CN113922532A

CN113922532A - An AC permanent magnet torque motor with radially unequal tooth width

Info

Publication number: CN113922532A
Application number: CN202111262196.8A
Authority: CN
Inventors: 王骞; 杨玉磊; 岳通; 魏国; 李勇; 胡建辉
Original assignee: Harbin Institute of Technology Shenzhen
Current assignee: Harbin Institute of Technology Shenzhen
Priority date: 2021-10-28
Filing date: 2021-10-28
Publication date: 2022-01-11

Abstract

An AC permanent magnet torque motor with radially unequal tooth widths relates to the field of electromechanical technology. The invention is to solve the problem of poor overload capacity of the existing radial equal tooth width AC permanent magnet torque motor. An AC permanent magnet torque motor with radially unequal tooth widths according to the present invention includes a stator and a rotor. In the radial section of the stator teeth, the circumferential length of the tooth root is greater than the circumferential length of the tooth tip. The invention increases the local width of the tooth root part of the motor stator while keeping the width of the tooth tip part unchanged. Compared with the traditional improved structure, the invention has larger slot area, higher winding utilization rate, lower copper consumption and lower motor heating. While effectively improving the overload capacity of the motor, the present invention avoids many additional adverse effects brought about by the traditional improvement method while increasing the overload capacity.

Description

Alternating current permanent magnet torque motor adopting radial unequal tooth widths

Technical Field

The invention belongs to an alternating current permanent magnet torque motor in the electromechanical technical field.

Background

The alternating-current permanent magnet torque motor has the characteristics of high torque density, small volume and mass, high control precision, flexible arrangement, maintenance-free property and the like, and has wide application in the fields of aerospace, national defense weapons, high-technology ships, robots and the like. The application of the direct drive permanent magnet torque motor technology improves the control precision and response speed of a motion control system, and becomes an important support technology in the fields of national aviation, aerospace, high-end equipment and the like. For an alternating-current permanent magnet torque motor, the torque overload capacity is an important performance index, and directly influences the dynamic response performance of a motion system, so that the maneuverability of equipment is influenced.

At present, a permanent magnet torque motor mostly adopts a straight tooth structure with equal radial tooth width and no tooth shoes. The structure has larger notch width, and can inhibit magnetic circuit saturation caused by armature reaction, thereby improving the torque overload capacity of the permanent magnet torque motor to a certain extent. However, in the case of high overload conditions, since the winding currents can often reach several times the rated current (typical values: 5 to 10 times), the armature reaction is very severe, which leads to a drastic increase in the saturation of the magnetic circuit of the machine, especially in the tooth root region of the stator core, which seriously affects the improvement of the overload capacity of the machine. In order to improve the overload capacity of the motor and reduce the saturation degree of a magnetic circuit in high overload, the tooth width of a stator is increased conventionally, but the tooth width has two adverse effects: on one hand, the area of the slot is reduced, the utilization rate of the winding is reduced, the copper consumption of the motor is increased, and the heating is serious; on the other hand, the width of the notch can be reduced due to the increase of the tooth width of the stator, adverse effects can be brought to magnetic circuit saturation, the leakage inductance of the motor can be increased, the leakage reactance voltage drop is increased, and the utilization rate of bridge arm voltage is reduced. Therefore, for the traditional alternating current permanent magnet torque motor adopting radial equal tooth widths, the improvement effect of the tooth width increase of the stator on the overload capacity is very limited.

Disclosure of Invention

The invention provides an alternating current permanent magnet torque motor with radial unequal tooth widths, aiming at solving the problem that the overload capacity of the existing alternating current permanent magnet torque motor with radial equal tooth widths is poor.

The AC permanent-magnet torque motor with radial unequal tooth widths comprises a stator and a rotor, wherein in the radial section of the stator teeth, the circumferential length of tooth roots is greater than that of tooth crests.

Furthermore, each stator tooth comprises N stator segments which are arranged in a stacking mode in the radial direction, N is a positive integer larger than or equal to 2, and the circumferential length of each stator segment decreases gradually from a tooth root to a tooth top layer by layer.

Further, the part of the stator segment at the bottom layer, which is larger than the stator segment at the top layer, is the shoulder of the stator segment, and the shoulders of all the stator segments in each stator tooth are parallel to the tooth crest.

Further, the part of the bottom layer stator segment larger than the top layer stator segment is a shoulder part of the stator segment, and the outer ends of the shoulder parts of all the stator segments in each stator tooth are inclined towards the direction of the tooth root.

Further, the radial length of each stator segment is the same.

Further, the radial length of each stator segment is different.

Further, the stator teeth are trapezoidal teeth.

The invention relates to an alternating-current permanent magnet torque motor which adopts radial unequal tooth widths to improve the torque overload capacity of the motor, which purposefully increases the local width of the tooth root part of a stator of the motor and simultaneously keeps the width of the tooth tip part unchanged. The motor overload capacity is effectively improved, and meanwhile, a plurality of additional adverse effects brought by the traditional improvement method when the overload capacity is improved are avoided.

Drawings

FIG. 1 is a schematic view of an unmodified stator tooth structure, wherein 1 is the stator tooth root, 2 is the stator tooth tip, and 3 is the magnetic circuit oversaturation region in the high overload state;

FIG. 2 is a schematic view of a stator tooth modified using conventional modification;

FIG. 3 is a schematic view of a stator tooth in a right angle shoulder configuration where N is equal to 2;

FIG. 4 is a schematic view of a stator tooth in a transition shoulder configuration when N equals 2;

FIG. 5 is a schematic view of a stator tooth in a right angle shoulder configuration where N is equal to 3;

FIG. 6 is a schematic view of a stator tooth of the transition shoulder configuration when N equals 3;

fig. 7 is a schematic view of a trapezoidal tooth.

Detailed Description

The traditional ac permanent magnet torque motor adopts a parallel straight tooth structure, as shown in fig. 1. Because the alternating-current permanent magnet torque motor can have a high overload working state, but in the state, because the width of the stator tooth is small, the problem of oversaturation (as shown in a position 3 in figure 1) can occur in a magnetic circuit of the stator tooth root 1, and the improvement of the overload capacity of the motor is limited. The existing solution is to increase the width of the stator teeth, the result is shown in fig. 2. Therefore, the problem of oversaturation of a stator tooth root magnetic circuit under a high overload working condition can be solved. However, as the width of the stator teeth increases, the slot area is also reduced, so that the utilization rate of the winding is reduced, the copper consumption of the motor is increased, and the heat generation is very serious. More importantly, the notch of the stator is reduced, so that the leakage inductance of the motor is increased, the leakage reactance voltage drop is also increased, and the utilization rate of bridge arm voltage is reduced.

Therefore, the problem cannot be thoroughly solved by simply increasing the tooth width of the stator in the prior art. To this end, the present invention provides the following embodiments to solve the above problems.

The first embodiment is as follows: the embodiment is specifically described with reference to fig. 3, 4, 5 and 6, and the ac permanent magnet torque motor adopting radial unequal tooth widths in the embodiment includes a stator and a rotor, each stator tooth includes N stator segments stacked in the radial direction, and N is a positive integer greater than or equal to 2. The circumferential length of the stator section decreases gradually from the tooth root to the tooth top.

The part of the bottom layer stator segment, which is larger than the top layer stator segment, is a shoulder part of the stator segment, and the stator teeth comprise a right-angle shoulder and a transition shoulder. Wherein, the right angle shoulder structure does: the shoulders of all the stator segments in each stator tooth are parallel to the tooth crest; the transition shoulder structure is: the outer ends of the shoulders of all the stator segments in each stator tooth are inclined towards the direction of the tooth root. The radial length of each stator segment, i.e. the height of the stator segment, may or may not be uniform.

The present embodiment has three starting points: firstly, the tooth root width is increased, and the problem of oversaturation of a magnetic circuit of the motor in a high overload state is solved; secondly, on the premise of meeting the first requirement, the area of the groove is increased as much as possible; third, the notch width is kept constant.

The second embodiment is as follows: referring to fig. 7, specifically describing the present embodiment, the ac permanent magnet torque motor using radial unequal tooth widths according to the present embodiment includes a stator and a rotor, and in a radial cross section of a stator tooth, a tooth root circumferential length is greater than a tooth tip circumferential length, that is: the stator teeth are trapezoidal teeth, namely the radial section of the stator teeth is trapezoidal.

In this embodiment, the width of the radial stator teeth is not uniform, the width at the tooth root is larger, and the width at the tooth top is smaller. The problem of magnetic circuit supersaturation of the stator tooth root area of the motor in a high overload state is relieved, and therefore the torque overload capacity of the alternating current permanent magnet torque motor can be further improved.

It can be seen that the stator tooth structure of the ac permanent magnet torque motor proposed by the present invention does not directly increase the overall width of the stator teeth, but only increases the local width of the stator tooth root portion having the problem of magnetic circuit saturation. The widened stator tooth root part is connected with the stator tooth tip part in different forms. The stator tooth structure of the alternating-current permanent magnet torque motor solves the problem of oversaturation of a magnetic circuit at the root part of the stator tooth under a high overload state, avoids adverse effects caused by reduction of groove area and increase of tooth tips in a traditional stator tooth width increasing mode, and effectively improves the torque overload capacity of the alternating-current permanent magnet torque motor.

Claims

1. An AC permanent magnet torque motor with radially unequal tooth width, comprising a stator and a rotor,

It is characterized in that, in the radial section of the stator teeth, the circumferential length of the tooth root is greater than the circumferential length of the tooth tip.

2. a kind of AC permanent magnet torque motor using radially unequal tooth width according to claim 1, is characterized in that,

Each stator tooth includes N stator segments arranged radially stacked, where N is a positive integer greater than or equal to 2,

The circumferential length of the stator segment decreases layer by layer from the tooth root to the tooth tip.

3. a kind of AC permanent magnet torque motor using radially unequal tooth width according to claim 2, is characterized in that,

The part of the bottom stator segment larger than its top stator segment is the shoulder of the stator segment, and the shoulders of all the stator segments in each stator tooth are parallel to the tooth top.

4. a kind of AC permanent magnet torque motor using radially unequal tooth width according to claim 2, is characterized in that,

The part of the bottom stator segment larger than the top stator segment is the shoulder of the stator segment, and the outer ends of the shoulders of all the stator segments in each stator tooth are inclined toward the tooth root direction.

5 . The AC permanent magnet torque motor using radially unequal tooth widths according to claim 2 , wherein the radial lengths of each stator segment are the same. 6 .

6 . The AC permanent magnet torque motor using radially unequal tooth widths according to claim 2 , wherein the radial lengths of each stator segment are different. 7 .

7. A kind of AC permanent magnet torque motor using radially unequal tooth width according to claim 1, is characterized in that,

The stator teeth are trapezoidal teeth.