WO2009055956A1

WO2009055956A1 - Square-wave three-phase brushless permanent magnet dc motor

Info

Publication number: WO2009055956A1
Application number: PCT/CN2007/003063
Authority: WO
Inventors: Tiecai Li; Yamei Qi; Zhaoyong Zhou; Xiang Kong; Weilong Lan; Feipeng Xu
Original assignee: Shenzhen Academy Of Aerospace Technology
Priority date: 2007-10-29
Filing date: 2007-10-29
Publication date: 2009-05-07
Also published as: CN101371425A; CN101371425B

Abstract

A square-wave three-phase brushless permanent magnet DC motor. The number of the magnetic poles on the iron core of the rotor (1) of the motor is: 2P=8. The number of the slots (21) in the iron core of the stator (2) of the motor is: Z=12. The iron core of the stator (2) includes three large teeth, three middle-sized teeth and six small teeth. The sum of the mechanical angels of one large tooth, one middle-sized tooth and two small teeth is 120 degree. Three-phase concentrated windings are wrapped around the large teeth and the middle-sized teeth separately. The windings of each phase only have two concentrated windings. The motor only has six concentrated windings.

Description

Square wave three-phase brushless permanent magnet DC motor

Field of the Invention This invention relates to permanent magnet motors and, more particularly, to a square wave three phase brushless permanent magnet DC motor suitable for direct drive and position, rate servo control applications. Background technique

The permanent magnet motor can be divided into two major categories: sine wave and square wave according to the driving current and back electromotive waveform. Generally, a sine wave permanent magnet motor is called a permanent magnet synchronous motor (PMSM), or a sine wave AC servo motor. Another type of square wave permanent magnet motor is called a square wave brushless DC motor (BLDCM).

During the 1980s, square wave permanent magnet motors have been widely used. The external characteristics of square wave permanent magnet motors are basically the same as those of brushed DC motors. The control is relatively simple, but its biggest disadvantage is the existence of large principle commutation torque fluctuations. In this regard, the researchers proposed a variety of compensation measures, but the actual application results are not satisfactory.

Since the torque fluctuation of the sine wave permanent magnet motor is much smaller than that of the square wave permanent magnet motor, in the precision servo drive application, the square wave permanent magnet motor was gradually replaced by the sine wave permanent magnet motor, which has become a modern industrial application. Mainstream. However, sinusoidal permanent magnet motors lead to a significant increase in the complexity of the control system and a significant increase in cost. More importantly, the force performance of the motor is drastically reduced.

On the other hand, the traditional square wave brushless DC motor and its control technology have been recognized as mature, and due to the aforementioned defects, it has been limited to applications where the requirements are not high, and there have been few studies at home and abroad. Summary of the invention

The invention solves the problems existing in the existing square wave permanent magnet motor and the sine wave permanent magnet motor, and proposes a new principle, a new structure, a high performance and a low cost square wave permanent magnet motor.

The technical solution of the present invention is to provide a square wave three-phase brushless permanent magnet DC motor, wherein the rotor core of the motor is provided with a plurality of pairs of permanent magnets, and the slots of the stator are equipped with three-phase windings, wherein The number of magnetic poles on the rotor core is 2P=8; the number of slots of the stator core is Z=12, correspondingly 12 teeth,

Confirmation The slot width of the slot is 0. 1~3. 0 wake up, the 12 teeth include three too teeth, three middle teeth and six small teeth; the three-phase windings are concentrated windings, respectively wound around On the large and middle teeth, the arrangement order of the windings and teeth is: A-phase winding on the large tooth → small tooth, medium tooth, / C-phase winding, a small tooth, large tooth, B-phase winding, a small tooth, a middle tooth The upper/A phase winding has a small tooth and a large tooth on the C phase winding and a small tooth → the middle tooth/B phase winding has a small tooth; its A represents a concentrated winding of the A phase winding, and /A represents an inverse of the A phase winding. Connect the concentrated windings, B, /B, C, /C and so on.

In a preferred embodiment of the invention, each large tooth on the stator core occupies a circumferential mechanical angle of 50° ± 5°, that is, an electrical angle of 200 ° ± 20 °; each middle tooth occupies a circumference of 40 ° ± 5 ° mechanical angle , that is, 160 ° ± 20 ° electrical angle; each small tooth occupies a circumference of 15 ° ± 5 ° mechanical angle; wherein each tooth occupies a circumferential mechanical angle containing the notch width; and a large tooth, a middle tooth, and then Add the sum of the mechanical angles of the two small teeth equal to 120 °.

In the present invention, the N and S magnetic poles of the respective permanent magnets on the rotor core are arranged in phase, and the permanent magnets are radially magnetized tile-shaped magnetic steel or parallel magnetized tile-shaped magnetic steel.

2〜2毫米。 The present invention, the physical air gap between the stator and the rotor is preferably 0. 2~2mm.

In the present invention, a Hall position sensor can be used as the rotor position sensor, and the magnetic sensitive direction of the Hall position sensor is consistent with the normal direction of the rotor, and is mounted on the stator bracket and maintained between the permanent magnet and the outer circumference of the rotor. 3 匪 air gap.

In the present invention, the physical dimension of the pole pitch D/8 of the permanent magnet on the rotor core is preferably 10 to 56 mm, where D is the outer diameter of the rotor.

In the present invention, the stator core may be formed by multi-layer splicing of silicon steel sheets, and each layer of spliced silicon steel sheets is composed of three shapes of large, medium and small fan-shaped punching pieces; Fan-shaped punching film-small pole fan-shaped punching piece, middle pole fan-shaped punching piece, small pole fan-shaped punching piece, large pole fan-shaped punching piece, small pole fan-shaped punching piece, middle pole fan-shaped punching piece, small pole fan-shaped punching piece, large pole fan-shaped punching A small pole fan-shaped piece, a medium-pole fan-shaped piece and a small-pole fan-shaped piece are arranged in a plane to form a stator punching piece, that is, a layer of spliced silicon steel sheet; adjacent two sector-shaped punching pieces The splicing is performed by a groove/land provided on the outer side of the yoke. Wherein a groove is arranged outside the yoke portion of the large and middle pole fan-shaped punching piece, and a boss is arranged outside the yoke portion of the small pole fan-shaped punching piece; or a boss is arranged outside the yoke portion of the large and middle pole fan-shaped punching piece, A groove is provided outside the yoke of the small pole fan-shaped punch. In another preferred embodiment of the present invention, wherein the plurality of silicon steel sheets are laminated into three shapes of sector-shaped teeth, and then the three kinds of teeth constitute the stator core; wherein the large teeth are formed by a large-pole fan-shaped sheet Pressed, the middle tooth pole is formed by laminating the middle pole fan-shaped punching piece, and the small tooth pole is formed by laminating the small pole fan-shaped punching piece; in each tooth pole, the yoke portion and the tooth portion of each fan-shaped punching piece Each has a positioning blind hole, and a plurality of fan-shaped punching pieces are riveted into an integral tooth pole by positioning blind holes; the three kinds of tooth poles are according to "A phase large tooth pole → small tooth pole → / C phase middle tooth pole 1 Small tooth pole → B phase large tooth pole a small tooth pole → A phase in the tooth pole a small tooth pole → C phase large tooth pole a small tooth pole / B phase in the tooth pole a small tooth pole" order into one Complete stator core.

In another preferred embodiment of the present invention, the stator core is formed by multi-layered integral silicon steel sheets by riveting or riveting with rivets; each layer of the whole silicon steel sheet has three tooth shapes at the same time, three tooth shapes. Press "A phase large tooth a small tooth → / C phase medium tooth a small tooth - B phase large tooth a small tooth - A phase medium tooth a small tooth a C phase large tooth - small tooth one / B phase medium tooth → small The order of the teeth is arranged circumferentially.

According to the above technical solution, the square wave three-phase brushless permanent magnet DC motor of the present invention has a magnetic pole number of 2P=8, wherein a magnetic pole covering technique is adopted, so that the air gap magnetic field has a flat top area of 120° or more; Non-uniform cogging and magnetically balanced small teeth minimize positioning torque. The motor has only two concentrated windings per phase, which is simple in structure and low in production cost. The output of the motor is 33% larger than that of the conventional sine wave permanent magnet servo motor, and the winding end is more than three times smaller than the conventional sine wave permanent magnet servo motor, so the copper consumption is greatly reduced. When the square wave three-phase brushless permanent magnet DC motor is driven by a three-phase square wave current, it can generate a stable torque, and its torque fluctuation index is equivalent to that of a sine wave permanent magnet servo motor. DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a schematic view showing the structure of a stator and a rotor of a motor according to a preferred embodiment of the present invention; FIG. 2 is a schematic view showing the structure of a motor assembly according to a preferred embodiment of the present invention;

Figure 3 is a schematic view showing the angular distribution of the stator slots in the embodiment shown in Figure 1;

4 is a schematic structural view of a stator punch formed by three fan-shaped punching sheets;

Figure 5 is another embodiment of a stator punch formed from three fan-shaped punches;

Figure 6 is another embodiment of a stator punch formed from three fan-shaped punches;

Figure 7 is a schematic view of a multi-layer silicon steel sheet composed of three kinds of tooth poles, and then composed of a complete stator core; Fig. 8 is a schematic view showing a complete stator core composed of a plurality of integral silicon steel sheets having three tooth shapes. detailed description

A preferred embodiment of the invention is illustrated in Figures 1 and 2. The general structure of the three-phase brushless permanent magnet DC motor can be seen from Fig. 2, the main components of which include the rotor 1, the stator 2, the rotating shaft 30, etc., and the physical air gap 5 between the rotor 1 and the stator 2 is 0. 2—2ram. The Hall position sensor is used as the rotor position sensor, and the magnetic sensitive direction of the Hall position sensor is consistent with the normal direction of the rotor, and is mounted on the stator bracket 6 and kept between the outer circumference of the rotor magnet (ie, the permanent magnet). ~3mm air gap.

As can be seen from Fig. 1, a plurality of pairs of permanent magnets 4 are mounted on the rotor core, and these permanent magnets generate an air gap magnetic field; in Fig. 1, there are 4 pairs of 8 permanent magnets, 8 poles N and S are arranged in phase, That is, the number of magnetic poles of the rotor is 2P=8. In a specific implementation, the permanent magnet 4 may be a radially magnetized tile-shaped magnetic steel or a parallel magnetized tile-shaped magnetic steel. The physical dimension of the pole pitch of the permanent magnet on the rotor core is 10 to 56 let, where D is the outer diameter of the rotor.

At the same time, the number of stator slots 21 is Z=12, corresponding to 12 teeth; the width of the slot 3 of the stator slot is 0. 1~3匪; 12 teeth include three large teeth, three middle teeth and six teeth. Small teeth, and arranged in the order of large teeth, small teeth, medium teeth and small teeth in the circumference. When assembled, three-phase windings are installed in the 12 slots of the stator core.

In this embodiment, the three-phase windings are concentrated windings, and the windings in the stator windings are directly wound around the insulation of the large and middle teeth. The arrangement order of the windings and the teeth is: A-phase winding and a small tooth on the large teeth → Middle tooth / C phase winding a small tooth a large tooth on the B phase winding a small tooth → middle tooth / A phase winding a small tooth a large tooth on the C phase winding → small tooth one medium tooth / B phase winding a small tooth; A represents a concentrated winding of the A-phase winding, /A represents a reverse-connected concentrated winding of the A-phase winding; B represents a concentrated winding of the B-phase winding, and /B represents a reverse-connected concentrated winding of the B-phase winding C represents a concentrated winding of the C-phase winding, and /C represents a reverse-connected concentrated winding of the C-phase winding. After such winding, the two concentrated windings of each phase are wound in series, which reduces the wiring and simplifies the process. It can be seen that the motor has only two concentrated windings per phase, and the three-phase motor has only six concentrated windings. The total number of windings of the motor is very small, which greatly simplifies the structure of the motor and reduces the cost, and the winding end is reduced to the conventional motor. /3~1/6 even More, it has been minimized, and copper consumption has dropped dramatically.

It can be seen from Fig. 3 that each large tooth of the stator core 2 occupies a circumference of 50° ± 5° mechanical angle, and since it is 4 pairs of magnetic stages, that is, 4X360° electrical angle, each large tooth occupies 200° ± 20° Angle, the concentrated winding is wider than 180° electrical angle, completely covering the pole pitch, that is, by artificially increasing the winding pitch, thereby collecting more air gap flux to achieve the purpose of square wave. Each middle tooth occupies a circumference of 40° ±5 . The mechanical angle, ie 160 ° ± 20 ° electrical angle, the concentrated winding is wider than 120 ° electrical angle. Each of the small teeth occupies a circumferential angle of 15° ± 5°, but does not have a winding; wherein the circumferential mechanical angle of each of the teeth is a slot width (0. l~3mm). The ratio of the circumference of the three teeth is: large teeth 50° ±5°, medium teeth 40° ±5°, small teeth 15° ±5°, and one large tooth + one middle tooth + two small teeth The total mechanical angle is equal to 120°. In specific implementation, the mechanical angle of the large, middle and small teeth may be 50°, 40°, 15°, or 48°, 42°, 15°, or 52°, 40°, 14°, or Other combinations of angles that meet the above requirements.

The solution adopted in the above embodiment may be referred to as a magnetic pole covering technique. Since the width of the two concentrated windings of the A phase is greater than or close to 160°, the concentrated winding on the large teeth generates a flat top air gap of 135° or more. The magnetic field, the concentrated winding on the middle teeth produces a flat topped gap magnetic field above 120° electrical angle. Since the two magnetic poles in each phase are spatially different by 180° mechanical angle, and the coverage of the two magnetic poles per phase is (200° +160°)/2=180°. Therefore, the phase winding back electromotive force of the two concentrated windings connected in series has a flat top region of 120° or more. Conventional square wave permanent magnet DC motors are unlikely to obtain an air gap magnetic field in the flat top region greater than 120°, which causes the commutation torque to fluctuate and causes the positioning torque to increase.

The frequency of the positioning torque of the traditional 8-pole 12-slot square-wave permanent magnet DC motor is 8X 12/4=24 times of positioning torque. Generally, the amplitude of the positioning torque is one-fourth of the torque fundamental wave, that is, 1 /24=4.1%, so the positioning torque is quite large. In the invention, after adopting three different tooth types of large, medium and small, the frequency of the positioning torque is 216 times of positioning torque, and the magnitude of the positioning torque can be roughly considered to be one of 216 of the fundamental torque of the torque, that is, 1/261=0.45. %. The comparison shows that the positioning torque is reduced by nearly 10 times. This large, medium and small tooth structure greatly reduces the positioning torque and overcomes the most deadly shortcoming of the traditional square wave permanent magnet DC motor, even better than the sine wave. Permanent magnet DC motor.

For the three-phase brushless permanent magnet DC motor of the present invention, the international application number is PCT/CN2007/000178, and the name is "brushless DC motor control system and its control method". The control system and method disclosed in the patent of the patent drive control, in which a new square wave brushless motor continuous current sampling and closed-loop control is adopted, and its comprehensive performance exceeds the sine wave AC servo system, and the torque fluctuation index is equivalent, but the output is improved 33 %, copper consumption has dropped significantly. The three-phase brushless permanent magnet DC motor of the invention can replace the existing sine wave AC servo motor and its servo unit, and becomes the main branch of the future servo motor and its servo unit.

In the embodiment shown in FIG. 4, the stator core 2 is formed by laminating and laminating a plurality of layers of spliced silicon steel sheets 7, wherein each layer of spliced silicon steel sheets is composed of three types of punching sheets, specifically large, medium and small. Extreme fan-shaped punch. The outer side of the yoke of the large pole fan-shaped punching piece 8 has two grooves, and the outer side of the yoke portion of the middle pole fan-shaped punching piece 9 also has two grooves, and the outer side of the yoke portion of the small pole fan-shaped punching piece 10 has two bosses, and the convex portion The table can be inserted into the aforementioned groove and seamed. In Fig. 4, the arrangement is as follows: a large pole fan-shaped punching piece, a small pole fan-shaped punching piece, a middle pole fan-shaped punching piece, a small pole fan-shaped punching piece, a large pole fan-shaped punching piece, a small pole fan-shaped punching piece, a middle pole fan shape A small pole fan-shaped punching piece, a large pole fan-shaped punching piece, a small pole fan-shaped punching piece, a middle pole fan-shaped punching piece, and a small pole fan-shaped punching piece. These punching pieces are spliced on one plane to form a stator punching piece, that is, A layer of spliced silicon steel sheet, multi-layer spliced silicon steel sheet can be obtained from a riveted laminated core to obtain a complete stator core.

In the specific implementation, the stator punching piece shown in FIG. 5 can also be used, which also includes a large pole fan-shaped punching piece 8, a middle pole fan-shaped punching piece 9, and a small pole fan-shaped punching piece 10; in FIG. 4, a small pole fan-shaped punching piece The outer side has an arc-shaped extension arm, and in Fig. 5, the outer pole fan-shaped piece and the middle-pole fan-shaped piece have an arc-shaped extension arm on the outer side. It is also possible to use the stator punch shown in Fig. 6, in which a boss is provided on the large and middle pole fan-shaped punches, and a groove is provided on the small-pole fan-shaped punch. In order to reduce the influence of the seam on the magnetic circuit of the stator core, the stator punches with different positions of the grooves and the bosses may be selected and laminated to form one stator as a whole.

In the embodiment shown in FIG. 7, a plurality of layers of silicon steel sheets are laminated into three shapes of sector-shaped tooth poles to form a stator core; a large tooth pole is formed by laminating a large-pole fan-shaped punching piece 1 1 , and a fan-shaped punch is formed. The yoke portion and the tooth portion of the sheet each have a positioning blind hole 12, and are riveted into an integral tooth pole by positioning the blind hole; the middle tooth pole is formed by laminating the middle pole fan-shaped punching piece 13, the yoke portion and the tooth of the fan-shaped punching piece Each of the portions has a positioning blind hole 14 and is riveted into an integral tooth pole by positioning the blind hole; the small tooth pole is formed by laminating the small pole fan-shaped punching piece 16 , and the yoke portion of the fan-shaped punching piece has a positioning on each side and the tooth portion The blind hole 15 is riveted into an integral tooth pole by positioning the blind hole. Each tooth pole is in accordance with "A phase large tooth pole, small tooth pole → / C phase, tooth tip, small tooth pole → B phase large tooth pole, small tooth pole → A phase, middle tooth, small tooth pole → C phase large tooth The sequence of a very small tooth pole / B phase in the tooth pole and a small tooth pole" A complete stator core.

In the embodiment shown in Fig. 8, each layer of silicon steel sheet is a complete stator sheet, that is, an integral silicon steel sheet 17, which contains three tooth shapes, three types of teeth according to A phase large teeth and one small tooth one / C Phase tooth small tooth → B phase large tooth → small tooth - A phase medium tooth → small tooth → C phase large tooth and small tooth → / B phase medium tooth small tooth 〃 sequential circumferential arrangement; The integral silicon steel sheet can be obtained by self-riveting or riveting together with a rivet to obtain a complete stator core. A blind hole 18 for achieving riveting is provided on each of the entire silicon steel sheets. The corresponding three-phase concentrated winding is wound directly on the insulation of the large and middle teeth by the winding in the stator winding, and is wound in the following order: A phase large tooth pole / A phase middle tooth pole; B phase large tooth pole One/B phase middle tooth pole; C phase large tooth pole one / C phase middle tooth pole, so that two concentrated windings of each phase are wound in series by winding, which reduces wiring and simplifies the process.

The square wave three-phase brushless permanent magnet DC motor of the invention has a series of advantages such as minimizing winding end, minimizing air gap, minimizing material, minimizing positioning torque and minimizing loss, and having higher power/volume ratio And the torque/volume ratio, the cost is minimized. Its controller can adopt the new concept of square wave brushless motor continuous current sampling and closed-loop control, and its comprehensive performance exceeds the sine wave AC servo system. The square wave three-phase brushless permanent magnet DC motor can replace the existing sine wave AC servo motor and its servo unit, and become the main branch of the future servo motor and its servo unit. '

Claims

Rights request

A square wave three-phase brushless permanent magnet DC motor, wherein a rotor core (1) of the motor is provided with a plurality of pairs of permanent magnets (4), and a slot (21) of the stator (2) is provided with a three-phase winding. It is characterized in that

The number of magnetic poles on the rotor core is 2P 2;

The slot number (Z) of the stator core is 12 and 12, and the width of the slot (3) of the slot is 0. 1~ 3. 0mm, and the 12 teeth include three large teeth and three Middle teeth and six small teeth;

The three-phase windings are concentrated windings, which are respectively wound on the large teeth and the middle teeth. The order of the windings and the teeth is: a large-toothed A-phase winding, a small tooth, a middle-toothed/C-phase winding, and a small-toothed one. B-phase winding on the large teeth - small teeth - medium teeth / A phase windings, a small tooth, a large tooth, a C-phase winding, a small tooth, a medium-toothed / B-phase winding, a small tooth, and A, which represents a phase A winding. Concentrated winding, /A represents a reversed concentrated winding of the A-phase winding, B, /B, C, /C and so on.

2. The three-phase brushless permanent magnet DC motor according to claim 1, wherein: each of the large teeth on the stator core occupies a circumferential angle of 50 ° ± 5 °, that is, 200 ° ± 20 ° Electrical angle; each middle tooth occupies a circumference of 40° ± 5 ° mechanical angle, ie 160 ° ± 20 ° electrical angle; each small tooth occupies a circumference of 15 ° ± 5 ° mechanical angle; wherein each tooth occupies a circumferential mechanical angle The slot width; and the sum of the mechanical angles of one large tooth, one middle tooth, and two small teeth is equal to 120°.

3. The square wave three-phase brushless permanent magnet DC motor according to claim 2, wherein N and S magnetic poles of each permanent magnet on the rotor core are arranged in phase, and the permanent magnet is radially magnetized. Tile-shaped magnetic steel, or parallel-magnetized tile-shaped magnetic steel.

2〜2醒醒。 The square-wave three-phase brushless permanent magnet DC motor according to claim 3, wherein the physical air gap between the stator and the rotor is 0. 2~2 wake up.

The sub-square wave three-phase brushless permanent magnet DC motor according to claim 4, wherein a Hall position sensor is used as the rotor position sensor, and the magnetic sensitive direction of the Hall position sensor and the rotor normal are The directions are the same, mounted on the stator bracket, and maintain a 1~3 hidden air gap between the rotor and the permanent magnet outer circle.

The square wave three-phase brushless permanent magnet DC motor according to claim 5, wherein the physical dimension of the pole pitch D/8 of the permanent magnet on the rotor core is 10 to 56 mm, wherein D is Rotor Outer diameter.

The three-phase brushless permanent magnet DC motor according to any one of claims 1 to 6, wherein the stator core is formed by laminating and laminating a plurality of layers of spliced silicon steel sheets, each of which The layer-spliced silicon steel sheet (7) is composed of large, medium and small fan-shaped punching pieces of three shapes; and according to "the big pole fan-shaped punching piece, a small pole fan-shaped punching piece, a middle pole fan-shaped punching piece, a small pole fan-shaped punching piece" Large pole fan-shaped punching piece→Small pole fan-shaped punching piece—medium pole fan-shaped punching piece, small pole fan-shaped punching piece, one pole fan-shaped punching piece, one small pole fan-shaped punching piece, one pole fan-shaped punching piece→small pole fan-shaped punching piece Arranged on a plane to form a stator punching piece, that is, a layer of spliced silicon steel sheet; adjacent two sector-shaped punching pieces are spliced by a groove/projection provided on the outer side of the yoke portion.

8. The three-phase brushless permanent magnet DC motor according to claim 7, wherein a groove is provided outside the yoke portion of the large and middle pole fan-shaped punches, and outside the yoke portion of the small-pole fan-shaped punching piece A boss is provided; or a boss is provided outside the yoke portion of the large and middle pole fan-shaped punches, and a groove is provided outside the yoke portion of the small-pole fan-shaped punch.

The three-phase brushless permanent magnet DC motor according to any one of claims 1 to 6, wherein the multi-layer silicon steel sheet is laminated into three shapes of sector-shaped teeth, and then three teeth. The pole is composed of the stator core; wherein the large tooth pole is formed by laminating the large pole fan-shaped punching piece, the middle tooth pole is formed by laminating the middle pole fan-shaped punching piece, and the small tooth pole is formed by laminating the small pole fan shaped piece. In each of the tooth poles, each of the yoke portion and the tooth portion of each of the fan-shaped punching pieces has a positioning blind hole, and the plurality of fan-shaped punching pieces are riveted into an integral tooth pole by positioning blind holes; Press "A phase large tooth pole → small tooth pole one / C phase middle tooth pole one small tooth pole one B phase large tooth pole one small tooth pole one A phase middle tooth pole one small tooth pole → C phase large tooth pole one small The order of the tooth pole →/B phase in the tooth pole and the small tooth pole is combined into a complete stator core.

10 . The three-phase brushless permanent magnet DC motor according to claim 1-6, wherein the stator core is formed by multi-layered integral silicon steel sheets by riveting or riveting with rivets; each layer of integral silicon steel sheets (17) There are three types of teeth at the same time, three types of teeth according to A-phase large teeth, one small tooth, one/C-phase medium tooth, small tooth, one B-phase large tooth, one small tooth, one A-phase, one tooth, one small tooth, C-phase The order of the large teeth and a small tooth → / B phase in the teeth and a small tooth".