A control device and control method for a five-axis magnetic suspension bearing

Abstract

The present invention discloses a control device and a control method for a five-axis magnetic levitation bearing, belonging to the field of magnetic levitation bearing control, including: 10 windings, 9 bridge arms and 1 DC voltage source in the five-axis magnetic levitation bearing; the upper and lower ends of each bridge arm are respectively connected to the positive and negative electrodes of the DC voltage source; every two pairs of radial control windings are divided into a group, and one ends of the 4 windings within each group are connected together, and the other ends are respectively connected to the midpoint of a bridge arm; the sum of the currents of any two pairs of radial control windings is equal, and the two groups of windings are connected to 8 bridge arms, or the two groups of windings are connected to 7 bridge arms, and one of the bridge arms is shared by the two groups of windings; the two ends of each axial control winding are respectively connected to the midpoint of a bridge arm; the windings do not form a loop; the bridge arm connected to only a single winding is a unipolar bridge arm, and the bridge arm connected to multiple windings is a unipolar or bipolar bridge arm. The present invention can reduce the number of switching devices in the five-axis magnetic levitation bearing system.

Description

Technical Field

[0001] The present invention belongs to the field of magnetic levitation bearing control, and more specifically, relates to a control device and a control method for a five-axis magnetic levitation bearing. Background Art

[0002] A magnetic levitation bearing is a typical mechatronic system and a typical bearing device that uses electromagnetic force to stably levitate a rotor. Its purpose is to replace traditional mechanical bearings and achieve contactless operation between the rotor and the stator. It has the characteristics of not requiring lubrication, having no friction, and having a long working life. Magnetic levitation bearings are widely used and are suitable for environments with high rotational speeds or requirements for clean spaces. For an active magnetic levitation bearing system, it mainly includes parts such as a rotor, a sensor, a controller, and an electromagnetic actuator. And the control topology, as the core of electromechanical conversion, plays a crucial role in the entire system.

[0003] The most common control topology is the H-bridge control topology. For each winding, two bridge arms are required for control. This control topology has low integration, low power density, a large number of components, high costs, and many potential failure points. To significantly reduce the switching devices of the control topology and improve its power density, in the patent document with the application publication number "CN109780057A", a power electronic controller and method based on a magnetic levitation bearing are provided, which includes: 4 unidirectional conduction devices, 4 controllable switches, and 4 windings; by changing the conduction time of the corresponding controllable switches of each winding to control the current passing through each winding, the control of the electromagnetic force generated by the four windings that control two degrees of freedom in the magnetic levitation bearing is realized.

[0004] In the above patent document, the windings are star-connected. For the four windings of a single eight-pole radial magnetic bearing, only four bridge arms are required for control, changing the way that a single coil in the previous structure requires two bridge arms for control, achieving the optimal use of devices. However, this solution is only applicable to the control of magnetic levitation bearings with two radial degrees of freedom. Currently, the most common five-axis magnetic levitation bearing in the industrial field has 4 radial degrees of freedom and 1 axial degree of freedom. The control topology structure provided in the above patent document cannot be applied to the control system of a five-axis magnetic levitation bearing.

[0005] Therefore, how to effectively reduce the switching devices in a five-axis magnetic levitation bearing system remains an urgent problem to be solved. Summary of the Invention

[0006] Aiming at the defects and improvement requirements of the prior art, the present invention provides a control device and a control method for a five-axis magnetic levitation bearing, aiming to reduce the number of switching devices in the five-axis magnetic levitation bearing system.

[0007] To achieve the above object, according to one aspect of the present invention, a control device for a five-axis magnetic levitation bearing is provided, including: 10 windings; the 10 windings are the windings in the five-axis magnetic levitation bearing, which are divided into 5 pairs of windings, among which 4 pairs of windings are respectively used to control 4 radial degrees of freedom, denoted as radial control windings; the remaining pair of windings is used to control the axial degree of freedom, denoted as axial control winding; it further includes: 9 bridge arms and 1 DC voltage source;

[0008] The upper ends of each bridge arm are connected to the positive pole of the DC voltage source, and the lower ends of each bridge arm are connected to the negative pole of the DC voltage source;

[0009] Every two pairs of radial control windings are divided into a group. One ends of the 4 radial control windings within each group are connected together, and the other ends are respectively connected to the midpoint of a bridge arm; the 4 pairs of radial control windings are connected to a total of 8 bridge arms, and the sum of the currents of any two pairs of radial control windings is equal; the two ends of each axial control winding are respectively connected to the midpoint of a bridge arm; the windings do not form a loop;

[0010] The bridge arm connected to only a single winding is a unipolar bridge arm, and the bridge arm connected to multiple windings is a unipolar or bipolar bridge arm.

[0011] Further, for the control device of the five-axis magnetic levitation bearing provided by the present invention, the 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3) and (La4, Lc4), a pair of axial control windings is denoted as (La5, Lc5), and the 9 bridge arms are sequentially denoted as B1 to B9, then:

[0012] The windings La1, Lc1, La2 and Lc2 are divided into a group. One ends of the windings La1, Lc1, La2 and Lc2 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B1, B2, B3 and B4;

[0013] The windings La3, Lc3, La4 and Lc4 are divided into another group. One ends of the windings La3, Lc3, La4 and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7 and B8;

[0014] The two ends of the winding La5 are respectively connected to the midpoints of bridge arms B4 and B9, and the two ends of the winding Lc5 are respectively connected to the midpoints of bridge arms B8 and B9;

[0015] The bridge arms B1, B2, B3, B5, B6 and B7 are all unipolar bridge arms; the bridge arms B4, B8 and B9 are all unipolar bridge arms, or the bridge arms B4, B8 and B9 are all bipolar bridge arms, or the bridge arms B4, B8 and B9 simultaneously include unipolar bridge arms and bipolar bridge arms.

[0016] Furthermore, for the control device of the five-axis magnetic levitation bearing provided by the present invention, the 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3), and (La4, Lc4), and one pair of axial control windings is denoted as (La5, Lc5). The 9 bridge arms are sequentially denoted as B1 to B9. Then:

[0017] The windings La1, Lc1, La2, and Lc2 are grouped together. One ends of the windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of the bridge arms B1, B2, B3, and B4.

[0018] The windings La3, Lc3, La4, and Lc4 are grouped into another group. One ends of the windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of the bridge arms B5, B6, B7, and B8.

[0019] One ends of the winding La5 are respectively connected to the midpoints of the bridge arms B3 and B9, and the other ends of the winding Lc5 are respectively connected to the midpoints of the bridge arms B8 and B4.

[0020] The bridge arms B1, B2, B5, B6, B7, and B9 are all single-polarity bridge arms; the bridge arms B3, B4, and B8 are all single-polarity bridge arms, or the bridge arms B3, B4, and B8 are all bipolar bridge arms, or the bridge arms B3, B4, and B8 simultaneously include single-polarity bridge arms and bipolar bridge arms.

[0021] According to another aspect of the present invention, a control device for a five-axis magnetic levitation bearing is provided, including: 10 windings; the 10 windings are the windings in the five-axis magnetic levitation bearing, and are divided into 5 pairs of windings in total. Among them, 4 pairs of windings are respectively used to control 4 radial degrees of freedom, denoted as radial control windings; the remaining pair of windings is used to control the axial degree of freedom, denoted as axial control windings; it further includes: 9 bridge arms and 1 DC voltage source;

[0022] The upper ends of each bridge arm are all connected to the positive pole of the DC voltage source, and the lower ends of each bridge arm are all connected to the negative pole of the DC voltage source;

[0023] Every two pairs of radial control windings are divided into a group. One ends of the 4 radial control windings in each group are connected together, and the other ends are respectively connected to the midpoint of a bridge arm; the 4 pairs of radial control windings are connected to a total of 7 bridge arms. Among them, one bridge arm is shared by two groups of radial control windings, and the sum of the currents of any two pairs of radial control windings is equal; the two ends of each axial control winding are respectively connected to the midpoint of a bridge arm; the windings do not form a loop;

[0024] The bridge arm connected to only a single winding is a single-polarity bridge arm, and the bridge arm connected to multiple windings is a single-polarity or bipolar bridge arm.

[0025] Further, for the control device of the five-axis magnetic levitation bearing provided by the present invention, the 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3), and (La4, Lc4), one pair of axial control windings is denoted as (La5, Lc5), and the 9 bridge arms are sequentially denoted as B1 to B9. Then:

[0026] The windings La1, Lc1, La2, and Lc2 are grouped together. One ends of the windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B1, B2, B3, and B4.

[0027] The windings La3, Lc3, La4, and Lc4 are grouped into another group. One ends of the windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7, and B4.

[0028] One ends of the winding La5 are respectively connected to the midpoints of bridge arms B4 and B9, and the other ends of the winding Lc5 are respectively connected to the midpoints of bridge arms B8 and B9.

[0029] Bridge arms B1, B2, B3, B5, B6, B7, and B8 are all single-polarity bridge arms; bridge arms B4 and B9 are both single-polarity bridge arms, or bridge arms B4 and B9 are both bipolar bridge arms, or one of bridge arms B4 and B9 is a single-polarity bridge arm and the other is a bipolar bridge arm.

[0030] Further, for the control device of the five-axis magnetic levitation bearing provided by the present invention, the 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3), and (La4, Lc4), one pair of axial control windings is denoted as (La5, Lc5), and the 9 bridge arms are sequentially denoted as B1 to B9. Then:

[0031] The windings La1, Lc1, La2, and Lc2 are grouped together. One ends of the windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B1, B2, B3, and B4.

[0032] The windings La3, Lc3, La4, and Lc4 are grouped into another group. One ends of the windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7, and B4.

[0033] One ends of the winding La5 are respectively connected to the midpoints of bridge arms B4 and B9, and the other ends of the winding Lc5 are respectively connected to the midpoints of bridge arms B4 and B8.

[0034] The bridge arms B1, B2, B3, B5, B6, B7, B8, and B9 are all single-polarity bridge arms; the bridge arm B4 is a single-polarity bridge arm, or the bridge arm B4 is a bipolar bridge arm.

[0035] According to another aspect of the present invention, there is also provided a control method for a control device based on the above five-axis magnetic levitation bearing, including:

[0036] Detect the position of the five-axis magnetic levitation bearing, compare it with the given position, and obtain the current command values of the 10 windings through closed-loop control;

[0037] Detect the current feedback values of each winding, compare them with the corresponding current command values, and obtain the modulation waves of the 10 windings through closed-loop control;

[0038] Establish the relationship between the modulation waves of the 9 bridge arm midpoints and the modulation waves of the 10 windings according to Kirchhoff's voltage law, and thereby obtain the mutual relationship between the modulation waves of the 9 bridge arm midpoints;

[0039] In the range of [0, V dc , dc , determine the modulation waves of each bridge arm midpoint that satisfy the mutual relationship, and obtain the desired signals of each bridge arm midpoint through carrier comparison;

[0040] Determine the drive signals of each fully controlled switch device in each bridge arm according to the desired signals of each bridge arm midpoint. The specific method is as follows: for a fully controlled switch device in any bridge arm, if the fully controlled switch device is located in the upper bridge arm, the drive signal of the fully controlled switch device is the same as the desired signal of the bridge arm midpoint; if the switch device is located in the lower bridge arm, the drive signal of the fully controlled switch device is opposite to the desired signal of the bridge arm midpoint;

[0041] Send the corresponding drive signals to each fully controlled switch device to make the five-axis magnetic levitation bearing located at the given position;

[0042] Among them, V dc represents the output voltage of the DC voltage source.

[0043] Generally speaking, through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0044] (1) The control device of the five-axis magnetic suspension bearing provided by the present invention utilizes the characteristic that the sum of the currents of two windings controlling each radial degree of freedom is equal, achieving the optimization of the number of bridge arms for controlling the eight windings in the radial direction. In some solutions, only eight bridge arms are required to control the eight windings in the radial direction. In other solutions, only seven bridge arms are needed to control the eight windings in the radial direction. On this basis, by multiplexing the bridge arms connected to the windings for controlling the radial direction to control the two windings in the axial direction, while ensuring the effective control of the five-axis magnetic suspension bearing, the optimization of the comprehensive number of bridge arms of the five-axis magnetic suspension bearing is realized. Finally, for the control device of the five-axis magnetic suspension bearing provided by the present invention, the number of bridge arms is nine, which is greatly reduced, and the number of fully controlled switching devices used is also greatly reduced, effectively solving the problems of low integration degree, low power density, large number of components, high cost, and many potential fault points in the existing control structure.

[0045] (2) The control device of the five-axis magnetic suspension bearing provided by the present invention flexibly adjusts between the number of switching devices and the overall operating loss by selecting the polarity of the multiplexed bridge arms. Specifically, by setting all bridge arms as single-polarity bridge arms, the number of fully controlled switching devices can be minimized. By setting the multiplexed bridge arms as bipolar bridge arms, the overall operating loss can be effectively reduced.

[0046] (3) The control method provided by the present invention can be completed based on the control device with a specific topological structure according to theories such as position detection, current detection, Kirchhoff's voltage law (KVL), and carrier comparison. The control is simple and has a wide application range. Description of the Drawings

[0047] Figure 1 Schematic diagram of the control device of the five-axis magnetic suspension bearing provided in Embodiment 1 of the present invention;

[0048] Figure 2 Schematic diagram of the control device of the five-axis magnetic suspension bearing provided in Embodiment 2 of the present invention;

[0049] Figure 3 Schematic diagram of the control device of the five-axis magnetic suspension bearing provided in Embodiment 3 of the present invention;

[0050] Figure 4 Schematic diagram of the control device of the five-axis magnetic suspension bearing provided in Embodiment 4 of the present invention;

[0051] Figure 5 Schematic diagram of the control device of the five-axis magnetic suspension bearing provided in Embodiment 5 of the present invention;

[0052] Figure 6 Schematic diagram of the control device of the five-axis magnetic suspension bearing provided in Embodiment 6 of the present invention;

[0053] Figure 7 Schematic diagram of the control device for the five-axis magnetic levitation bearing provided in Embodiment 7 of the present invention;

[0054] Figure 8 Schematic diagram of the control device for the five-axis magnetic levitation bearing provided in Embodiment 8 of the present invention;

[0055] Figure 9 Schematic diagram of the control method provided in Embodiment 9 of the present invention. Detailed implementation manners

[0056] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] In the present invention, terms such as "first" and "second" in the present invention and the accompanying drawings (if any) are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0058] Before explaining the technical solution of the present invention in detail, a brief introduction to the basic structure of the five-axis magnetic levitation bearing is as follows:

[0059] In the application of rotating machinery, the rotor needs to be supported in five directions (i.e., five axes), including four radial and one thrust bearings. In order to support the rotor, two-axis radial magnetic bearings are required on each side with one plane. In order to control the axial displacement of the rotor, a thrust bearing loaded on the thrust disc is also required.

[0060] The five-axis magnetic levitation bearing includes a total of 10 windings, which are divided into 5 pairs of windings. Among them, 4 pairs of windings are respectively used to control 4 radial degrees of freedom, and the remaining pair of windings is used to control the axial degree of freedom; the sum of the currents of each pair of windings for controlling the radial degrees of freedom is equal;

[0061] For ease of description, in the following embodiments, the windings for controlling the radial degrees of freedom are denoted as radial control windings, the windings for controlling the axial degrees of freedom are denoted as axial control windings, and among them, the 4 pairs of radial control windings in the magnetic levitation bearing are successively denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3) and (La4, Lc4), and a pair of axial control windings is denoted as (La5, Lc5).

[0062] Since the five-axis magnetic levitation bearing includes a total of 10 windings that control 5 degrees of freedom and need to be controlled, if the traditional H-bridge control topology is used, 20 bridge arms are required to control the 10 windings, resulting in low integration, low power density, a large number of components, high costs, and many potential failure points. To solve this problem, the present invention provides a control device and a control method for a five-axis magnetic levitation bearing. The overall concept is as follows: By taking advantage of the characteristic that the sum of the currents of the 2 windings controlling each radial degree of freedom is equal, the number of the 8 windings controlling the radial degrees of freedom is optimized. On this basis, the windings controlling the axial degrees of freedom reuse the bridge arms connected to the windings controlling the radial degrees of freedom, and the total number of bridge arms of the five-axis magnetic levitation bearing is optimized while ensuring the effective control of the five-axis magnetic levitation bearing.

[0063] Based on the above concept, when arranging the relevant control topology structure in the present invention, after arranging the 8 windings and the corresponding bridge arms in the radial direction, the 2 windings in the axial direction can be connected to the key points of the existing bridge arms to realize the reuse of the bridge arms, thereby realizing various topologies that meet the conditions.

[0064] Since the sum of the currents of the 2 windings controlling each radial degree of freedom is equal, the 8 windings controlling the radial direction in the present invention are further divided into two groups, each group containing the windings controlling two radial degrees of freedom. One ends of the four windings in each group are connected together, and the other ends are respectively connected to the midpoint of a bridge arm. It is easy to understand that in order to ensure that each winding can be independently controlled, it is necessary to ensure that in the obtained topology structure, the windings do not form a loop. Based on this limitation, 8 bridge arms can be used to control the 8 windings controlling the radial direction. At this time, the bridge arms connected by the two groups of windings are different; 7 bridge arms can also be used to control the 8 windings controlling the radial direction. At this time, one of the bridge arms is reused by the two groups of windings.

[0065] After the radial windings and the corresponding bridge arms are arranged, the two ends of the two axial windings are respectively connected to the midpoints of the two bridge arms. At this time, it is still necessary to ensure that the windings do not form a loop. The present invention finds that in the two arrangement schemes of the above 8 radial windings, in order to ensure that the windings do not form a loop, additional bridge arms need to be set, and when the total number of bridge arms is the least finally, 9 bridge arms are required. For the convenience of description, in the following embodiments, the 9 bridge arms are sequentially denoted as B1 to B9.

[0066] The following are the embodiments.

[0067] Embodiment 1:

[0068] A control device for a five-axis magnetic levitation bearing, as Figure 1 shown, includes: 10 windings in the five-axis magnetic levitation bearing, 9 bridge arms, and 1 DC voltage source;

[0069] AsFigure 1 As shown, the upper ends of each arm are connected to the positive pole of the DC voltage source, and the lower ends of each arm are connected to the negative pole of the DC voltage source;

[0070] As Figure 1 shown, windings La1, Lc1, La2, and Lc2 are grouped together. One end of windings La1, Lc1, La2, and Lc2 is connected together, and the other ends are respectively connected to the midpoints of arms B1, B2, B3, and B4;

[0071] Windings La3, Lc3, La4, and Lc4 are grouped into another set. One end of windings La3, Lc3, La4, and Lc4 is connected together, and the other ends are respectively connected to the midpoints of arms B5, B6, B7, and B8;

[0072] Both ends of winding La5 are respectively connected to the midpoint of arm B4 and B9, and both ends of winding Lc5 are respectively connected to the midpoint of arm B8 and B9; At this time, the axial control winding shares an additional arm, and at the same time multiplexes the arms connected by two radial control windings.

[0073] The arms are divided into unipolar arms and bipolar arms: The unipolar arm only contains one fully controlled switching device, and in addition, it also contains a unidirectional conduction device. The upper arm and the lower arm each contain one of the above devices; The upper and lower arms of the bipolar arm both include a fully controlled switching device and a unidirectional conduction device anti-parallel to the fully controlled switching device. The unipolar arm can only absorb current or release current, and the bipolar arm can both absorb current and release current.

[0074] In this embodiment, in order to minimize the number of switching devices, as Figure 1 shown, each arm is a unipolar arm. It is easy to understand that the polarity of the unipolar arm connected to each winding should be determined accordingly according to the direction of the current in the winding.

[0075] Embodiment 2:

[0076] A control device for a five-axis magnetic levitation bearing, as Figure 2 shown. This embodiment is similar to the above Embodiment 1. The difference is that in this embodiment, the multiplexed arms, that is, arms B4, B8, and B9 connected to multiple windings, are all bipolar arms; The remaining arms only connected to a single winding, that is, arms B1, B2, B3, B5, B6, and B7, are the same as those in Embodiment 1 above and are all unipolar arms.

[0077] Since a unipolar arm can only absorb current or release current, when a unipolar arm is connected to multiple windings, the currents in these multiple windings will be superimposed in the unipolar arm, and the arm needs to bear a relatively large current, resulting in relatively large operating losses. However, since a bipolar arm can both absorb current and release current, when a bipolar arm is connected to multiple windings, by controlling the direction of the winding current, the currents in multiple windings can be offset to a certain extent in the bipolar arm, and the current that the arm needs to bear is relatively small, and the operating losses are correspondingly reduced.

[0078] In this embodiment, the arm connected to multiple windings in the control device is set as a bipolar arm, which can reduce the overall operating losses of the system.

[0079] It is easy to understand that in practical applications, when there are multiple reused arms, according to the number of fully controlled switching devices and the specific requirements of operating losses, only some of the reused arms can be set as bipolar arms. For example, only one or two of the arms B4, B8, and B9 are set as bipolar arms.

[0080] Embodiment 3:

[0081] A control device for a five-axis magnetic suspension bearing, as Figure 3 shown, includes: 10 windings in the five-axis magnetic suspension bearing, 9 arms, and 1 DC voltage source;

[0082] As Figure 3 shown, the upper ends of each arm are connected to the positive pole of the DC voltage source, and the lower ends of each arm are connected to the negative pole of the DC voltage source;

[0083] Windings La1, Lc1, La2, and Lc2 are grouped together. One ends of windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of arms B1, B2, B3, and B4;

[0084] Windings La3, Lc3, La4, and Lc4 are grouped into another group. One ends of windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of arms B5, B6, B7, and B8;

[0085] Both ends of winding La5 are respectively connected to the midpoints of arms B3 and B9, and both ends of winding Lc5 are respectively connected to the midpoints of arms B8 and B4; At this time, two axial control windings reuse the arms connected by 3 radial control windings, and one end of one axial control winding is connected to the midpoint of an additional arm.

[0086] In this embodiment, in order to minimize the number of switching devices, as Figure 3As shown, each bridge arm is a unipolar bridge arm. It is easy to understand that the polarity of the unipolar bridge arm connected to each winding should be determined according to the direction of the current in the winding.

[0087] Embodiment 4:

[0088] A control device for a five-axis magnetic levitation bearing, as Figure 4 shown. This embodiment is similar to the above Embodiment 3. The difference is that in this embodiment, the multiplexed bridge arms, that is, bridge arms B3, B4, and B8 connected to multiple windings, are all bipolar bridge arms; the remaining bridge arms only connected to a single winding, that is, bridge arms B1, B2, B5, B6, B7, and B9, are the same as those in Embodiment 3 and are all unipolar bridge arms.

[0089] Similarly, in this embodiment, by setting the bridge arms multiplexed by multiple windings as bipolar bridge arms, the overall operating loss of the system can be reduced.

[0090] It is easy to understand that in practical applications, when there are multiple multiplexed bridge arms, according to the number of fully controlled switching devices and the specific requirements of operating loss, only some of the multiplexed bridge arms can be set as bipolar bridge arms. For example, only one or two of bridge arms B3, B4, and B8 can be set as bipolar bridge arms.

[0091] Embodiment 5:

[0092] A control device for a five-axis magnetic levitation bearing, as Figure 5 shown, includes: 10 windings in the five-axis magnetic levitation bearing, 9 bridge arms, and 1 DC voltage source;

[0093] As Figure 5 shown, the upper ends of each bridge arm are connected to the positive pole of the DC voltage source, and the lower ends of each bridge arm are connected to the negative pole of the DC voltage source;

[0094] Windings La1, Lc1, La2, and Lc2 are grouped together. One ends of windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B1, B2, B3, and B4;

[0095] Windings La3, Lc3, La4, and Lc4 are grouped into another group. One ends of windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7, and B4;

[0096] Both ends of winding La5 are respectively connected to the midpoints of bridge arms B4 and B9, and both ends of winding Lc5 are respectively connected to the midpoints of bridge arms B8 and B9.

[0097] In this embodiment, in order to minimize the number of switching devices, as Figure 5As shown, each bridge arm is a unipolar bridge arm. It is easy to understand that the polarity of the unipolar bridge arm connected to each winding should be determined accordingly according to the direction of the current in the winding.

[0098] Embodiment 6:

[0099] A control device for a five-axis magnetic levitation bearing, as Figure 6 shown. This embodiment is similar to the above Embodiment 5. The difference is that in this embodiment, the multiplexed bridge arms, that is, bridge arms B4 and B9 connected to multiple windings, are both bipolar bridge arms; the remaining bridge arms only connected to a single winding, that is, bridge arms B1, B2, B3, B5, B6, B7, and B8, are the same as those in Embodiment 5 and are all unipolar bridge arms.

[0100] Similarly, in this embodiment, by setting the bridge arms multiplexed by multiple windings as bipolar bridge arms, the overall operating loss of the system can be reduced.

[0101] It is easy to understand that in practical applications, when there are multiple multiplexed bridge arms, according to the number of fully controlled switching devices and the specific requirements of the operating loss, only some of the multiplexed bridge arms can be set as bipolar bridge arms. For example, only one of bridge arms B4 and B9 is set as a bipolar bridge arm, and the other is set as a unipolar bridge arm.

[0102] Embodiment 7:

[0103] A control device for a five-axis magnetic levitation bearing, as Figure 7 shown, including: 10 windings in the five-axis magnetic levitation bearing, 9 bridge arms, and 1 DC voltage source;

[0104] As Figure 7 shown, the upper ends of each bridge arm are connected to the positive pole of the DC voltage source, and the lower ends of each bridge arm are connected to the negative pole of the DC voltage source;

[0105] Windings La1, Lc1, La2, and Lc2 are grouped together. One ends of windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B1, B2, B3, and B4;

[0106] Windings La3, Lc3, La4, and Lc4 are grouped into another group. One ends of windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7, and B4;

[0107] Both ends of winding La5 are respectively connected to the midpoints of bridge arms B4 and B9, and both ends of winding Lc5 are respectively connected to the midpoints of bridge arms B4 and B8.

[0108] In this embodiment, in order to minimize the number of switching devices, as Figure 7As shown, each bridge arm is a unipolar bridge arm. It is easy to understand that the polarity of the unipolar bridge arm connected to each winding should be determined accordingly according to the direction of the current in the winding.

[0109] Embodiment 8:

[0110] A control device for a five-axis magnetic levitation bearing, as Figure 8 shown. This embodiment is similar to the above Embodiment 7. The difference is that in this embodiment, the multiplexed bridge arm, that is, the bridge arm B4 connected to multiple windings, is a bipolar bridge arm; the remaining bridge arms only connected to a single winding, that is, bridge arms B1, B2, B3, B5, B6, B7, B8, and B9, are the same as those in Embodiment 5 above and are all unipolar bridge arms.

[0111] Similarly, in this embodiment, by setting the bridge arm multiplexed by multiple windings as a bipolar bridge arm, the overall operating loss of the system can be reduced.

[0112] In the above Embodiments 1 to 4, 8 radial control windings are controlled by 8 bridge arms. In Embodiments 5 to 8, 7 radial control windings are controlled by 7 bridge arms. Finally, the total number of bridge arms of the device is 9. Compared with the traditional H-bridge control topology, the number of bridge arms is greatly reduced, and the number of fully controlled switch devices used is also greatly reduced, effectively solving the problems of low integration, low power density, large number of components, high cost, and many potential failure points in the existing control structure.

[0113] Embodiment 9:

[0114] Based on the control method of the control device for the five-axis magnetic levitation bearing provided in the above Embodiments 1 to 8, as Figure 9 shown, it includes:

[0115] Detect the position of the five-axis magnetic levitation bearing, compare it with the given position, and obtain the current command values of 10 windings through closed-loop control; after subtracting the detected position from the given position, perform PID control on the difference to complete the closed-loop control and obtain the current command values;

[0116] Detect the current feedback values of each winding, compare them with the corresponding current command values, and obtain the modulation waves of 10 windings through closed-loop control; after subtracting the detected current feedback values from the current command values, perform PI control on the difference to complete the closed-loop control and obtain the winding modulation waves;

[0117] Establish the relationship between the modulation waves at the midpoints of 9 bridge arms and the modulation waves of 10 windings according to Kirchhoff's voltage law, and thereby obtain the mutual relationship between the modulation waves at the midpoints of 9 bridge arms;

[0118] In [0, V dcDetermine the modulation waves of the midpoints of each bridge arm that satisfy the mutual relationship within the range of [], and obtain the desired signals of the midpoints of each bridge arm through carrier comparison; during the carrier comparison process, for the modulation wave greater than the carrier, it is recorded as the high level "1", and the modulation wave less than the carrier is recorded as the low level "0", and the result of the carrier comparison is the desired signal of the midpoint of each bridge arm. It is easy to understand that since the carrier is usually a triangular wave of 0 to 1, the finally obtained modulation wave should be kept between 0 and 1 as much as possible;

[0119] Determine the drive signals of each fully controlled switch device in each bridge arm according to the desired signals of the midpoints of each bridge arm. The specific method is as follows: for the fully controlled switch device in any bridge arm, if the fully controlled switch device is located in the upper bridge arm, the drive signal of the fully controlled switch device is the same as the desired signal of the midpoint of the bridge arm; if the switch device is located in the lower bridge arm, the drive signal of the fully controlled switch device is opposite to the desired signal of the midpoint of the bridge arm;

[0120] Apply the drive signals corresponding to the time of each fully controlled switch device to make the five-axis magnetic levitation bearing located at the given position;

[0121] Among them, V dc represents the output voltage of the DC voltage source.

[0122] The above control method provided by this embodiment can complete the control based on theories such as position detection, current detection, Kirchhoff's voltage law, and carrier comparison. The control is simple and has a wide application range.

[0123] Kirchhoff's voltage law, that is, in any closed loop, the algebraic sum of the voltage drops on each element is equal to the algebraic sum of the electromotive forces. That is, when starting from a point and going around the loop once and returning to that point, the algebraic sum of each section of voltage is always equal to zero. It is easy to understand that when establishing the relationship between the modulation waves of the midpoints of 9 bridge arms and the modulation waves of 10 windings according to Kirchhoff's voltage law, it needs to be completed in combination with the specific topological structure. The following is an example with the Figure 1 shown topological structure for illustration. Let {u a1 , u c1 , u a2 , u c2 , u a3 , u c3 , u a4 , u c4 , u a5 , u c5} represent the modulation waves of windings La1, Lc1, La2, Lc2, La3, Lc3, La4, Lc4, La5, and Lc5 respectively, and let {u1, u2, u3, u4, u5, u6, u7, u8, u9} represent the modulation waves of 9 bridge arms B1 to B9 respectively. Then, according to Kirchhoff's voltage law, the following relationship can be established:

[0124]

[0125] Substituting the modulation waves of each winding, the mutual relationship between the modulation waves of each bridge arm can be obtained; the calculation methods for the remaining topologies are similar and will not be listed one by one here.

[0126] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A control device for a five-axis magnetic levitation bearing, comprising: 10 windings; the 10 windings are the windings in the five-axis magnetic levitation bearing, which are divided into 5 pairs of windings. Among them, 4 pairs of windings are respectively used to control 4 radial degrees of freedom, denoted as radial control windings; the remaining pair of windings is used to control the axial degree of freedom, denoted as axial control winding; it is characterized in that it further includes: 9 bridge arms and 1 DC voltage source; The upper ends of each bridge arm are connected to the positive pole of the DC voltage source, and the lower ends of each bridge arm are connected to the negative pole of the DC voltage source; Every two pairs of radial control windings are divided into a group. One ends of the 4 radial control windings within each group are connected together, and the other ends are respectively connected to the midpoint of a bridge arm; the 4 pairs of radial control windings are connected to a total of 8 bridge arms, and the sum of the currents of any two pairs of radial control windings is equal; both ends of each axial control winding are respectively connected to the midpoint of a bridge arm; the windings do not form a loop; The bridge arm connected to only a single winding is a unipolar bridge arm, and the bridge arm connected to multiple windings is a unipolar or bipolar bridge arm.

2. The control device of the five-axis magnetic levitation bearing according to claim 1, wherein The 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3) and (La4, Lc4), a pair of axial control windings is denoted as (La5, Lc5), and the 9 bridge arms are sequentially denoted as B1 to B9. Then: The windings La1, Lc1, La2 and Lc2 are divided into a group. One ends of the windings La1, Lc1, La2 and Lc2 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B1, B2, B3 and B4; The windings La3, Lc3, La4 and Lc4 are divided into another group. One ends of the windings La3, Lc3, La4 and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7 and B8; Both ends of the winding La5 are respectively connected to the midpoints of bridge arms B4 and B9, and both ends of the winding Lc5 are respectively connected to the midpoints of bridge arms B8 and B9; The bridge arms B1, B2, B3, B5, B6 and B7 are all unipolar bridge arms; the bridge arms B4, B8 and B9 are all unipolar bridge arms, or the bridge arms B4, B8 and B9 are all bipolar bridge arms, or the bridge arms B4, B8 and B9 simultaneously include unipolar bridge arms and bipolar bridge arms.

3. The control device of the five-axis magnetic levitation bearing according to claim 1, characterized in that The 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3) and (La4, Lc4), a pair of axial control windings is denoted as (La5, Lc5), and the 9 bridge arms are sequentially denoted as B1 to B9. Then: The windings La1, Lc1, La2 and Lc2 are divided into a group. One ends of the windings La1, Lc1, La2 and Lc2 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B1, B2, B3 and B4; The windings La3, Lc3, La4 and Lc4 are divided into another group. One ends of the windings La3, Lc3, La4 and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7 and B8; Both ends of the winding La5 are respectively connected to the midpoints of bridge arms B3 and B9, and both ends of the winding Lc5 are respectively connected to the midpoints of bridge arms B8 and B4; The bridge arms B1, B2, B5, B6, B7, and B9 are all single-polarity bridge arms; the bridge arms B3, B4, and B8 are all single-polarity bridge arms, or the bridge arms B3, B4, and B8 are all bipolar bridge arms, or the bridge arms B3, B4, and B8 simultaneously include single-polarity bridge arms and bipolar bridge arms.

4. A control device for a five-axis magnetic suspension bearing, comprising: Ten windings; the ten windings are the windings in the five-axis magnetic levitation bearing, and are divided into 5 pairs of windings. Among them, 4 pairs of windings are respectively used to control 4 radial degrees of freedom, denoted as radial control windings; the remaining pair of windings is used to control the axial degree of freedom, denoted as axial control winding; it is characterized in that it further includes: 9 bridge arms and 1 DC voltage source; The upper ends of each bridge arm are connected to the positive pole of the DC voltage source, and the lower ends of each bridge arm are connected to the negative pole of the DC voltage source; Every two pairs of radial control windings are divided into a group. One ends of the 4 radial control windings within each group are connected together, and the other ends are respectively connected to the midpoint of a bridge arm; the 4 pairs of radial control windings are connected to a total of 7 bridge arms. Among them, one bridge arm is shared by two groups of radial control windings, and the sum of the currents of any two pairs of radial control windings is equal; both ends of each axial control winding are respectively connected to the midpoint of a bridge arm; the windings do not form a loop; The bridge arm connected to only a single winding is a single-polarity bridge arm, and the bridge arm connected to multiple windings is a single-polarity or bipolar bridge arm.

5. The control device of the five-axis magnetic levitation bearing according to claim 4, characterized in that, The 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3), and (La4, Lc4), a pair of axial control windings is denoted as (La5, Lc5), and the 9 bridge arms are sequentially denoted as B1 to B9. Then: The windings La1, Lc1, La2, and Lc2 are divided into a group. One ends of the windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of the bridge arms B1, B2, B3, and B4; The windings La3, Lc3, La4, and Lc4 are divided into another group. One ends of the windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of the bridge arms B5, B6, B7, and B4; Both ends of the winding La5 are respectively connected to the midpoints of the bridge arms B4 and B9, and both ends of the winding Lc5 are respectively connected to the midpoints of the bridge arms B8 and B9; The bridge arms B1, B2, B3, B5, B6, B7, and B8 are all single-polarity bridge arms; the bridge arms B4 and B9 are both single-polarity bridge arms, or the bridge arms B4 and B9 are both bipolar bridge arms, or one of the bridge arms B4 and B9 is a single-polarity bridge arm and the other is a bipolar bridge arm.

6. The control device of the five-axis magnetic suspension bearing according to claim 4, characterized in that The 4 pairs of radial control windings are sequentially denoted as (La1, Lc1), (La2, Lc2), (La3, Lc3), and (La4, Lc4), a pair of axial control windings is denoted as (La5, Lc5), and the 9 bridge arms are sequentially denoted as B1 to B9. Then: The windings La1, Lc1, La2, and Lc2 are divided into a group. One ends of the windings La1, Lc1, La2, and Lc2 are connected together, and the other ends are respectively connected to the midpoints of the bridge arms B1, B2, B3, and B4; Windings La3, Lc3, La4, and Lc4 are divided into another group. One ends of windings La3, Lc3, La4, and Lc4 are connected together, and the other ends are respectively connected to the midpoints of bridge arms B5, B6, B7, and B4; Both ends of winding La5 are respectively connected to the midpoints of bridge arms B4 and B9, and both ends of winding Lc5 are respectively connected to the midpoints of bridge arms B4 and B8; Bridge arms B1, B2, B3, B5, B6, B7, B8, and B9 are all single-polarity bridge arms; bridge arm B4 is a single-polarity bridge arm, or bridge arm B4 is a bipolar bridge arm.

7. A control method for a control device of a five-axis magnetic levitation bearing according to any one of claims 1 to 6, characterized in that Comprising: Detect the position of the five-axis magnetic levitation bearing, compare it with the given position, and obtain the current command values of 10 windings through closed-loop control; Detect the current feedback values of each winding, compare them with the corresponding current command values, and obtain the modulation waves of 10 windings through closed-loop control; Establish the relationship between the modulation waves of the midpoints of 9 bridge arms and the modulation waves of 10 windings according to Kirchhoff's voltage law, and thus obtain the mutual relationship between the modulation waves of the midpoints of 9 bridge arms; Determine the modulation waves of the midpoints of each bridge arm that satisfy the mutual relationship within the range of [0, V dc , and obtain the desired signals of the midpoints of each bridge arm through carrier comparison; Determine the drive signals of each fully controlled switch device in each bridge arm according to the desired signals at the midpoints of each bridge arm. The specific method is as follows: for the fully controlled switch device in any bridge arm, if the fully controlled switch device is located in the upper bridge arm, the drive signal of the fully controlled switch device is consistent with the desired signal at the midpoint of the bridge arm; if the switch device is located in the lower bridge arm, the drive signal of the fully controlled switch device is opposite to the desired signal at the midpoint of the bridge arm; Send the corresponding drive signals to each fully controlled switch device, so that the five-axis magnetic levitation bearing is located at the given position; Among them, V dc represents the output voltage of the DC voltage source.

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