WO2012119317A1

WO2012119317A1 - Ferrite three-section three-phase permanent magnet motor

Info

Publication number: WO2012119317A1
Application number: PCT/CN2011/071690
Authority: WO
Inventors: 杜坤梅; 曹立明
Original assignee: 浙江博望科技发展有限公司
Priority date: 2011-03-10
Filing date: 2011-03-10
Publication date: 2012-09-13
Also published as: CN103222154B; CN103222154A

Abstract

A ferrite three-section three-phase permanent magnet motor is provided, in which a stator iron core has a three-section structure made of soft magnetic ferrite, and each of the three phase windings A,B,C occupies one section; the slot number of the stator iron core is Z, the number of magnetic poles of the rotor is 2P, Z=2P=2X, in which X=5,6,7,...20; a plurality of slots used for embedding winding are formed in front and back, on the left and right of each tooth; each phase has 2X concentrated windings which are circularly arranged in accordance with the order of A->/A; the phase B and phase C have the same structure and the space phases of the three phase A, B, C stator iron cores differ from each other at 120º electric angle. The motor has advantages of small winding end, small positioning torque, less copper loss and iron loss et al.

Description

Ferrite three-stage three-phase permanent magnet motor

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a permanent magnet motor, and more particularly to a ferrite three-stage three-phase permanent magnet motor suitable for use in refrigerators, air conditioners, and high speed drive applications.

Background technique

The stator core of a permanent magnet motor generally uses a silicon steel sheet, and the rotor generally uses a rare earth permanent magnet, such as a neodymium iron boron permanent magnet. Silicon steel sheets and rare earth permanent magnet materials are becoming scarcer and increasingly expensive. In order to change this situation, people have made a lot of efforts.

One of the improvements is to use a motor without a stator core, which will inevitably increase the amount of permanent magnets.

Another improvement is to use hard ferrite magnet steel, which can avoid the use of rare earth permanent magnet materials, but it will inevitably lead to the magnetic load of the motor becoming lower, and can only be remedied by correspondingly increasing the electric load. Therefore, it is necessary to increase the amount of copper used. The loss of copper is increased, and more importantly, the force index of the motor will be greatly reduced.

Summary of the invention

In view of the above defects of the existing permanent magnet motor, the present invention solves the problems of large copper consumption and high cost of the conventional permanent magnet motor.

The technical proposal of the present invention is to provide a ferrite three-stage three-phase permanent magnet motor, wherein the rotor core of the motor is provided with a plurality of pairs of permanent magnets, and the stator core is provided with three-phase windings, wherein the stator core is A three-stage structure made of soft ferrite, the three-phase windings of A, B and C each occupy one segment; the permanent magnet in the rotor core is made of hard ferrite, and the number of magnetic poles is 2P=2X, wherein X =5,6,7,...20; for the first stage stator core where the A-phase winding is located, the number of slots is Z=2X; the outer end width M11 of each tooth, the inner end width M21, the tooth center The relationship of the width M31 is M11>M21>M31; and the relationship between the outer circular end axial length M12, the inner circular end axial length M22, and the axial center axial length M32 of each tooth is M12>M32, M22>M32; Grooves for inserting windings are formed on the front and rear of the teeth, and the left and right sides have 2X concentrated windings, which are wound around 2X teeth, and are arranged in an A→/A manner, where “/A "representing a concentrated winding of an inverting connection of phase A; the second and third stages of stator core and winding structure where the B and C phase windings are located and phase A the same.

In the present invention, the physical air gap between the stator core and the rotor core may be 0.2 to 3.0 mm; the width of the notch between the adjacent two teeth is 0.1 to 3.0 mm.

In each of the stator cores of the present invention, the soft ferrite has a volume resistance of 100 Ω to 50 K Ω and is selected from the group consisting of a manganese core soft ferrite, a nickel core soft ferrite, a microcrystalline silicon soft ferrite, or an SMC soft. One of the magnetic composite materials.

In a preferred embodiment of the present invention, each of the stator cores is formed by splicing 2X teeth, wherein the remaining surfaces except the splicing surface are covered by an insulating layer having a thickness of 0.02 ～ 0.5mm. In another preferred embodiment of the invention, the stator core is a unitary structure that is prefabricated. Each of the stator cores may be further divided into a plurality of segments in the axial direction, including a front portion forming a front groove at a front portion of the tooth, a rear portion forming a rear groove at a rear portion of the tooth, and a front portion at the front portion At least one intermediate segment between the rear segment

In the present invention, three micro-grooves may be uniformly disposed on the inner circular arc of the inner circular end of each of the teeth, and the micro-groove has a groove width of 1 to 2 mm and a groove depth of 0.3 to 2 mm.

In a preferred embodiment of the present invention, the N and S magnetic poles of each permanent magnet on the rotor core are arranged in phase; each of the permanent magnets is a radially magnetized tile-shaped hard ferrite magnet, or a parallel charge. Magnetic tile-shaped hard ferrite magnet steel.

In another preferred embodiment of the present invention, the permanent magnet is a radially magnetized hard ferrite magnet block and is embedded on a surface of the rotor core; each of the magnet blocks has a pole pitch of πD/ 2X, the axial physical dimension L is 30 to 200 mm, where D is the outer diameter of the rotor, the outer chord length of the magnetic block is πD/2X, and the inner diameter of the magnetic block is -πD/2Xn, where n = 1 to 3.

In the present invention, the outer circumference of the rotor core may be covered with a carbon fiber, glass fiber or aluminum protective cover having a thickness of 0.15 to 2 mm.

Due to the above technical solution, the three-phase permanent magnet motor of the present invention has a series of advantages such as minimizing winding end, minimizing air gap, minimizing material, minimizing positioning torque, and minimizing iron loss and copper loss, etc. High operating speeds, higher power/volume ratios and torque/volume ratios minimize costs. This three-phase permanent magnet motor can replace the existing induction motor, permanent magnet motor, or replace the air conditioner and refrigerator compressor drive motor, becoming the mainstream drive motor for high performance, energy saving air conditioner and refrigerator compressor in the future.

DRAWINGS

1 is a schematic view showing the structure of a motor assembly in a preferred embodiment of the present invention;

2 is a schematic view showing the structure of a stator and a rotor of a motor A in a preferred embodiment of the present invention;

Figure 3 is a front elevational view of the single tooth shown in Figure 2;

Figure 4 is a left side view of the single tooth shown in Figure 3;

Figure 5 is a schematic view showing the structure of a tile-shaped hard ferrite magnetron rotor in a preferred embodiment of the present invention;

Figure 6 is a schematic view showing the structure of a rotor composed of a radially magnetized hard ferrite magnet block in a preferred embodiment of the present invention;

Figure 7 is a schematic view showing a micro-groove provided on an inner circular arc of a tooth in another preferred embodiment of the present invention;

Figure 8 is a schematic illustration of further dividing each segment of the stator core into three segments in the axial direction in a preferred embodiment of the invention.

detailed description

FIG. 1 shows a preferred embodiment of the present invention. The main components of the ferrite three-phase three-phase permanent magnet motor include a rotor 1, a stator 2, a rotating shaft 30, and the like, and a physical gas between the rotor 1 and the stator 2. The gap 5 is 0.1 to 2 mm. The stator core is a three-stage structure made of soft ferrite, and the three-phase windings of A, B and C each occupy the first, second and third sections;

In the following embodiments, X=6 is taken, so there is Z=2P=2X=12; in the specific implementation, any value of X=5, 6, 7, 20 can also be taken. As shown in FIG. 2, in the following description, the phase A is taken as an example. The first stage stator core is formed by the teeth 40 of twelve independent soft ferrites, so the number of slots of the stator Z= 12.

As shown in FIGS. 3 and 4, the relationship between the width M11 of the outer circular end 50 of each of the teeth 40, the width M21 of the inner circular end 60, and the width M31 of the tooth core 70 is M11>M21>M31; and each tooth The axial length M12 of the outer end 50, the axial length M22 of the inner circular end 60, and the axial length M32 of the tooth center 70 are M12>M32, M22>M32; thus, both in the axial direction and the radial direction of the tooth. Forming front and rear grooves for placing the windings, left and right grooves; the advantage of this structure is that the windings are all mounted in the grooves, ideally the windings do not protrude from the left and right end faces in Figure 3, ie the thickness of the windings is limited In the left and right grooves of the teeth; at the same time, the windings do not protrude from the left and right end faces in Fig. 4, that is, the length of the windings is limited to the front and rear grooves of the teeth.

Among them, there are twelve concentrated windings in phase A, which are wound around twelve teeth, and the winding connection mode of phase A winding is A→/A→A→/A→A→/A→A→/A→A →/A→A→/A. The "/A" therein represents a concentrated winding of an inverting connection of phase A.

The second and third stages of the stator core and the winding structure of the B and C phase windings are the same as the A phase, and the spatial phases of the three-phase stator cores of the A, B, and C are 120° electrical angles. The winding connection mode of the B-phase winding is B→/B→B→/B→B→/B→B→/B→B→/B→B→/B; the winding connection mode of the C-phase winding is C→ /C→C→/C→C→/C→C→/C→C→/C→C→/C.

Due to the front and rear grooves and the left and right groove structures on each tooth, the outer edge of the concentrated winding is limited to the inside of the stator core. Compared with the conventional motor, this motor saves a large number of winding wires, using copper and iron. Significantly reduced, resulting in a higher power/volume ratio, higher torque/volume ratio, and the cost is minimized.

For a 12-pole motor with a rotor axial length to diameter ratio of 1/2, the axial length of the motor is L=D/2, and the number of turns per motor is N, the total length of each phase winding of the motor is 12N (D+лD/12). The conventional motor has a total length of 12N (D + 2 лD / 12) per phase winding; therefore, the winding wire in this embodiment is shortened by 1.207 times. Among them, the rotor uses hard ferrite, avoiding the use of rare earth permanent magnet materials, although the magnetic load of the motor is reduced by 2 times, it is necessary to increase the electric load by 2 times to remedy the motor performance, but the total length of the winding is shortened by 1.207 times, the motor The copper loss will be reduced by 1.458 times; and because the stator of the motor uses soft ferrite, the iron loss of the motor will be reduced by 3 to 10 times. Therefore, the integrated loss of this motor and the traditional concentrated winding three-phase permanent magnet motor Quite, even smaller; and because the magnetic load of the motor is reduced by 2 times, the positioning torque and torque fluctuation of the motor is 20~30% smaller than that of the traditional concentrated winding motor, and the noise is smaller than that of the traditional concentrated winding motor; Small, it is more advantageous to reduce the internal resistance of the motor.

Since the stator core is made of soft ferrite and operates at frequencies up to 10 kHz, it allows the motor to rotate at tens of thousands of revolutions per minute, which makes sense for high speed applications. The motor can be driven with a three-phase square wave or sinusoidal current.

In the specific implementation, for the twelve teeth of each segment of the stator core, the remaining surfaces except the splicing surface are covered by the insulating layer, and the thickness of the insulating layer may be 0.02-0.5 mm, after splicing into two, adjacent two The width of the notch 3 between the teeth is 0.1 to 3.0 mm. Among them, the volume resistance of the soft ferrite can be 100 Ω to 50 K Ω, so the core loss of the soft ferrite stator is 3 to 10 times or more smaller than that of the silicon steel sheet stator core. The soft ferrite here may be made of one of a manganese core soft ferrite, a nickel core soft ferrite, a microcrystalline silicon soft ferrite, or an SMC soft magnetic composite material, and the saturation magnetic density thereof is inevitably not Will be lower than the residual magnetic flux of the permanent ferrite, they are naturally matched.

For the stator core shown in FIG. 2, a single independent tooth can be formed by a certain process in a sintering process, a bonding process, an injection process, or a mixing process, and the forward or reverse can be wound for each tooth. The windings in series are then spliced into a unitary stator core assembly. In the embodiment shown in Fig. 7, three inner grooves are uniformly disposed on the inner circular arc of each of the teeth, and the groove width is 1 to 2 mm, and the groove depth is 0.3 to 2 mm.

Of course, it is also possible to manufacture a length of stator core (in which case there are no separate teeth) by means of integral prefabrication, and then directly use a shuttle or hand-wound three-phase winding on the integral stator core.

In the embodiment shown in FIG. 5, the N and S magnetic poles of the respective permanent magnets on the rotor core are arranged, and the permanent magnets here are radially magnetized tile-shaped hard ferrite magnets or parallel magnetized. Tile-shaped hard ferrite magnet steel. It can be seen from the figure that the outer circumference of the ferrite magnet has a chamfer angle of not more than 15° and a length not larger than 1/4 of the outer arc of the ferrite magnet, as shown in Fig. 5. The motor's rotor has the same direct-axis reluctance and cross-axis reluctance, and belongs to a hidden pole motor. The running noise of this motor is smaller than that of a salient pole motor.

In the embodiment shown in FIG. 6, the permanent magnet is a radially magnetized hard ferrite magnet block having a pole pitch of πD/12 and an axial physical dimension L of 30 to 200 mm, wherein D is outside the rotor. The outer diameter of the magnetic block is πD/12, and the inner diameter of the magnetic block is -πD/12n, n=1~3. Shown in Figure 6 is a rotor consisting of a radially magnetized hard ferrite magnet block of n = 1.25. In the permanent magnet shown in Fig. 6, the direct magnetoresistance of the rotor is larger than the cross-axis reluctance and has a salient pole effect. The motor can obtain salient pole torque during operation, and the output is larger than that of the hidden pole motor.

As shown in FIG. 2, in the embodiment, a protective sleeve having a thickness of 0.15-2 mm is sleeved on the outer circumference of the rotor, and the protective sleeve can be made of carbon fiber, glass filament or aluminum, and can be prevented from rotating on the rotor when the motor rotates at a high speed. The permanent magnet centrifugal force is too large to fall off.

As shown in FIG. 8, in another embodiment of the present invention, each segment of the stator core is further divided into three sections in the axial direction, including a front section (left side section in FIG. 8) forming a front groove at a front portion of the tooth, The rear portion of the tooth forms a rear section of the rear groove (the right side section in Fig. 8), and an intermediate section (the middle section in Fig. 8) between the front and rear sections. In the specific implementation, the number of intermediate segments may be one or more; when the lengths of the current segment and the rear segment are fixed, the axis of the entire stator core can be adjusted by increasing the number of intermediate segments or adjusting the length of the intermediate segment. To the length. The axial segmented structure can be applied to the case where a plurality of teeth shown in FIG. 2 are spliced into a stator core, that is, each tooth in each segment of the stator core is divided into a plurality of segments, and the figure is shown in FIG. 4 The corresponding left-side structure of a single tooth, its main view structure is shown in Figure 3; of course, this axial segmented structure can also be applied to the overall prefabricated stator core, in this case, the overall pre-fabrication of multiple segments.

The ferrite three-stage three-phase permanent magnet motor in the above embodiment is generally used as an electric motor and is driven by a three-phase square wave or sine wave current; it is suitable for refrigerators, air conditioners, and high-speed driving applications; when it is driven by a rotating machine, It can also be a three-phase permanent magnet generator.

Claims

A ferrite three-stage three-phase permanent magnet motor, wherein a rotor core (1) of the motor is provided with a plurality of pairs of permanent magnets (4), and a stator core (2) is provided with a three-phase winding, which is characterized in that The stator core is a three-stage structure made of soft ferrite, and the three-phase windings of A, B and C each occupy one segment; the permanent magnet in the rotor core is made of hard ferrite, and the number of magnetic poles is 2P. = 2X, where X = 5, 6, 7, ... 20; for the first stage stator core where the A phase winding is located, the number of slots is Z = 2X; the outer end of each tooth has a width M11, an inner end The relationship between the width M21 and the tooth center width M31 is M11>M21>M31; and the relationship between the outer circumferential end axial length M12, the inner circular end axial length M22, and the axial center axial length M32 of each tooth is M12>M32, M22>M32; thus forming grooves for inserting windings in front and rear, left and right sides of the teeth; A phase has 2X concentrated windings, respectively wound around 2X teeth, and arranged in a cycle of A→/A, Wherein "/A" denotes a concentrated winding of an inverting connection of the A phase; the second and third stator cores and winding structures of the B and C phase windings are identical to the A phase And A, B, C three spatial phase difference between each of the stator core 120 ° electrical angle.
The ferrite three-stage three-phase permanent magnet motor according to claim 1, wherein a physical air gap between the stator core and the rotor core is 0.2 to 3.0 mm; The width of the notch (3) is 0.1 to 3.0 mm; the outer circumference of the rotor core is covered with a carbon fiber, glass fiber or aluminum protective cover having a thickness of 0.15 to 2 mm.
The ferrite three-phase three-phase permanent magnet motor according to claim 1, wherein the soft ferrite has a volume resistance of 100 Ω to 50 K Ω and is selected from the group consisting of a manganese core soft ferrite and a nickel core soft. One of a ferrite, a microcrystalline silicon soft ferrite, or an SMC soft magnetic composite.
The ferrite three-section three-phase permanent magnet motor according to claim 1, wherein each of said stator cores is formed by splicing 2X teeth, wherein all surfaces except the splicing surface are The insulating layer is covered with a thickness of 0.02 to 0.5 mm.
The ferrite three-stage three-phase permanent magnet motor according to claim 1, wherein each of said stator cores is a unitary structure which is prefabricated as a whole, and the surface thereof is covered with an insulating layer. The thickness of the insulating layer is 0.02 to 0.5 mm.
The ferrite three-phase three-phase permanent magnet motor according to any one of claims 1 to 5, wherein N and S magnetic poles of respective permanent magnets on the rotor core are arranged in phase; each of said The magnet is a radially magnetized tile-shaped hard ferrite magnet, or a parallel magnetized tile-shaped hard ferrite magnet.
The ferrite three-stage three-phase permanent magnet motor according to claim 6, wherein the ferrite magnet has a diameter of not more than 15° on both sides of the outer circumference and a length not larger than the ferrite magnet The outer arc is 1/4 of the chamfer.
The ferrite three-phase three-phase permanent magnet motor according to any one of claims 1 to 5, wherein the permanent magnet is a radially magnetized hard ferrite magnet block and is embedded in The surface of the rotor core; the pole pitch of each of the magnet blocks is πD/2X, and the axial physical dimension L is 30-200 mm, wherein D is the outer diameter of the rotor, and the outer chord length of the magnet block is πD/2X, The inner diameter of the magnetic block is -πD/2Xn, where n = 1 to 3.
The ferrite three-stage three-phase permanent magnet motor according to any one of claims 1 to 5, wherein three micro-grooves are evenly disposed on an inner circular arc of the inner end of each of the teeth. The microgroove has a groove width of 1 to 2 mm and a groove depth of 0.3 to 2 mm.
A ferrite three-section three-phase permanent magnet motor according to any one of claims 1 to 5, wherein each of said stator cores is further divided into a plurality of sections in the axial direction, including in front of said teeth The portion forms a front section of the front groove, a rear section of the rear groove at the rear of the tooth, and at least one intermediate section between the front and rear sections.