric material layer, an electrode structure layer, a flexible substrate layer and a packaging layer.

[0025] Furthermore, the graphene film layer is a two-dimensional carbon material with a thickness of a single atomic layer, which has excellent mechanical properties and electrical conductivity and is used to convert externally applied mechanical strain into a detectable electrical signal.

[0026] Furthermore, the piezoelectric polymer in the piezoelectric material layer is coated with polyvinylidene fluoride. This piezoelectric material generates an electric charge when subjected to mechanical pressure. Combined with graphene, this enables highly sensitive strain detection. Graphene's conductivity allows these charges to be collected and conducted, thereby outputting a corresponding signal.

[0027] Furthermore, the graphene strain sensor is equipped with upper and lower electrodes to transfer the charge generated by the graphene and piezoelectric material to an external circuit for signal processing. The electrodes are made of highly conductive silver paste. The two layers of electrodes are attached to both sides of the graphene film, forming a complete electric field path.

[0028] Furthermore, the flexible base layer of the graphene strain sensor is a flexible film material PI (polyimide).

[0029] Furthermore, in order to prevent the sensitivity of the graphene strain sensor from being affected by external factors such as moisture and dust, a silicone rubber packaging layer is added to the outside of the sensor to ensure the stability and life of the sensor.

[0030] The graphene temperature sensor is a multi-layer structure, and its physical structure is mainly composed of a graphene film layer, a thermal coupling layer, an electrode structure layer, a flexible substrate layer and a packaging layer.

[0031] The graphene temperature sensor has the same structure as the graphene strain sensor except for the thermal coupling layer, and does not have a piezoelectric material layer.

[0032] Furthermore, the thermal coupling layer of the graphene temperature sensor uses copper plating, which enables heat to be evenly and effectively conducted to the graphene film, improving the graphene temperature sensor's ability to respond to external heat and ensuring that the graphene layer can accurately reflect temperature changes.

[0033] The graphene accelerometer has a multi-layer structure, and its physical structure is mainly composed of a graphene film layer, a diaphragm structure layer, a mass block, a flexible substrate layer, an electrode structure layer, and a packaging layer.

[0034] The graphene acceleration sensor has the same structure as the graphene strain sensor except for the diaphragm structure layer and the mass block, and does not have a piezoelectric material layer.

[0035] Furthermore, the core of the graphene accelerometer consists of a diaphragm structure, a mechanical structure that responds to external acceleration. Graphene is attached to this diaphragm. When subjected to acceleration, the diaphragm deforms, causing strain in the graphene layer. This, in turn, changes the electrical properties of the graphene, generating an electrical signal that reflects the acceleration.

[0036] Furthermore, the graphene accelerometer design incorporates a tiny mass connected to a vibrating diaphragm. When acceleration acts on the sensor, inertia causes the mass to shift relative to the diaphragm, which in turn strains the graphene film attached to the diaphragm. The presence of the mass makes the sensor more sensitive to changes in acceleration, thereby increasing its sensitivity.

[0037] Furthermore, each flexible detection ring of the first-level stepped shaft is provided with 8 temperature sensors, 8 acceleration sensors and 48 strain sensors, and each flexible detection ring of the second-level stepped shaft is provided with 4 temperature sensors, 4 acceleration sensors and 24 strain sensors.

[0038] Furthermore, the sensors within the flexible detection collar are arranged symmetrically around the periphery. The temperature sensor has a power of 10 milliwatts, an operating voltage of 5V, and an operating current of 2mA. The acceleration sensor has a power of 30 milliwatts, an operating voltage of 5V, and an operating current of 6mA. The strain sensor has a power of 50 milliwatts, an operating voltage of 5V, and an operating current of 10mA.

[0039] In order to print the sensors and supporting circuits in the flexible detection collar on the flexible film, the circuits are manufactured using semiconductor technology and the most basic circuit elements without packaging are used for design and production.

[0040] The supporting circuit of the temperature sensor consists of a step-down voltage-stabilized power supply circuit, a modulation amplifier circuit, an RC oscillation circuit, a power amplifier circuit and an antenna auxiliary circuit.

[0041] Furthermore, the temperature sensor's step-down voltage regulator circuit regulates the 12V input voltage provided by the receiving coil to a precise 5V output. Excess input voltage is dissipated as heat through linear voltage regulation, thereby maintaining output voltage stability.

[0042] Furthermore, the step-down voltage regulator circuit of the temperature sensor includes a differential amplifier for comparing the output voltage with a 5V reference voltage. If the output voltage deviates from 5V, the differential amplifier controls the internal power transistor to adjust the output voltage to 5V.

[0043] Furthermore, the step-down and voltage-stabilizing power supply circuit of the temperature sensor monitors the output voltage in real time through an internal negative feedback loop. When the voltage fluctuates, the negative feedback circuit will quickly adjust the conduction state of the transistor to ensure that the output voltage always remains stable.

[0044] Furthermore, in order to protect the voltage regulator and the load, the step-down voltage-stabilizing power supply circuit of the temperature sensor also integrates an overheat protection circuit and a short-circuit protection circuit. When the current is too large or the temperature is too high, it will automatically limit the current or shut down the output.

[0045] Furthermore, after receiving a stable 5V voltage supply, the temperature sensor detects subtle voltage changes through a circuit composed of a Schottky diode and capacitor. The sensor signal is amplified by a 40x amplifier circuit consisting of two operational amplifiers. It then generates a frequency-adjustable square wave through an RC square wave oscillator circuit. This square wave is then modulated by the power amplifier circuit and the antenna auxiliary circuit before being emitted.

[0046] The supporting circuit of the acceleration sensor is composed of a step-down voltage-stabilizing power supply circuit, an amplifying and modulating circuit, an RC oscillating circuit, a power amplifying circuit and an antenna auxiliary circuit.

[0047] Furthermore, the principle of the step-down and voltage-stabilizing power supply circuit of the acceleration sensor is the same as above.

[0048] Furthermore, after the acceleration sensor obtains a 5V stable voltage supply and collects data, it is filtered and processed. The sensor signal is amplified by a 40x amplifier circuit composed of two operational amplifiers, and then an adjustable frequency square wave is generated through an RC square wave oscillation circuit. The square wave is modulated by the power amplifier circuit and the antenna auxiliary circuit before being emitted.

[0049] The supporting circuit of the strain sensor is composed of a step-down voltage-stabilizing power supply circuit, an amplifying and modulating circuit, an RC oscillating circuit, a power amplifying circuit and an antenna auxiliary circuit.

[0050] Furthermore, the principle of the step-down and voltage-stabilized power supply circuit of the strain sensor is the same as above.

[0051] Furthermore, after receiving a stable 5V voltage supply, the strain sensor performs preliminary modulation on the generated subtle signal through a bridge structure. The sensor signal is amplified by a 40x amplifier circuit composed of two operational amplifiers, and then generates an adjustable frequency square wave through an RC square wave oscillation circuit. The square wave is modulated by the power amplifier circuit and the antenna auxiliary circuit before being emitted.

[0052] Furthermore, an emitter core is provided on the support, and a transmitting coil is wound on the top of the emitter core. The transmitting coil is located directly below the flexible detection ring. The transmitting coil is connected to an external power supply. Secondary receiving coils are provided in the supporting circuits of the strain sensor, acceleration sensor and temperature sensor. The flexible detection ring is powered by a wireless charging mode of a rotating device.

[0053] Furthermore, in this wireless charging mode, the supporting circuit of each sensor in the flexible test ring is integrated with a secondary receiving coil, and the induced voltage received by the secondary receiving coil is converted into a stable voltage through the power supply circuit and supplied to the sensor's signal amplification and modulation module, signal oscillation transmission module, power amplification module, and antenna transmission module.

[0054] Furthermore, in this wireless charging mode, magnetic coupling resonance is used to achieve wireless charging. The transmitting coil and the secondary receiving coil are tuned to the same resonant frequency. The secondary receiving coil resonates with the transmitting coil, receives the alternating magnetic field, and generates an induced current.

[0055] Furthermore, in this wireless charging mode, since the continuous rotation of the rotor will cause the distance and alignment status between the coils to change, the system is equipped with a frequency tracking system in the transmitting coil circuit to monitor the frequency changes of the receiving coil in real time, and change the frequency of the transmitting coil to make it the same as the frequency of the receiving coil, so as to adjust the resonant frequencies of the primary and secondary coils in real time to achieve dynamic matching.

[0056] Furthermore, in this wireless charging mode, the transmitting coil and the secondary receiving coil use copper wires with a small skin effect and a high quality factor.

[0057] Furthermore, in this wireless charging mode, the optimal coil turns formula was analyzed based on the series resonance model of the transmitting coil and the secondary receiving coil, and it was determined that the primary and secondary coils were both 12 turns. The simulation circuit model obtained that the output voltage of the secondary coil of each sensor was 12V, which was supplied to the power supply circuit for step-down filtering and rectification to obtain a 5V stable voltage supply.

[0058] Furthermore, in this wireless charging mode, the emitter core material uses Mn-Zn ferrite with high magnetic permeability to increase the degree of coupling and improve the transmission efficiency.

[0059] The sensor signal is transmitted through the oscillation circuit and antenna amplifier and received by the frequency scanning device.

[0060] Furthermore, based on the formula of RC oscillation circuit frequency By changing the size of the resistor in the oscillation circuit, the frequency signal emitted by each sensor oscillation circuit is different. The swept frequency radar can arrange all signals according to frequency to achieve the purpose of identifying different sensor signals.

[0061] Furthermore, the horizontal distance between the frequency scanning device and the flexible detection ring is 10 cm, and the smaller transmission distance ensures that the signal will not be excessively attenuated.

[0062] Furthermore, in this wireless charging mode, after the device is started, the rotor first rotates slowly to charge the sensor circuit on the detection collar. After the sensor enters the working state and the scanning device receives the signal from the sensor, the rotor starts to enter the normal rotation speed.

[0063] Furthermore, in this wireless charging mode, the vertical distance between the transmitting coil and the lowest point of the flexible detection ring is 5 cm, and the output of wireless charging will be more stable at a small distance.

[0064] Furthermore, in this wireless charging mode, the transmitting coil is powered by an external power supply.

[0065] The beneficial effects of the present invention are:

[0066] 1) The present invention designs a flexible detection ring structure and installs four flexible rings on the first and second step shafts respectively. The rings contain a sufficient number of flexible sensors, which are placed on the rotor in a magnetic levitation state to directly detect strain, torsion, amplitude, and temperature-related data reflecting the rotor motion state in real time. The collected data is sufficient and rich in layers, allowing users to understand the motion state of the magnetic levitation rotor in a timely manner, adjust the control strategy based on the rotor motion state, and ensure the stable operation of the magnetic bearing rotor system.

[0067] 2) This invention achieves wireless charging and sensor signal transmission between the transmitting coil and the secondary receiving coils of each sensor in the flexible loop by designing a transmitting coil, iron core, and support, as well as designing the sensor's supporting circuitry and frequency tracking system within the emitter circuit. The sensor's supporting circuitry includes a step-down, voltage-stabilized power supply circuit, an amplification and modulation circuit, an RC oscillator circuit, a power amplifier circuit, and antenna auxiliary circuitry, ensuring that the signals collected by the sensor are transmitted stably and accurately. The frequency tracking system ensures dynamic frequency matching between the transmitting and receiving coils, ensuring a stable and accurate wireless charging path.

[0068] 3) The present invention ensures the flexibility of the sensor while also ensuring high sensitivity of the detection signal by designing the physical structures of the three graphene flexible sensors.

[0069] 4) This invention reduces the impact of vibration on the operation of the magnetic bearing system by designing a vibration isolation system consisting of vibration isolation supports and spring-elastic damping elements. The vibration isolation supports effectively isolate external vibrations, reducing their impact on the system and suppressing resonance, ensuring stable rotor suspension. The spring-elastic damping elements provide flexible support, absorb external vibration energy, and reduce vibration transmission to the magnetic bearing system. This vibration isolation system improves the control stability of the control system and reduces the probability of rotor instability accidents.

[0070] 5) The present invention effectively protects the internal components of the magnetic bearing stator by designing a cover to prevent the intrusion of dust, moisture, and other contaminants, thereby improving the reliability and service life of the magnetic bearing. The cover also secures the stator assembly within the bearing housing, ensuring the stable position of the electromagnetic coil and other internal components, thereby maintaining an appropriate gap between the stator and rotor and reducing noise generated during operation of the magnetic bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 This is a schematic diagram of the detection device for the magnetic bearing and the flexible detection collar;

[0072] Figure 2 This is a front view of the detection device for the magnetic bearing and the flexible detection collar;

[0073] Figure 3This is a schematic diagram of the bottom of the detection device for the magnetic bearing and the flexible detection collar;

[0074] Figure 4 This is a schematic diagram of the structure of an eight-pole heteropolar magnetic bearing;

[0075] Figure 5 This is a schematic diagram of the arrangement and distribution of the ring sensors for the flexibility detection of the two-stage stepped rotor;

[0076] Figure 6 This is a schematic diagram of the acceleration sensor's accessory circuit;

[0077] Figure 7 This is a schematic diagram of the strain sensor's accessory circuit;

[0078] Figure 8 This is a schematic diagram of the temperature sensor's accessory circuit;

[0079] Figure 9 It is a partial enlarged schematic diagram of the step-down voltage-stabilized power supply circuit;

[0080] Figure 10 It is a partial enlarged schematic diagram of the modulation amplifier circuit;

[0081] Figure 11 This is a partially enlarged schematic diagram of the RC oscillation signal transmitting circuit;

[0082] Figure 12 This is a partial enlarged schematic diagram of the power amplifier circuit and antenna auxiliary circuit.

[0083] In the figure: 1. Magnetic bearing rotor; 11. First-stage stepped shaft; 12. Second-stage stepped shaft; 13. Third-stage stepped shaft; 2. Magnetic bearing stator; 21. Magnetic pole; 3. Support; 31. Spring elastic element; 4. Flexible detection collar; 41. Strain sensor; 42. Acceleration sensor; 43. Temperature sensor; 5. Emitter core; 6. Emitter coil; 7. Outer cover; 8. Core support. DETAILED DESCRIPTION

[0084] Refer to the attached Figure 1 ~Attached Figure 12 , the specific implementation steps can be described as follows:

[0085] like Figures 1 to 3 As shown, a magnetic bearing rotor condition monitoring device based on a flexible detection collar includes a magnetic bearing rotor 1, a magnetic bearing stator 2, a support 3, a flexible detection collar 4 and an emitter core 5. Four spring elastic elements 31 are installed at the bottom of the support 3; the four emitter cores 5 are arranged on the core support 8, and the core support 8 is fixed to the support 3 through threaded holes; two magnetic bearing stators 2 are fixed to the bracket of the support 3; the transmitting coil 6 is wound on the emitter core 5; and an outer cover 7 is installed on the outer side of the magnetic bearing stator 2. Figure 4As shown, the magnetic bearing rotor 1 realizes suspended operation by controlling the magnetic poles 21 distributed circumferentially on the inner ring, and the magnetic poles 21 adopt an eight-pole heteropolar magnetic bearing magnetic pole; the magnetic bearing rotor 1 is a stepped shaft structure, and includes a primary stepped shaft 11, a secondary stepped shaft 12 and a tertiary stepped shaft 13 from the middle to the end; there are two flexible detection rings 4 fixed on the primary stepped shaft 11 and the secondary stepped rotor 12; the diameter of the primary stepped shaft 11 is twice the diameter of the secondary stepped shaft 12, and the diameter of the secondary stepped shaft 12 is twice the diameter of the tertiary stepped shaft 13; each flexible detection ring 4 on the primary stepped shaft 11 is integrated with 64 sensors, including 8 temperature sensors, 8 acceleration sensors, and 48 strain sensors; each flexible detection ring 4 on the secondary stepped shaft 12 is integrated with 32 sensors, including 4 temperature sensors, 4 acceleration sensors, and 24 strain sensors; the sensor arrangement distribution diagram of the flexible detection ring 4 on the secondary stepped shaft 12 is shown in the attached figure. Figure 5 As shown, circumferential symmetry is achieved, and the arrangement and distribution of sensors of the flexible detection collar 4 on the first-level stepped shaft 11 are similar; the flexible detection collar 4 includes an acceleration sensor auxiliary circuit schematic diagram, a strain sensor auxiliary circuit schematic diagram, and a temperature sensor auxiliary circuit schematic diagram as shown in the attached figure. Figure 6 , Attachment Figure 7 , Attachment Figure 8 As shown, the supporting circuits corresponding to these three sensors are the same, including the buck-stabilized power supply circuit, modulation amplifier circuit, RC oscillation signal transmission circuit, power amplifier circuit and antenna auxiliary circuit as shown in the attached figure. Figure 9 , Attachment Figure 10 , Attachment Figure 11 , Attachment Figure 12 As shown in the figure, ports with the same number indicate that the circuits here are connected to each other; the sensor supporting circuits on the flexible detection ring 4 are all printed directly on the PI flexible material using semiconductor technology, and are protected by an insulating layer and a heat-insulating layer; the flexible detection ring 4 is fixed to the magnetic bearing rotor 1 by a polyurethane glue with strong viscosity, certain elasticity and impact resistance.

[0086] Each sensor supporting circuit on the flexible detection ring 4 includes a small secondary receiving coil; the emitter coil 6 connected to the external power supply is wound on the emitter core 5, and wireless charging is achieved by magnetic resonance. The resonant frequency of the transmitting coil and the secondary receiving coil is adjusted in real time through the frequency tracking system to ensure the stable operation of the magnetic resonance; the secondary receiving coil provides the 12V output voltage to the step-down regulated power supply circuit (such as Figure 9 ) processing, after the processing of voltage reduction, filtering, rectification and voltage regulation, the output voltage is 5V, which is supplied to the three sensor auxiliary circuits ( Figure 6 、 Figure 7 、 Figure 8 ) output sensor signal, modulation amplifier circuit (such as Figure 10As shown) amplify the signal, RC oscillation signal transmission circuit (as shown Figure 11 As shown) to generate a square wave with adjustable frequency, a power amplifier circuit and an antenna auxiliary circuit (such as Figure 12 As shown in the figure), the sensor sends a signal; finally, the sensor sends the detection signal to the frequency sweeping device for processing; by changing the RC oscillation signal transmitting circuit (as shown in the figure), the sensor sends a signal to the frequency sweeping device; Figure 11 The resistance value of the resistor in the sensor is adjusted to realize the emission of square waves of different frequencies and distinguish the individual signals of each sensor. After receiving the signals, the frequency sweeping device transmits them to the host computer program for analysis and processing, completing the real-time collection of the strain, torsion, amplitude, and temperature data of the magnetic bearing rotor 1, so as to analyze the motion mode of the rotor at this time and adjust the control strategy in time to maintain the stable operation of the magnetic bearing system.

[0087] Specifically, after receiving a stable 5V voltage supply, temperature sensor 43 collects subtle voltage changes through a circuit consisting of a Schottky diode and capacitor. The sensor signal is amplified by a 40x amplifier circuit consisting of two operational amplifiers. It then passes through an RC square wave oscillator circuit to generate a square wave with an adjustable frequency. This signal is then modulated by a power amplifier circuit (Vmax ≈ VCC) and the antenna-attached circuit before being emitted.

[0088] After the acceleration sensor 42 receives a stable 5V voltage supply and collects data, it is filtered and processed. The sensor signal is amplified by a 40x amplifier circuit composed of two operational amplifiers, and then an adjustable frequency square wave is generated through an RC square wave oscillation circuit. The square wave is modulated by the power amplifier circuit (Vmax≈VCC) and the antenna auxiliary circuit and then emitted.

[0089] After receiving a stable 5V voltage supply, the strain sensor 41 performs preliminary modulation on the generated subtle signal through a bridge structure. The sensor signal is amplified by a 40x amplifier circuit consisting of two operational amplifiers, and then passes through an RC square wave oscillation circuit to generate a square wave with adjustable frequency. The square wave is modulated by the power amplifier circuit (Vmax≈VCC) and the antenna auxiliary circuit before being emitted.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A magnetic bearing rotor condition monitoring device based on a flexible detection collar, characterized in that: The invention comprises a magnetic bearing rotor (1), a magnetic bearing stator (2) and a support (3), wherein the magnetic bearing stator (2) is fixed on a bracket of the support (3), the inner ring of the magnetic bearing stator (2) is circumferentially distributed with magnetic poles (21), the two ends of the magnetic bearing rotor (1) respectively pass through the magnetic bearing stator (2) and are magnetically suspended and connected to the magnetic poles (21), a flexible detection collar (4) is sleeved on the magnetic bearing rotor (1), and the flexible detection collar (4) is provided with a strain sensor (41), an acceleration sensor (42) and a temperature sensor (43) for directly measuring state signals of strain, torsion, amplitude and temperature of the magnetic bearing rotor (1), respectively; an emitter core is provided on the support (3) (5), a transmitting coil (6) is wound around the top of the emitter core (5), and the transmitting coil (6) is located just below the flexible detection collar (4). The transmitting coil (6) is connected to an external power supply. The supporting circuits of the strain sensor (41), the acceleration sensor (42) and the temperature sensor (43) are all provided with secondary receiving coils, which are wirelessly charged with the transmitting coil (6) by magnetic coupling resonance during the rotation process. The supporting circuit sends the detected signal to the frequency sweeping device through the buck stabilization circuit, the modulation amplifier circuit, the RC oscillation circuit, the power amplifier circuit and the antenna auxiliary circuit to obtain real-time status data to adjust and realize the stable operation of the magnetic bearing rotor (1); The transmitting coil (6) and the secondary receiving coil are both made of copper wire, with 12 turns of coils. The emitter core (5) is made of Mn-Zn ferrite with high magnetic permeability. The vertical distance between the transmitting coil (6) and the lowest point of the flexible detection ring (4) is 5 cm. The detection signal of the sensor is transmitted and handed over to the sweeping device for processing. By changing the resistance value of the resistor in the RC oscillation circuit, the transmission of square waves of different frequencies is achieved to distinguish the individual signals of each sensor. After receiving the signal, the sweeping device hands it over to the host computer program for analysis and processing, completing the real-time acquisition of the strain, torsion, amplitude and temperature data of the magnetic bearing rotor.

2. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 1, characterized in that: The base material of the flexible detection ring (4) is PI organic polymer flexible material, and the strain sensor (41), acceleration sensor (42) and temperature sensor (43) all use graphene sensors. The strain sensor (41) is a multi-layer structure, including a graphene film layer, a piezoelectric material layer, an electrode structure layer, a flexible base layer and a packaging layer; the temperature sensor (43) is a multi-layer structure, including a graphene film layer, a thermal coupling layer, an electrode structure layer, a flexible base layer and a packaging layer; the acceleration sensor (42) is a multi-layer structure, including a graphene film layer, a diaphragm structure layer, a mass block layer, a flexible base layer, an electrode structure layer and a packaging layer.

3. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 1, characterized in that: A spring elastic element (31) is provided at the bottom of the support (3); the magnetism of adjacent magnetic poles (21) is opposite; and an outer cover (7) is installed on the outer side of the magnetic bearing stator (2).

4. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 1, characterized in that: The magnetic bearing rotor (1) is a stepped shaft structure, comprising a first-level stepped shaft (11), a second-level stepped shaft (12) and a third-level stepped shaft (13) from the middle to the end, wherein the diameter of the first-level stepped shaft (11) is twice the diameter of the second-level stepped shaft (12), and the diameter of the second-level stepped shaft (12) is twice the diameter of the third-level stepped shaft (13), and a flexible detection collar (4) is sleeved on both ends of the first-level stepped shaft (11) and the outer ends of the second-level stepped shafts (12) on both sides.

5. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 4, characterized in that: Each flexible detection collar (4) of the first-stage stepped shaft (11) is provided with 8 temperature sensors (43), 8 acceleration sensors (42) and 48 strain sensors (41), and each flexible detection collar (4) of the second-stage stepped shaft (12) is provided with 4 temperature sensors (43), 4 acceleration sensors (42) and 24 strain sensors (41).

6. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 2, characterized in that: The piezoelectric material layer adopts piezoelectric polymer material, the piezoelectric polymer adopts polyvinylidene fluoride coating, the electrode structure layer includes two layers of electrodes, the electrode material adopts highly conductive material silver paste, the flexible base layer adopts flexible thin film material PI, the packaging layer adopts silicone rubber material, the thermal coupling layer adopts copper plating material, and the diaphragm structure layer is a vibrating membrane structure.

7. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 1, characterized in that: The step-down voltage regulator circuit is used to accurately regulate the 12V input voltage provided by the secondary receiving coil to a 5V output, and a differential amplifier for comparing the output voltage with the 5V reference voltage is provided inside the step-up voltage regulator circuit; after the temperature sensor (43) obtains the 5V stable voltage supply, the voltage change is collected through a circuit composed of a Schottky diode and a capacitor. The sensor signal is amplified by a 40-fold amplification circuit composed of two operational amplifiers, and then a square wave with adjustable frequency is generated through an RC oscillation circuit. The square wave is modulated by the power amplifier circuit and the antenna auxiliary circuit and then emitted.

8. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 7, characterized in that: After the acceleration sensor (42) receives a 5V stable voltage supply, it collects data and undergoes filtering processing. The sensor signal is amplified by a 40-fold amplifier circuit composed of two operational amplifiers, and then generates a square wave with adjustable frequency through an RC square wave oscillation circuit. The square wave is modulated by the power amplifier circuit and the antenna auxiliary circuit before being emitted.

9. The magnetic bearing rotor condition monitoring device based on a flexible detection collar according to claim 8, characterized in that: After the strain sensor (41) receives a 5V stable voltage supply, the generated signal is preliminarily modulated through a bridge structure. The sensor signal is amplified by a 40-fold amplifier circuit composed of two operational amplifiers, and then a square wave with adjustable frequency is generated through an RC square wave oscillation circuit. The square wave is modulated by the power amplifier circuit and the antenna auxiliary circuit before being emitted.

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