CN108809027B - Disc type bearingless asynchronous motor - Google Patents

Abstract

The invention discloses a disc type bearingless asynchronous motor, comprising a stator and a double disc rotor, wherein the stator comprises an axial stator iron core, a permanent magnet ring and a radial stator iron core which are connected in sequence; The side and the inner side of the radial stator core are respectively provided with axial stator core slots and radial stator core slots, and axial suspension windings and axial torque windings are arranged in the axial stator core slots. The slots are provided with radial torque windings and radial suspension windings; the double-disc rotor consists of an axial rotor core penetrating the stator, and disc rotors respectively coaxially connected to both ends of the axial rotor core and connected to the axial rotor. The radial rotor core in the middle of the core is composed of a radial rotor core. The axial rotor core is coaxially connected with a rotating shaft extending out of the outer end of the disc rotor. The inner end of the disc rotor is provided with an axial rotor slot. An axial rotor guide bar is provided, and a radial rotor guide bar is arranged on the radial rotor iron core.

Description

A disc bearingless asynchronous motor

technical field

The invention relates to the technical field of motor manufacturing, in particular to a disc type bearingless asynchronous motor capable of realizing stable suspension of a rotor with three degrees of freedom and generating rotational torque in both the axial direction and the radial direction.

Background technique

Bearingless asynchronous motors have no friction, wear, lubrication and sealing, and are easy to achieve higher speed and higher power operation. They have broad applications in aerospace, turbomolecular pumps, flywheel energy storage, sealed pumps, high-speed motorized spindles, etc prospect.

At present, the bearingless asynchronous motor uses a set of additional suspension windings superimposed on the torque winding of the stator slot of the traditional asynchronous motor. The magnetic field of the winding, and the pole pairs of the magnetic field of the suspension winding is P _B , the magnetic field of the torque winding is P _M , and only when the relationship between the two satisfies the relationship of P _B = P _M ±1, can a stable and controllable radial direction be generated on the rotor. Suspension force. The radial displacement of the rotor is detected by the radial displacement sensor, and a closed-loop displacement control system is constructed to realize the stable suspension of the rotor, and the principle of torque generation is the same as that of an ordinary asynchronous motor. On the one hand, the magnetic field of the torque winding interacts with the magnetic field of the suspension winding to generate radial suspension force; on the other hand, the magnetic field of the torque winding interacts with the rotating magnetic field of the rotor to generate torque. Therefore, the difference between torque control and displacement control is There is strong coupling, the control is complex, it is difficult to establish an accurate mathematical model, and the control precision is low. In addition, in addition to the torque winding magnetic field in the rotor bar will induce a rotor rotating magnetic field with the same number of pole pairs as the torque winding magnetic field, the suspension winding magnetic field will also induce in the rotor bar the same number of pole pairs as the suspension winding magnetic field. The same rotor rotating magnetic field, the rotating magnetic field has a weakening effect on the generation of the suspension force, and also increases the complexity of torque control and displacement control, especially when running with load, which will cause system instability. Suspension failed. Some scholars have proposed a bearingless asynchronous motor structure with a split-phase structure of the rotor bar, but the number of pole pairs between the suspension winding and the torque winding of the motor still needs to satisfy the relationship of P _B = P _M ±1, and the magnetic field of the torque winding is not only To generate torque with the magnetic field of the rotor, and generate levitation force with the magnetic field of the suspension winding, there is a complex coupling relationship. The decoupling control between the two is very complicated, and the amount of calculation is large, which limits the promotion of its industrial application.

To realize the stable suspension of the rotor with five degrees of freedom, it needs to be composed of an axial magnetic bearing + a radial two-degree-of-freedom magnetic bearing + a two-degree-of-freedom bearingless asynchronous motor, or an axial magnetic bearing + two two-degree-of-freedom bearingless asynchronous motors The motor, or a two-degree-of-freedom bearingless asynchronous motor + a three-degree-of-freedom magnetic bearing constitute a five-degree-of-freedom suspension drive system. In these three structures, an axial suspension control unit is inevitably required, resulting in a five-degree-of-freedom bearingless drive system. The asynchronous motor system has a long axial length and a high critical speed, which makes it difficult to achieve higher power and higher speed rotation, and is bulky and expensive.

Therefore, the study of a bearingless asynchronous motor with axial and radial suspension functions is of great significance to reduce the volume and cost of the bearingless asynchronous motor, and to promote the development of the industrial application process of the bearingless asynchronous motor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a disc bearingless asynchronous motor with a novel structure, capable of stably suspending the rotor with three degrees of freedom, and generating rotational torque in both the axial and radial directions, providing a new solution for special electrical transmission.

The present invention is achieved through the following technical solutions:

A disc type bearingless asynchronous motor comprises a stator and a double disc rotor, the stator comprises an axial stator iron core, a permanent magnet ring and a radial stator iron core which are coaxially connected in sequence from the outside to the inside; The two sides and the inner side of the radial stator core are respectively provided with axial stator core slots and radial stator core slots, and axial suspension windings with different pole pairs are sequentially arranged in the axial stator core slots along the axial direction outward. and axial torque windings, the radial stator core slots are arranged radially outward in turn with radial torque windings and radial suspension windings with different pole pairs; It is composed of an axial rotor core, a disc rotor coaxially connected to both ends of the axial rotor core, and a radial rotor core connected to the middle of the axial rotor core. The inner end of the disc rotor is provided with an even number of axial rotor slots, and the axial rotor slots are provided with axial rotor bars or rotor windings adopting a split-phase structure. Radial rotor bars or rotor windings are provided with a split-phase structure.

A further solution of the present invention is that the number of pole pairs of the axial torque winding and the radial torque winding are respectively the same as those of the axial rotor bars or rotor windings and the radial rotor bars or rotor windings.

A further solution of the present invention is that the permanent magnet ring is made of rare earth permanent magnets or ferrite permanent magnets.

A further solution of the present invention is that the rotational speed of the motor is n , the current frequency and the number of pole pairs of the radial torque winding (5) are f _j , P _j respectively, and the current frequency and the number of pole pairs of the axial torque winding (4) are f _z and P _z respectively, satisfying: f _j × P _z = P _j × f _z .

The advantages of the present invention compared with the prior art are:

Integrating axial suspension/rotation and radial suspension/rotation, it has a bearingless asynchronous motor with high torque density and high suspension force density, which can realize stable suspension with three degrees of freedom, providing a new solution for special electric drives. Program.

Description of drawings

1 is a schematic diagram of the axial structure and magnetic flux of the present invention;

FIG. 2 is a left side view at A of FIG. 1 .

FIG. 3 is a right side view at B of FIG. 1 .

Detailed ways

As shown in Figures 1 to 3, a disc type bearingless asynchronous motor is taken as an example where the number of axial stator and rotor slots and the number of radial stator and rotor slots are equal to 12; it includes a stator and a double disc rotor, and the stator includes from An axial stator core 1, a permanent magnet ring 3, and a radial stator core 2, which are coaxially connected in sequence from the outside to the inside; the two sides of the axial stator core 1 and the inner side of the radial stator core 2 are respectively provided with axial stator core slots 2. Radial stator core slots, in which axial suspension windings 6 and axial torque windings 4 with different pole pairs are arranged in turn along the axial direction outwards. Radial torque windings 5 and radial suspension windings 7 with different pole pairs are arranged radially outward in turn. The axial suspension windings 6 and radial suspension windings 7 are both concentrated windings, and electromagnetic waves with good electrical conductivity are used. After the coil is wound, it is formed by infiltrating paint and drying; the double-disc rotor consists of an axial rotor core 11 penetrating the stator, and left disc rotors 8 and right coaxially connected to the left and right ends of the axial rotor core 11 respectively. The disc rotor 9 is composed of a radial rotor core 12 connected to the middle of the axial rotor core 11. The axial rotor core 11 is coaxially connected with a rotating shaft 10 extending from the outer ends of the left disc rotor 8 and the right disc rotor 9. The inner ends of the left disc rotor 8 and the right disc rotor 9 are respectively provided with twelve axial rotor slots, and the axial rotor slots are respectively provided with left axial rotor bars or rotors adopting a phase separation structure. Windings 13, right axial rotor bars or rotor windings 19, the radial rotor core 12 is provided with radial rotor bars or rotor windings 14 adopting a phase separation structure, the axial torque windings 4 and the radial The number of pole pairs of the torque winding 5 is the same as that of the left axial rotor bar or rotor winding 13 , the right axial rotor bar or rotor winding 19 , and the radial rotor bar or rotor winding 14 , respectively.

The permanent magnet ring 3 is made of rare earth permanent magnets or ferrite permanent magnets. The axial stator core 1, the radial stator core 2, the axial rotor core 11, the left disc rotor 8, the right disc rotor 9, the radial The rotor cores 12 are all made of materials with good magnetic conductivity.

The suspension principle is:

The permanent magnet ring 3 generates a left static bias magnetic flux 17 and a right static bias magnetic flux 18, wherein the left static bias magnetic flux 17 starts from the N pole of the permanent magnet ring 3 and passes through the axial stator core 1 and the axial stator iron core. 1 and the air gap between the left disc rotor 8, the left disc rotor 8, the axial rotor core 11, the radial rotor core 12, the air gap between the radial rotor core 12 and the radial stator core 2, the radial stator The iron core 2 returns to the S pole of the permanent magnet ring 3 to form a closed path; the right static bias magnetic flux 18 starts from the N pole of the permanent magnet ring 3 and passes through the axial stator core 1, the axial stator core 1 and the right disc rotor 9. The air gap between the right disc rotor 9, the axial rotor core 11, the radial rotor core 12, the air gap between the radial rotor core 12 and the radial stator core 2, the radial stator core 2 returning to the permanent magnet ring 3 The S pole forms a closed path. Both the axial suspension winding 6 and the radial suspension winding 7 are powered by a DC power supply, and the radial suspension control magnetic flux 16 generated after the radial suspension winding 7 is energized passes through one side of the radial stator core 2, the radial rotor core 12 and the magnetic flux 16. One side gap between radial stator cores 2, radial rotor core 12, axial rotor core 11, the other side air gap between radial rotor core 12 and radial stator core 2, and the other side of radial stator core 2 A closed loop is formed on the side; the axial suspension windings 6 on both sides of the axial stator core 1 are energized in the same direction. After the axial suspension winding 6 is energized, an axial suspension control magnetic flux 15 is generated, which passes through the axial stator core 1 and the left disc rotor 8 The air gap, the left disc rotor 8 , the axial rotor core 11 , the right disc rotor 9 , the air gap between the right disc rotor 9 and the axial stator core 1 form a closed loop.

The axial suspension control magnetic flux 15 and the radial suspension control magnetic flux 16 interact with the left static bias magnetic flux 17 and the right static bias magnetic flux 18 to generate stable radial and axial suspension forces, respectively.

According to the prior art, displacement sensors are installed on the axial stator and radial stator respectively to establish a displacement closed-loop system. When the rotor deviates from the axial and radial equilibrium positions, the axial suspension winding and the radial displacement are adjusted through negative displacement feedback. The current value of the suspension winding generates the suspension force that makes the rotor return to the equilibrium position, and realizes the stable suspension of the rotor in the axial and radial directions.

The principle of rotation is:

The number of left axial rotor bars or rotor windings 13 on both sides of the axial stator core 1 is the same as the number of right axial rotor bars or rotor windings 19; Rotor bar or rotor winding 13 , right axial rotor bar or rotor winding 19 , radial rotor bar or rotor winding 14 adopt a phase split structure, left axial rotor bar or rotor winding 13 , right axial rotor bar Or the number of pole pairs of the rotor winding 19 is the same as the number of pole pairs of the axial torque winding 4, and the number of pole pairs of the radial rotor bar or rotor winding 14 is the same as that of the radial torque winding 5; the left axial rotor bar or The rotor winding 13, the right axial rotor bar or rotor winding 19, the radial rotor bar or rotor winding 14 cut the magnetic fields of the axial torque winding 4 and the radial torque winding 5, and the generated axial rotor rotating magnetic field, diameter The rotating magnetic field to the rotor has the same number of magnetic field pole pairs as the axial torque winding 4 and radial torque winding 5; while the magnetic field of the axial suspension winding, the magnetic field of the radial suspension winding and the magnetic field of the permanent magnet ring 3 are in the left axial direction of the rotor bar. Or rotor rotating magnetic field is not induced in rotor winding 13 , right axial rotor bar or rotor winding 19 , radial rotor bar or rotor winding 14 .

The radial torque winding 5 and the axial torque winding 4 are energized to drive the motor to rotate. Assuming that the motor speed is n , the current frequency and the number of pole pairs of the radial torque winding 5 are f _j , P _j respectively, and the axial torque winding 4 The current frequency and the number of pole pairs are respectively f _z and P _z , then it must satisfy: f _j × P _z = P _j × f _z .

The outer layer of the axial stator slot is the axial torque winding 4, and the arrangement refers to the winding arrangement of ordinary asynchronous motors; the inner layer is the axial suspension winding 6, which is a concentrated winding, and the left and right axial suspension windings 6 are connected in series with each other in the same direction or in parallel. The outer layer of the radial stator slot is the radial torque winding 5, and the arrangement is the same as that of the ordinary asynchronous motor; the inner layer is the radial suspension winding 7, and the radial suspension winding 7 is the concentrated winding, which is divided into the x-direction suspension control winding and the y-direction suspension. For the control winding, the windings on the three teeth in the +x direction and the -x direction are connected in series to form the suspension control winding in the x direction; the windings on the three teeth in the +y direction and the -y direction are connected in series as the suspension control winding in the y direction. The protruding parts of the left disc rotor 8 and the right disc rotor 9 are provided with axial rotor slots, and the left axial rotor bars or rotor windings 13 and the right axial rotor bars or rotor windings 19 are poured in the axial rotor slots. ; The outer layer insulation of the left axial rotor bar or rotor winding 13, the right axial rotor bar or rotor winding 19, and the phase separation through the termination part, the left axial rotor bar or rotor winding 13, the right axial The number of pole pairs of the rotor bar or rotor winding 19 should be the same as the number of pole pairs of the axial torque winding 4, as shown in Figure 2 and Figure 3, that is, the cage bar or rotor winding, and the phases are: 13a, 13d, 13g , 13j are short-circuited as one phase; 13c, 13f, 13i, 13l are short-circuited as one-phase; 13b, 13e, 13h, and 13k are short-circuited as one-phase, and each phase forms a closed loop by itself. The radial rotor bars or rotor windings 14 use the same phase separation method, that is: the 1st, 4th, 7th, and 10th bars are connected as one phase, the second, 5, 6, and 11 bars are connected as one phase, and the third , 6, 9, 12 bars are connected as one phase; radial suspension winding 7, radial torque winding 5 and left axial rotor bar or rotor winding 13, right axial rotor bar or rotor winding 19 are arranged coaxially Arrange in the direction. In this way, when the motor is running, the left axial rotor bar or rotor winding 13 and the right axial rotor bar or rotor winding 19 only cut the magnetic field of the torque winding to generate the rotor rotating magnetic field, and cut the magnetic field of the suspension winding and the permanent magnetic field. The bias magnetic field produced by the magnets does not produce the rotor induced magnetic field.

Claims (4)

1. A disc type bearingless asynchronous motor, comprising a stator and a double disc rotor, characterized in that: the stator comprises an axial stator core (1), a permanent magnet ring (3), an axial stator core (1), a permanent magnet ring (3), Radial stator core (2); both sides of the axial stator core (1) and the inner side of the radial stator core (2) are respectively provided with axial stator core slots and radial stator core slots, the axial stator core Axial suspension windings (6) and axial torque windings (4) with different numbers of pole pairs are sequentially arranged in the core slots along the axial direction outward, and the radial stator core slots are sequentially arranged with poles along the radial direction outward. Logarithmic unequal radial torque windings (5) and radial suspension windings (7); the double-disc rotor consists of an axial rotor core (11) penetrating the stator and coaxially connected to the axial rotor core respectively (11) Disk rotors at both ends and radial rotor cores (12) connected to the middle of the axial rotor core (11), the axial rotor cores (11) being coaxially connected with a rotating shaft extending out of the outer end of the disc rotor (10), the inner end of the disc rotor is provided with an even number of axial rotor slots, the axial rotor slots are provided with axial rotor bars or rotor windings adopting a split-phase structure, and the radial rotor core (12) is provided with radial rotor bars or rotor windings (14) adopting a phase-splitting structure. 2 . The disc bearingless asynchronous motor according to claim 1 , wherein the number of pole pairs of the axial torque winding ( 4 ) and the radial torque winding ( 5 ) is respectively the same as that of the axial rotor. 3 . The same for bars or rotor windings, radial rotor bars or rotor windings (14). 3 . The disc type bearingless asynchronous motor according to claim 1 , wherein the permanent magnet ring ( 3 ) is made of rare earth permanent magnets or ferrite permanent magnets. 4 . 4 . The disc type bearingless asynchronous motor according to claim 1 , wherein the motor speed is n , the current frequency and the number of pole pairs of the radial torque winding (5) are f _j , P _j , respectively, 5 . The current frequency and the number of pole pairs of the axial torque winding (4) are respectively f _z and P _z , satisfying: f _j × P _z = P _j × f _z .

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