CN103222166B - A kind of three-phase permanent-magnetic servo - Google Patents

Abstract

A kind of three-phase permanent-magnetic servo, its rotor (1) number of magnetic poles 2P is 16, stator (2) tooth number Z is 24, this tooth comprises 12 canine tooths (8), six little teeth (9) and six micro-teeth (10), 12 concentratred winding are contained on 12 canine tooths respectively, and winding circulates arrangement in the following order: the canine tooth of the canine tooth-micro-tooth-dress winding of little tooth-dress winding.The mechanical angle of each canine tooth, little tooth and micro-tooth is 22.5 ° ± 2.5 °, 10 ° ± 2.5 °, 5 ° ± 2.5 ° respectively.This motor can reduce teeth groove square.

Description

A three-phase permanent magnet servo motor

technical field

This invention relates to permanent magnet motors, and more particularly, to a three-phase permanent magnet servo motor suitable for direct drive and position and velocity servo control applications.

Background technique

The permanent magnet DC motor involved in the present invention mainly refers to a servo motor capable of effectively generating low torque ripple. Among them, torque fluctuation mainly includes: lower cogging torque component (detent torque), lower current and potential harmonic torque component. At present, the main goals of this type of servo motor design are: small torque fluctuation, large output power (large product of speed and torque), large overload capacity, small size, low price and so on.

The main reasons for torque fluctuation include: (1) The torque fluctuation presented by the product of the stator current harmonic and the back EMF harmonic; (2) When the stator current is zero, the rotor rotates, and the positioning torque fluctuation presented by the magnetic permeability change due to the cogging effect .

The main methods for suppressing torque fluctuations include: (1) traditional fractional slot winding design; (2) concentrated winding design that optimizes cogging and magnetic pole coordination, such as the Chinese invention named "High Efficiency Permanent Magnet Brushless Motor", publication number CN1856921A patent application. Among them, the motor manufacturing process of the traditional fractional slot winding design is complicated and the production cost is high. The concentrated winding design with optimized cogging and magnetic pole matching has the characteristics of high cost performance, but it is only suitable for low-speed servo motors with more than 20 magnetic poles.

In the Chinese invention patent application whose publication number is CN101371425A, a square wave three-phase brushless permanent magnet DC motor with a magnetic pole number 2P=16, a tooth slot number Z=24, and a structure of large, medium and small teeth is disclosed. The motor has excellent performance and high cost performance, but there are still deficiencies. Because the size of the two teeth with windings is different, it brings a lot of inconvenience to the manufacture. For example, the processing molds, tooling and processes of the teeth cannot be consistent, and the processing molds, tooling and processes of the windings cannot be consistent; what is more serious is : Due to the different spatial dimensions of the slots, the number of turns and wire diameters of the two windings of each phase will inevitably be inconsistent, which will adversely affect the performance of the motor, such as causing the torque generated by the current of the two windings to be asymmetrical in space. In addition, the structure of the large, medium and small teeth of the motor does not have a strong inhibitory effect on the positioning torque. The electrical angles of the two teeth of each phase of the motor are: 200°±20° and 160°±20°, and its opposite potential waveform has a flat top area above 120°, which can realize a square wave permanent magnet servo motor. However, in order to obtain the highest winding utilization and the widest flat-top area, the ideal electrical angle should be 180°, and the motor deviates from the ideal electrical angle by ±20°, which will inevitably cause its winding utilization to decrease to sin(140°/180°× 90°)=0.940, and the opposite potential plateau of the motor is therefore not optimal.

Contents of the invention

The invention aims to solve the problems existing in the existing sine wave permanent magnet servo motor and square wave permanent magnet servo motor, and proposes a three-phase permanent magnet servo motor with new principle, new structure, high performance and high cost performance.

In order to solve the above-mentioned technical problems, the present invention provides a three-phase permanent magnet servo motor, the rotor iron core of the motor is equipped with a plurality of pairs of permanent magnets, and the tooth slots of the stator are equipped with three-phase windings, wherein the rotor iron core The number of magnetic poles 2P=16; the number of slots of the stator core Z=24, correspondingly there are twenty-four teeth, the slot width of the slot is 0.1-3.0mm; the twenty-four teeth include ten Two large teeth, six small teeth, and six smaller micro-tooths; the three-phase windings are twelve concentrated windings, which are respectively installed on the twelve large teeth, and the arrangement of the windings and teeth Sequence: small teeth → install large teeth of phase A winding → micro teeth → install large teeth of phase C winding → small teeth → install large teeth of phase B winding → micro teeth → install large teeth of phase A winding → small teeth → install Large teeth of phase C winding→micro teeth→large teeth of phase B winding→small teeth→large teeth of phase A winding→micro teeth→large teeth of phase C winding→small teeth→large teeth of phase B winding → micro teeth → install large teeth of phase A winding → small teeth → install large teeth of phase C winding → micro teeth → install large teeth of phase B winding; each large tooth on the stator core occupies a circumference of 22.5°± 2.5° mechanical angle, that is, 180°±20° electrical angle; each small tooth occupies a 10°±2.5° mechanical angle of the circumference, that is, 80°±20° electrical angle; each micro tooth occupies a 5°±2.5° mechanical angle of the circumference , that is, 40°±20°electrical angle; wherein the circular mechanical angle occupied by each tooth includes the width of the notch, and the mechanical angle of four large teeth, two small teeth, and two microtooths The sum equals 120°.

In the present invention, the N and S magnetic poles of the permanent magnets on the rotor core are arranged alternately, and the permanent magnets may be radially magnetized tile-shaped magnets or parallel magnetized tile-shaped magnets. The two sides of the outer circle of the tile-shaped magnet are preferably provided with chamfered corners with an angle not greater than 7.5° and a length not greater than 1/4 of the arc length of the magnet. The physical air gap between the stator and the rotor may be 0.5-4mm.

In a preferred solution of the present invention, the stator core is composed of thirteen parts, including a one-piece annular core composed of six small teeth and six micro-teeth which are self-riveted and laminated by multi-layer silicon steel sheets. Twelve independent large-tooth iron cores formed by self-riveting and lamination of multi-layer silicon steel sheets; the yoke of the annular iron core and the large-tooth iron core are respectively provided with grooves/bosses, and are interlocked to form a complete Stator core.

In another preferred solution of the present invention, the stator core is also composed of thirteen parts, including a one-piece annular iron core formed by self-riveting and laminating of multi-layer silicon steel sheets containing twelve large teeth. Six independent small-tooth iron cores formed by self-riveting and pressing of silicon steel sheets, and six independent micro-tooth iron cores formed by self-riveting and pressing of multi-layer silicon steel sheets; the yoke and small The tooth and micro-tooth iron cores are respectively provided with grooves/bosses, and are engaged with each other to form a complete stator iron core.

In another preferred solution of the present invention, the stator core is composed of twenty-four parts, including twelve independent large teeth, six independent small teeth, and six Each tooth has grooves/bosses on both sides of the yoke, and the yokes of adjacent teeth engage with each other to form a complete stator core.

It can be seen from the above technical scheme that the number of magnetic poles of the three-phase permanent magnet servo motor of the present invention is 2P=16, and the large teeth with windings occupy an electrical angle of 180°, so that the opposite potential waveform has a flat top area of nearly 135° electrical angle , and the large tooth width is not easily affected by the armature reaction, so that the motor has a stronger overload capacity; two kinds of non-uniform small teeth are specially used to suppress the positioning torque, so that the positioning torque is reduced to one ten thousandth level. Each phase of the electric motor has only two concentrated windings, and the structures and turns of the two concentrated windings are exactly the same, the manufacture is simple, the process is consistent, and the production cost is very low. The output of the motor is 30% 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 three-phase permanent magnet servo motor is driven by a three-phase square wave current, it can generate stable torque, and its torque fluctuation index is equivalent to that of a sine wave permanent magnet servo motor. The three-phase permanent magnet servo motor has a series of advantages such as small winding end, less copper consumption, small loss, small air gap, high magnetic load, small positioning torque and strong overload capacity.

Description of drawings

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

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 diagram of a stator punch formed by inlaying large teeth;

Fig. 5 is a schematic structural view of a stator punch formed by inlaying small teeth and micro teeth;

Fig. 6 is a schematic diagram of the structure of twenty-four teeth that are independent and interlocking;

Fig. 7 is a schematic diagram of the rotor structure of the sine wave magnetic field motor.

detailed description

A preferred embodiment of the present invention is shown in FIG. 1 and FIG. 2 . The general structure of this three-phase permanent magnet servo motor can be seen from Fig. 2. Its main components include rotor 1, stator 2, rotating shaft 30, etc. The physical air gap 5 between rotor 1 and stator 2 is 0.5-4 mm. The rotor position sensor 6 can be any one of a photoelectric encoder, a resolver, and a magnetic encoder.

It can be seen from FIG. 1 that eight pairs of permanent magnets 4 are installed on the rotor core, and these permanent magnets N and S are arranged in phases, and the number of magnetic poles of the rotor is 2P=16. During specific implementation, the permanent magnet 4 may be a radially magnetized tile-shaped magnet, or a parallel magnetized tile-shaped magnet. The physical dimension of the pole pitch πD/8 of the permanent magnet on the rotor core is 50-200 mm, where D is the outer diameter of the rotor. This structure can obtain the opposite potential waveform tending to 135° square wave, and cooperate with the square wave stator current to realize the operation of the square wave permanent magnet servo motor with small torque fluctuation. Since the phases of the 3rd and 6th harmonics in the two opposite potential square waves are the same, the subtraction is zero, so the line back EMF waveform of this structure still tends to be a sine wave. When the sine wave current is used to drive the three-phase sine wave stator current and The product of the 3rd and 6th harmonics in the three-phase opposite potential square wave does not present torque fluctuation, and the output power of the motor is improved by about 30%.

It can be seen from Fig. 1 that the number of stator slots Z=24, that is, there are twenty-four teeth and twelve slots correspondingly; the width of the notch 3 of the stator slot is 0.1-3mm; among the twenty-four teeth It includes twelve large teeth 8 equipped with windings, six small teeth 9 without windings, and six micro teeth 10 without windings, and the order of small teeth → large teeth → micro teeth → large teeth → small teeth in the circumference Teeth → large teeth → micro teeth → large teeth → small teeth → large teeth → micro teeth → large teeth are arranged in this order, that is, twelve slots are formed. Among them, only twelve large teeth 8 are installed with three-phase windings, and the windings on each large tooth have two winding sides and respectively occupy a slot on both sides thereof.

As shown in Figure 3, each large tooth on the stator core occupies a mechanical angle of 22.5° of the circumference, that is, an electrical angle of 180°; each small tooth occupies a mechanical angle of 10° of the circumference, that is, an electrical angle of 80°; A mechanical angle of 5° on the circumference, that is, an electrical angle of 40°; in order to obtain a three-phase symmetrical winding, the sum of the mechanical angles of four large teeth, two small teeth, and two micro teeth is 4×22.5°+2×10° +2×5°=120°. The circumferential mechanical angle occupied by each tooth includes the width of a notch 3. For example, the circumferential mechanical angle of 10° occupied by the small tooth shown in Figure 3 is the width of a small tooth plus the width of the left and right half notches. The circumferential mechanical angle of the notch (3) in the present embodiment has a width of 1.0 mm.

The motor has the most ideal large tooth width, and the electrical angle is P×22.5°=4×22.5°=180°, so the maximum winding utilization of the motor is sin(180°/180°×90°)=1.0 , the opposite potential plateau region of this embodiment is correspondingly optimal. This uneven cogging structure not only ensures the three-phase symmetry, but also suppresses the positioning moment.

In this embodiment, the twelve three-phase windings are concentrated windings, and the stator windings are directly wound on the large teeth treated with surface insulation with a winding machine or manually. The arrangement of the windings and the teeth is: → small teeth → assembly Large teeth of phase A winding→micro teeth→large teeth of phase C winding→small teeth→large teeth of phase B winding→micro teeth→large teeth of phase A winding→small teeth→large teeth of phase C winding →Small teeth→Large teeth of B-phase winding→Small teeth→Large teeth of A-phase winding→Micro teeth→Large teeth of C-phase winding→Small teeth→Large teeth of B-phase winding→Micro teeth→A Large teeth of the phase winding → small teeth → large teeth of the C-phase winding → small teeth → large teeth of the B-phase winding; details are shown in Figure 1.

After winding in this way, the two concentrated windings of each phase are connected in series, which reduces 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 twelve 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. At the same time, the end of the winding is reduced to that of the traditional motor. 1/3 to 1/6 or even more, reaching the minimum, so the copper consumption is greatly reduced.

As shown in Figure 4, in one embodiment of the present invention, the stator core is composed of thirteen parts interlocking and splicing, including six small teeth 9 and six micro-teeth 10, which are self-riveted and laminated by multi-layer silicon steel sheets. The one-piece annular iron core 11 formed is twelve independent large-tooth iron cores 8 formed by self-riveting and lamination of multi-layer silicon steel sheets; the yoke of the annular iron core 11 and the large-tooth iron core 8 are respectively equipped with grooves/bosses, and engage with each other to form a complete stator core.

For this structure, four series A-phase windings can be wound on the four large-tooth iron cores of A-phase first, and four series-connected B-phase windings can be wound on the four large-tooth iron cores of B phase. Four C-phase windings in series are wound on the four large-toothed iron cores of C-phase, and then twelve large-toothed iron cores equipped with A, B, and C three-phase windings are embedded on the annular iron core 11, which constitutes Stator core assembly with A, B, C three-phase windings. In this embodiment, the independent large-tooth iron core can be insulated very conveniently, and then the large-tooth iron core can be wound with an automatic or semi-automatic winding machine. Its winding manufacturing process is very good; at the same time, the use of the integral structure annular iron core 11 can fully guarantee the geometric accuracy of the stator iron core assembly.

The motor in this embodiment has an ideal tooth width design, which is 23° for large teeth, 9° for small teeth, and 5° for micro teeth, 2×(2×23°+9°+5°)=120°, which can constitute A, B, C three-phase symmetrical winding, and the positioning torque is well suppressed. The motor can be driven by three-phase square wave current or three-phase sine wave current, which can generate stable torque, and has the advantages of small winding end, less copper consumption, small loss, small air gap, small positioning torque and strong overload capacity. Series advantages.

As shown in Figure 5, in another embodiment of the present invention, contrary to the embodiment shown in Figure 4, its one-piece annular iron core 12 contains twelve large teeth, and six small teeth 9 and six micro teeth 10 is independent, and is also mutually interlocked to form a complete stator core.

During the specific assembly, the twelve large teeth are first insulated; since the small teeth and micro teeth are not installed at this time, the opening of the annular iron core 12 is very large, and an automatic winding machine can be used to wind each of the large teeth 8 on the large teeth 8. phase winding. For example, four series A phase windings are respectively wound on the four large teeth of the A phase, and then four series B phase windings are respectively wound on the four large teeth of the B phase, and then four series B windings are wound on the four large teeth of the C phase. Four C-phase windings in series are respectively wound on the large-tooth iron core, and then the six small-tooth iron cores and six micro-tooth iron cores after insulation treatment are embedded into the yoke of the annular iron core 12 to form the A, B, C three-phase winding stator core assembly.

The motor can be driven by three-phase square wave current or three-phase sine wave current, which can generate stable torque, and has the advantages of small winding end, less copper consumption, small loss, small air gap, small positioning torque and strong overload capacity. Series advantages.

As shown in Figure 6, in another embodiment of the present invention, there are twelve independent teeth, that is, twelve independent large teeth, six independent small teeth and Six independent micro-tooths; grooves/bosses are provided on both sides of the yoke of each tooth, and the yokes of adjacent teeth engage with each other to form a complete stator core. Among them, each large tooth occupies a 22.5° mechanical angle of the circumference, which is 180° electrical angle; each small tooth occupies a 10° mechanical angle of the circumference, which is 80° electrical angle; each micro tooth occupies a 5° mechanical angle of the circumference, which is 40° electrical angle.

In this embodiment, the stator winding can be wound on the independent large teeth with surface insulation treatment by automatic, semi-automatic winding machine, or manually, and then use the positioning tool to wind the six large teeth with windings, three The small teeth without windings and the three small teeth without windings mesh with each other in order to form a stator assembly. After winding in this way, the two concentrated windings of each phase are connected in series, which reduces wiring and simplifies the process.

The motor can be driven by three-phase square wave current or three-phase sine wave current, which can generate stable torque, and has the advantages of small winding end, less copper consumption, small loss, small air gap, small positioning torque and strong overload capacity. Series advantages.

As shown in Fig. 7, in another embodiment of the present invention, in order to obtain the air-gap magnetic field tending to the sine wave or the opposite potential waveform of the sine wave, tile-shaped magnets are used, and angles are provided on both sides of the outer circle of the magnets. The chamfered angle is not more than 7.5° and the length is not more than 1/4 of the outer arc length of the magnetic steel. The physical air gap between the stator and the rotor of the three-phase permanent magnet servo motor is 2.0 mm. After such a design, an air gap magnetic field tending to a sine wave or a sinusoidal opposite potential waveform can be obtained. Therefore, even if there is a non-sinusoidal current in the three-phase stator current, excessive torque fluctuations will not be generated. The motor is driven by three-phase sine wave current, which can generate stable torque, and has a series of advantages such as small winding end, less copper consumption, small loss, small air gap, small positioning torque and strong overload capacity.

The present invention is not limited to the above specific embodiments, wherein, the circumferential mechanical angle occupied by each large tooth on the stator core may be 22.5°±2.5°, that is, 180°±20° electrical angle; The angle can be 10°±2.5°, that is, 80°±20° electrical angle; the mechanical angle of each microtooth can be 5°±2.5°, that is, 40°±20° electrical angle; similarly, each The circular mechanical angle occupied by each tooth includes the width of the notch 3, and at the same time, it is necessary to ensure that the sum of the mechanical angles of every four large teeth, two small teeth, and two small teeth is equal to 120°; for example, the large tooth is 22°, Small tooth 9.5°, micro tooth 6.5°, 2×(2×22°+9.5°+6.5°)=120°, another example is large tooth 23°, small tooth 10°, micro tooth 4°, 2×(2× 23°+10°+4°)=120°, etc.

The motor of the present invention has the most ideal large-tooth tooth width, and its electrical angle is 180°±20°, so its winding utilization rate is greater than 0.985 (sin (200°/180°×90°)=0.985), the motor's The plateau region of the opposite potential is optimized accordingly.

Claims (9)

1. a three-phase permanent-magnetic servo, the rotor core (1) of described motor is equipped with multipair permanent magnet (4), in the teeth groove of stator (2), three-phase windings is housed, it is characterized in that, number of magnetic poles 2P=16 on described rotor core, the physical size of the pole span π D/8 of the permanent magnet on rotor core is 50 ~ 200mm, and wherein D is rotor diameter, the groove number Z=24 of described stator core, should have 24 teeth mutually, and notch (3) width of described groove is 0.1 ~ 3.0mm, described 24 teeth comprise the canine tooth (8) of 12, six little teeth (9) and six less micro-teeth (10), described three-phase windings is 12 concentratred winding, be loaded on described 12 canine tooths respectively, the ordering of described winding and tooth: the canine tooth of the canine tooth → micro-tooth → dress B phase winding of the canine tooth → little tooth → dress C phase winding of the canine tooth → micro-tooth → dress A phase winding of the canine tooth → little tooth → dress B phase winding of the canine tooth → micro-tooth → dress C phase winding of the canine tooth → little tooth → dress A phase winding of the canine tooth → micro-tooth → dress B phase winding of the canine tooth → little tooth → dress C phase winding of the canine tooth → micro-tooth → dress A phase winding of the canine tooth → little tooth → dress B phase winding of the canine tooth → micro-tooth → dress C phase winding of little tooth → dress A phase winding, each canine tooth on described stator core accounts for circumference 22.5 ° ± 2.5 ° mechanical angles, namely 180 ° ± 20 ° electrical degrees, each little tooth accounts for circumference 10 ° ± 2.5 ° mechanical angles, namely 80 ° ± 20 ° electrical degrees, each micro-tooth accounts for circumference 5 ° ± 2.5 ° mechanical angles, namely 40 ° ± 20 ° electrical degrees, wherein circumferential mechanical angle shared by each tooth comprises the width of a described notch (3), and wherein four canine tooths, two little teeth, the mechanical angle sum of adding two micro-teeth equal 120 °.

2. three-phase permanent-magnetic servo according to claim 1, is characterized in that, on described rotor core, N, S magnetic pole of each permanent magnet alternately, and described permanent magnet is the tile-shaped magnet steel of radial magnetizing or the tile-shaped magnet steel of parallel magnetization.

3. three-phase permanent-magnetic servo according to claim 2, is characterized in that, the cylindrical both sides of described tile-shaped magnet steel are provided with that angle is not more than 7.5 °, length is not more than the top rake of the cylindrical arc length 1/4 of magnet steel.

4. three-phase permanent-magnetic servo according to claim 3, is characterized in that, the physical air gap between described stator and rotor is 0.5 ~ 4mm.

5. the three-phase permanent-magnetic servo according to any one of claim 1-4, it is characterized in that, described stator core is made up of 13 parts, comprise containing six little teeth and six micro-teeth by the integral type annular core (11) of multilayer silicon steel sheet from riveting repeatedly pressure, by multilayer silicon steel sheet from riveting repeatedly 12 of pressure independently canine tooth iron cores (8); The yoke portion of described annular core and canine tooth iron core are respectively equipped with groove/boss, and the stator core that engaged formation is complete.

6. three-phase permanent-magnetic servo according to claim 5, it is characterized in that, the A phase winding of wherein first connecting around four on four canine tooth iron cores, around the B phase winding of four series connection on another four canine tooth iron cores, around the C phase winding of four series connection on another four canine tooth iron cores, then the canine tooth iron core described 12 being equipped with winding embeds in described annular core (11) respectively, forms the stator core assemblies that A, B, C three-phase windings is housed.

7. the three-phase permanent-magnetic servo according to any one of claim 1-4, it is characterized in that, described stator core is made up of 13 parts, comprise containing 12 canine tooths by the integral type annular core (12) of multilayer silicon steel sheet from riveting repeatedly pressure, by multilayer silicon steel sheet from riveting repeatedly six of pressure independently little tooth iron core and by multilayer silicon steel sheet from riveting repeatedly six of pressure independently micro-tooth iron cores; The yoke portion of described annular core and little tooth, micro-tooth iron core are respectively equipped with groove/boss, and the stator core that engaged formation is complete.

8. three-phase permanent-magnetic servo according to claim 7, it is characterized in that, wherein first on described annular core, insulation processing is implemented to 12 canine tooths, then coiling A, B, C three-phase windings is distinguished, again six little tooth iron cores and six micro-tooth iron cores are embedded the yoke portion of described annular core (12), form the stator core assemblies that A, B, C three-phase windings is housed.

9. according to the three-phase permanent-magnetic servo according to any one of claim 1-4, it is characterized in that, described stator core is made up of 24 parts, namely comprises 12 independent canine tooths of repeatedly being pressed from riveting by multilayer silicon steel sheet, six little teeth of independence and six micro-teeth of independence; The both sides, yoke portion of each tooth are provided with groove/boss, the stator core that the engaged formation in yoke portion of adjacent teeth is complete.