Displacement sensor, magnetic levitation rotating machine

Abstract

The utility model provides a kind of displacement sensor, magnetic suspension rotating machinery, displacement sensor includes radial core, radial core is formed by silicon steel punching sheet stacking, and silicon steel punching sheet includes annular body and multiple displacement detection probe groups, each displacement detection probe group includes the first probe pair with first and second probes, the second probe pair with third and fourth probes, the first probe pair in the pair of displacement detection probe groups symmetrical about the rotation axis of rotating shaft respectively has each coil in series connection to form first radial detection inductance circuit, the second probe pair respectively has each coil in series connection to form second radial detection inductance circuit, first radial detection inductance circuit and second radial detection inductance circuit are connected in parallel to form radial displacement differential detection circuit.The utility model ensures that sensor single-point failure does not affect its overall function, effectively prolongs the single use life of displacement sensor, reduces production cost and maintenance cost.

Description

Technical Field

[0001] This utility model belongs to the field of displacement sensor design technology, specifically relating to a displacement sensor and a magnetically levitated rotating machine. Background Technology

[0002] In the operation of magnetic levitation bearings, shaft displacement monitoring plays a crucial role in the stable and efficient operation of the system. Traditional displacement measurement schemes employ separate axial and radial displacement sensors, which introduces a series of problems. First, the independent sensor setup significantly increases the axial length of the shaft, limiting the potential for increasing shaft speed and failing to meet the compact structure requirements of high-speed equipment. Second, the multi-sensor layout complicates the installation process, requiring precise calibration of the positional relationships of multiple components, which not only increases installation costs but also makes measurements prone to inaccuracies due to installation errors. Furthermore, displacement sensors in magnetic levitation systems are typically installed within the internal structure of rotating machinery, and traditional magnetic levitation sensors often lack sufficient redundancy and fault tolerance. When a sensor fails, the entire rotating machinery often needs to be disassembled, increasing production and maintenance costs. Utility Model Content

[0003] Therefore, this utility model provides a displacement sensor and a magnetically levitated rotating machine, which can overcome the shortcomings of insufficient redundancy and fault tolerance of displacement sensors in related technologies. When the sensor fails, the entire equipment needs to be disassembled and reassembled for maintenance, resulting in high production and maintenance costs.

[0004] To address the aforementioned problems, this utility model provides a displacement sensor, characterized in that it includes a radial iron core formed by stacking silicon steel laminations. Each silicon steel lamination includes an annular body and an even number of displacement detection probe groups evenly spaced along the circumference of the annular body and located on the inner wall of the annular body. Each displacement detection probe group includes a first probe pair and a second probe pair spaced along the circumference of the annular body. The first probe pair includes a first probe and a second probe spaced along the circumference of the annular body, and the second probe pair includes a first probe and a second probe spaced along the circumference of the annular body. The third and fourth probes, which are spaced apart in the direction, are symmetrical about the axis of rotation of the displacement detection probe group. The coils wound in a self-inductive manner on the first and second probes of the first probe pair are connected in series to form a first radial detection inductance circuit. The coils wound in a self-inductive manner on the third and fourth probes of the second probe pair are connected in series to form a second radial detection inductance circuit. The first radial detection inductance circuit and the second radial detection inductance circuit are connected in parallel to form a radial displacement differential detection circuit. The magnetic poles generated by the coils of the two probes in the same probe pair are opposite in polarity.

[0005] In some embodiments, within the same displacement detection probe group, the magnetic polarities generated by the coils wound on the two adjacent probes of the first probe pair and the second probe pair are the same; and / or, the first radial detection inductor circuit has a first radial displacement differential pressure measurement point located on the coil series connection line of the two first probe pairs, and the second radial detection inductor circuit has a second radial displacement differential pressure measurement point located on the coil series connection line of the two second probe pairs.

[0006] In some implementations, the circumferential widths of the two probes within the same probe pair are not equal.

[0007] In some embodiments, the displacement sensor further includes a first axial core and a second axial core, both of which are formed by stacking silicon steel laminations and are respectively stacked on the axial end faces of the radial core.

[0008] In some embodiments, each of the first probes on the first axial core and the second axial core has a coil wound in a self-inductive manner connected in series to form a first axial detection inductor circuit, and each of the third probes and the fourth probe has a coil wound in a self-inductive manner connected in series to form a second axial detection inductor circuit. The first axial detection inductor circuit has a first axial displacement differential pressure measurement point on the coils of each of the first probes and the second probes on the first axial core and the coils of each of the first probes and the second probes on the second axial core. The second axial detection inductor circuit has a second axial displacement differential pressure measurement point on the coils of each of the third probes and the fourth probes on the first axial core and the coils of each of the third probes and the fourth probes on the second axial core. The first axial detection inductor circuit and the second axial detection inductor circuit are connected in parallel to form an axial displacement differential detection circuit.

[0009] In some embodiments, on the projection obtained by projecting onto any radial plane of the rotating shaft, the first axial core and the second axial core coincide, and the projections of each displacement detection probe group of the first axial core and each displacement detection probe group of the radial core do not overlap; and / or, in the state where the displacement sensor is in the initial position, the axial thickness center plane of each probe of the first axial core coincides with the first end face of the magnetically conductive section of the rotating shaft, and the axial thickness center plane of each probe of the second axial core coincides with the second end face of the magnetically conductive section.

[0010] In some embodiments, the number of coil turns wound on each of the first, second, third, and fourth probes is equal.

[0011] In some embodiments, on the projection obtained by projecting onto any radial plane of the rotating shaft, each displacement detection probe group on the first axial iron core and each displacement detection probe group on the radial iron core are evenly spaced and alternately arranged in the circumferential direction of the rotating shaft.

[0012] This utility model also provides a magnetically levitated rotating machine, including the above-mentioned displacement sensor, for detecting the axial and radial displacement of the rotating shaft of the magnetically levitated rotating machine.

[0013] The displacement sensor and magnetically levitated rotating mechanism provided by this utility model have the following beneficial effects:

[0014] Within the same displacement detection probe group, there are two probe pairs, namely the first probe pair and the second probe pair. These probe pairs, centrally symmetrical about the axis of rotation of the shaft, are connected in series and form parallel first and second radial detection inductor circuits. During sensor operation, the first and second radial detection inductor circuits can simultaneously detect the radial displacement of the shaft in real time. The first and second radial detection inductor circuits, performing radial displacement detection simultaneously, form a redundant design. If one set fails, the other set can continue to detect the radial displacement of the shaft without needing to reconfigure the displacement transmission circuit. By repairing the sensor, it is ensured that a single point failure of the sensor will not affect its overall function, effectively extending the service life of the displacement sensor and reducing production and maintenance costs. At the same time, since the coils and probes of the first and second radial detection inductor circuits in this application are all located on the same ring body and arranged radially along the circumference of the ring body, compared with the prior art of setting multiple displacement sensors to eliminate maintenance after a single failure, the displacement sensor is simpler to assemble in the corresponding equipment and occupies less axial space of the shaft. This allows the shaft length to be shorter, which is beneficial to increasing the maximum speed of the shaft. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. The drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0016] Figure 1 This is a three-dimensional structural schematic diagram of the displacement sensor in an embodiment of this utility model;

[0017] Figure 2 yes Figure 1The axial projection diagram of the silicon steel lamination in the figure shows a displacement detection probe group within the dashed rectangle.

[0018] Figure 3 yes Figure 1 The axial projection diagram of the radial iron core (in the state after the coil is wound) shows the coil winding method and the corresponding magnetic pole polarity formed in the two displacement detection probe groups that are symmetrically arranged.

[0019] Figure 4 yes Figure 1 The diagram shows the structure of the first axial core and the second axial core (in the state after the coil is wound). The diagram shows the corresponding magnetic polarity formed by the coils in the two displacement detection probe groups.

[0020] Figure 5 This is a schematic diagram of the operation of the displacement sensor in this embodiment of the present invention when the rotating shaft is axially offset;

[0021] Figure 6 This is a schematic diagram of the radial displacement differential detection circuit (equivalent) in an embodiment of this utility model;

[0022] Figure 7 This is a schematic diagram of the axial displacement differential detection circuit (equivalent) in an embodiment of this utility model.

[0023] The attached figures are labeled as follows:

[0024] 1. Radial core; 2. First axial core; 3. Silicon steel lamination; 31. Ring; 32. First probe pair; 321. First probe; 322. Second probe; 33. Second probe pair; 331. Third probe; 332. Fourth probe; 4. Second axial core; 100. Radial displacement differential detection circuit; 200. Axial displacement differential detection circuit; 301. Magnetic section; 302. Non-magnetic section. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0026] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0027] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0028] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0029] See also Figures 1 to 7 As shown, according to an embodiment of the present invention, a displacement sensor is provided, including a radial iron core 1, which is formed by stacking silicon steel laminations 3. The silicon steel laminations 3 include an annular body 31 and an even number of displacement detection probe groups (not labeled in the figure, as shown in the figure) evenly spaced along the circumference of the annular body 31 and located on the inner ring wall of the annular body 31. Figure 2 (As shown within the dashed rectangle), generally speaking, the aforementioned displacement detection probe group consists of at least four probes, such as... Figure 1In one specific embodiment shown, there are four probes. Of course, depending on the actual detection requirements, there can be six, eight, etc. The following description assumes that four sets of displacement detection probes are provided on the annular body 31. Each displacement detection probe set includes a first probe pair 32 and a second probe pair 33 spaced apart along the circumference of the annular body 31. The first probe pair 32 includes a first probe 321 and a second probe 322 spaced apart along the circumference of the annular body 31. The second probe pair 33 includes a third probe 331 and a fourth probe 332 spaced apart along the circumference of the annular body 31. Each pair of displacement detection probes symmetrical about the rotation axis (i.e., the object of the displacement sensor; it can be understood that the annular body 31 of the aforementioned displacement sensor is fitted radially outside the rotation axis) contains... In some first probe pairs 32, the coils 5 wound in a self-inductive manner on the first probe 321 and the second probe 322 are connected in series to form a first radial detection inductance circuit (not labeled in the figure). Similarly, in second probe pairs 33, the coils 5 wound in a self-inductive manner on the third probe 331 and the fourth probe 332 are connected in series to form a second radial detection inductance circuit (not labeled in the figure). The first radial detection inductance circuit has a first radial displacement differential pressure measurement point U0 located on the series connection line of the coils 5 of the two first probe pairs 32. The second radial detection inductance circuit has a second radial displacement differential pressure measurement point U0' located on the series connection line of the coils 5 of the two second probe pairs 33. The first and second radial detection inductance circuits are connected in parallel to form a radial displacement differential detection circuit 100 (e.g., ...). Figure 6 (As shown), and the magnetic poles generated by the coils 5 of the two probes within the same probe pair are opposite in polarity, see details. Figure 3 As shown, it can be understood that each probe extends radially toward the center of the rotating shaft.

[0030] In this technical solution, two probe pairs, namely the first probe pair 32 and the second probe pair 33, are simultaneously present in the same displacement detection probe group. These probe pairs, forming a central symmetry about the axis of rotation of the rotating shaft, are connected in series and form a first radial detection inductor circuit and a second radial detection inductor circuit connected in parallel. During sensor operation, the first and second radial detection inductor circuits can simultaneously detect the radial displacement of the rotating shaft in real time. The first and second radial detection inductor circuits, which perform radial displacement detection simultaneously, form a redundant design. When one set fails, the other set can continue to detect the radial displacement of the rotating shaft, eliminating the need for pin... Repairing the displacement sensor ensures that a single point of failure will not affect its overall function, effectively extending the single-use lifespan of the displacement sensor and reducing production and maintenance costs. Furthermore, since the coils and probes of the first and second radial detection inductor circuits in this application are all located on the same annular body 31 and arranged radially along the circumference of the annular body 31, compared to the prior art method of using multiple displacement sensors to prevent repairs after a single failure, the assembly of the displacement sensor in the corresponding equipment is simpler, and it occupies less axial space on the rotating shaft. This allows for a shorter shaft length, which in turn helps to increase the maximum rotational speed of the shaft.

[0031] It should be noted that, for the radial core 1, the aforementioned radial displacement differential detection circuit 100 is configured with two displacement detection probe groups corresponding to a pair of rotation axes about the shaft, such as... Figure 3 As shown in the figure, the radial core 1 is equipped with two pairs of displacement detection probe groups. Correspondingly, the radial displacement differential detection circuit 100 also has two independent sets, enabling real-time detection of the radial displacement of the shaft in different directions. Figure 3 Taking the orientation shown as an example, one of the two sets of radial displacement differential detection circuits 100 is used to detect displacement in the positive and negative directions of the X-axis, and the other set is used to detect displacement in the positive and negative directions of the Y-axis.

[0032] In some embodiments, within the same displacement detection probe group, the magnetic polarity of the coils 5 wound on two adjacent probes in the first probe pair 32 and the second probe pair 33 is the same, see details below. Figure 3 As shown, the magnetic poles generated by the coils 5 on the two probes that are close to each other in the same displacement detection probe group have the same polarity, which can reduce the short-circuit coupling of the magnetic fields generated by the two probes respectively and improve the magnetic field utilization efficiency.

[0033] In some implementations, the circumferential widths of the two probes within the same probe pair are not equal; that is, one probe in the same probe pair is wider than the other. For example... Figure 2As shown, the circumferential width of the first probe 321 is smaller than the circumferential width of the second probe 322, and the circumferential width of the third probe 331 is smaller than the circumferential width of the fourth probe 332. In a preferred embodiment, the circumferential widths of the first probe 321 and the third probe 331 are equal, and the circumferential widths of the second probe 322 and the fourth probe 332 are equal.

[0034] In this technical solution, the probe with a larger circumferential width in the same probe pair has a larger area and is mainly responsible for the main measurement magnetic circuit. It can increase the rate of change of the sensor coil inductance and improve sensitivity, but at the same time, it will reduce the linearity of the sensor. At this time, because the probe with a smaller width has a smaller area, the magnetic flux will be locally enhanced in the narrow area, forming a high magnetoresistance path. This can compensate for the magnetic flux density loss in the wide area and reduce the introduced magnetic field distortion. The two work together to improve sensitivity and linearity without increasing the axial and radial dimensions of the sensor. Furthermore, when the silicon steel lamination 3 is used to prepare the axial iron core, the corresponding position of the magnetic conductive section 301 of the axial iron core and the rotating shaft will change with the axial position of the rotating shaft. Since the detection of the axial position relies on the change of the area of ​​the magnetic conductive material corresponding to the probe in the axial magnetic conductive section 301 of the rotating shaft and the probe, the change in the inductance of the probe coil is caused. The design of arranging two probes with a wider and a narrower width in the same probe pair is particularly suitable.

[0035] In some implementations, the circumferential width of the two probes that are close to each other in the same displacement detection probe group is greater than the circumferential width of the two probes that are far apart from each other. This makes the wide pole of the sensor closer to the positive X and Y directions of the rotor, which matches the output direction of the magnetic levitation bearing configured on the shaft, resulting in better detection performance of the sensor.

[0036] In some embodiments, the displacement sensor further includes a first axial core 2 and a second axial core 4, which are respectively stacked on the axial end faces of the radial core 1. As a preferred embodiment, both the first axial core 2 and the second axial core 4 are formed by stacking silicon steel laminations 3. In a specific embodiment, the axial stack thickness of the first axial core 2 and the second axial core 4 is equal. See [link to relevant documentation]. Figure 5 As shown, all are 2Z0 (Z0 is half of the axial stack of the first axial core 2 or the second axial core 4).

[0037] In this technical solution, the displacement sensor also includes a first axial core 2 and a second axial core 3 located on the two end faces of the radial core 1, respectively. This enables the displacement sensor of this invention to simultaneously detect the radial and axial directions of the rotating shaft, thus making it an axial-radial self-sensing sensor with a compact structure. It can simultaneously detect the radial and axial directions of the rotating shaft, which is beneficial for further shortening the axial length of the rotating shaft. More importantly, the axial core and the radial core 1 in this invention are both formed by stacking silicon steel laminations 3 of the same structure, that is, the stacked laminations are of the same specification and model. This avoids the manufacturing difficulties caused by multiple core materials and complex structures, reduces the types and quantities of parts, and lowers the process requirements and management costs in the production process.

[0038] In some embodiments, each of the first probes 321 and second probes 322 on the first axial core 2 and the second axial core 4 has a coil 5 wound in a self-inductive manner connected in series to form a first axial detection inductance circuit, and each of the third probes 331 and fourth probes 332 has a coil 5 wound in a self-inductive manner connected in series to form a second axial detection inductance circuit. The first axial detection inductance circuit has a first axial displacement differential pressure measuring point Uz located on the series connection line of the coil 5 on each of the first probes 321 and second probes 322 of the first axial core 2 and the coil 5 on each of the first probes 321 and second probes 322 of the second axial core 4. The second axial detection inductance circuit has a second axial displacement differential pressure measuring point Uz' located on the series connection line of the coil 5 on each of the third probes 331 and fourth probes 332 of the first axial core 2 and the coil 5 on each of the third probes 331 and fourth probes 332 of the second axial core 4. The first axial detection inductance circuit and the second axial detection inductance circuit are connected in parallel to form an axial displacement differential detection circuit 200.

[0039] In this technical solution, differential detection of the axial displacement of the rotating shaft is formed by either a first axial displacement differential pressure measuring point Uz or a second axial displacement differential pressure measuring point Uz', which can significantly improve the sensitivity of axial position detection. Specifically, the aforementioned differential refers to the connection method of the coil in the circuit. Figure 4In the specific embodiment shown, a total of eight sets of coils are provided. The first probe pairs 32 (four sets in total) in each displacement detection probe group on the first axial iron core 2 and the first probe pairs 32 (four sets in total) in each displacement detection probe group on the second axial iron core 4 together constitute four sets of coils out of the aforementioned eight sets of coils. The four sets of coils on the first axial iron core 2, after being connected in series, and the four sets of coils on the second axial iron core 2, after being connected in series, are differentially reversed to form the aforementioned first axial detection inductance circuit. The first axial displacement differential pressure measurement point Uz is located on the series connection line between the two sets of series-connected coils. The second probe pairs 33 (four sets in total) in each displacement detection probe group on the first axial iron core 2 and the second probe pairs 33 (four sets in total) in each displacement detection probe group on the second axial iron core 4 together constitute the other four sets of coils out of the aforementioned eight sets of coils. The four sets of coils on the first axial iron core 2, after being connected in series... The first set of coils and the four sets of coils on the second axial iron core 2, which are connected in series, are differentially reversed to form the aforementioned second axial detection inductance circuit. The first axial displacement differential pressure measurement point Uz' is located on the series connection between the two sets of series coils. The first axial detection inductance circuit and the second axial detection inductance circuit, which are connected in parallel, form a dual redundant axial displacement measurement sensor probe. Thus, assuming that when the rotation axis moves to the left, the total inductance of each coil 5 on the first axial iron core 2 increases, resulting in an increased voltage, while the total inductance of each coil 5 on the second axial iron core 4 decreases, resulting in a decreased voltage. The output voltage = ↑ - ↓ = 2 × ↑ (amplitude doubles), thus improving the detection sensitivity. The first axial detection inductance circuit and the second axial detection inductance circuit are connected in parallel, and their output voltages remain consistent during normal operation. The aforementioned radial displacement differential detection circuit 100 can also improve the detection sensitivity on the same principle, which will not be elaborated further.

[0040] In some embodiments, on the projection obtained by projecting onto any radial plane of the rotating shaft, the first axial core 2 and the second axial core 4 completely coincide, and the projections of each displacement detection probe group of the first axial core 2 and each displacement detection probe group of the radial core 1 have no overlapping portion. That is, each displacement detection probe group of the radial core 1 is offset from each displacement detection probe group of the first axial core 2 and the second axial core 4 in the circumferential direction of the rotating shaft. This can effectively prevent the axial dimension of the sensor from increasing due to the cross-overlap between the two, that is, it can further reduce the axial dimension of the displacement sensor, thereby further reducing the displacement sensor's occupation of the axial space of the rotating shaft and shortening the shaft length.

[0041] In some embodiments, on the projection obtained by projecting onto any radial plane of the rotating shaft, each displacement detection probe group on the first axial iron core 2 and each displacement detection probe group on the radial iron core 1 are evenly spaced and alternately arranged in the circumferential direction of the rotating shaft. This ensures that the number of turns of the coil 5 wound on each probe is at a reasonable level, which is beneficial to further reduce the size of the sensor.

[0042] See details Figure 5 As shown, in some embodiments, when the displacement sensor is in its initial position, the axial thickness center plane of each probe of the first axial core 2 coincides with the first end face of the magnetically conductive section 301 of the rotating shaft, and the axial thickness center plane of each probe of the second axial core 2 coincides with the second end face of the magnetically conductive section 301, so as to ensure that both the first axial core 2 and the second axial core 4 have a large applicable detection range for axial displacement detection of the rotating shaft.

[0043] In some embodiments, the number of turns of the coil 5 wound on each of the first probe 321, second probe 322, third probe 331 and fourth probe 332 is equal. The same number of turns ensures that the self-inductance value (L) of all probes is completely consistent, thereby achieving strict symmetry of the displacement-self-inductance relationship. This makes the sensitivity of the X-axis and Y-axis sensors matched, the magnetic field coupling coefficient balanced, and effectively eliminates cross interference (such as the problem of false increase of Y-axis signal caused by X offset). In addition, it is worth emphasizing that, as mentioned above, this utility model proposes to adopt a differential connection. If the same number of coil turns is not guaranteed, the nonlinear error of the sensor will increase, affecting the detection accuracy of the sensor.

[0044] The following combination Figure 5 The working principle of the displacement sensor in this invention after the axial displacement of the rotating shaft is explained:

[0045] When the axial displacement of the rotating shaft changes, the impedance of the coils 5 wound on each probe on the first axial core 2 and the second axial core 4 will change accordingly, thus obtaining the axial displacement of the rotating shaft based on the impedance change of the probe coils. The rotating shaft includes a magnetically conductive section 301 and non-magnetically conductive sections 302 at both ends of the magnetically conductive section 301. The axial center plane of the magnetically conductive section 301 is located in the middle of the sensor core assembly, that is, the axial centerline of the magnetically conductive section 301 coincides with the axial centerline of the sensor core assembly (i.e., the aforementioned axial centerline of the radial core 1). Specifically, as shown in the figure... Figure 5The orientation shown is for reference. The left and right end faces of the magnetically conductive section 301 are located at the axial midpoint of the first axial core 2 and the second axial core 4, respectively. The non-magnetically conductive sections 302 on both sides of the magnetically conductive section 301 are made of non-magnetic material, so that only the magnetically conductive section 301 is magnetic within the detection range of the sensor, thus ensuring the detection effect. Secondly, the maximum axial displacement of the magnetically conductive section 301 on one side is not greater than the distance from the two axial end faces of the magnetically conductive section 301 to the end faces of the first axial core 2 or the second axial core 4, respectively. This can be achieved by setting corresponding protective bearings on the rotating shaft.

[0046] The specific method for detecting the axial displacement of the shaft is as follows: When the shaft moves in the Z+ direction (i.e., the shaft moves to the left), the detection overlap area of ​​the first axial core 2 and the magnetic section 301 increases, while the detection overlap area of ​​the second axial core 4 and the magnetic section 301 decreases; when the shaft moves in the Z- direction (i.e., the shaft moves to the right), the detection overlap area of ​​the second axial core 4 and the magnetic section 301 increases, while the detection overlap area of ​​the first axial core 2 and the magnetic section 301 decreases. Therefore, the axial displacement of the shaft can be detected by differential calculation using the inductance of the first axial core 2 coil and the inductance of the second axial core 4 coil. The axial displacement of the shaft is:

[0047]

[0048] Wherein, △Lz is the total change in inductance after the differential connection of the coils of the first probes 32 of the first axial iron core 2 and the second axial iron core 4, respectively; △Lz' is the total change in inductance after the differential connection of the coils of the second probes 33 of the first axial iron core 2 and the second axial iron core 4, respectively; and δ0 is the radial gap between each probe and the rotating shaft when the rotating shaft is at the suspension center. Figure 7 As shown, the equivalent circuit of the axial redundant sensor differentially modulates the inductance change signals of the probe coils corresponding to the upper and lower circumferences of the sensor core, thereby obtaining the axial displacement of the shaft.

[0049]

[0050] △Z and △Z' represent the axial displacement detected in the Z direction by the first probe pair 32 and the second probe pair 33 of the sensor when the shaft moves; μ0 is the air gap permeability; N is the number of turns of the coil 5 wound on each probe; b1 is the circumferential width of the probe with the larger circumferential width; b2 is the circumferential width of the probe with the smaller circumferential width; L z1 L is the total inductance value of the coils 5 connected in series on each of the first probe pairs 32 on the first axial iron core 2. z2 L is the total inductance value of the coils 5 connected in series on each of the second probe pairs 33 on the first axial iron core 2. z1' is the total inductance value of the coils 5 connected in series on each of the first probe pairs 32 on the second axial iron core 4, L z2 ' is the total inductance value of the coils 5 connected in series on each of the second probe pairs 33 on the second axial iron core 4.

[0051] Figure 3 The diagram shows the operation of the displacement sensor when the rotating shaft is radially offset. When the rotating shaft is radially offset downwards, the sensor... Figure 3 The indicated orientation is for reference. The radial gaps between the two sets of radial probes below the circumference of the radial core 1 (i.e., the first probe pair 32 and the second probe pair 33) and the rotating shaft decrease, while the radial gaps between the two sets of radial probes above the circumference of the radial core 1 (i.e., the first probe pair 32 and the second probe pair 33) and the rotating shaft both increase. Finally, the differential signal of the inductance change of the corresponding upper and lower probe coils is used to obtain the radial displacement of the rotating shaft. For further details, please refer to... Figure 3 As shown, the upper first probe pair 32 and the lower first probe pair 32 are defined as a set of radial displacement detection probes, and the upper second probe pair 33 and the lower second probe pair 33 are defined as another set of radial displacement detection probes. These two sets of probes are independent of each other, while ensuring that there is no interference between adjacent magnetic poles. The magnetic poles are arranged in NSSN or SNNS, and they are also driven independently. When one of the two sets of radial probes has a problem, the system can quickly switch to ensure that a single point of failure does not affect the overall function and ensure the continuous operation of the system.

[0052] The specific method for detecting radial offset of the shaft is as follows:

[0053] Assuming that when the shaft does not experience radial offset, i.e., the shaft is at the center of rotation in a suspended state, the initial gap of the radial probe is δ0, the number of coil turns is N, the magnetic area is A0, the initial inductances are L01, L02, L03, and L04, and the input voltages are Us and Us' (for the first and second radial detection inductor circuits mentioned above, respectively), then:

[0054] When the rotor undergoes radial displacement downwards At this time, the radial distance δ1 between the lower probe of radial core 1 (i.e., the lower first probe pair 32 and the second probe pair 33) and the rotating shaft decreases, and the corresponding inductances L3, L4, L3', and L4' increase. The radial distance δ2 between the upper probe (i.e., the upper first probe pair 32 and the second probe pair 33) and the rotating shaft increases, and the inductances L1, L2, L1', and L2' decrease. At this time:

[0055] Therefore, the radial output voltage of the upper and lower sets of probes of radial core 1 is:

[0056]

[0057]

[0058] Figure 6 The diagram shows the radial equivalent circuit of the redundant sensor. In the equivalent circuit for radial detection of the sensor, it can be seen that the equivalent circuit connecting the two sets of radial probes is divided into two paths and connected in parallel. The four radial probe coils in the same group are connected in series, and the four radial probes in the other group are connected in series, together forming a radial redundant sensor. Finally, the inductance change signals of the corresponding probe coils on the upper and lower circumferences of the sensor core are differentially processed to obtain the radial displacement of the rotating shaft.

[0059] According to an embodiment of the present invention, a magnetically levitated rotating machine is also provided, including the above-mentioned displacement sensor, for detecting the axial and radial displacement of the rotating shaft of the magnetically levitated rotating machine.

[0060] According to an embodiment of the present invention, a method for detecting and controlling the displacement of a rotating shaft in a magnetically levitated rotating machine is also provided, comprising the following steps:

[0061] The output parameters (such as output voltage and other electrical signal parameters) of the first radial detection inductor circuit, the second radial detection inductor circuit, the first axial detection inductor circuit, and the second axial detection inductor circuit are acquired simultaneously, and the real-time radial and axial displacement of the rotating shaft is detected based on the output parameters of the first radial detection inductor circuit and the first axial detection inductor circuit.

[0062] When the output parameters of the first radial detection inductor circuit exceed the first preset range value (the aforementioned range value can be reasonably selected according to the actual application conditions), the real-time radial displacement of the shaft is detected based on the output parameters of the second radial detection inductor circuit; and / or, when the output parameters of the first axial detection inductor circuit exceed the second preset range value, the real-time axial displacement of the shaft is detected based on the output parameters of the second axial detection inductor circuit, and the hardware-level fast switching achieves a seamless transition.

[0063] In order to address the shortcomings of low redundancy tolerance and low versatility of sensors, the technical solution of this utility model proposes to adopt independent probe redundancy, with axial and radial probes each configured with dual redundancy, to ensure that a single point of failure does not affect the overall function, and to quickly detect faults and switch to backup probes, ensuring continuous operation of the system. Even if a single probe fails, the system can still operate normally, avoiding instability of the magnetic levitation bearing due to sensor failure.

[0064] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0065] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above description is only a preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A displacement sensor, characterized in that, The device includes a radial core (1), which is formed by stacking silicon steel laminations (3). The silicon steel laminations (3) include an annulus (31) and an even number of displacement detection probe groups evenly spaced along the circumferential direction of the annulus (31) and located on the inner ring wall of the annulus (31). Each displacement detection probe group includes a first probe pair (32) and a second probe pair (33) spaced along the circumferential direction of the annulus (31). The first probe pair (32) includes a first probe (321) and a second probe (322) spaced along the circumferential direction of the annulus (31). The second probe pair (33) includes a third probe spaced along the circumferential direction of the annulus (31). The head (331) and the fourth probe (332) are a pair of displacement detection probe groups symmetrical about the axis of rotation. The coils (5) wound in a self-inductive manner on the first probe (321) and the second probe (322) in the first probe pair (32) are connected in series to form a first radial detection inductance circuit. The coils (5) wound in a self-inductive manner on the third probe (331) and the fourth probe (332) in the second probe pair (33) are connected in series to form a second radial detection inductance circuit. The first radial detection inductance circuit and the second radial detection inductance circuit are connected in parallel to form a radial displacement differential detection circuit (100). The magnetic poles generated by the coils (5) of the two probes in the same probe pair are opposite.

2. The displacement sensor according to claim 1, characterized in that, Within the same displacement detection probe group, the magnetic polarity of the coils (5) wound on the two adjacent probes of the first probe pair (32) and the second probe pair (33) is the same; and / or, the first radial detection inductor circuit has a first radial displacement differential pressure measurement point (U0) on the series connection of the coils (5) of the two first probe pairs (32), and the second radial detection inductor circuit has a second radial displacement differential pressure measurement point (U0') on the series connection of the coils (5) of the two second probe pairs (33).

3. The displacement sensor according to claim 2, characterized in that, The circumferential widths of the two probes within the same probe pair are not equal.

4. The displacement sensor according to any one of claims 1 to 3, characterized in that, It also includes a first axial core (2) and a second axial core (4), both of which are formed by stacking silicon steel laminations (3) and are respectively stacked on the axial end faces of the radial core (1).

5. The displacement sensor according to claim 4, characterized in that, The first axial detection inductor circuit is formed by connecting the coils (5) wound in a self-inductive manner on each of the first probes (321) and the second probes (322) on the first axial core (2) and the second axial core (4). The second axial detection inductor circuit is formed by connecting the coils (5) wound in a self-inductive manner on each of the third probes (331) and the fourth probes (332). The first axial detection inductor circuit has coils (5) on each of the first probes (321) and the second probes (322) on the first axial core (2) and the first probes (332) on the second axial core (4). The first axial displacement differential pressure measurement point (Uz) is connected in series with the coil (5) on the first axial core (2) and the coil (5) on the second probe (322). The second axial detection inductor circuit has a second axial displacement differential pressure measurement point (Uz') on the series connection of the coil (5) on each of the third probe (331) and the fourth probe (332) of the first axial core (2) and the coil (5) on each of the third probe (331) and the fourth probe (332) of the second axial core (4). The first axial detection inductor circuit and the second axial detection inductor circuit are connected in parallel to form an axial displacement differential detection circuit (200).

6. The displacement sensor according to claim 4, characterized in that, On the projection obtained by projecting onto any radial plane of the rotating shaft, the first axial core (2) coincides with the second axial core (4), and the projections of each displacement detection probe group of the first axial core (2) and each displacement detection probe group of the radial core (1) do not overlap; and / or, when the displacement sensor is in the initial position, the axial thickness center plane of each probe of the first axial core (2) coincides with the first end face of the magnetic conductive section (301) of the rotating shaft, and the axial thickness center plane of each probe of the second axial core (4) coincides with the second end face of the magnetic conductive section (301).

7. The displacement sensor according to claim 6, characterized in that, The number of turns of the coil (5) wound on each of the first probe (321), the second probe (322), the third probe (331) and the fourth probe (332) is equal.

8. The displacement sensor according to claim 7, characterized in that, On the projection obtained by projecting onto any radial plane of the rotating shaft, each displacement detection probe group on the first axial iron core (2) and each displacement detection probe group on the radial iron core (1) are evenly spaced and alternately arranged in the circumferential direction of the rotating shaft.

9. A magnetically levitated rotating machine, characterized in that, The displacement sensor, including any one of claims 1 to 8, is used to detect the axial and radial displacement of the shaft of the magnetically levitated rotating machinery.

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