Suspension force decoupling control method for high-speed bearingless stator excitation type reluctance motor

Abstract

The embodiment of the invention discloses a suspension force decoupling control method for a high-speed bearingless stator excitation type reluctance motor, and relates to the technical field of bearingless reluctance motors. The method comprises the step of detecting a rotor position angle in real time in a motor operation process to judge a phase winding conduction mode. And the suspension force is projected to the corresponding stator pole direction according to the obtained phase winding conduction mode, and the suspension force needing to be generated by the stator pole of the corresponding phase winding can be obtained. A suspension current reference value can be calculated according to the analytic expression of the suspension force and the suspension current. The suspension current loop controls the on-off of a switching tube in the H-bridge circuit by outputting a duty ratio signal so as to control the output suspension current. The control method is simple and reliable, the suspension force decoupling of the high-speed bearingless stator excitation type reluctance motor is realized, and the stability of a motor suspension system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of bearingless reluctance motors, and in particular to a suspension force decoupling control method for a high-speed bearingless stator excitation type reluctance motor. Background Art

[0002] The stator-rotor structure of the stator-excited reluctance motor is similar to that of the switched reluctance motor, and has high reliability and robustness. The excitation magnetic field of the motor is provided by the DC excitation current, and no controlled rectifier device and angle position sensor are required during power generation operation. Therefore, the stator-excited reluctance motor has the advantages of simple and flexible power generation control and high power generation reliability.

[0003] The bearingless technology is combined with the stator excitation type reluctance motor to form a high-speed bearingless stator excitation type reluctance motor. The suspension magnetic field generated by the motor suspension winding is superimposed on the DC excitation magnetic field. The suspension force on the rotor can be controlled by controlling the suspension winding current. The motor suspension winding and the excitation winding are both DC windings, the suspension control is simple, and the mutual inductance between the suspension winding and the excitation winding and the armature winding is very small, and the coupling effect between the windings is weak. However, due to its salient pole structure, the high-speed bearingless stator excitation type reluctance motor has a cross-coupling effect between the radial suspension forces, that is, the radial suspension force is not only affected by the suspension current in the corresponding direction, but also by the suspension current in the orthogonal direction. The cross-coupling between the radial suspension forces seriously affects the stability of the motor suspension operation.

[0004] To address this problem, a research group has proposed a scheme for decoupling control of the radial suspension force of a high-speed bearingless stator-excited reluctance motor based on an asynchronous rotating coordinate system. However, this scheme regards the armature current as an ideal square wave when considering the influence of the armature current. Under high-speed conditions, due to the influence of current commutation and advance angle control methods, there is a large difference between the armature current and the ideal square wave. It is still unable to effectively solve the problem that the cross-coupling between the radial suspension forces seriously affects the stability of the motor's suspension operation. In addition, the calculation process of this method is relatively complicated, and the computing power requirements of the controller are high, which also limits its potential for use under high-speed conditions.

[0005] Therefore, how to design a method that can enhance the cross-coupling between radial suspension forces, which seriously affects the stability of motor suspension operation, has become a topic that needs to be studied. Summary of the invention

[0006] The embodiment of the present invention provides a decoupling control method for the suspension force of a high-speed bearingless stator excitation reluctance motor. The stator pole that generates the suspension force is determined according to the rotor position angle. According to the determined projection relationship, the suspension force in the XY stationary coordinate system is projected to the stator pole direction corresponding to the current rotor angle, and the suspension force that should be generated by each phase stator pole can be obtained. According to the analytical expression of the suspension force and the suspension current, the suspension current reference value can be obtained to achieve the decoupling of the suspension force, thereby ultimately improving the cross-coupling between radial suspension forces, which seriously affects the stability of the motor suspension operation.

[0007] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0008] A suspension force decoupling control method for a high-speed bearingless stator excitation reluctance motor, comprising:

[0009] S1. Using an eddy current sensor to obtain the current position of the rotor of the high-speed bearingless stator excitation type reluctance motor, and determining the required suspension force set values ​​in the X-axis and Y-axis directions according to the current position of the rotor; the suspension force set value required to achieve stable suspension corresponds to the actual rotor position and can be pre-set.

[0010] S2. Use the rotary transformer to obtain the rotor position angle θ r , and determine the conduction mode of the three-phase winding, the conduction mode of the three-phase winding includes: the existence of current in the three-phase armature windings A, B, and C;

[0011] S3, decomposing the given value of the suspension force to obtain the given value of the suspension force corresponding to the stator pole in the conduction mode;

[0012] S4. Establish a mapping relationship between the given value of the suspension force corresponding to the stator pole and the suspension current, and obtain the suspension current reference values ​​in the X-axis and Y-axis directions; wherein the Maxwell stress tensor method can be used to express the suspension force generated by each stator pole with the suspension current.

[0013] S5, using the current Hall sensor to collect the actual suspension current in the X-axis and Y-axis directions; wherein, the X-axis suspension current I is obtained by using the current Hall sensor sx and Y-axis suspension current I sy The difference between the value and the suspension current reference value is used as the input of the PI controller. The high and low voltage duty cycle analog signals output by the PI controller are used to adjust the on and off of the switch tube in the H-bridge circuit to achieve suspension current regulation, thereby controlling the radial displacement of the rotor.

[0014] S6. Using the difference between the actual suspension current and the suspension current reference value as a PI controller, wherein the PI controller outputs a PWM signal to a control circuit of the high-speed bearingless stator excitation type reluctance motor.

[0015] In this embodiment, S1 includes: using an eddy current sensor to obtain the current position x of the rotor, x and the rotor position reference value x * After the difference is made, it is input into the X-axis displacement PID controller, and the X-axis displacement PID controller outputs the required suspension force set value F in the X-axis direction. x * ; Use the eddy current sensor to obtain the current position of the rotor y, y and the rotor position reference value y * After the difference is made, it is input into the Y-axis displacement PID controller, and the Y-axis displacement PID controller outputs the required suspension force set value F in the Y-axis direction. y * .

[0016] Specifically, the types of conduction modes include: AB phase conduction, BC phase conduction and AC phase conduction; wherein, when θ r ∈[0,15°), sampling gets i mA and i mB ; When θ r ∈[15°, 30°), sampling gets i mB and i mC ; When θ r ∈[30°~45°). For example: using a rotary transformer to obtain the rotor position angle θ r , the phase winding conduction mode is determined according to the real-time rotor position angle. The conduction modes of each phase winding under different rotor position angles are shown in Table 1 (taking the rotor position mechanical angle of 0-45° as an example):

[0017] Table 1

[0018]

[0019] Sampling to get i mA and i mC ,i mA 、i mB 、i mC It is the instantaneous value of the sampled three-phase armature winding current of A, B, and C.

[0020] In this embodiment, S3 includes: dividing the suspension force generated by each phase stator pole on the rotor into a λ region and a μ region, wherein the λ region covers six stator poles close to the X-axis plane and the μ region covers six stator poles close to the Y-axis plane; dividing F x * and F y * Decomposed into a given value of the suspension force generated by each independent stator pole. When the rotor angle in the AB phase conduction mode is between 0 and 15°, that is, when the A and B phases are conducting, the suspension force generated by the Y-axis suspension current at the A and B phase stator poles is given by FA1 and F B1 In other words, the suspension force F in the X direction is x and the suspension force F in the Y direction y The decomposition of is expressed as:

[0021] in:

[0022]

[0023] F A1 、F B1 and F C1 It represents the suspension force generated by the Y-axis suspension current at the stator poles of phase A, phase B and phase C, F A2 、F B2 and F C2 It represents the suspension force generated by the X-axis suspension current at the stator poles of phase A, phase B and phase C. represents the suspension force generated by the Y-axis suspension current only, F μA is the magnitude of the suspension force generated at the stator pole of phase A in the μ direction, F μB is the magnitude of the suspension force generated at the B-phase stator pole in the μ direction; represents the suspension force generated by the X-axis suspension current only, F λA is the magnitude of the suspension force generated at the stator pole of phase A in the λ direction, F λB is the magnitude of the suspension force generated at the B-phase stator pole in the λ direction. Specifically, the direction of the suspension force generated by each stator pole on the rotor is always from the rotor center to the stator pole center, and the positive direction of the force is consistent with the positive direction of the coordinate axis. According to the projection relationship determined by the motor structure, the suspension force in the X direction is given by F x * and the suspension force given value F in the Y direction y * Decomposed into the suspension force generated by each independent stator pole. The suspension force generated by each phase stator pole on the rotor is divided into the λ region and the μ region. The λ region covers the six stator poles close to the X-axis plane, and the μ region covers the six stator poles close to the Y-axis plane. Introduce six unit direction vectors and The specific numerical correspondence is shown in Table 2:

[0024] Table 2

[0025]

[0026] When the rotor angle is between 15° and 30° in the BC phase conduction mode, that is, when the B and C phases are conducting, the suspension force generated by the Y-axis suspension current at the B and C phase stator poles is F B1 and F C1 Indicates that the suspension force F in the X directionx and the suspension force F in the Y direction y The decomposition of is expressed as:

[0027] in:

[0028]

[0029] F μC is the magnitude of the suspension force generated at the C-phase stator pole in the μ direction, F λC is the magnitude of the suspension force generated at the C-phase stator pole in the λ direction;

[0030] In the AC phase conduction mode, when the rotor angle is between 30° and 45°, that is, when phases A and C are conducting, the suspension force generated by the Y-axis suspension current in phases A and C is F A1 and F C1 Indicates that the suspension force F in the X direction x and the suspension force F in the Y direction y The decomposition of is expressed as: in:

[0031]

[0032] In this embodiment, in S4, the corresponding relationship between the suspension force and the suspension current corresponding to each stator pole is established, including: and The expression in the XY stationary coordinate system is:

[0033] Then, the Maxwell stress tensor method is used to express the suspension force generated by each stator pole with the suspension current, that is, a mapping model between the suspension force generated by each stator pole and the suspension current is established:

[0034] Among them, K represents the motor mechanical characteristic constant, i sy represents the Y-axis suspension current, i sx represents the X-axis suspension current, μ0 represents the air magnetic permeability, L Fe represents the core length, R represents the rotor radius, l gap Indicates the air gap length, N s Indicates the number of turns of the suspension coil, A M , B M and C M are three coupling coefficients, and their expressions are shown in Table 3:

[0035] Table 3

[0036]

[0037] Among them, N f Represents the number of turns of the excitation coil, N m Represents the number of turns of the armature coil, i f In this embodiment, in S4, the acquisition of the suspension current reference values ​​in the X-axis and Y-axis directions includes: the suspension force given value F in the X-axis direction x * and the suspension force given value F in the Y direction y * expression:

[0038]

[0039] Written in matrix form as shown in formula (17): Thus, the X-axis suspension current reference value i is further obtained. sx * and Y-axis suspension current reference value i sy *:

[0040]

[0041] In the preferred embodiment, the high-speed bearingless stator excitation type reluctance motor adopts a bearingless double-salient pole motor with a 12 / 8 pole structure. The stator pole adopts a parallel tooth structure, including 4 large slots and 8 small slots; the armature coil is embedded on each stator pole, the excitation coil is embedded in the large slot of the stator, the X-axis and Y-axis suspension coils are embedded in the large slot of the stator, and the suspension coils that are radially opposite in space are reversely connected in series to form the X-axis and Y-axis suspension windings respectively; four sets of eddy current sensors are used, and the eddy current sensors obtain the rotor position signal by measuring the distance between the probe and the shaft reference ring. The armature current and the excitation current are detected by four sets of current Hall sensors; the X-axis suspension current and the Y-axis suspension current are detected by two sets of current Hall sensors.

[0042] The embodiment of the present invention provides a method for decoupling control of the suspension force of a high-speed bearingless stator excitation type reluctance motor, which detects the rotor position angle in real time during the operation of the motor to determine the conduction mode of the phase winding. The suspension force is projected to the corresponding stator pole direction according to the obtained conduction mode of the phase winding, and the suspension force required to be generated by the stator pole of the corresponding phase winding can be obtained. According to the analytical expression of the suspension force and the suspension current, the suspension current reference value can be calculated. The suspension current loop controls the on and off of the switch tube in the H-bridge circuit by outputting a duty cycle signal, thereby controlling the output suspension current. The control method of the present invention is simple and reliable, realizes the decoupling of the suspension force of the high-speed bearingless stator excitation type reluctance motor, and improves the stability of the motor suspension system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 This is the block diagram of the suspension force decoupling control of a high-speed bearingless stator excitation reluctance motor;

[0045] Figure 2 It is a schematic diagram of the projection of the X-axis and Y-axis suspension forces;

[0046] Figure 3 (a) to Figure 3 (d) is a schematic diagram of the suspension force waveform before decoupling under no-load conditions;

[0047] Figure 4 (a) to Figure 4 (d) is a schematic diagram of the suspension force waveform before decoupling under load conditions;

[0048] Figure 5 (a) to Figure 5 (d) is a schematic diagram of the suspension force waveform after decoupling under no-load conditions;

[0049] Figure 6 (a) to Figure 6 (d) is a schematic diagram of the suspension force waveform after decoupling under load conditions. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention. It can be understood by those skilled in the art that, unless specifically stated, the singular forms "one", "one", "said" and "the" used herein may also include plural forms. It should be further understood that the term "including" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say that an element is "connected" or "coupled" to another element, it can be directly connected or coupled to other elements, or there may also be intermediate elements. In addition, the "connection" or "coupling" used here may include wireless connection or coupling. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as generally understood by those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0051] Figure 1 Suspension force decoupling control frame for high-speed bearingless stator excitation reluctance motor Figure 1 ) Use the eddy current sensor to obtain the current rotor position x and the rotor position reference value x * After the difference is made and the x-direction displacement PID controller is used to adjust, the required suspension force F in the x-axis direction is obtained. x * ; Use the eddy current sensor to obtain the current rotor position y and the rotor position reference value y * After the difference is made and the Y-direction displacement PID controller is used to adjust, the required suspension force F in the Y-axis direction is obtained. y * .

[0052] Using a rotary transformer to obtain the rotor position angle θ r , the phase winding conduction mode is determined according to the real-time rotor position angle. The conduction modes of each phase winding under different rotor position angles are shown in the following table (taking the rotor position mechanical angle of 0 to 45° as an example):

[0053]

[0054] where i mA ,,i mB ,i mC It is the instantaneous value of the sampled three-phase armature winding current of A, B, and C.

[0055] Combined with the stator pole distribution law, it is believed that the direction of the suspension force generated by each stator pole on the rotor is always

[0056] The center of the sub-axis points to the center of the stator pole, and the positive direction of the specified force is consistent with the positive direction of the coordinate axis. According to the projection relationship determined by the motor structure, the suspension force in the X direction is given a value F x * and the suspension force given value F in the Y direction y * Decomposed into the suspension force generated by each independent stator pole. The suspension force generated by each phase stator pole on the rotor is divided into the λ region and the μ region. The λ region covers the six stator poles close to the X-axis plane, and the F region covers the six stator poles close to the Y-axis plane. Introduce six unit direction vectors and The specific numerical correspondence is shown in the following table:

[0057]

[0058] The suspension current reference value can be obtained based on the analytical formula of suspension force and suspension current. The suspension current loop outputs high and low voltage duty ratio analog signals to control the on and off of the switch tube in the H-bridge circuit, thereby realizing the control of the suspension current.

[0059] Figure 2 It is a schematic diagram of the projection of the suspension force on the X-axis and Y-axis, so that the direction of the suspension force generated by each phase stator pole always points to the center of the stator pole.

[0060] 1) When the rotor angle is between 0 and 15°, that is, when phases A and B are conducting, the suspension force generated by the Y-axis suspension current at the stator poles of phases A and B is F A1 and F B1 express:

[0061]

[0062] In the formula, represents the suspension force generated by the Y-axis suspension current only, F μA is the magnitude of the suspension force generated at the stator pole of phase A in the μ direction, F μB is the magnitude of the suspension force generated at the B-phase stator pole in the μ direction.

[0063] The suspension force generated by the X-axis suspension current at the stator poles of phase A and phase B is given by F A2 and F B2 express:

[0064]

[0065] In the formula, represents the suspension force generated by the X-axis suspension current only, F λA is the magnitude of the suspension force generated at the stator pole of phase A in the λ direction, F λB is the magnitude of the suspension force generated at the B-phase stator pole in the λ direction.

[0066] At this time, the suspension force F in the X direction x and the suspension force F in the Y direction y It can be expressed as:

[0067]

[0068] Using the Maxwell stress tensor method, the suspension force in the X direction and the suspension force in the Y direction are expressed by the suspension current in the X and Y directions:

[0069]

[0070] Matrix operations can be simplified to obtain:

[0071]

[0072] 2) When the rotor angle is between 15° and 30°, that is, when phases B and C are conducting, according to the stator-rotor overlap rule, F x and F y Projected onto the stator pole directions of phase B and phase C respectively.

[0073] The suspension force generated by the Y-axis suspension current at the B-phase and C-phase stator poles is given by F B1 and F C1 express:

[0074] In the formula, represents the suspension force generated by the Y-axis suspension current only, F μB is the magnitude of the suspension force generated at the B-phase stator pole in the μ direction, F μC is the magnitude of the suspension force generated at the C-phase stator pole in the μ direction.

[0075] The suspension force generated by the X-axis suspension current at the B-phase and C-phase stator poles is given by F B2 and F C2 express:

[0076]

[0077] In the formula, represents the suspension force generated by the X-axis suspension current only, F λB is the magnitude of the suspension force generated at the B-phase stator pole in the λ direction, F λC is the magnitude of the suspension force generated at the C-phase stator pole in the λ direction.

[0078] Suspension force F in the X direction x and the suspension force F in the Y direction y It can be expressed as:

[0079]

[0080] Using the Maxwell stress tensor method, the suspension force generated by each stator pole is expressed as the suspension current:

[0081]

[0082] Simplifying the array operation yields:

[0083]

[0084] 3) When the rotor angle is between 30° and 45°, that is, phases A and C are conducting, according to the stator-rotor overlap rule, F x and F y Projected onto the stator pole direction of phase A and phase C respectively.

[0085] The suspension force generated by the Y-axis suspension current in phase A and phase C is given by F A1 and F C1 express:

[0086]

[0087] In the formula, represents the suspension force generated by the Y-axis suspension current only, F μA is the magnitude of the suspension force generated at the stator pole of phase A in the μ direction, F μC is the magnitude of the suspension force generated at the C-phase stator pole in the μ direction.

[0088] The suspension force generated by the X-axis suspension current in phase A and phase C is given by F A2 and F C2 express:

[0089]

[0090] In the formula, represents the suspension force generated by the X-axis suspension current only, F λA is the magnitude of the suspension force generated at the stator pole of phase A in the λ direction, F λC is the magnitude of the suspension force generated at the C-phase stator pole in the λ direction.

[0091] Among them, the suspension force F in the X direction x and the suspension force F in the Y direction y It can be expressed as:

[0092]

[0093] Using the Maxwell stress tensor method, the suspension force generated by each stator pole is expressed as the suspension current:

[0094]

[0095] Matrix operations can be simplified to obtain:

[0096]

[0097] Figure 3 (a) to Figure 3 (d) is a schematic diagram of the suspension force waveform before decoupling under no-load conditions. When the excitation current is 2A, the Y-axis suspension current is 1A, and the X-axis suspension current is 0A, Figure 3 It can be seen from (d) that although no X-axis suspension current is applied, the suspension force in the X-axis direction still fluctuates with the rotor position angle. The suspension force cross-coupling coefficient ζ is defined as the ratio of the suspension force in the x-direction generated by coupling to Fy when only the suspension force in the y-direction needs to be generated. Its magnitude is shown in formula (16):

[0098]

[0099] Figure 4 (a) to Figure 4 (d) is a schematic diagram of the suspension force waveform before decoupling under load conditions. When the excitation current is 2A, the Y-axis suspension current is 1A, and the X-axis suspension current is 0A, Figure 4 It can be seen from (d) that although no X-axis suspension current is applied, the X-axis suspension force still fluctuates with the rotor position angle under load conditions. At the same time, due to the influence of the armature current, Figure 3 (c) Figure 4 (c) The Y-axis suspension force is distorted. The maximum value of ξ in one electrical cycle is 49.8%.

[0100] Figure 5 (a) to Figure 5 (d) is a schematic diagram of the suspension force waveform after decoupling under no-load conditions. Under the conditions of excitation current of 2A and armature current of 2A, after the suspension current calculated by the decoupling block diagram is passed, compared with Figure 3 (d) Figure 5 The suspension force in the X-axis direction shown in (d) hardly changes with the rotor position angle. At this time, the maximum value of ξ in one electrical cycle is 0.6%, and the suspension force cross-coupling coefficient is reduced by 98% compared with before decoupling.

[0101] Figure 6 (a) to Figure 6 (d) is a schematic diagram of the suspension force waveform after decoupling under load conditions. When the excitation current is 2A and the armature current is 2A, the suspension current calculated by the decoupling block diagram is input. Compared with Figure 4 (c) Figure 6 The suspension force in the X-axis direction shown in (d) hardly changes with the rotor position angle. At this time, the maximum value of ξ in one electrical cycle is 1.2%, and the suspension force cross-coupling coefficient is reduced by 97% compared with before decoupling.

[0102] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for controlling the suspension force decoupling of a high-speed bearingless stator excitation reluctance motor, characterized in that: include: S1. Using an eddy current sensor to obtain the current position of the rotor of the high-speed bearingless stator excitation type reluctance motor, and determining the required suspension force given values ​​in the X-axis and Y-axis directions according to the current position of the rotor; S2. Use the rotary transformer to obtain the rotor position angle θ r , and determine the conduction mode of the three-phase winding, the conduction mode of the three-phase winding includes: the existence of current in the three-phase armature windings A, B, and C; S3, decomposing the given value of the suspension force to obtain the given value of the suspension force corresponding to the stator pole in the conduction mode; S4, establishing a mapping relationship between the given value of the suspension force corresponding to the stator pole and the suspension current, and obtaining the suspension current reference values ​​in the X-axis and Y-axis directions; S5, using the current Hall sensor to collect the actual suspension current in the X-axis and Y-axis directions; S6. Using the difference between the actual suspension current and the suspension current reference value as a PI controller, wherein the PI controller outputs a PWM signal to a control circuit of the high-speed bearingless stator excitation type reluctance motor.

2. The method according to claim 1, characterized in that In S1, it includes: The eddy current sensor is used to obtain the current position x of the rotor, x and the reference value x of the rotor position in the X-axis direction. * After the difference is made, it is input into the X-axis displacement PID controller, and the X-axis displacement PID controller outputs the required suspension force set value F in the X-axis direction. x * ; Use the eddy current sensor to obtain the rotor's current position y, y and the rotor position reference value y in the Y-axis direction * After the difference is made, it is input into the Y-axis displacement PID controller, and the Y-axis displacement PID controller outputs the required suspension force set value F in the Y-axis direction. y * .

3. The method according to claim 1, characterized in that The types of conduction modes include: AB phase conduction, BC phase conduction and AC phase conduction; Among them, when θ r ∈[0,15°), sampling gets i mA and i mB ; When θ r ∈[15 o , 30 o ), sample to get i mB and i mC ; When θ r ∈[30 o ~45 o ), sample to get i mA and i mC ,i mA 、i mB 、i mC It is the instantaneous value of the sampled three-phase armature winding current of A, B, and C.

4. The method according to claim 2, characterized in that: In S3, this includes: The suspension force generated by each phase stator pole on the rotor is divided into a λ region and a μ region, wherein the λ region covers six stator poles close to the X-axis plane, and the F region covers six stator poles close to the Y-axis plane; F x * and F y * Decomposed into a given value of the suspension force generated by each independent stator pole.

5. The method according to claim 4, characterized in that Suspension force F in the X direction in the AB phase conduction mode x and the suspension force F in the Y direction y The decomposition of in: F A1 、F B1 and F C1 It represents the suspension force generated by the Y-axis suspension current at the stator poles of phase A, phase B and phase C, F A2 、F B2 and F C2 It represents the suspension force generated by the X-axis suspension current at the stator poles of phase A, phase B and phase C. represents the suspension force generated by the Y-axis suspension current only, F μA is the magnitude of the suspension force generated at the stator pole of phase A in the μ direction, F μB is the magnitude of the suspension force generated at the B-phase stator pole in the μ direction; represents the suspension force generated by the X-axis suspension current only, F λA is the magnitude of the suspension force generated at the stator pole of phase A in the λ direction, F λB is the magnitude of the suspension force generated at the B-phase stator pole in the λ direction, and Represent six unit direction vectors respectively; Suspension force F in the X direction in the BC phase conduction mode x and the suspension force F in the Y direction y The decomposition of is expressed as: in: F μC is the magnitude of the suspension force generated at the C-phase stator pole in the μ direction, F λC is the magnitude of the suspension force generated at the C-phase stator pole in the λ direction; Suspension force F in the X direction in AC phase conduction mode x and the suspension force F in the Y direction y The decomposition of is expressed as: in:

6. The method according to claim 5, characterized in that In S4, the establishing of the corresponding relationship between the suspension force and the suspension current corresponding to each stator pole includes: Establish a mapping model between the suspension force and suspension current generated by each stator pole: Among them, K represents the motor mechanical characteristic constant, i sy represents the Y-axis suspension current, i sx represents the X-axis suspension current, μ0 represents the air magnetic permeability, L Fe represents the core length, R represents the rotor radius, l gap Indicates the air gap length, N s Indicates the number of turns of the suspension coil, A M , B M and C M are the three coupling coefficients.

7. The method according to claim 6, characterized in that In S4, obtaining the suspension current reference values ​​in the X-axis and Y-axis directions includes:

8. The method according to claim 1, characterized in that The stator poles of the high-speed bearingless stator excitation reluctance motor adopt a parallel tooth structure, including 4 large slots and 8 small slots; The armature coil is embedded in each stator pole, the excitation coil is embedded in the large slot of the stator, the X-axis and Y-axis suspension coils are embedded in the large slot of the stator, and the suspension coils that are radially opposite to each other in space are connected in reverse series to form the X-axis and Y-axis suspension windings respectively; Four sets of eddy current sensors are used, and the eddy current sensors obtain rotor position signals by measuring the distance between the probe and the shaft reference ring.

9. The method according to claim 1, characterized in that: The armature current and the excitation current are detected by four sets of current Hall sensors; Two sets of current Hall sensors are used to detect the X-axis suspension current and the Y-axis suspension current.

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