WO2011014994A1

WO2011014994A1 - Permanent magnet synchronous motor

Info

Publication number: WO2011014994A1
Application number: PCT/CN2009/073225
Authority: WO
Inventors: 禇惠南; 金亦石; 廖传德
Original assignee: Zhe Huinan; Jin Yishi; Liao Chuande
Priority date: 2009-08-05
Filing date: 2009-08-13
Publication date: 2011-02-10
Also published as: CN101626185A

Abstract

A permanent magnet synchronous motor includes a stator component and a rotor component. The stator component includes a casing (3), a stator core (1) and an armature winding (2), and the rotor component includes a rotor shaft (11), a magnetic-shield sleeve (12), magnetic poles (13), a permanent magnet (17) and insulation gaskets (20). The rotor shaft (11) is a hollow shaft radially provided with an inner vent hole (23), and the rotor shaft (11) is axially provided with an outer vent hole (22) communicated with the inner vent hole (23) of the hollow shaft. A magnetic-shield sleeve vent hole (24) is radially arranged on the magnetic-shield sleeve (12) and a magnetic pole vent hole (25) is radially arranged on the magnetic pole (13). The inner vent hole (23) is communicated with the magnetic-shield sleeve vent hole (24) and the magnetic pole vent hole (25) so as to form a radiant heat dissipation structure crossed in axial direction and radial direction. The motor controls temperature rise during operation, reduces risk of demagnetization of neodymium-iron-boron permanent magnet and eddy heat, and has a long operating life.

Description

Permanent magnet synchronous motor

The invention relates to the research and manufacture of a permanent magnet synchronous motor in the field of motor manufacturing. Background technique

The rare earth permanent magnet synchronous motor has the characteristics of small size, light weight and high efficiency, and has wide applications in various fields of the national economy. However, in actual use, after a period of use, its performance will be significantly reduced, or even not working properly. The reason is that the temperature rise of the rotor is too high, causing the loss of magnetism caused by the NdFeB permanent magnet used in the rotor. The NdFeB permanent magnet material has a resistivity of 1.44 χ 1 (Γ ⁶ Ω·m, which has a certain conductivity, which generates eddy current loss in an alternating magnetic field, thereby generating heat. The thermal conductivity of NdFeB is 7.7 _ra //mA°C, poor heat transfer, and the NdFeB magnet is easy to oxidize and rust, making the heat on the magnetic steel more difficult to conduct outward, which aggravates the temperature rise of the rotor. Excessive rotor temperature rise will The danger of demagnetization of NdFeB permanent magnets affects the life of the motor.

At present, the main ways to solve the temperature rise of the rare earth permanent magnet synchronous motor rotor and ensure that the NdFeB permanent magnet does not demagnetize are:

Application (Patent) No.: 200610041946.8, a rare earth permanent magnet synchronous motor. The permanent magnet 14 in the entire length of the electrode rotor is divided into a plurality of small segments in the radial direction, or divided into several layers in a tangential direction, and the segments are interposed between the segments and the layers by an insulating adhesive. The eddy current loss generated in the alternating magnetic field due to the conductivity of the neodymium iron boron permanent magnet 14 is reduced. Solving the problem by enhancing the insulation between the permanent magnets of the rotor and reducing the eddy current heating;

Application (Patent) No.: 03258885.2, rare earth permanent magnet synchronous motor with ventilation slots. The utility model is provided with an axial ventilation groove between the magnetic steel and the magnetic shielding sleeve, and a spiral ventilation groove is arranged on the surface of the rotor. From improving the rotor ventilation structure, strengthening ventilation cooling and cooling to solve the problem;

Application (patent) number: 00226188.X, rare earth permanent magnet synchronous motor. It changes the structure of the stator core and the magnetic steel trough, and adopts a high magnetic permeability, low loss silicon steel sheet and a high magnetic energy product, high coercivity NdFeB material. Solve the no-load loss from the change of the stator and rotor structure and select high-quality materials, and reduce the temperature rise to solve the problem.

The above three methods solve the problem of temperature rise of the rotor from a certain aspect. Although certain effects have been achieved, the problem has not been completely solved fundamentally. Because the temperature rise of the rotor is too high, the neodymium iron boron permanent magnet is demagnetized, affecting forever. The possibility of the life of a magnetic synchronous motor still exists. Summary of the invention

In order to fundamentally solve the problem of excessive temperature rise of the rotor in the use of the permanent magnet synchronous motor and ensure its service life, the present invention provides a permanent magnet synchronous motor, which adopts a new external circulation ventilation cooling structure from the rotor to enhance the cooling and cooling of the rotor. Effect; Enhance the permanent magnet insulation layer, reduce eddy current heating, and improve the service life of the motor.

As a further improvement of the present invention, a magnetic pole is used, and a high-quality NdFeB permanent magnet material is used to enhance the magnetic permeability.

The technical solution adopted by the present invention to solve the technical problem is: a permanent magnet synchronous motor, which is composed of two major components, a stator and a rotor, wherein the stator component is composed of a casing, a stator core, and an armature winding, The rotor component includes a rotor shaft, a magnetic isolation sleeve, a magnetic pole, a permanent magnet and an insulating gasket. The magnetic isolation sleeve and the magnetic pole are sequentially disposed outside the hollow shaft, and the permanent magnet is disposed between two adjacent magnetic poles. The insulating spacer is disposed at two ends of the permanent magnet, the rotor shaft is a hollow shaft, and an inner vent hole penetrating through the two ends is disposed inside the hollow shaft, and is disposed radially on the rotor shaft along the rotor shaft An outer venting hole communicating with the venting hole in the hollow shaft, wherein the magnetic shielding sleeve is radially disposed with a magnetic venting venting hole, and a magnetic pole venting hole is radially disposed on the magnetic pole, The magnetic venting vents and the magnetic venting holes communicate with the inner venting holes, and the three form a radiating heat dissipating structure that intersects the axial direction and the radial direction.

A copper wedge for radially pressing is disposed on the outer insulating spacer of the permanent magnet, and an insulating baffle for pressing is disposed at both ends of the axial direction, and an end ring is disposed on an outer side of the insulating baffle. An annular slot is disposed on the outer peripheral surface of the magnetic pole, and a copper piece is disposed in the slot. The copper piece, the copper wedge piece, and the end ring are coupled and fixed to form a rotor starting cage.

The magnetic pole is a split magnetic pole composed of a plurality of magnetic poles, and the middle of each split magnetic pole is fixed by the through-hole bolt and the magnetic isolation sleeve, and the eight-character shape having a cross-sectional shape of "8" is adopted at both ends. The pin is fixed to the magnetic isolation sleeve.

A plurality of annular grooves communicating with the radially inner venting holes of the hollow core shaft are defined in the magnetic isolation sleeve; and the magnetic shielding sleeve ventilation holes are defined in each annular groove.

The permanent magnet is made of a high-quality rare earth neodymium-iron-boron permanent magnet material with good magnetic properties and high thermal conductivity, and each magnetic pole is composed of a plurality of blocks, and the cross-sectional shape thereof is fan-shaped. The copper wedge has a width greater than a cross-sectional width of the permanent magnet and a length greater than an axial length of the split pole.

Compared with the prior art, the beneficial effects of the present invention are:

1. The rotor shaft of the rotor component of the present invention adopts a hollow structure, and at the same time, a radial outer vent hole is opened in a radial direction of the rotor shaft, and the radially outer vent hole is electrically connected to the axial inner vent hole, and at the same time, the rotor component The magnetic isolation sleeve and the magnetic pole are respectively provided with a magnetic shielding vent hole and a magnetic pole venting hole which are electrically connected to the outer vent hole of the rotor shaft, so that an axial and radial intersection is formed on the rotor component and the rotor shaft is The central radiating heat radiating structure can well control the temperature rise of the motor during operation, reduce the risk of demagnetization of the NdFeB permanent magnet, and at the same time, use insulating pads at both ends of the permanent magnet to reinforce the permanent magnet. Insulation layer reduces eddy current heating and prolongs the life of the motor.

2. The invention adopts a magnetic isolation sleeve on the rotor and a split magnetic pole to reduce the magnetic flux leakage coefficient, so that the motor efficiency and power factor are significantly improved.

3. The existing motor rotor is generally formed by laminating silicon steel sheets, and the starting cage is generally formed by aluminum die casting. The rotor of the present invention is composed of a split magnetic pole with good magnetic permeability, and the starting cage is composed of a copper wedge. At 20 ° C, the resistivity of aluminum is 0.0283 Ω..TM^, the resistivity of copper is 0.0112. 匪² , and the resistivity of aluminum is 1.6 times that of copper. When the stator of the motor enters the three-phase alternating current, the starting torque is generated immediately in the stator coil and the entire motor rotor is rapidly rotated in the direction of the rotating magnetic field. Obviously, the cage is started for the same size motor, because the copper starting cage The induced current is much larger than the induced current of the aluminum starting cage. The larger the current, the greater the electromagnetic force it receives in the rotating magnetic field. The higher the starting torque, the faster the starting, the starting current in the stator coil. The smaller the motor, the better the no-load characteristics of the motor.

In summary, the permanent magnet synchronous motor of the invention has the advantages of low temperature rise, high efficiency, good performance, easy matching with the stator of the ordinary three-phase asynchronous motor, energy saving and consumption reduction, and completely solves the long-term operation of the permanent magnet synchronous motor due to temperature rise. The high temperature causes the NdFeB permanent magnet to be easily demagnetized, which affects its technical performance. It ensures its wide and reliable application in all areas of the national economy. DRAWINGS

The invention will now be further described with reference to the drawings and embodiments.

Figure 1 is a structural view of the present invention;

Figure 2 is a longitudinal sectional structural view of the rotor;

Figure 3 is a left side view of Figure 2;

Figure 4 is a longitudinal sectional structural view of a magnetic isolation sleeve and a split magnetic pole assembly;

Figure 5 is a left side view of Figure 4;

Figure 6 is a longitudinal sectional structural view of the magnetic isolation sleeve;

Figure 7 is a left side view of Figure 6;

Figure 8 is a longitudinal sectional structural view of a single split magnetic pole;

Figure 9 is a left side view of Figure 8; Figure 10 is a front view of a single permanent magnet;

Figure 11 is a left side view of Figure 10.

Fig. 12 is a characteristic diagram of the motor 30KW of the present invention.

Figure 13 is a characteristic diagram of the motor 315KW of the present invention.

Description of the symbols

1 stator core 2 armature winding

3 housing 4 cis 3⁄4;

5 bearing cover 6 protective cover

7 bearing 8 fan blade

9 thermal resistance sensor 10 copper wedge

11 hollow core shaft 12 magnetic isolation sleeve

13 Split magnetic pole 14 Through hole bolt

15 Insulation baffle 16 End ring

17 permanent magnets 18 copper sheets

19 key 20 insulation pad

21 八 pin 22 outer vent

23 Inner vents 24 Magnetic vents

25 permanent magnet through hole 26 slot

27 Screw 28 Ring groove Detailed embodiment:

The invention will now be further described with reference to the accompanying drawings and embodiments.

In Figure 1, a permanent magnet synchronous motor consists of two parts, a stator and a rotor. The stator component is composed of a casing and a stator core 1 and an armature winding 2. The casing is composed of a casing 3, an end cover 4, a bearing cover 5, and a protective cover 6, and the structure thereof is basically the same as that of a conventional three-phase asynchronous motor. The stator of a conventional three-phase asynchronous motor can be directly matched with the rotor component of the present invention to form a permanent magnet synchronous motor, which is a major feature of the present invention; another major feature of the present invention is the structural change of the rotor component, in FIG. 2 and In Fig. 3, the hollow mandrel 11, the magnetic shield 12, and the split magnetic pole 13 are coaxially assembled from the inside to the outside. Each of the split poles 13 is fixed to the outer circumference of the magnetic shield 12 by a radial equal angle according to FIG. 4 and FIG. 5; at both ends, the split pin 21 is respectively used to make the split magnetic pole 13 It is closely matched with the magnetic shielding sleeve 12. Between the magnetic shielding sleeve 12 and the hollow mandrel 11, under the premise that the axial spacing of each annular groove 28 in the inner hole of the magnetic shielding sleeve 12 and the radial inner venting hole 23 of the hollow mandrel 11 is aligned, The key 19 secures its coupling. In Two permanent magnets 17 are respectively arranged between two adjacent split magnetic poles 13, and two permanent magnets are adjacent to each other.

17 is opposite in polarity. The permanent magnet 17 is composed of a plurality of blocks. The lower end is provided with an insulating spacer 20 at the contact with the magnetic shield 12, and after the upper end is provided with the insulating spacer 20, the copper wedge 10 is used to press it radially; at each end of each split magnetic pole 13, a screw 27 is used. The insulating baffle 15 is fixed thereon to prevent the permanent magnet 17 from being ejected axially. A copper sheet 18 is embedded in each of the slots 26 of the split magnetic pole 13. An end ring 16 is mounted on the outer side of the insulating baffle 15, and the end ring 16 is coupled with the copper wedge 10 and the copper piece 18 by means of splicing or riveting to form a rotor starting cage for generating an induction in an alternating magnetic field. The current forms a loop. The assembled rotor component is assembled with the assembled stator component by a bearing 7 mounted on both ends of its hollow mandrel 11, and is equipped with a thermal resistance sensor 9 to cool the vane 8, the shield 6.

In order to form the outer ventilation structure of the rotor component, as shown in FIG. 2, the center of the hollow mandrel 11 is drilled in the axial direction with an outer venting hole 22 through which two ends pass, and in the middle portion thereof, a plurality of rows of radial directions are drilled in the axial direction. An angular distribution, a radially inner venting opening 23 communicating with the outer venting opening 22, is formed as an hollow mandrel 11 having an external venting cooling passage; as shown in Figures 6 and 7, the magnetically permeable sleeve 12 is made of a non-magnetically permeable material The center is drilled into an inner hole matching the outer diameter of the hollow mandrel 11, the inner hole is provided with a key groove, and is coaxial with the inner hole, and the axial spacing is equal to the radial inner vent hole 23 of the hollow mandrel 11 An annular groove 28, in each of the annular grooves 28, is bored at a radial equiangular angle with a magnetic venting opening 24 for mounting the through-hole bolt 14. As shown in Fig. 4, the through-hole bolt 14 is threaded on the outside, and the center is drilled in the axial direction with a vent hole through which two ends pass.

As shown in FIG. 8 and FIG. 9, it is composed of a plurality of strip-shaped magnetic materials, the cross section of which is fan-shaped, and the longitudinal section is a rectangular split magnetic pole 13. In the center of the fan-shaped symmetry, a row and magnetic isolation are drilled in the axial direction. The sleeve 12 has a through hole 25 corresponding to the magnetic venting hole 24 in each annular groove 28 for mounting the through hole bolt 14 and providing a ventilation passage; and having an axial through hole and a radial non-through radial direction The slot 26 has two symmetrical short slots on either side thereof.

As shown in FIG. 5, the splayed pin 21 has a cross-sectional shape of "8", a longitudinal shape, two incomplete cylindrical shapes at both ends, and a rectangular parallelepiped in the middle, which assembles the magnetic isolation sleeve 12 and the split magnetic pole 13 The fit is tight and no radial turbulence occurs.

In order to improve the magnetic permeability of the permanent magnet 17, as shown in FIG. 10 and FIG. 11, the permanent magnet 17 is made of a high-quality rare earth neodymium-iron-boron permanent magnet material with good magnetic properties and high thermal conductivity, and its cross-sectional shape is fan-shaped; The eddy current heat generation of the permanent magnet 17 is reduced, and the insulating spacer 20 is placed in contact with the magnetic shield 12 and the copper wedge 10 .

The copper wedge 10 has a width larger than the cross-sectional width of the permanent magnet 17, and is intended to be inserted into the wedge groove of the split magnetic pole 13 to compress the permanent magnet 17; the length thereof is made larger than the axial length of the split magnetic pole 13. It is used to form a rotor starting cage with the copper sheet 18 and the end ring 16. Figure 12 and Figure 13 are the load characteristic curves of the motor of the present invention measured by GB/T 1029-1993 "Three-phase synchronous motor test method". It can be seen from the figure that the efficiency of the motor of the invention is significantly higher than that of the ordinary three-phase. Synchronous motor.

Claims

A permanent magnet synchronous motor comprising two major components, a stator and a rotor, the stator component being composed of a casing, a stator core (1) and an armature winding (2), the rotor component comprising a rotor axis

(11), a magnetic isolation sleeve (12), a magnetic pole (13), a permanent magnet (17), and an insulating spacer (20), wherein the magnetic isolation sleeve (12) and the magnetic pole (13) are sequentially disposed on the hollow shaft (11) Externally, the permanent magnet (17) is disposed between two adjacent magnetic poles (13), and the insulating gasket is disposed at both ends of the permanent magnet (17)

(20), characterized in that: the rotor shaft (11) is a hollow shaft, and inside the hollow shaft (11) is an inner vent hole (23) penetrating through the two ends, on the rotor shaft (11) An outer venting hole (22) communicating with the vent hole (23) in the hollow shaft is disposed radially along the rotor shaft (11), and a magnetic shielding sleeve is arranged radially on the magnetic shielding sleeve (12) a hole (24), a magnetic pole vent (25) is disposed on the magnetic pole (13), the magnetic vent vent (24) and the magnetic vent (25) and the inner venting The holes (23) are in communication, and the three form a radiating heat dissipation structure that intersects the axial direction and the radial direction.

2. The permanent magnet synchronous motor according to claim 1, wherein: a copper wedge (10) for radially pressing is disposed on an outer insulating spacer (20) of the permanent magnet (17), An insulating baffle (15) for pressing is disposed at both axial ends, and an end ring (16) is disposed outside the insulating baffle (15), and an outer peripheral surface of the magnetic pole (13) is disposed An annular slot (26) in which a copper sheet (18) is disposed, the copper sheet (18), the copper wedge (10), and the end ring

(16) Together with the joints, they form a rotor starting cage.

3. A permanent magnet synchronous motor according to claim 1 or 2, wherein: said magnetic pole (13) is a split magnetic pole composed of a plurality of magnetic poles, and a through-hole bolt is used in the middle of each split magnetic pole ( 14) Fixed with the magnetic isolation sleeve (12), and the octagonal pin (21) with a cross-sectional shape of "8" at both ends is fixed to the magnetic isolation sleeve (12).

4. A permanent magnet synchronous motor according to claim 1, wherein: said magnetic isolation sleeve (12) is provided with a radially inner venting opening (23) with said hollow mandrel (11) a plurality of annular grooves (28) communicating with each other; the magnetic venting holes (24) are opened in each of the annular grooves (28).

5. A permanent magnet synchronous motor according to claim 1, wherein: said permanent magnet

Each of the magnetic poles of (17) is composed of a plurality of blocks, and its cross-sectional shape is fan-shaped.

6. A permanent magnet synchronous motor according to claim 2, wherein: said copper wedge (10) has a width greater than a cross-sectional width of said permanent magnet (17) and a length greater than a split magnetic pole (13). The axial length of the ).