Six-degree-of-freedom hexagonal precise compensation decoupling bearingless permanent magnet synchronous motor

Abstract

The utility model provides a six-degree-of-freedom hexagonal bearingless permanent magnet synchronous motor with precise compensation and decoupling, the problem of precise compensation and strong decoupling can be solved, a permanent magnet adopts an integrated installation mode and is fixed on a stator and a rotor, and a six-pole 12-slot winding installation structure is adopted. Freedom-degree suspension force in six directions can be generated when the rotor rotates by 60 degrees every time, stable suspension of the motor rotor can be guaranteed by shifting the rotor by 60 degrees, and a six-freedom-degree magnetic field air gap is generated. A coil is wound in each stator groove, when current passes through the coils, corresponding degree-of-freedom control can be achieved, six permanent magnet rings and six triangular permanent magnets are installed on the surface of the rotor in an adsorption mode, an integrated installation mode is adopted, high-frequency output of torque can be achieved, and six-degree-of-freedom stable suspension can be achieved. The device is simple and convenient in structure, and can achieve the effects of compensation of rotor position offset, fast dynamic response and accurate compensation of strong coupling.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, and particularly relates to a bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation decoupling. Background Art

[0002] A bearingless permanent magnet synchronous motor uses two sets of windings with different pole pairs (torque winding and suspension winding) in the stator slots to jointly generate a magnetic field. By controlling the magnitude and direction of the superimposed synthetic magnetic field, the magnitude and direction of the suspension force can be controlled. It has the advantages of no mechanical friction between the stator and rotor of the magnetic bearing, no need for lubrication, low running noise, and long service life. At the same time, it inherits the excellent characteristics of the permanent magnet synchronous motor, has a simple motor structure and reliable operating performance, and has broad application prospects in special fields such as aerospace, life science, ultra-clean transmission, and corrosive gas or liquid transmission.

[0003] The control strategy of traditional bearingless motor controllers is mainly position control. However, in more and more unstructured environments, contact operation tasks between the end sensor and the environment are also required, such as in the field of high-precision transmission. Although traditional high-rigidity position control can accurately reach the accurate position, it cannot meet the requirements of some stable magnetic field operation tasks.

[0004] To solve the above problems, the existing research is mainly divided into two methods, namely, structural design and control strategy. For the structural design aspect, relevant research realizes the change of the magnetic field air gap by designing different mechanisms. Although this method can achieve the change of the motor magnetic field, this type of method is still affected by the mechanical structure. For the control strategy aspect, it is common to use control methods such as control circuit boards, and the saturation of the magnetic flux density of the magnetic field is achieved by changing the parameters of the torque suspension force. However, this method has disadvantages such as insufficient decoupling accuracy. Therefore, the method to solve the above problems is to propose a control method with six-degree-of-freedom precise compensation decoupling.

[0005] In addition, universities such as Beihang University, Huazhong University of Science and Technology, and Xi'an Jiaotong University have also successively carried out research work on the theoretical research, topological structure innovation, and control system optimization of bearingless permanent magnet synchronous motors, and optimized and analyzed the operating performance of the motors from different angles. Content of the Utility Model

[0006] To solve the above problems, the utility model provides a magnetic gear rotating motor that can appropriately maintain the air gap for a long time. The suspension winding is wound on the permanent magnet stator, and the torque winding is wound on the permanent magnet rotor. The magnetic field self-decoupling function of the torque winding and the suspension winding can be compensated by offsetting the rotor by 60°. According to the position of the permanent magnet rotor, the radial force control winding is selected for the three-axis directions of X, Y, and Z to control the magnetic field in six degrees of freedom.

[0007] The specific solution is as follows:

[0008] A bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation and decoupling, including a motor body and a rotating shaft passing through the center of rotation of the motor body. The motor body consists of a permanent magnet stator, a torque winding, a suspension winding, and a permanent magnet rotor. The permanent magnet rotor and the permanent magnet stator are arranged inside and outside. Triangular permanent magnets and permanent magnet rings are integrally adsorbed and installed on the permanent magnet rotor. The surfaces of the triangular permanent magnets and the permanent magnet rings are permanently fixed on the permanent magnet stator through plastic glue. The triangular permanent magnets are placed outside the permanent magnet rings. The permanent magnet rotor is fixedly installed on the rotating shaft. The permanent magnet stator is provided with through slots along the circumferential direction. Each through slot is divided into upper and lower layers in the circumferential direction. The suspension winding and the torque winding are respectively placed in the upper and lower layers, and a magnetic isolation thin sheet is installed in the middle to effectively block the magnetic field from shifting the rotor and is integrally installed with the through slot to achieve the function that the suspension winding and the torque winding do not interfere with each other and generate strong self-decoupling.

[0009] The torque generation principle of the bearingless permanent magnet synchronous motor is the same as that of the traditional synchronous reluctance switched motor. It only relies on the difference in magnetic reluctance between the quadrature axis and the direct axis magnetic circuits of the motor rotor. According to the principle that magnetic lines of force always close along the path with the minimum magnetic reluctance, a reluctance torque is generated. When the direct axis of the permanent magnet rotor of the bearingless permanent magnet synchronous motor is not coaxial with the N and S poles of the magnetic field generated by the permanent magnet stator winding, the coefficient between the quadrature axis and the direct axis magnetic reluctances of the rotor is offset with the air-gap magnetic field, thereby generating a reluctance torque and achieving stable suspension.

[0010] Six permanent magnet rings and six triangular permanent magnets are integrally adsorbed and installed on the surface of the permanent magnet rotor along the circumferential direction.

[0011] The angles of the suspension winding and the torque winding in the fan-shaped stage are 60°, 120°, 180°, 240°, 300°, and 360°; and they are distributed along the circumference on the stator.

[0012] When the offset angle of the hexagonal stage reaches 360°, the rotational speed can reach 30000 r / min and the power can reach 15 kw. The strong coupling interference force between the torque winding and the suspension winding changes from the original rotor offset to generate a stable torque suspension force, making the interference force between the rotor and the stator tend to 0. As the rotational speed gradually increases, stable pulsed power is output, generating sufficient air-gap magnetic density to provide the controllability of the suspension system.

[0013] Because too high a rotational speed will cause vibration and offset, affecting the stability of the rotor and the magnitude of the output power, the stability of the rotor can be compensated, thereby providing a stable torque suspension force. Every 60° rotation of the offset angle of the hexagonal permanent magnet stage will convert the rotational speed of the rotor into a stable magnetic field, and stable suspension and torque can be achieved.

[0014] Implementing permanent magnet stators and rotors in three axial directions and six degrees of freedom eliminates the original radial unbalanced force. The levitation force generated by the levitation winding current is decomposed into radial and axial components, achieving radial and axial levitation operation without the need to add a radial magnetic levitation bearing.

[0015] The permanent magnet stator is composed of a stator core, and the permanent magnet rotor is composed of a rotor core.

[0016] One end of the motor body is also equipped with a pulse air plate, and a rolling bearing is provided at the end of the rotating shaft.

[0017] During the process of precise compensation coupling control in the radial levitation, it includes:

[0018] When no levitation current is passed through the levitation winding, due to the hexagonal offset angle distribution structure of the motor, the three axes X, Y, and Z directions of the motor rotor are all in a balanced state.

[0019] By controlling the windings in six axial directions, a magnetic field with six degrees of freedom can be generated at each angle within a 60° rotation range of the rotor. When a positive-direction current is passed through the levitation winding, an axial magnetic levitation force in the negative X direction will be generated. By controlling the magnitudes of the levitation currents in the positive and negative X windings, the levitation force displacement of the permanent magnet rotor can be changed. When a positive-direction current is passed through the torque winding, a radial magnetic levitation force in the negative Y direction will be generated. By controlling the directions of the torque currents in the positive and negative Y windings, the torque levitation force of the permanent magnet stator can be changed. When the combined direction of the torque levitation forces generated by the levitation winding and the torque winding is in the positive Z direction, a total levitation resultant force will be achieved. By controlling the magnitudes of the torque levitation forces in the positive and negative Z windings, the angles of the offset positions in the positive and negative Z directions of the rotor can be changed, with an error not exceeding 0.2 mm.

[0020] When the radial levitation force undergoes an eccentric displacement, the offset angle of the hexagonal surface permanent magnet can be changed. Every 60° rotation of the hexagonal angle will convert the rotational speed of the rotor into a stable magnetic field, and stable levitation and torque can be achieved. The hexagonal six-degree-of-freedom angle can achieve the phenomenon of compensation coupling, gradually becoming stable. As the rotational speed of the rotor increases, the rotor will inevitably have a strong coupling problem. Through the formation of the six-degree-of-freedom hexagonal permanent magnet magnetic field, a stable torque levitation force is provided, ensuring that the rotor and the stator do not interfere with each other. The radial displacement of the motor remains floating within a relatively stable range, achieving the levitation effect, effectively avoiding the function of strong magnetic field coupling, and the current of each winding is correspondingly reduced while ensuring that the air-gap magnetic density is not saturated. Moreover, each hexagonal six-degree-of-freedom angle should be within the integer range, effectively reducing the energy consumption problem of the motor.

[0021] Meanwhile, through the control law of the controller, a radial displacement sensor is used to collect information on the rotor position direction and output the true current, so as to eliminate the mutual coupling relationship between the control loops in the system. A controller that enables a multivariable system to achieve complete decoupling can adopt either the form of state feedback combined with input transformation or the form of output feedback combined with a compensation device.

[0022] Since there are no windings and permanent magnet rings on the rotor of the bearingless permanent magnet synchronous motor, the generation of its radial suspension force depends on enabling the torque winding and the suspension force to have radial suspension forces in three directions. At the same time, it can also compensate for the stability of the rotor, thereby providing a stable torque suspension force. When the permanent magnet rotor of the hexagonal precision compensation coupled bearingless permanent magnet synchronous motor is stably suspended at the center of the permanent magnet stator, the air-gap magnetic field of the motor points vertically to the circumferential surface along the Z axis of the permanent magnet rotor and is evenly distributed. The suspension forces in the symmetric directions are of the same magnitude and opposite to the direction of the magnetic field generated by the torque winding, finally forming six air-gap magnetic fields, cracking the strong coupling problem between the rotor and the stator. Therefore, the resultant hexagonal torque suspension force after compensation coupling is 0.

[0023] The rotor of a common motor is fixed on the rotating shaft, and the stator and rotor are always concentric. Therefore, the torque suspension force generated on the rotor surface is also 0.

[0024] The beneficial effects of the present invention are as follows: When the permanent magnet rotor is suspended, it will cause the rotor to be offset from the center of the stator, resulting in uneven distribution of the air-gap magnetic field in the six-degree-of-freedom direction. Therefore, an angle of 60° can be used to compensate for the stability of the rotor, thereby providing a stable torque suspension force. At the same time, on the air-gap magnetic field on the surface of the permanent magnet rotor, by synthesizing and decomposing the radial forces of each permanent magnet, the magnitude of the radial force received by the permanent magnet rotor can be obtained. When the rotor is stably suspended through sensor decoupling control, the interference force received by the rotor is almost 0. For a six-degree-of-freedom hexagonal precision compensation coupled bearingless permanent magnet synchronous motor, the smaller the air-gap magnetic field, the greater the magnetic density on the same side. When it is stable, the magnetic density in the circumferential direction forms a six-elliptical ring. At this time, the suspension force generated on the rotor points to the place where the air-gap magnetic field is the smallest. The air-gap magnetic densities at the edges of the triangular permanent magnet end faces cancel each other out, and the air-gap magnetic density surrounds the rotor surface, enabling the rotor to accurately compensate for the strong coupling problem of the motor.

[0025] As the offset angle of the triangular permanent magnet increases with the permanent magnet rotor, the rotational speed gradually increases to 30,000 r / min, causing the offset angle of the permanent magnet rotor to increase. The offset angle of the triangular permanent magnet can compensate for the stability of the rotor, thereby providing a stable torque suspension force. The suspension winding with the same number of pole pairs as the torque winding is installed in the stator slots of the bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation coupling, and the two are distributed in a hexagonal circumference. If a current of 10 A is applied to the suspension winding, a radial suspension force that cancels the eccentric suspension force of the permanent magnet rotor and the interference force other than the motor itself will be generated on the surface of the permanent magnet rotor (the current range that can cancel the interference force is 8 A - 40 A), precisely compensating the strong coupling problem between the rotor and the stator, thereby realizing the stable suspension of the permanent magnet rotor of the bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation coupling. Description of the Drawings

[0026] Figure 1 It is a 3D structural view of the present invention.

[0027] Figure 2 It is a schematic diagram of the connection end of the 2D of the present invention.

[0028] Figure 3 It is a diagram of the precise compensation coupling offset angle of the magnetic field stage of the present invention.

[0029] List of Reference Numerals:

[0030] 1 - Permanent magnet stator, 2 - Triangular permanent magnet, 3 - Permanent magnet ring, 4 - Rolling bearing, 5 - Rotating shaft, 6 - Suspension winding, 7 - Permanent magnet rotor, 8 - Rotor core, 9 - Torque winding, 10 - Stator core, 11 - Heat dissipation air plate. Detailed Embodiment

[0031] The following further clarifies the present invention in conjunction with the drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0032] As shown in the figure, this embodiment provides a bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation coupling through a suspension winding and a torque winding. Its structure is as Figure 1 shown. The motor includes: a permanent magnet rotor (7), a permanent magnet stator (1), a triangular permanent magnet (2), a suspension winding (6), a torque winding (9), and a heat dissipation air plate (11). The suspension magnetic field includes: air gap radial 1, 2, air gap axial 3, 4, and

[0033] The permanent magnet rotor of the motor is composed of a rotor iron core. The permanent magnets are adsorbed and installed on the rotor and stator, and the triangular permanent magnets are integrally installed in a circumferential manner on the permanent magnet rotor. The permanent magnet ring of the permanent magnet rotor is made of copper material. The magnetic flux can flow transversely, longitudinally, and in the resultant direction of the transverse and longitudinal directions through the rotor iron core.

[0034] The permanent magnet stator of the motor is composed of a stator iron core, and the stator iron core includes a radial stator iron core and an axial stator iron core.

[0035] For the generation of the radial suspension force of the bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation coupling, 24-slot suspension windings (6) are wound in the stator slots and with 6-pole torque windings (9) and When the motor operates at low load, the air-gap magnetic density generated by the current in the torque winding (9) is negligible. At this time, the symmetric magnetic flux is generated by 6 triangular permanent magnets. If the current in the suspension winding (6) and is zero, the rotor will not generate a radial suspension force; when is energized with a positive current, a circular magnetic flux will be generated, the air-gap magnetic density at the right side 1 will decrease, and the air-gap magnetic density at the left side 3 will increase, thereby generating a torque suspension force in the positive direction of the Z axis;

[0036] If is energized with a negative current, a torque suspension force in the negative direction of the Z axis will be generated. Similarly, the radial suspension force in the Z-axis direction can be obtained by passing the corresponding current in the winding Therefore, by controlling the current in the suspension windings (6) and the direction of the suspension winding can be controlled to achieve the stable suspension of the permanent magnet rotor (7), thereby providing a stable resultant torque suspension force.

[0037] When a stable saturated air-gap magnetic field is generated on the surface of the rotor center, there will be a left-right offset state at the edge of the rotor. The magnitude of the coil current can be adjusted to increase a larger magnetic field, which is evenly distributed at 60° on the edge of the rotor, so as to break the existence of magnetic field coupling and form 6 circular magnetic densities and

[0038] Based on the novel permanent magnet rotor and the permanent magnet stator with six-degree-of-freedom hexagonal precise compensation coupling in the radial and axial directions, the simulation analysis and simulation method of OPBPMSM are implemented.

[0039] The rotor can generate suspension forces in 6 directions of freedom every 60° of rotation, enabling the rotor to be stably suspended.

[0040] Based on a bearingless permanent magnet synchronous motor with six - degree - of - freedom hexagonal precise compensation coupling, the use of the offset angle of triangular permanent magnets can compensate for the magnetic field self - decoupling function of the torque winding and the suspension winding.

[0041] The offset angles of the hexagonal permanent magnets are 60°, 120°, 180°, 240°, 300°, and 360° in sequence.

[0042] When the offset angle of the hexagonal permanent magnet reaches 60°, the rotational speed can reach 5000 r / min. And for each rotation of the hexagonal offset angle, the speed can gradually increase. When the angle of the pulse offset stage reaches 120°, the rotational speed can reach 10000 r / min. When the stage angle reaches 180°, the rotational speed reaches 15000 r / min. The pulse air plate passes the current of the winding, increasing the speed and providing a stable magnetic field. When the angle continues to increase to 240°, the rotational speed can reach 20000 r / min. The hexagonal permanent magnet passes the current to make the output air - gap magnetic density perpendicularly pass through the surface of the permanent magnet rotor, forming a stable hexagonal circular magnetic field, thus achieving stable suspension. When the hexagonal stage angle reaches 300°, the rotational speed can reach 25000 r / min, and the magnetic fields in the air gap gradually cancel each other out. When the offset angle of the hexagonal stage reaches 360°, the rotational speed can reach 30000 r / min, and the power can reach 15 kw. The strong coupling interference force between the torque winding and the suspension winding is transformed from the original rotor offset to a stable torque suspension force, making the interference force between the stator and the rotor tend to 0. As the rotational speed gradually increases, stable pulse power is output, generating sufficient air - gap magnetic density and providing controllability for the suspension system.

[0043] Because too high a rotational speed will cause vibration offset, affecting the stability of the rotor and the magnitude of the output power, it can compensate for the smoothness of the rotor, thus providing a stable torque suspension force. For each 60° rotation of the offset angle of the triangular permanent magnet stage, the rotational speed of the rotor is converted into a stable magnetic field, and stable suspension and torque can be achieved.

[0044] Implementing permanent magnet stators and rotors in three axial directions and six degrees of freedom eliminates the original radial unbalanced force. The suspension force generated by the suspension winding current is decomposed into radial and axial components, realizing radial and axial suspension operation without the need to add a radial magnetic suspension bearing and enabling precise compensation coupling.

[0045] The main technical problem to be solved in the embodiments of the present invention is that a bearingless permanent magnet synchronous motor with six - degree - of - freedom hexagonal precise compensation coupling and a 60° offset angle in a triangle can control the air - gap magnetic density in three axial directions and the movement in the X, Y, and Z axis directions of six degrees of freedom. Using the simulation method, high - precision rotational speed, accurate displacement self - detection, and the accuracy and dynamic response speed of rotor offset displacement can be achieved.

[0046] The technical means disclosed in the solution of the present utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present utility model.

Claims

1. A bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation and decoupling, characterized in that, It includes a motor body and a rotating shaft (5) passing through the center of rotation of the motor body. The motor body consists of a permanent magnet stator (1), a torque winding (9), a suspension winding (6), and a permanent magnet rotor (7). The permanent magnet rotor (7) and the permanent magnet stator (1) are arranged inside and outside. On the permanent magnet rotor (7), a triangular permanent magnet (2) and a permanent magnet ring (3) are integrally adsorbed and installed. The surfaces of the triangular permanent magnet (2) and the permanent magnet ring (3) are permanently fixed on the permanent magnet stator (1) through plastic glue. The triangular permanent magnet (2) is placed outside the permanent magnet ring (3). The permanent magnet rotor (7) is fixedly installed on the rotating shaft (5). 24 through slots are opened on the permanent magnet stator (1) along the circumferential direction. Each through slot is divided into upper and lower layers in the circumferential direction. The suspension winding (6) and the torque winding (9) are placed in the upper and lower layers respectively. A magnetic isolation thin sheet is installed in the middle and is integrally installed with the through slot to achieve the function that the suspension winding (6) and the torque winding (9) do not interfere with each other and generate strong self-decoupling.

2. The bearingless permanent magnet synchronous motor with six - degree - of - freedom hexagon precise compensation and decoupling according to claim 1, characterized in that, 6 permanent magnet rings (3) and 6 triangular permanent magnets (2) are integrally adsorbed and installed on the surface of the permanent magnet rotor (7) evenly along the circumferential direction.

3. A bearingless permanent magnet synchronous motor with six - degree - of - freedom hexagonal precise compensation and decoupling according to claim 1, characterized in that, The angles of the fan-shaped stages of the suspension winding (6) and the torque winding (9) are 60°, 120°, 180°, 240°, 300°, 360°; and they are distributed on the stator along the circumference.

4. A bearingless permanent magnet synchronous motor with six - degree - of - freedom hexagonal precise compensation and decoupling according to claim 1, characterized in that, The permanent magnet stator (1) is composed of a stator core (8), and the permanent magnet rotor (7) is composed of a rotor core (10).

5. A bearingless permanent magnet synchronous motor with six-degree-of-freedom hexagonal precise compensation and decoupling according to claim 1, characterized in that, A pulse air plate (11) is also installed at one end of the motor body, and a rolling bearing (4) is provided at the end of the rotating shaft (5).

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