Three-stage magnetic circuit isolation type bearingless electrically excited double salient pole motor and control method

Abstract

The embodiment of the present invention discloses a three-stage magnetic circuit isolation type bearingless electric excitation double salient pole motor and a suspension control method, which relates to the technical field of bearingless motors. The motor stator includes a torque module stator, a suspension module stator and a magnetic isolation sleeve. The single-phase torque module stator is composed of four torque module stator cores. The three-phase torque module stator core is embedded in a magnetic isolation sleeve made of a magnetic isolation magnetic circuit and fixed. The torque module stator core is wound with a torque excitation winding and an armature winding. The suspension module stator is composed of four suspension module stator cores. The suspension module stator core is embedded in a magnetic isolation sleeve and fixed. The suspension module stator core is wound with a suspension excitation winding and a suspension winding. The rotor can be stably suspended by controlling the suspension winding current. The motor realizes the decoupling of the torque flux path and the suspension flux path, ensures the suspension stability of the motor when the torque flux path reaches saturation, and ensures the suspension accuracy when improving the motor torque density.

Description

Technical Field

[0001] The present invention relates to the technical field of bearingless motors, and in particular to a three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor and a suspension control method thereof. Background Art

[0002] The more-electric aircraft engine is a new type of aircraft engine that has developed along with the more-electric aircraft. Its important features are the built-in starter generator and the magnetic bearing that supports the engine rotor. The magnetic bearing technology eliminates the gear transmission mechanism and mechanical bearings, avoids mechanical wear, and simplifies the overall structure of the engine. However, the magnetic bearing occupies a large axial space, and the unbalanced magnetic pull seriously interferes with the magnetic bearing. This structure makes the more-electric aircraft engine face many challenges in terms of integration and rotor stability.

[0003] If the magnetic suspension function is integrated into the starter generator by using the suspension winding to form a bearingless starter generator, then the suspension and electric / generating integrated operation can be achieved by simply controlling the suspension winding current. Compared with the magnetic bearing starter generator, the bearingless starter generator effectively releases the axial space of the engine, which is conducive to the development of high-speed and high-power motors; secondly, the bearingless starter generator can control the suspension winding current to actively control the radial electromagnetic force, which is conducive to the stable suspension of the rotor.

[0004] The bearingless electrically excited double salient pole motor has inherited the advantages of simple and reliable structure of the electrically excited double salient pole motor and is suitable for high temperature and high speed working environment. However, due to the coupling between the motor torque flux path and the suspension flux path, when the excitation current is increased to improve the motor torque density, the saturation of the torque flux path will cause the suspension flux path to be saturated as well, and the suspension force on the rotor will be affected by the saturation of the motor magnetic field and show nonlinear characteristics. The problem of being unable to accurately control the suspension force on the rotor under saturation seriously affects the control performance of the suspension control system, causing the motor suspension to lose accuracy or even become unstable. The suspension control problem under the condition of core magnetic saturation is a common problem faced when improving the torque density of bearingless electrically excited double salient pole motors and most reluctance bearingless motors.

[0005] Therefore, how to improve the bearingless electrically excited double-pole motor so that the suspension flux path is not affected when the torque flux path reaches magnetic saturation and the suspension accuracy is guaranteed while improving the motor torque density has become a topic that needs to be studied. Summary of the invention

[0006] An embodiment of the present invention provides a three-stage magnetic circuit isolation type bearingless electrically excited double-pole motor and a suspension control method thereof, which realizes stable suspension of the motor when the torque flux path reaches magnetic saturation, and ensures suspension accuracy while improving the motor torque density.

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

[0008] In a first aspect, an embodiment of the present invention provides a three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor, comprising: a stator core, an armature winding (2), an excitation winding, a suspension winding, a magnetic isolation sleeve (8), and a rotor core (9);

[0009] The rotor core (9) constitutes the rotor of the motor and the rotor core (9) is a salient pole structure;

[0010] The motor rotor is composed of three rotor sections, which are axially arranged in parallel with an electrical angle of 120 degrees. Each rotor section corresponds to a single-phase torque module stator, so that the self-inductance of the torque excitation winding (3) remains unchanged during the rotation of the rotor.

[0011] The stator core comprises a torque module stator core (1) and a suspension module stator core (4), and both the torque module stator core (1) and the suspension module stator core (4) are salient pole structures;

[0012] The torque module stator core (1) and the suspension module stator core (4) are embedded in a magnetic isolation sleeve (8) and fixed therein; the magnetic isolation sleeve (8) is made of magnetic isolation material; and the magnetic fluxes between the torque module stator core (1) and the suspension module stator core (4) are isolated from each other.

[0013] The torque module stator core (1) is of an E-type structure; a single-phase stator is formed by four torque module stator cores (1), each torque module stator core (1) is placed at a 90° mechanical angle in the circumferential direction, and the three-phase stator is placed in parallel in the axial direction, and a total of 12 torque module stator cores are fixed by embedding a magnetic isolation sleeve (8).

[0014] A single torque module stator core (1) is divided into three stator teeth, and an armature winding (2) and a torque excitation winding (3) are wound on the middle large tooth; the torque excitation winding (3) provides a bias magnetic field for the torque magnetic flux, and the three-phase torque module stator shares the torque excitation winding (3); in each torque module stator core (1), four sets of A-phase armature coils are connected in series in sequence to form an A-phase armature winding, and the first output terminal A+ and the second output terminal A- of the A-phase armature winding are connected to an external control circuit, and the connection mode of the B-phase armature winding and the C-phase armature winding is the same as that of the A-phase armature winding; the four sets of torque excitation coils are connected in series in sequence to form a torque excitation winding (3), and the first output terminal F1+ and the second output terminal F1- of the torque excitation winding (3) are connected to an external control circuit.

[0015] The suspension module stator core (4) is a C-shaped structure; the three-phase stator shares the suspension module stator core, each suspension module stator core (4) is placed at a 90° mechanical angle in the circumferential direction, and a total of four suspension module stator cores (4) are fixed by being embedded in a magnetic isolation sleeve (8).

[0016] A single suspension module stator core (4) is divided into two stator teeth, one side of the teeth is wound with a suspension winding, and the other side of the teeth is wound with a suspension excitation winding (7); the suspension winding is divided into an X-axis suspension winding (5) and a Y-axis suspension winding (6), and the X-axis suspension winding (5) and the Y-axis suspension winding (6) are both composed of two sets of radially opposite suspension coils connected in series. The first output terminal X+ and the second output terminal X- of the X-axis suspension winding (5) are connected to an external control circuit, and the first output terminal Y+ and the second output terminal Y- of the Y-axis suspension winding (6) are connected to an external control circuit; the suspension excitation winding (7) is composed of four sets of suspension excitation coils connected in series, and the first output terminal F2+ and the second output terminal F2- of the suspension excitation winding (7) are connected to an external control circuit. In this embodiment, since the excitation magnetic flux path, the torque magnetic flux path, and the suspension magnetic flux path are all short magnetic circuits, the core loss is small and the motor efficiency is high.

[0017] The X-axis suspension control circuit and the Y-axis suspension control circuit are both full-bridge inverter circuits; in the X-axis suspension control circuit, the MOSFET switch tube Q1 is connected in series with the MOSFET switch tube Q2, the MOSFET switch tube Q3 is connected in series with the MOSFET switch tube Q4, the drains of the MOSFET switch tube Q1 and the MOSFET switch tube Q3 are connected to the positive electrode of the DC voltage source US1, the sources of the MOSFET switch tube Q2 and the MOSFET switch tube Q4 are connected to the negative electrode of the DC voltage source US1, and the first output terminal X+ and the second output terminal X- of the X-axis suspension winding (5) are connected to the source of the MOSFET switch tube Q1 and the MOSFET switch tube Q3, respectively. The source of the ET switch tube Q3 is connected; in the Y-axis suspension control circuit, the MOSFET switch tube Q5 is connected in series with the MOSFET switch tube Q6, the MOSFET switch tube Q7 is connected in series with the MOSFET switch tube Q8, the drains of the MOSFET switch tube Q5 and the MOSFET switch tube Q7 are connected to the positive electrode of the DC voltage source US2, the sources of the MOSFET switch tube Q6 and the MOSFET switch tube Q8 are connected to the negative electrode of the DC voltage source US2, and the first output terminal Y+ and the second output terminal Y- of the Y-axis suspension winding (6) are respectively connected to the source of the MOSFET switch tube Q5 and the source of the MOSFET switch tube Q7.

[0018] In a second aspect, an embodiment of the present invention provides a suspension control method, comprising:

[0019] Step 1, data acquisition stage, including: detecting the radial position of the rotor of the motor by a radial displacement sensor in the X-axis direction installed on the motor end cover, and obtaining the actual position of the rotor of the motor in the X-axis direction; and detecting the radial position of the rotor of the motor by a radial displacement sensor in the Y-axis direction installed on the motor end cover, and obtaining the actual position of the rotor of the motor in the Y-axis direction, wherein the X-axis and the Y-axis are orthogonal to each other;

[0020] Step 2, data processing stage, comprising: respectively detecting the current feedback value of the X-axis suspension winding (5) and the current feedback value of the Y-axis suspension winding (6) of the motor through a current detection unit; and obtaining the current reference value of the X-axis suspension winding (5) through an X-axis displacement adjustment link by taking the difference between the preset reference displacement of the motor in the X-axis direction and the actual displacement of the rotor in the X-axis direction;

[0021] Step 3, data analysis phase, including: obtaining a current reference value of the Y-axis suspension winding (6) by passing the difference between the preset reference displacement of the motor in the Y-axis direction and the actual displacement of the rotor in the Y-axis direction through a Y-axis displacement adjustment link;

[0022] Furthermore, the difference between the current reference value of the X-axis suspension winding (5) and the current feedback value of the X-axis suspension winding (5) is passed through the X-axis suspension current adjustment link to obtain a duty cycle signal of the X-axis suspension control circuit; the difference between the current reference value of the Y-axis suspension winding (6) and the current feedback value of the Y-axis suspension winding (6) is passed through the Y-axis suspension current adjustment link to obtain a duty cycle signal of the Y-axis suspension control circuit;

[0023] Step 4, control execution phase, includes: adjusting the current of the X-axis suspension winding (5) and the current of the Y-axis suspension winding (6) by adjusting the switch duty ratio of the X-axis suspension control circuit and the Y-axis suspension control circuit.

[0024] The X-axis displacement adjustment link is proportional-integral-differential (PID) control; the Y-axis displacement adjustment link is proportional-integral-differential (PID) control; the X-axis suspension current adjustment link is proportional-integral (PI) control; the Y-axis suspension current adjustment link is proportional-integral (PI) control.

[0025] The three-stage magnetic circuit isolation type bearingless electric excitation double salient pole motor and its suspension control method provided by the embodiment of the present invention, the motor stator includes a torque module stator, a suspension module stator and a magnetic isolation sleeve, the single-phase torque module stator is composed of 4 torque module stator cores, the three-phase torque module stator core is embedded in the magnetic isolation sleeve made of magnetic isolation magnetic circuit, and the torque module stator core is wound with torque excitation winding and armature winding. The suspension module stator is composed of 4 suspension module stator cores, the suspension module stator core is embedded in the magnetic isolation sleeve, and the suspension module stator core is wound with suspension excitation winding and suspension winding, the suspension winding includes X-axis suspension winding and Y-axis suspension winding, and the rotor can be stably suspended by controlling the suspension winding current. The motor rotor is composed of three-segment rotors, and the three-segment rotors are placed at an electrical angle of 120°, corresponding to the three-phase torque module stator. The motor realizes the decoupling of the torque flux path and the suspension flux path, ensures the suspension stability of the motor when the torque flux path reaches saturation, and ensures the suspension accuracy when improving the motor torque density. In general, based on the traditional bearingless electrically excited double-pole motor, this embodiment modularizes the motor stator to decouple the motor suspension flux path from the torque flux path, thereby realizing stable suspension of the motor when the torque flux path reaches magnetic saturation, and ensuring the suspension accuracy when improving the motor torque density. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] Figure 1 A 3D structural schematic diagram of a three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor provided in an embodiment of the present invention;

[0028] Figure 2a , Figure 2b A 3D structural cross-sectional view of a three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor provided by an embodiment of the present invention, wherein Figure 2a The motor rotor is shown. Figure 2b The motor rotor is hidden;

[0029] Figure 3a , Figure 3b A schematic diagram of the 3D structure of the rotor of the electric excitation part of a bearingless hybrid excitation synchronous motor provided in an embodiment of the present invention;

[0030] Figure 4a , Figure 4b A schematic diagram of the torque excitation magnetic flux flow direction and the suspension excitation magnetic flux flow direction provided by an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the X-axis suspension control circuit and the Y-axis suspension control circuit of the bearingless hybrid excitation synchronous motor provided in an embodiment of the present invention;

[0032] Figure 6 A block diagram of the suspension control principle of a bearingless hybrid excitation synchronous motor provided by an embodiment of the present invention;

[0033] The reference numerals in the accompanying drawings represent: 1-torque module stator core, 2-armature winding, 3-torque excitation winding, 4-suspension module stator core, 5-X-axis suspension winding, 6-Y-axis suspension winding, 7-suspension excitation winding, 8-magnetic isolation sleeve, 9-rotor core. DETAILED DESCRIPTION

[0034] 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.

[0035] The embodiment of the present invention provides a three-stage magnetic circuit isolation type bearingless electrically excited double salient pole motor and a suspension control method thereof. The structure of the three-stage magnetic circuit isolation type bearingless electrically excited double salient pole motor is as follows: Figure 1As shown in Figure 2, in order to better show the winding structure of the motor, Figure 2b The motor rotor is hidden.

[0036] The motor comprises a stator core, an armature winding (2), an excitation winding, an X-axis suspension winding (5), a Y-axis suspension winding (6), a magnetic isolation sleeve (8), and a rotor core (9). The stator core comprises a torque module stator core (1) and a suspension module stator core (4); and the excitation winding comprises a torque excitation winding (3) and a suspension excitation winding (7).

[0037] The rotor of the motor is composed of three parallel rotor sections, which correspond to the three-phase torque module stators respectively, and each rotor section is staggered by 120 electrical degrees to ensure that the self-inductance of the torque excitation winding (3) remains unchanged when the rotor rotates. Each rotor section is composed of a rotor core (9), and the rotor core (9) is a salient pole structure.

[0038] The stator of the motor is composed of a stator core and a magnetic isolation sleeve (8), wherein the stator core comprises a torque module stator core (1) and a suspension module stator core (4). The torque module stator core (1) is an E-type structure, and the single-phase stator is composed of four torque module stator cores (1), each torque module stator core (1) is placed at a 90° mechanical angle along the circumferential direction, and the three-phase stator cores A, B, and C correspond to the three-stage rotor, and a total of 12 torque module stator cores (1) are embedded in the magnetic isolation sleeve (8) and fixed.

[0039] Take the stator core of phase A torque module as an example. Figure 3a The winding method of the stator core of the A-phase torque module is shown.

[0040] In this embodiment, each torque module stator core (1) is divided into three stator teeth, the middle tooth is a large tooth, and the teeth on both sides are small teeth. The pole arc length of the large tooth is twice that of the small tooth, and the armature coil and the excitation coil are wound on the middle large tooth. Figure 3aThe winding method is connected in sequence to form the A-phase armature winding. The A-phase armature winding is composed of four sets of A-phase armature coils, and each set of armature coils has two terminals, namely the first terminal and the second terminal. The first terminal of the first set of A-phase armature coils serves as the first output terminal A+ of the A-phase armature winding, the second terminal of the first set of A-phase armature coils is connected to the first terminal of the second set of A-phase armature coils, the second terminal of the second set of A-phase armature coils is connected to the first terminal of the third set of A-phase armature coils, the second terminal of the third set of A-phase armature coils is connected to the first terminal of the fourth set of A-phase armature coils, and the second terminal of the fourth set of A-phase armature coils serves as the second output terminal A- of the A-phase armature winding. The first output terminal A+ and the second output terminal A- of the A-phase armature winding are connected to the external control circuit. The connection mode of the B-phase armature winding and the C-phase armature winding is the same as that of the A-phase armature winding. The output terminals of the B-phase armature winding are the first output terminal B+ of the B-phase armature winding and the second output terminal B- of the B-phase armature winding; the output terminals of the C-phase armature winding are the first output terminal C+ of the C-phase armature winding and the second output terminal C- of the C-phase armature winding. The first output terminal B+ and the second output terminal B- of the B-phase armature winding are connected to the external control circuit; the first output terminal C+ and the second output terminal C- of the C-phase armature winding are connected to the external control circuit.

[0041] The middle large tooth is also wound with a torque excitation winding (3) for providing a bias magnetic field for the torque flux. The three-phase torque module stator shares the torque excitation winding (3). The torque excitation coil is arranged according to Figure 3a The torque excitation winding (3) is formed by connecting the four sets of torque excitation coils in sequence in a winding manner. Each set of torque excitation coils has two terminals, namely, a first terminal and a second terminal. The first terminal of the first set of torque excitation coils serves as the first output terminal F1+ of the torque excitation winding (3), the second terminal of the first set of torque excitation coils is connected to the first terminal of the second set of torque excitation coils, the second terminal of the second set of torque excitation coils is connected to the first terminal of the third set of torque excitation coils, the second terminal of the third set of torque excitation coils is connected to the first terminal of the fourth set of torque excitation coils, and the second terminal of the fourth set of torque excitation coils serves as the second output terminal F1- of the torque excitation winding (3). The first output terminal F1+ and the second output terminal F1- of the torque excitation winding (3) are connected to an external control circuit, and the torque magnetic flux path bias magnetic field can be adjusted by adjusting the current of the torque excitation winding (3).

[0042] When a positive current flows into the torque excitation winding (3), the torque excitation flux flows in the following direction: Figure 4aAs shown, the torque excitation magnetic flux only flows in a single torque module stator core (1) and its corresponding rotor core (9), and the excitation magnetic flux paths between different torque module stator cores (1) are independent of each other. At the same time, compared with the traditional bearingless electrically excited double-pole motor, the motor torque excitation magnetic flux path is shorter, the core loss is smaller, and the excitation efficiency is higher.

[0043] The suspension module stator core (4) is a C-shaped structure. The three-phase stator shares the suspension module stator core (4). A total of four suspension module stator cores (4) are embedded in the magnetic isolation sleeve (8) for fixation. Each suspension module stator core (4) is staggered at a mechanical angle of 90°. The winding method of the suspension module stator core (4) is as follows: Figure 3b shown.

[0044] In this embodiment, each suspension module stator core (4) is divided into two stator teeth, the pole arc lengths of the teeth on both sides are the same, one side tooth is wound with a suspension coil, and the other side tooth is wound with a suspension excitation coil. Figure 3b The winding method is connected in sequence to form an X-axis suspension winding (5). The X-axis suspension winding (5) is composed of two sets of X-axis suspension coils, the two sets of X-axis suspension coils are radially opposite, and each set of X-axis suspension coils has two terminals, namely a first terminal and a second terminal. The first terminal of the first set of X-axis suspension coils serves as the first output terminal X+ of the X-axis suspension winding (5), the second terminal of the first set of X-axis suspension coils is connected to the first terminal of the second set of X-axis suspension coils, and the second terminal of the second set of X-axis suspension coils serves as the second output terminal X- of the X-axis suspension winding (5). The first output terminal X+ and the second output terminal X- of the X-axis suspension winding (5) are connected to an external control circuit.

[0045] Y-axis suspension coil Figure 3b The Y-axis suspension winding (6) is formed by connecting two sets of Y-axis suspension coils in a winding manner. The two sets of Y-axis suspension coils are radially opposite to each other. Each set of Y-axis suspension coils has two terminals, namely, a first terminal and a second terminal. The first terminal of the first set of Y-axis suspension coils serves as the first output terminal Y+ of the Y-axis suspension winding (6), the second terminal of the first set of Y-axis suspension coils is connected to the first terminal of the second set of Y-axis suspension coils, and the second terminal of the second set of Y-axis suspension coils serves as the second output terminal Y- of the Y-axis suspension winding (6). The first output terminal Y+ and the second output terminal Y- of the Y-axis suspension winding (6) are connected to an external control circuit.

[0046] The structure of the X-axis suspension control circuit is as follows Figure 5The X-axis suspension control circuit is a full-bridge inverter circuit. Specifically, in the X-axis suspension control circuit, the MOSFET switch tube Q1 is connected in series with the MOSFET switch tube Q2, the MOSFET switch tube Q3 is connected in series with the MOSFET switch tube Q4, the drains of the MOSFET switch tube Q1 and the MOSFET switch tube Q3 are connected to the positive electrode of the DC voltage source US1, the sources of the MOSFET switch tube Q2 and the MOSFET switch tube Q4 are connected to the negative electrode of the DC voltage source US1, and the first output terminal X+ and the second output terminal X- of the X-axis suspension winding (5) are connected to the source of the MOSFET switch tube Q1 and the source of the MOSFET switch tube Q3 respectively.

[0047] The structure of the Y-axis suspension control circuit is as follows Figure 5 The Y-axis suspension control circuit is a full-bridge inverter circuit. Specifically, in the Y-axis suspension control circuit, the MOSFET switch tube Q5 is connected in series with the MOSFET switch tube Q6, the MOSFET switch tube Q7 is connected in series with the MOSFET switch tube Q8, the drains of the MOSFET switch tube Q5 and the MOSFET switch tube Q7 are connected to the positive electrode of the DC voltage source US2, the sources of the MOSFET switch tube Q6 and the MOSFET switch tube Q8 are connected to the negative electrode of the DC voltage source US2, and the first output terminal Y+ and the second output terminal Y- of the Y-axis suspension winding (6) are respectively connected to the source of the MOSFET switch tube Q5 and the source of the MOSFET switch tube Q7.

[0048] The suspension excitation coil wound on the stator teeth on the other side is Figure 3b The suspension excitation winding (7) is formed by connecting the four suspension excitation coils in sequence in a winding manner. The suspension excitation winding (7) is formed by four sets of suspension excitation coils, each set of suspension excitation coils has two terminals, namely a first terminal and a second terminal. The first terminal of the first set of suspension excitation coils serves as the first output terminal F2+ of the suspension excitation winding (7), the second terminal of the first set of suspension excitation coils is connected to the first terminal of the second set of suspension excitation coils, the second terminal of the second set of suspension excitation coils is connected to the first terminal of the third set of suspension excitation coils, the second terminal of the third set of suspension excitation coils is connected to the first terminal of the fourth set of suspension excitation coils, and the second terminal of the fourth set of suspension excitation coils serves as the second output terminal F2- of the suspension excitation winding (7). The first output terminal F2+ and the second output terminal F2- of the suspension excitation winding (7) are connected to an external control current, and the bias magnetic field of the suspension magnetic flux path can be adjusted by adjusting the current size of the suspension excitation winding (7).

[0049] When a positive current flows into the suspension excitation winding (7), the suspension excitation magnetic flux flows in the following direction: Figure 4bAs shown, the suspension excitation magnetic flux only flows in a single suspension module stator core (4) and its corresponding rotor core (9), and the excitation magnetic flux paths between different suspension module stator cores (4) are independent of each other. At the same time, compared with the traditional bearingless electric excitation double-pole motor, the motor suspension excitation magnetic flux path is shorter, the core loss is smaller, and the excitation efficiency is higher.

[0050] The technical problems solved by the embodiments of the present invention are mainly that the suspension flux path of the traditional bearingless electrically excited double-pole motor is coupled with the torque flux path, the saturation of the torque flux path will cause the suspension flux path to be saturated as well, the suspension control is difficult under the core magnetic saturation condition, and the suspension accuracy cannot be guaranteed when the motor torque density is improved. A three-stage magnetic circuit isolation type bearingless electrically excited double-pole motor with simple suspension control, reliable operation, stable suspension, and high torque density and a suspension control method thereof are provided. Compared with the prior art, the solution provided by this embodiment has at least the following advantages:

[0051] The three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor realizes the decoupling of the suspension flux path and the torque flux path. When the torque flux path reaches magnetic saturation, the suspension flux path is not affected, thus ensuring the suspension accuracy while improving the motor torque density.

[0052] The excitation flux path, suspension flux path and torque flux path of the three-stage magnetic circuit isolation bearingless electrically excited double-salient pole motor are all short magnetic circuits, the motor has small core loss and high efficiency.

[0053] The three-stage magnetic circuit isolation type bearingless electrically excited double salient pole motor places the torque module stator core (1) at a 90° mechanical angle interval along the circumferential direction, and the torque flux is radially symmetrical, thereby eliminating the influence of unilateral magnetic pulling force and improving the suspension stability.

[0054] The three-stage magnetic circuit isolation type bearingless electrically excited double-pole motor inherits the advantages of the traditional bearingless electrically excited double-pole motor, has a simple and reliable structure, and is suitable for high temperature and high speed working environment.

[0055] Based on the structure of the above three-stage bearingless magnetic circuit isolation type bearingless electrically excited double salient pole motor, this embodiment also provides a suspension control method for the motor, and its specific suspension control principle block diagram is as follows: Figure 6 shown.

[0056] In this embodiment, the radial position of the rotor of the motor is detected by a radial displacement sensor in the X-axis direction installed on the motor end cover, and the actual displacement ΔX of the rotor in the X-axis direction is obtained. The radial position of the rotor of the motor is detected by a radial displacement sensor in the Y-axis direction installed on the motor end cover, and the actual displacement ΔY of the rotor in the Y-axis direction is obtained, wherein the X-axis and the Y-axis are orthogonal to each other.

[0057] The current detection unit detects the current feedback value iX of the X-axis suspension winding (5) and the current feedback value iY of the Y-axis suspension winding (6) of the motor respectively.

[0058] The difference between the preset reference displacement X* of the motor in the X-axis direction and the actual displacement ΔX of the rotor in the X-axis direction is passed through an X-axis displacement adjustment link to obtain a current reference value iX* of the X-axis suspension winding (5).

[0059] The difference between the preset reference displacement Y* of the motor in the Y-axis direction and the actual displacement ΔY of the rotor in the Y-axis direction is passed through a Y-axis displacement adjustment link to obtain a current reference value iY* of the Y-axis suspension winding (6).

[0060] The difference between the X-axis suspension winding (5) current reference value iX* and the X-axis suspension winding (5) current feedback value iX is passed through the X-axis suspension current adjustment link to obtain a duty cycle signal D1 of the X-axis suspension control circuit.

[0061] The difference between the Y-axis suspension winding (6) current reference value iY* and the Y-axis suspension winding (6) current feedback value iY is passed through the Y-axis suspension current adjustment link to obtain a duty cycle signal D2 of the Y-axis suspension control circuit.

[0062] By adjusting the switch duty ratio of the X-axis suspension control circuit and the Y-axis suspension control circuit, the X-axis suspension winding (5) current and the Y-axis suspension winding (6) current are adjusted, so that the X-axis suspension winding (5) current tracks its reference value and the Y-axis suspension winding (6) current tracks its reference value, thereby achieving the purpose of controlling the radial suspension force.

[0063] Among them, the X-axis displacement adjustment link is proportional-integral-differential PID control is proportional-integral-differential (PID) control. The Y-axis displacement adjustment link is proportional-integral-differential PID control is proportional-integral-differential (PID) control. The X-axis suspension current adjustment link is proportional-integral (PI) control. The Y-axis suspension current adjustment link is proportional-integral (PI) control.

[0064] The embodiment of the present invention designs a three-stage magnetic circuit isolation type bearingless electrically excited double salient pole motor and a suspension control method thereof, which relates to the technical field of bearingless motors, and provides a three-stage magnetic circuit isolation type bearingless electrically excited double salient pole motor scheme that can realize decoupling of suspension flux path and torque flux path, simple suspension control, stable rotor suspension, and small core loss. The motor stator includes a torque module stator, a suspension module stator, and a magnetic isolation sleeve. The single-phase torque module stator is composed of four torque module stator cores. The three-phase torque module stator core is embedded in a magnetic isolation sleeve made of a magnetic isolation magnetic circuit and fixed. The torque module stator core is wound with a torque excitation winding and an armature winding. The suspension module stator is composed of four suspension module stator cores. The suspension module stator core is embedded in a magnetic isolation sleeve and fixed. The suspension module stator core is wound with a suspension excitation winding and a suspension winding. The suspension winding includes an X-axis suspension winding and a Y-axis suspension winding. The stable suspension of the rotor can be achieved by controlling the suspension winding current. The motor rotor is composed of three sections, which are placed at an electrical angle of 120° and correspond to the three-phase torque module stator respectively. The motor realizes the decoupling of the torque flux path and the suspension flux path, ensures the suspension stability of the motor when the torque flux path reaches saturation, and ensures the suspension accuracy when improving the motor torque density. At the same time, the motor excitation flux path, torque flux path, and suspension flux path are all short magnetic paths, which effectively reduces the motor core loss and improves the motor efficiency.

[0065] 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 three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor, characterized in that: include: Stator core, armature winding (2), excitation winding, suspension winding, magnetic isolation sleeve (8), rotor core (9); The stator core comprises a torque module stator core (1) and a suspension module stator core (4), and both the torque module stator core (1) and the suspension module stator core (4) are salient pole structures; The torque module stator core (1) and the suspension module stator core (4) are embedded in a magnetic isolation sleeve (8) and fixed therein; the magnetic isolation sleeve (8) is made of magnetic isolation material; and the magnetic fluxes between the torque module stator core (1) and the suspension module stator core (4) are isolated from each other. The stator core (1) of a single torque module is divided into three stator teeth, and the armature winding (2) and the torque excitation winding (3) are wound on the middle large tooth; The torque excitation winding (3) provides a bias magnetic field for the torque magnetic flux, and the stators of the three-phase torque module share the torque excitation winding (3); The excitation winding comprises a torque excitation winding (3) and a suspension excitation winding (7); The suspension winding comprises an X-axis suspension winding (5) and a Y-axis suspension winding (6); The rotor core (9) constitutes the rotor of the motor and the rotor core (9) is a salient pole structure; The motor rotor is composed of three rotor sections, which are axially arranged in parallel with an electrical angle of 120°, and each rotor section corresponds to a single-phase torque module stator, so that the self-inductance of the torque excitation winding (3) remains unchanged during the rotation of the rotor; The stator core (1) of a single torque module is divided into three stator teeth, an armature winding (2) and a torque excitation winding (3) are wound on the middle large tooth, four sets of A-phase armature coils are connected in series in sequence to form the A-phase armature winding, a first output terminal A+ and a second output terminal A- of the A-phase armature winding are connected to an external control circuit, and a B-phase armature winding and a C-phase armature winding are connected in the same manner as the A-phase armature winding; four sets of torque excitation coils are connected in series in sequence to form the torque excitation winding (3), a first output terminal F1+ and a second output terminal F1- of the torque excitation winding (3) are connected to an external control circuit.

2. The segmented magnetic circuit isolation type bearingless electrically excited double salient pole motor according to claim 1, characterized in that: The torque module stator core (1) is an E-type structure; A single-phase stator is formed by four torque module stator cores (1), each torque module stator core (1) is placed at a mechanical angle of 90° along the circumferential direction, and the three-phase stator is placed in parallel axially. A total of 12 torque module stator cores are fixed by embedding a magnetic isolation sleeve (8).

3. The segmented magnetic circuit isolation type bearingless electrically excited double salient pole motor according to claim 1, characterized in that: The stator core (4) of the suspension module is a C-shaped structure; The three-phase stator shares a suspension module stator core, each suspension module stator core (4) is placed at a mechanical angle of 90° along the circumferential direction, and a total of four suspension module stator cores (4) are fixed by being embedded in a magnetic isolation sleeve (8).

4. The segmented magnetic circuit isolation type bearingless electrically excited double salient pole motor according to claim 3, characterized in that: A single suspension module stator core (4) is divided into two stator teeth, one side tooth is wound with a suspension winding, and the other side tooth is wound with a suspension excitation winding (7); The suspension winding is divided into an X-axis suspension winding (5) and a Y-axis suspension winding (6), and both the X-axis suspension winding (5) and the Y-axis suspension winding (6) are composed of two sets of suspension coils that are radially opposite to each other and are connected in series.

5. The segmented magnetic circuit isolation type bearingless electrically excited double salient pole motor according to claim 4, characterized in that: The first output terminal X+ and the second output terminal X- of the X-axis suspension winding (5) are connected to the external control circuit, and the first output terminal Y+ and the second output terminal Y- of the Y-axis suspension winding (6) are connected to the external control circuit; The suspension excitation winding (7) is composed of four sets of suspension excitation coils connected in series, and a first output terminal F2+ and a second output terminal F2- of the suspension excitation winding (7) are connected to an external control circuit.

6. The segmented magnetic circuit isolation type bearingless electrically excited double salient pole motor according to claim 1, characterized in that: Both the X-axis suspension control circuit and the Y-axis suspension control circuit are full-bridge inverter circuits; In the X-axis suspension control circuit, the MOSFET switch tube Q1 is connected in series with the MOSFET switch tube Q2, the MOSFET switch tube Q3 is connected in series with the MOSFET switch tube Q4, the drain electrodes of the MOSFET switch tube Q1 and the MOSFET switch tube Q3 are connected to the positive electrode of the DC voltage source US1, the source electrodes of the MOSFET switch tube Q2 and the MOSFET switch tube Q4 are connected to the negative electrode of the DC voltage source US1, and the first output terminal X+ and the second output terminal X- of the X-axis suspension winding (5) are connected to the source electrode of the MOSFET switch tube Q1 and the source electrode of the MOSFET switch tube Q3 respectively; In the Y-axis suspension control circuit, the MOSFET switch tube Q5 is connected in series with the MOSFET switch tube Q6, the MOSFET switch tube Q7 is connected in series with the MOSFET switch tube Q8, the drain electrodes of the MOSFET switch tube Q5 and the MOSFET switch tube Q7 are connected to the positive electrode of the DC voltage source US2, the source electrodes of the MOSFET switch tube Q6 and the MOSFET switch tube Q8 are connected to the negative electrode of the DC voltage source US2, and the first output terminal Y+ and the second output terminal Y- of the Y-axis suspension winding (6) are respectively connected to the source electrode of the MOSFET switch tube Q5 and the source electrode of the MOSFET switch tube Q7.

7. A suspension control method, characterized in that: The suspension control method is used for a three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor. The three-stage magnetic circuit isolation type bearingless electrically excited double-salient pole motor comprises: a stator core, an armature winding (2), an excitation winding, a suspension winding, a magnetic isolation sleeve (8), and a rotor core (9); the stator core comprises a torque module stator core (1) and a suspension module stator core (4); the torque module stator core (1) and the suspension module stator core (4) are both salient pole structures; The torque module stator core (1) and the suspension module stator core (4) are embedded in a magnetic isolation sleeve (8) and fixed therein; the magnetic isolation sleeve (8) is made of magnetic isolation material; the magnetic flux between the torque module stator core (1) and the suspension module stator core (4) is isolated from each other; a single torque module stator core (1) is divided into three stator teeth, and an armature winding (2) and a torque excitation winding (3) are wound on the middle large tooth; The torque excitation winding (3) provides a bias magnetic field for the torque magnetic flux, and the three-phase torque module stator shares the torque excitation winding (3); the excitation winding includes the torque excitation winding (3) and the suspension excitation winding (7); the suspension winding includes an X-axis suspension winding (5) and a Y-axis suspension winding (6); the rotor core (9) constitutes the rotor of the motor and the rotor core (9) is a salient pole structure, wherein the X-axis suspension control circuit and the Y-axis suspension control circuit are both full-bridge inverter circuits; The motor rotor is composed of three rotor sections, which are axially arranged in parallel with an electrical angle of 120°, and each rotor section corresponds to a single-phase torque module stator, so that the self-inductance of the torque excitation winding (3) remains unchanged during the rotation of the rotor; The stator core (1) of a single torque module is divided into three stator teeth, and an armature winding (2) and a torque excitation winding (3) are wound on the middle large tooth. Four sets of A-phase armature coils are connected in series in sequence to form the A-phase armature winding. The first output terminal A+ and the second output terminal A- of the A-phase armature winding are connected to an external control circuit. The connection method of the B-phase armature winding and the C-phase armature winding is the same as that of the A-phase armature winding. The four sets of torque excitation coils are connected in series in sequence to form the torque excitation winding (3). The first output terminal F1+ and the second output terminal F1- of the torque excitation winding (3) are connected to the external control circuit. The suspension control method comprises: Step 1, data acquisition stage, including: detecting the radial position of the rotor of the motor by a radial displacement sensor in the X-axis direction installed on the motor end cover, and obtaining the actual position of the rotor of the motor in the X-axis direction; and detecting the radial position of the rotor of the motor by a radial displacement sensor in the Y-axis direction installed on the motor end cover, and obtaining the actual position of the rotor of the motor in the Y-axis direction, wherein the X-axis and the Y-axis are orthogonal to each other; Step 2, data processing stage, comprising: respectively detecting the current feedback value of the X-axis suspension winding (5) and the current feedback value of the Y-axis suspension winding (6) of the motor through a current detection unit; and obtaining the current reference value of the X-axis suspension winding (5) through an X-axis displacement adjustment link by taking the difference between the preset reference displacement of the motor in the X-axis direction and the actual displacement of the rotor in the X-axis direction; Step 3, data analysis phase, including: obtaining a current reference value of the Y-axis suspension winding (6) by passing the difference between the preset reference displacement of the motor in the Y-axis direction and the actual displacement of the rotor in the Y-axis direction through a Y-axis displacement adjustment link; Furthermore, the difference between the current reference value of the X-axis suspension winding (5) and the current feedback value of the X-axis suspension winding (5) is passed through the X-axis suspension current adjustment link to obtain a duty cycle signal of the X-axis suspension control circuit; the difference between the current reference value of the Y-axis suspension winding (6) and the current feedback value of the Y-axis suspension winding (6) is passed through the Y-axis suspension current adjustment link to obtain a duty cycle signal of the Y-axis suspension control circuit; Step 4, control execution phase, includes: adjusting the current of the X-axis suspension winding (5) and the current of the Y-axis suspension winding (6) by adjusting the switch duty ratio of the X-axis suspension control circuit and the Y-axis suspension control circuit.

8. The suspension control method according to claim 7, characterized in that: The X-axis displacement adjustment link is proportional-integral-differential (PID) control; The Y-axis displacement adjustment link is proportional-integral-differential (PID) control; The X-axis suspension current regulation link is proportional-integral (PI) control; The Y-axis suspension current adjustment link is proportional-integral (PI) control.

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