CN113507190A

CN113507190A - Electric roller permanent magnet synchronous motor

Info

Publication number: CN113507190A
Application number: CN202110916724.0A
Authority: CN
Inventors: 陈露; 王运; 王从容
Original assignee: Zhuhai Xingzhiliu Motor Co ltd; Zhuhai Motion Control Motor Co ltd
Current assignee: Zhuhai Xingzhiliu Motor Co ltd; Zhuhai Motion Control Motor Co ltd
Priority date: 2021-08-10
Filing date: 2021-08-10
Publication date: 2021-10-15

Abstract

The electric drum permanent magnet synchronous motor provided by the present invention includes a front bearing, an outer rotor, an inner stator and a rear bearing. The ring is fixedly connected, and the inner stator is provided with a fixed shaft that is fixedly connected to the inner stator. Both ends of the fixed shaft are fixedly connected to the inner ring of the front bearing and the inner ring of the rear bearing respectively; the outer rotor is a salient pole structure, and the quadrature axis inductance Lq is greater than the direct-axis inductance Ld; the inner stator includes a stator core and windings without toothed shoes, the stator iron core without toothed shoes contains a multiple of 3 teeth, and the windings are three-phase concentrated windings, and the three-phase concentrated windings are connected by star or angle. lead out. On the premise of ensuring the torque density and performance of the motor, the invention improves the performance of the outer rotor permanent magnet synchronous electric drum motor, improves the stability and reliability, and at the same time significantly reduces the material cost and production cost, and also improves the production efficiency. .

Description

Electric roller permanent magnet synchronous motor

Technical Field

The invention relates to the technical field of motors, in particular to an electric roller permanent magnet synchronous motor.

Background

The development of the express logistics industry, the conveying and sorting line of which needs a large number of electric rollers, therefore, an outer rotor permanent magnet synchronous motor integrated with the rollers is developed. Along with the rapid development of intelligent sorting equipment, higher requirements are put forward on the performance index, reliability and stability of the motor; meanwhile, the price of raw materials of the motor and the labor cost are increased rapidly, the price of the motor is increased continuously, and the requirements of customers cannot be met. For many years, much work has been done in the aspect of improving the performance of the motor, for example, the cooperation of different numbers of poles and slots is adopted to reduce the cogging torque and improve the performance index of the motor, and different position sensors are adopted to change the structure of the motor so as to improve the reliability of the motor, but all the work is based on the traditional motor structure and design concept.

The cross section and the schematic diagram of a stator punching sheet of a traditional outer rotor permanent magnet motor are shown in fig. 1 and fig. 2, and the motor comprises a stator yoke portion (1), stator teeth (2), a shaft hole (3), tooth shoes (4) and stator slots (5), wherein the stator tooth pitch is equal to the tooth shoe width tp + the slot opening width b0, and a coil is placed in the stator slots (5) through the slot openings (5 a). In the motor design teaching materials or reference books, including conventional motor designs, it is considered that increasing the tooth shoe width tp and reducing the notch width b0 are beneficial to improving the motor output and reducing the cogging torque and noise, so that the common consensus formed for a long time is that on the premise of ensuring that a coil can be placed in a stator slot (5), the notch (5a) is as small as possible, the notch width of a common medium-sized and small-sized motor is 1.8-3.5 mm, the tooth shoe width tp is close to the stator pitch, and the tooth shoe width tp is larger than the stator tooth width t. As can be seen from fig. 1 and 2, the stator slot (5) is formed by the stator yoke (1), the stator teeth (2) and the tooth shoes (4), and the coil is currently placed in the stator slot (5) and wound on the stator teeth (2), and there are 2 methods: the coil is manually off-line, the coil is wound outside, and then is manually placed into the slot through the notch (5a), and the method has the defects of high labor intensity of workers, low off-line efficiency, large copper consumption at the end part of the coil and the like; the second method is to use an automatic winding machine to wind the coil into the slot one by one, which has the defects of slow winding speed, low slot fullness rate and the like. From the perspective of a magnetic circuit, referring to fig. 1, many magnetic lines of force form a closed loop from an N pole through a tooth shoe (4) of a stator, an S pole and a rotor yoke, the magnetic flux of the closed loop is leakage flux and does not participate in energy conversion, and the oversaturation of the tooth shoe (4) and a local rotor magnetic circuit is caused to affect the output of a main magnetic circuit and a motor, so that the utilization rate of a permanent magnet material is reduced.

Therefore, the existing motors are optimized based on the traditional concept and method of motor design, no special design is carried out aiming at the particularity of the electric roller motor, the problems of high motor cost, low winding efficiency, high manufacturing process difficulty and the like still exist, and the design is not ideal.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention combines the working characteristics and the structural requirements of the electric roller permanent magnet synchronous motor and the modern motor control technology, and aims to provide the electric roller permanent magnet synchronous motor, improve the performance, stability and reliability of the outer rotor permanent magnet synchronous electric roller motor, and reduce the material cost and the production cost.

In order to achieve the above purpose, the invention provides the following technical scheme:

an electric roller permanent magnet synchronous motor comprises a front bearing, an outer rotor, an inner stator and a rear bearing, wherein the outer rotor is sleeved outside the inner stator, two ends of the outer rotor are fixedly connected with an outer ring of the front bearing and an outer ring of the rear bearing respectively, a fixed shaft fixedly connected with the inner stator is arranged in the inner stator in a penetrating manner, two ends of the fixed shaft are fixedly connected with an inner ring of the front bearing and an inner ring of the rear bearing respectively, the outer rotor is of a salient pole structure, and quadrature axis inductance Lq is greater than direct axis inductance Ld; the inner stator comprises a stator core without tooth shoes and a winding, the stator core without tooth shoes comprises multiple teeth of 3, the winding is a three-phase concentrated winding, and the three-phase concentrated winding is star-connected or angle-connected and led out.

Further, the stator core without the tooth shoe is formed by laminating a plurality of layers of stator punching sheets without the tooth shoe, and the thickness of the stator punching sheet without the tooth shoe is 0.25 mm-0.5 mm.

Furthermore, the stator punching sheet of the toothless shoe is formed by punching a silicon steel sheet with the thickness of 0.25 mm-0.5 mm.

Further, the tooth crest of the stator tooth of the stator core without the tooth shoe is set to be circular arc, and the circular arc radius R _ t of the stator tooth is smaller than the radius R of the stator core without the tooth shoe.

Furthermore, the value range of the arc radius R _ t of the stator teeth is more than or equal to 0.35R and less than or equal to R _ t.

Further, the winding is a three-phase single-layer concentrated winding or a three-phase double-layer concentrated winding.

Furthermore, a plurality of magnetic pole tiles which are uniformly distributed are arranged on the outer rotor along the circumference of the outer rotor, and a raised step which is integrated with a rotor yoke part is arranged between every two adjacent magnetic pole tiles to form the salient pole structural type permanent magnet rotor.

Further, the quadrature axis inductance Lq is greater than 1.2 times the direct axis inductance Ld.

Further, a front end cover is sleeved and fixed outside the outer ring of the front bearing, a rear end cover is sleeved and fixed outside the outer ring of the rear bearing, a position sensor is further arranged on one side of the front end cover or the rear end cover, and the position sensor can be a Hall sensor or a magnetic encoding sensor or a photoelectric sensor.

The invention has the beneficial effects that:

the invention provides an electric roller permanent magnet synchronous motor, which comprises a front bearing, an outer rotor, an inner stator and a rear bearing, wherein the outer rotor is sleeved outside the inner stator, two ends of the outer rotor are respectively and fixedly connected with an outer ring of the front bearing and an outer ring of the rear bearing, a fixed shaft fixedly connected with the inner stator is arranged in the inner stator in a penetrating way, two ends of the fixed shaft are respectively and fixedly connected with an inner ring of the front bearing and an inner ring of the rear bearing, the outer rotor is of a salient pole structure, and quadrature axis inductance Lq is greater than direct axis inductance Ld; the inner stator comprises a stator core without tooth shoes and a winding, the stator core without tooth shoes comprises multiple teeth of 3, the winding is a three-phase concentrated winding, and the three-phase concentrated winding is led out in a star connection or an angle connection mode.

The invention has the beneficial effects that: the outer rotor of the invention is a salient pole structure, and the quadrature axis inductance Lq is greater than the direct axis inductance Ld, not only can adopt the motor control technology with a position sensor, but also can adopt the FOC sensorless motor control technology of a high-frequency pulse injection method, so that the motor has lower cost, simpler structure and more reliability; the stator core of the inner stator adopts a toothless shoe design, so that the problem of difficult coil inserting is solved, the full rate of the slot is higher, and the production cost is further reduced; the arc design of the stator core tooth top of the inner stator reduces potential harmonic waves, reduces tooth space torque and improves the motor performance. The electric roller permanent magnet synchronous motor provided by the invention has the advantages that on the premise of ensuring the torque density and performance of the motor, the performance of the outer rotor permanent magnet synchronous electric roller motor is improved, the stability and the reliability are improved, meanwhile, the material cost and the production cost are obviously reduced, and the production efficiency is improved.

Drawings

Fig. 1 is a schematic cross-sectional view of a conventional outer rotor permanent magnet motor;

fig. 2 is a schematic diagram of a stator punching sheet of a conventional outer rotor permanent magnet motor;

FIG. 3 is a schematic structural diagram of an outer rotor permanent magnet motor according to the present invention;

FIG. 4 is a schematic view of a stator lamination without tooth shoes according to the present invention;

fig. 5 is a schematic view of a stator core without tooth shoes according to the present invention;

FIG. 6 is a schematic cross-sectional view of an outer rotor permanent magnet machine of the present invention;

FIG. 7 is a schematic view of an outer rotor of the present invention;

fig. 8 is a schematic view of an application of the outer rotor permanent magnet motor of the present invention to an electric roller 1;

fig. 9 is a schematic view of an application of the outer rotor permanent magnet motor of the present invention to an electric roller 2;

FIG. 10 shows the cogging torque simulation result of the outer rotor permanent magnet motor prototype of the present invention;

FIG. 11 is a simulation result of the line potential of the outer rotor permanent magnet motor sample of the present invention;

in the figure, 1-stator yoke, 2-stator teeth, 3-shaft hole, 4-tooth shoe, 5-stator slot, 5 a-notch, 6-coil, 7-outer rotor yoke, 8-pole tile, 9-rotor raised step, 10-outer rotor, 61-position sensor, 151/152-bearing, 62-end cap, 63-shaft, 64-winding and signal line, 11-roller left side output shaft, 12-roller bearing, 13-roller, 14-outer rotor permanent magnet motor, 20-inner stator, 21-stator yoke, 22-stator teeth, 23-shaft hole, 24-stator slot

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 3-11, fig. 3 is a schematic structural diagram of an outer rotor permanent magnet motor of the present invention, fig. 4 is a schematic diagram of a stator punching sheet without a tooth shoe of the present invention, fig. 5 is a schematic diagram of a stator core without a tooth shoe of the present invention, fig. 6 is a schematic cross-sectional diagram of an outer rotor permanent magnet motor of the present invention, fig. 7 is a schematic diagram of an outer rotor of the present invention, fig. 8 is a schematic diagram 1 of an application of an outer rotor permanent magnet motor of the present invention on an electric drum, fig. 9 is a schematic diagram 2 of an application of an outer rotor permanent magnet motor of the present invention on an electric drum, fig. 10 is a simulation result of cogging torque of a prototype of an outer rotor permanent magnet motor of the present invention, and fig. 11 is a simulation result of line potential of an outer rotor permanent magnet motor of the present invention.

The electric roller permanent magnet synchronous motor provided by the invention has the advantages that on the premise of ensuring the torque density and performance of the motor, the performance of the outer rotor permanent magnet synchronous electric roller motor is improved, the stability and the reliability are improved, meanwhile, the material cost and the production cost are obviously reduced, and the production efficiency is improved.

Referring to fig. 3 and 6, the electric drum permanent magnet synchronous motor in the present embodiment includes a front bearing 152, an outer rotor 10, an inner stator 20, and a rear bearing 151, wherein the outer rotor 10 is sleeved outside the inner stator 20, two ends of the outer rotor 10 are fixedly connected to an outer ring of the front bearing 152 and an outer ring of the rear bearing 151, respectively, the inner stator 20 includes a stator core without a tooth shoe and a fixing shaft 63 penetrating through the stator core without the tooth shoe, two ends of the fixing shaft 63 are fixedly connected to an inner ring of the front bearing 152 and an inner ring of the rear bearing 151, respectively, and the outer rotor is rotatably connected to the fixing shaft 63 through the front bearing 152 and the rear bearing 151.

Referring to fig. 4 and 5, the inner stator 20 includes a stator core without tooth shoes, which preferably includes 12 teeth, and a winding, which is preferably a three-phase concentrated winding composed of 6 or 12 coils 6, and the three-phase concentrated winding is star-connected or angle-connected to be led out.

Referring to fig. 5 again, the stator core without the tooth shoe is formed by laminating a plurality of layers of stator punching sheets without the tooth shoe, and the stator punching sheets without the tooth shoe are preferably formed by punching silicon steel sheets with the thicknesses of 0.25mm, 0.35mm and 0.5 mm; as shown in fig. 5, the stator core without tooth shoes includes a stator yoke portion 21, stator teeth 22 without tooth shoes, shaft holes 23, and stator slots 24.

Referring to fig. 4 and 5, the stator laminations without tooth shoes have 12 stator teeth 22 without tooth shoes, and thus correspond to 12 stator slots 24, and are typically stamped from 0.5mm thick low loss silicon steel sheet material. The intersection point of the central line of each stator tooth and the tooth top arc is on the circumference with the radius of R, 12 stator teeth can not be uniformly distributed, but the uniform distribution is preferred, and when the uniform distribution is carried out, the included angle between the adjacent teeth is 30-degree mechanical angle. Finite element simulation of a motor magnetic field shows that the radius of a stator addendum arc ranges from 0.35R to R _ t and the cogging torque is smaller when the addendum arc center is on a tooth center line, in the embodiment, R is 26.25mm, and R _ t is 11.25 mm.

In the three-phase fractional slot concentrated armature winding of the stator core with 14 poles/12 slot toothless shoes of the embodiment, 12 concentrated coils are wound on 12 teeth, 4 coils are arranged on each phase, the coils on the 1 st tooth and the 2 nd tooth are reversely connected in series to form a coil group A1, the coils on the 7 th tooth and the 8 th tooth are reversely connected in series to form a coil group A2, and A1 and A2 are reversely connected in parallel or in series to form an A-phase winding; similarly, the coils on the 3 rd and 4 th teeth are reversely connected in series to form a coil group B1, the coils on the 9 th and 10 th teeth are reversely connected in series to form a coil group B2, and B1 and B2 are reversely connected in parallel or in series to form a phase B winding; the coils on the 5 th and 6 th teeth are connected in series in an opposite direction to form a coil group C1, the coils on the 11 th and 12 th teeth are connected in series in an opposite direction to form a coil group C2, and C1 and C2 are connected in parallel in an opposite direction or in series to form a C-phase winding; and finally, the star connection or the angle connection of the three-phase winding is led out by an outgoing line. Based on the 14-pole/12-slot matching, the winding connection mode can greatly weaken 5 th order and 7 th order harmonics, and improve the potential waveform.

In the embodiment, the stator core of the inner stator 20 adopts a toothless shoe design, so that the problem of difficult coil inserting is solved, the full rate of the slots is higher, and the production cost is further reduced; the circular arc design of the stator core tooth top of the inner stator 20 reduces potential harmonic waves, reduces cogging torque and improves the motor performance; as shown in particular in fig. 10 and 11.

Referring to fig. 4-7, in the present embodiment, preferably, the outer rotor 10 includes a circular ring surrounded by 14 pole tiles 8 and a rotor protruding step 9, the inner circle radius of the pole tiles 8 is the same as the outer circle radius, which improves the utilization rate of the permanent magnetic material when cutting the pole tiles 8, and simultaneously makes the air gap between one pole (a single pole tile 8) and the surface of the inner stator core uneven, the waveform of the small air gap flux density distribution in the middle is improved, and the width of the pole tile 8 is about 0.67 of the pole pitch.

In addition, as shown in fig. 6 and 7, the outer rotor 10 has a rotor raised step 9 between 2 magnetic pole tiles 8, in this embodiment, there are 14 magnetic pole tiles 8, and they are uniformly distributed along the circumference, the inner arc radius of the rotor raised step 9 is approximately equal to that of the magnetic pole tiles 8, and they are made into one body with the outer rotor yoke 7, so as to form a salient pole type outer rotor permanent magnet motor rotor, so that the outer rotor permanent magnet motor of this embodiment has a direct axis inductance Ld not equal to the quadrature axis inductance Lq, and Lq >1.2 Ld.

The outer rotor 10 of the invention is a salient pole structure, and the quadrature axis inductance Lq is larger than the direct axis inductance Ld, not only can adopt the motor control technology with a position sensor, but also can adopt the FOC position sensorless motor control technology of a high-frequency pulse injection method, so that the motor cost is lower, the structure is simpler and more reliable.

As shown in fig. 3, a position sensor 61 is further disposed on one side of the front end cover or the rear end cover of the outer rotor permanent magnet synchronous motor, the position sensor 61 may be a hall sensor or a magnetic encoder sensor or a photoelectric sensor, and the position sensor 61 is used for detecting the position of the outer rotor.

Fig. 8 and 9 are schematic diagrams of an application of an outer rotor permanent magnet motor to an electric roller, and the outer rotor permanent magnet synchronous motor is pressed into the electric roller of the roller by adopting a coaxial structure or a structure of independent left and right output shafts according to whether a position sensor 61 is installed or not or the type of the position sensor 61.

Fig. 10 and 11 are cogging torque and line potential waveform plots based on the following parameters: the tooth width of the stator punching sheet without the tooth shoe is 5mm, the tooth top arc radius is 11.25mm, the outer diameter of the stator punching sheet without the tooth shoe is 52.5mm, 12 coils form a 3-phase stator winding, 2 paths of the stator winding are connected in parallel, the number of turns of each coil is 50, the length of an iron core is 60mm, the rotor permanent magnet is 38UH, and the rotating speed is 100 rpm; as can be seen from fig. 10 and 11, the motor performance is better, the cogging torque is small, and the line potential harmonic content is small.

While the present invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An electric drum permanent magnet synchronous motor, which comprises a front bearing, an outer rotor, an inner stator, and a rear bearing, the outer rotor is sleeved outside the inner stator, and the two ends of the outer rotor are respectively connected with the front bearing. The outer ring of the bearing and the outer ring of the rear bearing are fixedly connected, the inner stator is provided with a fixed shaft which is fixedly connected with the inner stator, and the two ends of the fixed shaft are respectively connected with the inner ring and the inner ring of the front bearing. The inner ring of the rear bearing is fixedly connected, and is characterized in that:

The outer rotor is a salient pole structure, and the quadrature-axis inductance Lq is greater than the direct-axis inductance Ld;

The inner stator includes a stator iron core without toothed shoes and a winding, the stator iron core without toothed shoes contains a multiple of 3 teeth, and the winding is a three-phase concentrated winding, and the three-phase concentrated winding is star-connected or angular. Take out.

2 . The permanent magnet synchronous motor of the electric drum according to claim 1 , wherein the stator iron core of the toothless shoe is formed by laminating the stator punching sheets of the multi-layer toothless shoe. The thickness of the stator punch is 0.25mm to 0.5mm.

3 . The permanent magnet synchronous motor of the electric drum according to claim 2 , wherein the stator punched sheet of the toothless shoe is punched from a silicon steel sheet with a thickness of 0.25 mm to 0.5 mm. 4 .

4. The permanent magnet synchronous motor of the electric drum according to claim 3, characterized in that: the tooth tip of the stator of the stator iron core without the toothed shoe is set as an arc shape, and the arc radius of the stator tooth is R_t is smaller than the radius R of the stator core of the toothless shoe.

5 . The permanent magnet synchronous motor of the electric drum according to claim 4 , wherein the value range of the arc radius R_t of the stator teeth is 0.35R≤R_t≤R. 6 .

6 . The permanent magnet synchronous motor of an electric drum according to claim 4 , wherein the winding is a three-phase single-layer concentrated winding or a three-phase double-layer concentrated winding. 7 .

7. The electric drum permanent magnet synchronous motor according to any one of claims 1-6, characterized in that: the outer rotor is provided with a plurality of magnetic pole tiles evenly distributed along its circumference, and adjacent two magnetic poles are provided with a plurality of magnetic pole tiles. A raised step integrated with the rotor yoke is provided between the tiles to form the salient pole structure permanent magnet rotor.

8 . The permanent magnet synchronous motor of the electric drum according to claim 7 , wherein the quadrature-axis inductance Lq is greater than 1.2 times the direct-axis inductance Ld . 9 .

9 . The electric drum permanent magnet synchronous motor according to claim 8 , wherein a front end cover is sleeved and fixed on the outer ring of the front bearing, and a rear end cover is sleeved and fixed on the outer ring of the rear bearing. 10 . The end cover, one side of the front end cover or the rear end cover is also provided with a position sensor, and the position sensor can be a Hall sensor, a magnetic encoder sensor or a photoelectric sensor.