CN201509142U - Large pole square wave three-phase brushless permanent magnet DC motor - Google Patents

Abstract

The utility model relates to a large-pole square-wave three-phase brushless permanent magnet DC motor, wherein the number of magnetic poles on the rotor core is 2P=4, the number of slots of the stator core is Z=6, and the six teeth of the stator include three One large tooth and three small teeth; the sum of the mechanical angle of one large tooth and one small tooth is equal to 120°, and the electrical angle is P×120°=240°; the three-phase concentrated windings are respectively wound on the three large teeth, each The phase has only one winding; the stator core includes a large-tooth iron core (9) and three small-tooth iron cores (8); there are three large teeth on the large-tooth iron core, and the Each of the yokes is provided with a wedge-in groove (11), and there are three wedge-in grooves in total; each small-tooth iron core is wedged into one of the wedge-in grooves of the large-tooth iron core through its tail. This motor has the advantages of small positioning torque, simple structure, low production cost, very convenient winding of windings, and less copper consumption.

Description

Large pole square wave three-phase brushless permanent magnet DC motor

technical field

The utility model relates to a permanent magnet DC motor, in particular to a large-pole square wave three-phase brushless permanent magnet DC motor, which is suitable for direct drive and position and speed servo control applications.

Background technique

Permanent magnet motors can be divided into two categories: sine wave and square wave according to the driving current and back EMF waveform. A sine wave permanent magnet motor is generally 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 were widely used. The external characteristics of square wave permanent magnet motors are basically the same as those of brushed DC motors, and the control is relatively simple, but its biggest disadvantage is that there are large principle commutation torque fluctuations. In this regard, researchers have proposed a variety of compensation measures, but the actual application effect is not ideal.

Since the torque fluctuation of the sine wave permanent magnet motor is much smaller than that of the square wave permanent magnet motor, during the 1990s, in the application of precision servo drive, the square wave permanent magnet motor was gradually replaced by the sine wave permanent magnet motor, and it has become the current industrial application mainstream. However, the sine wave permanent magnet motor will greatly increase the complexity and cost of the control system, and more importantly, the power index of the motor will drop significantly.

On the other hand, the traditional square-wave brushless DC motor and its control technology are recognized as mature. Due to the aforementioned defects, it is limited to applications with low requirements, and there are few researches on it at home and abroad.

In order to solve the above-mentioned technical problems, the utility model applicant of this patent has previously applied for a patent of 'square wave three-phase brushless permanent magnet direct current motor', the announcement number is CN101371425A, which discloses a motor with the number of poles 2P=8, but the There is still the problem of large iron loss when the motor is used at high speed.

Utility model content

The utility model aims to solve the existing problems of the existing square wave permanent magnet motor and the sine wave permanent magnet motor, and proposes a large pole square wave permanent magnet motor with a new principle, a new structure, high performance and low cost of 2P=4.

The technical scheme of the utility model is to provide a large-pole square wave three-phase brushless permanent magnet DC motor, the rotor iron core of the motor is equipped with multiple pairs of permanent magnets, and the stator slot is equipped with three-phase windings, which is characterized in that , the number of magnetic poles on the rotor core is 2P=4; the number of slots of the stator core is Z=6, correspondingly there are 6 teeth, and the 6 teeth include three large teeth and three small teeth; The above-mentioned three-phase windings are concentrated windings, which are respectively wound on three large teeth, and each phase has only one winding; the arrangement order of the windings and teeth is: A-phase winding on the large tooth → small tooth → B-phase winding on the large tooth →Small teeth→C-phase windings on large teeth→small teeth; A represents a concentrated winding of A-phase winding, B represents a concentrated winding of B-phase winding, and C represents a concentrated winding of C-phase winding.

In the utility model, the stator core includes a large-tooth iron core and three small-tooth iron cores; three large teeth are arranged on the large-tooth iron core, and the yokes between two adjacent large teeth are respectively provided with There is one wedging slot, and there are three wedging slots in total; each of the small-toothed iron cores is wedged into one of the wedging-in-slots of the large-toothed iron core through its tail.

In the present utility model, the large-tooth iron core can be an integral large-tooth iron core, or composed of three single large-tooth iron cores. At this time, between two adjacent single large-tooth iron cores The centerlines of the stator slots of the two large teeth are spliced together.

In the utility model, the large-tooth iron core and each small-tooth iron core can be composed of multi-layer tooth silicon steel sheets. Specifically, it can be riveted into an integral structure through blind holes. Wherein, the large-tooth iron core and each small-tooth iron core preferably have the same number of layers of silicon steel sheets; the wedge-in groove may be a dovetail-shaped structure.

In the utility model, the width of the notch (5) of the groove between the adjacent large teeth and the small teeth on the stator core is preferably 0.1-3.0mm; each large tooth occupies a mechanical angle of 75°-117° of the circumference , that is, 150°～234° electrical angle; each small tooth occupies a 45°～3° mechanical angle of the circumference, that is, 90°～6° electrical angle; and the sum of the mechanical angles of a large tooth and a small tooth is equal to 120°, The electrical angle is P×120°=240°.

In the utility model, the permanent magnets N and S magnetic poles on the rotor core are arranged alternately, and the permanent magnets are radially magnetized tile-shaped magnets or parallel magnetized tile-shaped magnets; the stator The physical air gap between the rotor and the rotor is 0.2-3mm; the pole pitch of the permanent magnet on the rotor core is (1-0.8)×πD/4, where D is the outer diameter of the rotor. The pole pitch of the permanent magnet is (1～0.8) times of the motor pole pitch πD/4. With the decrease of this multiple, the air gap magnetic field of the motor will change to a sine wave. When this multiple decreases to (0.8～0.6) times, the air-gap magnetic field will be more similar to a sine wave.

In the utility model, a Hall position sensor is used as the rotor position sensor. The magnetic sensitivity direction of the Hall position sensor is consistent with the normal direction of the rotor, and is installed on the stator bracket, and is kept 1～2 between the outer circle of the rotor permanent magnet. 3mm air gap.

It can be seen from the above technical scheme that the number of magnetic poles of the large pole square wave three-phase brushless permanent magnet DC motor of the present invention is 2P=4, wherein the magnetic pole covering technology is adopted to make the air gap magnetic field have a flat top with an electrical angle of more than 120° Zone; use non-uniform cogging and magnetic balance small teeth to minimize the positioning moment. The electric motor has only one concentrated winding for each phase, has simple structure and low production cost. Because the small teeth are embedded, the small teeth are not installed first, and the space is left to make the winding of the concentrated winding very convenient. Even if the machine automatically winds, it can guarantee a slot full rate of more than 85%. The output of this motor is 33% larger than that of the traditional sine wave permanent magnet servo motor, and the winding end is more than 3 times smaller than that of the traditional distributed winding 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.

Description of drawings

The utility model will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

Fig. 1 is a schematic view of the stator and rotor sectional structure of an electric motor in a preferred embodiment of the utility model;

Fig. 2 is a schematic diagram of the motor assembly structure in a preferred embodiment of the present invention;

Fig. 3 is a schematic diagram of stator cogging angle distribution in the embodiment shown in Fig. 1;

Fig. 4 is a schematic structural view of a single large tooth silicon steel sheet in Fig. 1;

Fig. 5 is a schematic structural view of a single small tooth silicon steel sheet in Fig. 1;

Fig. 6 is a three-dimensional structural schematic diagram of a small-tooth iron core composed of a plurality of small-tooth silicon steel sheets shown in Fig. 5;

Fig. 7 is a schematic diagram of a stator core composed of a large-toothed iron core and three small-toothed iron cores;

Fig. 8 is a schematic diagram of a stator core composed of three large-tooth iron cores and three small-tooth iron cores.

In the figure, 1 is the rotor core, 2 is the permanent magnet, 3 is the yoke, 4 is the stator slot, 5 is the notch, 6 is the large tooth, 7 is the single large tooth core, 8 is the small tooth, and 9 is the The overall large-tooth iron core, 10 is the small-tooth silicon steel sheet, 11 is the wedge groove, 12 is the positioning blind hole, 13 is the tail of the small-tooth silicon steel sheet, 201 is the rotating shaft, 202 is the rotor, 203 is the stator, 204 is the physical gas Gap, 205 is the stator support.

Detailed ways

A preferred embodiment of the utility model is shown in Fig. 1 to Fig. 7 . As can be seen from Fig. 2, the general structure of this three-phase brushless permanent magnet DC motor, its main components include a rotating shaft 201, a rotor 202, a stator 203, etc., and the physical air gap 204 between the rotor 202 and the stator 203 is 0.2- 3mm. Wherein, the Hall position sensor is used as the rotor position sensor. The magnetic sensitive direction of the Hall position sensor is consistent with the normal direction of the rotor. ~3mm air gap.

It can be seen from Figure 1 that 2 pairs of 4 permanent magnets are installed on the rotor core 1, and the 4 magnetic poles N and S are arranged alternately, that is to say, the number of magnetic poles of the rotor is 2P=4, and these permanent magnets generate an air gap magnetic field . During specific implementation, the permanent magnet 2 may be a radially magnetized tile-shaped magnet, or a parallel magnetized tile-shaped magnet. The pole pitch of the permanent magnet on the rotor core is (1-0.8)×πD/4, where D is the outer diameter of the rotor.

At the same time, the number of slots of the stator core Z=6, corresponding to 6 slots and 6 teeth; the width of the notch 5 of the stator slot 4 is 0.1-3mm; the 6 teeth include three large teeth and three small teeth , and are arranged cyclically in the order of large teeth → small teeth → large teeth → small teeth within the circumference.

In this embodiment, the three-phase windings are concentrated windings, which are directly wound on the large teeth after insulation treatment with a winding machine (stator winding inner winding machine), and the order of arrangement of the windings and teeth is: A phase winding on the large teeth Small tooth → B-phase winding on the large tooth → small tooth → C-phase winding on the large tooth → small tooth; where A represents a concentrated winding of the A-phase winding, B represents a concentrated winding of the B-phase winding, and C represents the C-phase winding A concentrated winding. It can be seen that the motor has only three concentrated windings, and the total number of windings of the motor is very small, which greatly simplifies the structure of the motor and reduces the cost. At the same time, the end of the winding is reduced to more than three times smaller than that of the traditional motor, which is minimized, so the copper consumption is greatly reduced. .

It can be seen from Figure 3 that each large tooth occupies a mechanical angle of 75° to 117° on the circumference, that is, an electrical angle of 150° to 234°; each small tooth occupies a mechanical angle of 45° to 3° on the circumference, that is, 90° to 6° Electrical angle; and the sum of the mechanical angles of a large tooth and a small tooth is equal to 120°, and the electrical angle is P×120°=240°. The circular mechanical angle occupied by each tooth includes the slot width.

As shown in Figures 4 to 7, the stator core includes a large-tooth iron core 9 and three small-tooth iron cores 8 with an integral structure; three large teeth 6 are arranged on the large-tooth iron core, and two adjacent The yoke 3 between the large teeth is respectively provided with a wedging groove 11, and there are three wedging grooves in total; each small-tooth iron core 8 is wedged into one of the wedging grooves 11 of the large-tooth iron 9 through its tail.

During specific implementation, the large-tooth iron core 9 is composed of multiple layers of large-tooth silicon steel sheets. The yoke and teeth of each layer of large-tooth silicon steel sheets are provided with positioning blind holes 12, and the multi-layer large-tooth silicon steel sheets are riveted through these blind holes. into an overall structure. Similarly, each small-tooth iron core 8 is composed of multiple layers of small-tooth silicon steel sheets; each layer of small-tooth silicon steel sheets 10 is also provided with positioning blind holes 12, and the multi-layer small-tooth silicon steel sheets are riveted into an overall structure through these blind holes. . In this embodiment, the large-tooth iron core 9 and each small-tooth iron core 8 have the same number of layers of silicon steel sheets.

It can be seen from Fig. 4 and Fig. 7 that the wedge-in groove 11 is a dovetail-shaped structure with a large inside and a small mouth; correspondingly, the tail 13 of each small tooth silicon steel sheet 10 is also a dovetail-shaped structure, and the final composition The afterbody of the small-toothed iron core can just in time be engaged with wedging into groove 11.

During specific assembly, after the large-tooth iron core is made, first insulate the large teeth, and then use a winding machine to wind A, B, and C three-phase windings on the three large teeth, and then wind the three small teeth. The tooth cores 8 are respectively inserted into the three wedging slots 11 of the large tooth core 9, namely forming a stator core with a three-phase winding.

In order to make the winding of the three-phase winding more convenient, in the embodiment shown in FIG. The benchmark is divided into three parts to become three single large-tooth iron cores 7, and the three single large-tooth iron cores are respectively insulated, and then wound on the three single large-tooth iron cores with a winding machine. Make A, B, and C three-phase windings, and then connect three large-tooth iron cores and three small-tooth iron cores, according to A-phase single large-tooth iron core → small-tooth iron core → B-phase single large-tooth iron core → Small-tooth iron core→C-phase single large-tooth iron core→small-tooth iron core constitutes a stator core with three-phase winding.

Among them, the structure of the three single large-tooth iron cores is exactly the same, which is convenient for processing and production, and then the three single large-tooth iron cores can be optionally buckled into a complete large-tooth iron core by setting bosses and concave holes. For example, the buckle structure shown in FIG. 6 in the aforementioned patent publication number CN101371425A is adopted.

As can be seen from the foregoing embodiments, the number of magnetic poles of the large-pole square-wave three-phase brushless permanent magnet DC motor of the present invention is 2P=4, wherein the magnetic pole covering technology is adopted to make the air-gap magnetic field have an electric angle of more than 120°. Flat top area; using non-uniform cogging and magnetic balance small teeth to minimize the positioning moment. The electric motor has only one concentrated winding for each phase, has simple structure and low production cost.

The most important thing is that because the small-toothed iron core is wedged in, the small teeth can be removed before winding, leaving a space to make the winding of concentrated winding very convenient, even if the machine automatically winds, it can guarantee more than 85% slot full rate.

The output of this motor is 33% larger than that of the traditional sine wave permanent magnet servo motor, and the winding end is more than 3 times smaller than that of the traditional 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. Specifically, the control system and method disclosed in the utility model patent with the international application number PCT/CN2007/000178 and the name "Brushless DC motor control system and its control method" can be used for drive control.

Claims (8)

1. a large pole type square wave three-phase brushless permanent magnet DC motor, many pairs of permanent magnets (2) are housed on the rotor iron core (1) of the motor, and three-phase windings are housed in the stator slot (4), which characterized in that, The number of magnetic poles on the rotor core 2P=4; The number of slots of the stator core is Z=6, correspondingly there are 6 teeth, and the 6 teeth include three large teeth (6) and three small teeth (8); The three-phase windings are concentrated windings, which are respectively wound on three large teeth, and each phase has only one winding; The arrangement order of the windings and teeth is: A-phase winding on the large tooth → small tooth → B-phase winding on the large tooth → small tooth → C-phase winding on the large tooth → small tooth; where A represents a concentrated winding of the A-phase winding , B represents a concentrated winding of the B-phase winding, and C represents a concentrated winding of the C-phase winding. 2. the large pole type square wave three-phase brushless permanent magnet direct current motor according to claim 1, is characterized in that, The stator core includes a large tooth core (9) and three small tooth cores (8); Three large teeth are provided on the large-tooth iron core, and a wedging groove (11) is respectively provided on the yoke between two adjacent large teeth, and there are three wedging grooves in total; Each of the small-tooth iron cores is wedged into one of the wedging grooves of the large-tooth iron core through its tail. 3. the large pole type square wave three-phase brushless permanent magnet direct current motor according to claim 2, is characterized in that, The large-tooth iron core is an integrated integral large-tooth iron core; Alternatively, the large-tooth iron core is composed of three single-piece large-tooth iron cores, and two adjacent single-piece large-tooth iron cores are spliced together at the centerline of the stator slots of the two large teeth. 4. The large-pole square-wave three-phase brushless permanent magnet DC motor according to claim 3, characterized in that, the integral large-tooth iron core or single large-tooth iron core is composed of multi-layer large-tooth silicon steel sheets, The multi-layer large-tooth silicon steel sheets are riveted into an integral structure through positioning blind holes (12) arranged on the yoke and tooth portions of each layer of large-tooth silicon steel sheets; The small-toothed silicon steel sheet is riveted into an integral structure through positioning blind holes arranged on each layer of the small-toothed silicon steel sheet. 5. The large-pole square-wave three-phase brushless permanent magnet DC motor according to claim 4, wherein the large-tooth iron core has the same number of layers of silicon steel sheets as each small-tooth iron core; The entry groove is a dovetail structure. 6. The large-pole square-wave three-phase brushless permanent magnet DC motor according to any one of claims 2-5, characterized in that the slot between the adjacent large teeth and small teeth on the stator core The width of the notch (5) is 0.1-3.0mm; each large tooth occupies a mechanical angle of 75°-117° of the circumference, that is, an electrical angle of 150°-234°; each small tooth occupies a mechanical angle of 45°-3° of the circumference, That is, the electrical angle is 90° to 6°; and the sum of the mechanical angles of a large tooth and a small tooth is equal to 120°, and the electrical angle is P×120°=240°. 7. According to the described large-pole type square wave three-phase brushless permanent magnet direct current motor of claim 6, it is characterized in that, each permanent magnet N on the described rotor core, S magnetic poles are arranged alternately, and described permanent magnet is radially charged Magnetic tile-shaped magnets, or parallel-magnetized tile-shaped magnets; The physical air gap between the stator and the rotor is 0.2-3mm; The pole pitch of the permanent magnets on the rotor core is (1˜0.8)×πD/4, where D is the outer diameter of the rotor. 8. The large-pole square-wave three-phase brushless permanent magnet DC motor according to claim 7, wherein a Hall position sensor is used as the rotor position sensor, and the magnetic sensitivity direction of the Hall position sensor is in line with the rotor position. The normal direction is consistent, installed on the stator bracket, and maintains an air gap of 1 to 3 mm between the outer circle of the permanent magnet of the rotor.

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