TWI678864B - Permanent magnet motor - Google Patents

Abstract

The permanent magnet motor of the present invention includes: a stator having a plurality of windings; a rotor provided with a plurality of magnet placement slots and a plurality of magnetically isolated empty slots, the plurality of magnet placement slots including a plurality of circumferentially arranged slots; The circumferential magnet placement grooves and a plurality of widthwise magnet placement grooves are arranged alternately in the circumferential direction of each of the circumferential magnet placement grooves and each of the widthwise magnet placement grooves, and the plurality of magnetically isolated empty grooves are close to each other. The magnet is placed in a slot and distributed to a d-axis magnetic flux path direction of the rotor.

Description

Permanent magnet motor

The invention relates to a permanent magnet motor.

In order to respond to requirements such as different speed, load, efficiency, etc., the required characteristics are generally obtained through the different configuration number, position or angle of the magnets in the rotor. For example, Taiwan Certificate No. 129116 has the characteristics of elastic change. However, this magnetic field only provides a magnetic field to a single magnetic pole, which results in the need for two magnetic field magnets between two adjacent magnetic poles. This will increase the cost of the magnet. In addition, there is a certain distance between the two webs toward the magnets, which results in a reduction in the spreading angle of the magnetic poles, which is not conducive to the output characteristics of the motor.

US8044548 discloses that a plurality of circumferential and widthwise magnet placement grooves are provided in the rotor, and the plurality of circumferential and widthwise magnet placement grooves each contain a magnet. For example, the arrangement of the circumferential and widthwise magnet placement grooves is different. The magnetic parts are made of different magnetic flux densities or magnetization directions on the d-axis and q-axis. In addition, the rotor of this patent can also be provided with a magnetically isolated slot. However, the magnetically isolated slot of this patent cannot take into account the d-axis and q-axis magnetic flux paths. The q-axis magnetic flux path is even blocked, so it cannot be obtained at the same time. Better speed and torque.

Therefore, it is necessary to provide a novel and progressive permanent magnet motor to solve the above problems.

The main object of the present invention is to provide a permanent magnet motor that can plan a desired magnetic flux path to achieve a preset performance.

In order to achieve the above object, the present invention provides a permanent magnet motor including: a stator having a plurality of windings; a rotor provided with a plurality of magnet placement slots and a plurality of magnetically isolated empty slots, the plurality of magnet placement slots Including a plurality of circumferential magnet placement grooves arranged in a circumferential direction and a plurality of width magnet placement grooves arranged in a width direction, each of the circumferential magnet placement grooves and each of the width direction magnet placement grooves are alternately arranged in the circumferential direction, the A plurality of magnetically isolated slots are close to the magnet placement slot and are distributed to a d-axis magnetic flux path direction of the rotor.

10‧‧‧ Stator

11‧‧‧winding

12‧‧‧Tooth

23‧‧‧arc

24‧‧‧ Inner Face

30‧‧‧ Magnet

13‧‧‧Stator slot

20‧‧‧rotor

21‧‧‧Magnet placement slot

211‧‧‧Circular magnet placement slot

212‧‧‧pieces placement slot for magnet

213‧‧‧ rib

22‧‧‧Magnetic Isolation Slot

221‧‧‧Straight groove

222‧‧‧Non-linear groove

223‧‧‧End

224‧‧‧Straight

40‧‧‧ magnetic flux center axis

50‧‧‧ magnetic pole center axis

60‧‧‧ clearance

70‧‧‧Second magnet placement slot

A‧‧‧ magnetic pole spread angle

B‧‧‧ Magnetic pole angle

d-axis‧‧‧d axis

Sd‧‧‧d axis magnetic flux path direction

q-axis‧‧‧q axis

Sq‧‧‧q axis magnetic flux path direction

Figure 1 is a schematic diagram of the d-axis and q-axis positions.

FIG. 2 is a schematic diagram of a d-axis magnetic flux path.

FIG. 3 is a schematic diagram of a q-axis magnetic flux path.

FIG. 4 is a schematic diagram of armature reaction magnetic axis deviation.

FIG. 5 is a schematic structural diagram of a rotor according to a preferred embodiment of the present invention.

FIG. 6 is a partially enlarged view of FIG. 5.

7 to 11 are schematic diagrams of different configurations of the magnets disposed in the partial magnet placement grooves in a preferred embodiment of the present invention.

FIGS. 12 to 17 are schematic diagrams of different configurations of all magnet placement slots in a preferred embodiment of the present invention, in which the ends of adjacent teeth of the stator of FIG. 17 have a relatively large distance.

18 to 20 are schematic diagrams of a second magnet placement slot according to a preferred embodiment of the present invention.

FIG. 21 is a schematic diagram of another preferred embodiment of the present invention, showing different configurations of the magnetic isolation slot.

The following only illustrates the possible implementation aspects of the present invention by way of examples, but is not intended to limit the scope of the present invention to be protected, which will be described first.

Please refer to FIGS. 1 to 6, which show a preferred embodiment of the present invention. The permanent magnet motor 1 of the present invention includes a stator 10 and a rotor 20.

The stator 10 is provided with a plurality of windings 11. The rotor 20 is provided with a plurality of magnet placement grooves 21 and a plurality of magnetic isolation slots 22. The plurality of magnet placement grooves 21 include a plurality of circumferential magnet placement grooves 211 and a plurality of widthwise arrangement grooves. The widthwise magnet placement grooves 212, each of the circumferential magnet placement grooves 211 and each of the widthwise magnet placement grooves 212 are alternately arranged in the circumferential direction, and the plurality of magnetically-isolated empty grooves 22 are close to the magnet placement grooves and distributed to the One d-axis magnetic flux path direction Sd of the rotor 20. In this way, a desired magnetic flux path can be planned to achieve a preset performance.

The plurality of magnet placement grooves 21 accommodate a plurality of magnets 30. The plurality of circumferential magnet placement grooves 211 at least partially accommodate a portion of the plurality of magnets 30. The plurality of widths toward at least one of the plurality of magnet placement grooves 212. A part of the plurality of magnets 30 is partially accommodated. In this embodiment, each of the magnet placing slots is provided with a magnet 30, which has the effects of high efficiency, high output characteristics, smoothness, and stability. However, different configurations can also be made according to the performance requirements of different motors. For example, only one or all of the plurality of circumferential magnet placement grooves 211 may be accommodated with a plurality of magnets, and the plurality of widthwise magnet placement grooves 212 are not accommodated with magnets (as shown in FIGS. 7 and 8). ) To obtain a higher rotation speed; or a plurality of magnets may be accommodated in only one or all of the plurality of frames toward the magnet placement grooves 212, and the plurality of circumferential magnet placement grooves 211 do not contain magnets (such as (Shown in FIGS. 9 and 10) to obtain a higher rotation speed; or a plurality of magnets can be accommodated in one of the plurality of magnets and one of the plurality of circumferential magnets 211 The unit is equipped with a plurality of magnets (as shown in Figure 11), which can allow a single steering motor to have the smallest armature response, or The plurality of magnets for receiving magnets 212 are spaced apart to accommodate a plurality of magnets, and each of the plurality of magnets for receiving magnets circumferentially accommodating grooves 211 is provided. Of course, all magnet placement slots may be provided with no magnets, thus forming a reluctance motor. The configuration of the plurality of magnets can be selectively "polarized" during manufacture. Taking FIG. 8 as an example, the magnets 30 in the plurality of circumferential magnet placement grooves 211 can be configured as NSNS ... to form 8 poles, or The configuration is NNSS ... made into 4 poles; in the configuration shown in Fig. 9, it can also be selectively changed to 8 poles or 4 poles. When the number of the plurality of circumferential magnet placement grooves 211 is a multiple of 4, the "polarization" can be selectively performed. Preferably, when the pole is changed to 4 poles, a magnetic conductive material may be additionally accommodated in the magnet placement groove 212 where the magnet is not accommodated, so that the magnetic flux is smooth and continuous and the output performance is improved.

Among them, when there is no armature reaction, a magnetic flux central axis 40 of the permanent magnet motor is located on a magnetic pole central axis 50. When the winding 11 of the stator 10 is energized, a magnetic field is generated, and the magnetic field and the magnetic fields of the plurality of magnets 30 are generated. After the interaction, a new magnetic flux central axis 40 will be synthesized, which is the effect caused by the armature reaction (Figure 4). The new magnetic flux central axis 40 will deviate from the magnetic pole central axis 50, and the plurality of magnetically isolated spaces The groove 22 can generate magnetic resistance, which reduces the problem that the magnetic flux central axis 40 deviates from the magnetic pole central axis 50 caused by the armature reaction. At this time, the armature response can be optimized to reduce the magnetic flux central axis 40 from the magnetic pole. The central axis 50 causes a decrease in effective magnetic flux, resulting in a decrease in output performance.

The plurality of magnets 30 preferably have the same physical characteristics. The physical characteristics include at least one of the shape and size of the material of the magnet. However, the plurality of magnets 30 may also have different physical characteristics according to different characteristics. For example, the materials of the plurality of magnets 30 may be the same or different, or may have the same or different external dimensions; the shape of at least one of the plurality of magnets 30 may be the same as or different from the plurality of magnet placement slots 21. For example, at least one of the plurality of widthwise magnet placement grooves 212 extends between opposite two end faces of adjacent two circumferential magnet placement grooves 211, the magnet 30 is rectangular and the magnet 30 is inserted into the magnet placement After the groove 21 is placed, there is still a gap 60 (FIG. 5) at one end of the magnet placement groove 21. Preferably, the two end faces completely correspond to the range of the widthwise magnet placement groove 212, and the clearance 60 can reduce magnetic field leakage.

Compared to the outer periphery of the rotor 20, the plurality of magnetically-isolated slots 22 are arc-extended along the q-axis magnetic flux path direction Sq of the rotor 20 and the arc opening is radially outward, that is, the complex number Each magnetically isolated slot 22 is arcuately distributed toward the circumferential magnet placement slot 211 so as to retain some q-axis magnetic flux path directions Sq, which can take into account both the q-axis magnetic flux path directions Sq and reduce the armature response.

The outer ends of the plurality of magnets 30 can be retracted relative to the outer periphery of the rotor 20 (as shown in FIGS. 12 to 17), which can reduce the influence of the armature response on the magnet demagnetization. The armature reaction causes the magnetic flux central axis 40 to deviate from the magnetic pole central axis 50, which will cause the magnetic field of the magnet 30 disposed near the outer edge of the rotor 20 to increase in magnetic field. Reversed magnetic poles may cause the magnet to demagnetize. If the enhanced magnetic field is the same as the magnetic pole of the magnet 30 arranged in the width direction, the magnetic circuit may be saturated. Both configurations will affect the magnetic flux distribution.

The plurality of windings 11 of the stator 10 are windings with adjustable current distribution, so as to adjust a d-axis and a q-axis magnetic flux ratio entering the rotor 20. By adjusting the d-axis and q-axis magnetic flux ratios that enter the rotor 20, the offset of the magnetic flux central axis 40 from the magnetic pole central axis 50 due to the armature reaction can be adjusted, which means that the effective magnetic flux can be adjusted. This means that the output performance of the permanent magnet motor can be adjusted. For example, by adjusting the winding current, the offset of the magnetic flux central axis caused by the armature reaction can be compensated in advance, so that the magnetic flux central axis 40 overlaps with the magnetic pole central axis 50, the effective magnetic flux is large, and the output performance is improved .

The plurality of web-direction magnet placement grooves 212 can be directly opened on the outer periphery of the rotor 20 (as shown in FIGS. 1 to 12), which is convenient for manufacturing and placing the magnet 30. It is flush with or retracted a distance toward the magnet placement groove 212. However, the rotor 20 may further include ribs 213 (as shown in FIGS. 13 to 17) provided at the outer ends of the plurality of web-oriented magnet placement grooves 212, or the web-oriented magnet placement grooves are not completely penetrated. Opening on the outer peripheral edge of the rotor increases the structural strength of the rotor 20 and prevents the magnet 30 from detaching due to centrifugal force. The rib 213 may be flush with or retracted a distance from the outer peripheral edge of the rotor 20.

The stator 10 further includes a plurality of teeth 12 extending in the radial direction, and the plurality of windings 11 are wound around the teeth 12. The stator 10 further includes a plurality of stator slots 13 in which the plurality of windings 11 are accommodated. The slot openings of the stator slots 13 may be necked. The width of the slot openings of the stator slots 13 is negatively related to the amount of magnetic leakage. 14 and FIG. 17 are examples. The slot opening width of FIG. 14 is small, and the magnetic flux leakage is large, and the magnetic flux is small. The slot opening width of FIG. 17 is large, and the magnetic flux leakage is large. The plurality of magnets 30 form a magnetic pole unfolding angle A formed between the adjacent widthwise magnet placement grooves 212 smaller than a magnetic pole angle B defined by the central axis of the adjacent widthwise magnet placement grooves 212. The magnetic flux of each magnetic pole can be short-circuited to adjacent magnetic poles through the teeth 12 of the stator 10, causing magnetic leakage. The short-circuited magnetic flux cannot interact with the magnetic flux generated by the winding 11 of the stator 10, resulting in a decrease in effective magnetic flux. The output performance is affected, therefore, it is preferable that the smaller the magnetic pole spread angle A, the smaller the leakage magnetic flux.

The outer periphery of the rotor 20 may include one or more eccentric arc sections (as shown in FIGS. 14 to 17) or straight sections, so that the air gap between the rotor 20 and the stator 10 is gradually increased and decreased, and further, The gradual increase and decrease of the cross-link magnetic flux can reduce the cogging torque. Taking FIG. 15 as an example, the outer periphery of the rotor 20 includes a plurality of arc segments 23, and at least one (preferably all) of the plurality of arc segments 23 has a different center from the rotor 20. However, the outer periphery of the rotor may include one or more concentric arc segments.

An inner peripheral surface 24 (FIG. 16) may be provided on the outer periphery of the rotor 20 near the d-axis. The outer periphery of the rotor 20 is located near the d-axis or the magnetic pole central axis 50 is the position where the magnetic flux of the magnetic pole is the strongest. In order to generate a large turn torque, the inner shrinkage surface 24 is appropriately set at this position. Some air gaps can be added to increase the magnetic resistance to reduce the cogging torque.

Please refer to FIGS. 18 to 20 in conjunction with reference. The rotor 20 may further include a plurality of second magnet placement grooves 70 disposed between adjacent magnet orientation grooves 212. At least one of the plurality of second magnet placement slots 70 is provided with at least one magnet 30, which can increase the main magnetic pole magnetic flux and increase the torque. The second magnet placement groove 70 may be provided between part or all of the adjacent magnet orientation grooves 212, and the second magnet placement groove 70 may be provided in part or all of the second magnet placement grooves. The two magnet placement slots 70 may be a single-layer configuration (as shown in FIGS. 18 and 19) or a multi-layer configuration (as shown in FIG. 20).

In other embodiments as shown in FIG. 21, the plurality of magnetically-isolated slots 22 are distributed near the outer periphery of the rotor 20 pointed by the d-axis magnetic flux path direction Sd (see FIG. 2). For example, the ends of the plurality of magnetically-isolated slots 22 are close to the outer periphery of the rotor 20 and are arc-shaped distributed along the outer periphery of the rotor 20 to minimize the armature response.

In all the embodiments described above, with reference to FIGS. 5 and 6, the plurality of magnetically isolated slots 22 include a straight slot 221 extending radially along one of the rotors 20 and a plurality of straight slots 221 on both sides of the straight slot 221. Non-linear groove 222, at least one of the plurality of non-linear grooves 222 includes an end section 223 perpendicular to one of the sections toward the magnet placement groove 212, and an end section 223 extending radially from the end section 223 toward the rotor 20. The straight section 224 can define a better magnetic isolation and magnetic flux path, and can have both output performance and reduced cogging torque. However, the magnetically isolated slot can also be an oblique straight slot, an arc slot, or other types.

Claims (18)

A permanent magnet motor includes: a stator having a plurality of windings; a rotor provided with a plurality of magnet placement slots and a plurality of magnetic isolation slots, the plurality of magnet placement slots including a plurality of circumferentially arranged circles The magnet placing grooves and a plurality of width-oriented magnet placing grooves are arranged alternately in the circumferential direction of each of the circumferential magnet placing grooves and each of the width-oriented magnet placing grooves, and the plurality of magnetically isolated empty grooves are close to the The magnets are placed in slots and distributed in the direction of a d-axis magnetic flux path of the rotor. The permanent magnet motor according to claim 1, wherein the plurality of circumferential magnet placement slots are provided with a plurality of magnets, and the plurality of widthwise magnet placement slots are not provided with a magnet. The permanent magnet motor according to claim 1, wherein the plurality of magnets in the magnet holding slots are provided with a plurality of magnets, and the magnets in the magnets in each magnet positioning slot are located on a q axis of the rotor. No magnets are accommodated in the circumferential magnet placement slots. The permanent magnet motor according to claim 1, wherein the plurality of magnet placement slots accommodate a plurality of magnets, and the plurality of circumferential magnet placement slots at least partially accommodate a portion of the plurality of magnets, the plurality of At least part of the web-shaped magnet placement groove is provided with a part of the plurality of magnets. The permanent magnet motor according to claim 4, wherein the plurality of magnets have different physical characteristics, and the physical characteristics include at least one of a material shape and a size of the magnet. The permanent magnet motor according to claim 1, wherein the plurality of magnet holding grooves are provided with a plurality of magnets, and at least one of the shapes of the magnets is different from the shape of the magnet holding grooves containing the magnets. The permanent magnet motor according to claim 1, wherein the plurality of magnet placement slots are provided with a plurality of magnets, and the plurality of magnetically isolated slots are distributed to one of the rotors which is directed near the direction of the d-axis magnetic flux path. Outer periphery. The permanent magnet motor according to claim 1, wherein the plurality of magnet placement slots are provided with a plurality of magnets, and the plurality of magnetically isolated slots are along a q axis of the rotor compared to an outer peripheral edge of the rotor. The magnetic flux path is arc-extended and the arc opening faces radially outward. The permanent magnet motor according to claim 8, wherein the plurality of windings of the stator are windings with adjustable current distribution, so as to adjust the magnetic flux ratio of a d-axis and a q-axis entering the rotor. The permanent magnet motor according to claim 1, wherein the plurality of magnets are provided with a plurality of magnets in the magnet placement slots, and the outer ends of the plurality of magnets are retracted relative to an outer peripheral edge of the rotor. The permanent magnet motor according to claim 1, wherein the rotor further includes a rib provided at the outer end of the plurality of webs toward the magnet placement groove. The permanent magnet motor according to claim 1, wherein the plurality of magnet placement slots are provided with a plurality of magnets, and the plurality of magnets form a magnetic pole with an opening angle smaller than that of the adjacent magnet placement slots. A magnetic pole angle defined by the central axis of the magnet placement slot. The permanent magnet motor according to claim 1, wherein an outer periphery of one of the rotors includes a plurality of arc segments, and at least one of the plurality of arc segments has a different center from the rotor. The permanent magnet motor according to claim 1, wherein the plurality of magnet placement slots are provided with a plurality of magnets, and an outer peripheral edge of the rotor is provided with an inner contraction surface near a d-axis. The permanent magnet motor according to claim 1, wherein the rotor further includes a plurality of second magnet placement grooves provided between adjacent magnet orientation grooves. The permanent magnet motor according to claim 15, wherein at least one of the plurality of second magnet placement slots is provided with at least one magnet. The permanent magnet motor according to claim 1, wherein the plurality of magnetically isolated slots include a straight slot extending radially along one of the rotors and a plurality of non-linear slots located on two sides of the straight slot, the plurality of non-linear slots At least one of the linear grooves includes an end section perpendicular to one of the webs toward the magnet placement groove and a straight section extending from the end section toward the radial direction of the rotor. The permanent magnet motor according to any one of claims 1 to 17, wherein the plurality of webs extend to at least one of the magnet placement grooves between opposite two end surfaces of adjacent two circumferential magnet placement grooves, the The two end faces completely correspond to the range of the web-oriented magnet placement slot.