Rotors and rotating electric machines

Abstract

The goal is to improve the torque of rotating electrical machinery. [Solution] A rotor according to one aspect of the present invention is a wound-field rotor, characterized in that it has magnetic wedges arranged along the q-axis in the space between poles.

Description

Technical Field

[0001] The present invention relates to a rotor and a rotating electrical machine.

Background Art

[0002] Conventionally, there has been a demand for higher rotational speeds of rotating electrical machines. When the rotation of a rotating electrical machine is increased in speed, iron loss increases. Therefore, as one of the solutions, in a rotating electrical machine capable of high-speed rotation, the adoption of a wound field magnet type rotor that can have a variable field magnet has been considered (for example, Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a rotating electrical machine to which a wound field magnet type rotor is applied, when the maximum armature current is energized, at the phase where the maximum torque is obtained, the reluctance torque becomes negative due to the influence of magnetic saturation, which has been a factor in the reduction of the maximum torque of the rotating electrical machine and the increase in the size of the rotating electrical machine. Therefore, conventionally, there has been room for improvement in the torque of the rotating electrical machine.

[0005] The present invention has been made in view of the above points, and an object thereof is to improve the torque of a rotating electrical machine.

Means for Solving the Problems

[0006] The rotor according to one aspect of the present invention is A wound-field rotor having magnetic wedges arranged along the q-axis in the space between poles, characterized by the following.

Effects of the Invention

[0007] According to one aspect of the present invention, the torque of a rotating electric machine can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a partial side view showing the schematic configuration of the motor 100 according to Embodiment 1 of the present invention. [Figure 2] This is a side view showing the schematic configuration of the rotor 300 according to Embodiment 1 of the present invention. [Figure 3] This is a partial side view showing the schematic configuration of a conventional motor 1100. [Figure 4] This graph shows a comparison of the torque characteristics of motor 100 and motor 1100. [Modes for carrying out the invention]

[0009] The following description of a rotating electric machine according to an embodiment of the present invention will be made with reference to the drawings. Note that in the following drawings, the scale and number of components in each structure may differ from the actual structure in order to make the components easier to understand.

[0010] <Embodiment 1> Figure 1 is a side view showing a schematic configuration of a motor 100 according to Embodiment 1 of the present invention. Figure 1 shows a sector-shaped section of the vicinity of one of the eight rotor teeth 311 of the circular motor 100. The motor 100 rotates around a shaft 400 that extends along the central axis J. The motor 100 is an example of a rotating electric machine. Figure 1 is a side view of the motor 100 as seen from the direction in which the central axis J extends.

[0011] The central axis J extends from the front to the back in Figure 1. Unless otherwise specified, the direction in which the central axis J extends is simply called the "axial direction." In the axial direction, the front side in Figure 1 is called the "one axial side," and the back side in Figure 1 is called the "other axial side." The terms "one side" and "other side" are merely descriptive terms and do not limit the actual positional relationship or direction. The radial direction centered on the central axis J is simply called the "radial direction," and the circumferential direction centered on the central axis J, that is, around the axis of the central axis J, is simply called the "circumferential direction." In the radial direction, the side approaching the central axis J is called the "inside radial direction," and the side moving away from the central axis J is called the "outside radial direction." In the circumferential direction, when looking from one axial side to the other axial side, the clockwise side is called the "one circumferential side," and the counterclockwise side is called the "other circumferential side."

[0012] In this specification, "extending in the axial direction" includes not only cases where the material extends strictly in the axial direction, but also cases where the material extends in a direction inclined to the axial direction by an angle of less than 45°. Furthermore, in this specification, "extending radially" includes not only cases where the material extends strictly radially, i.e., perpendicular to the axial direction, but also cases where the material extends in a direction inclined to the radial direction by an angle of less than 45°. Furthermore, "parallel" includes not only cases where the material is strictly parallel, but also cases where the angle between the material and the material is inclined to each other by an angle of less than 45°. Furthermore, "spreading in a direction perpendicular to the axial direction" includes not only cases where the material spreads in a direction perpendicular to the axial direction, but also cases where the material spreads in a direction inclined to the direction perpendicular to the axial direction by an angle of less than 45°.

[0013] The motor 100 has a stator 200, a rotor 300 positioned opposite the stator 200 radially inward with an air gap in between, and a shaft 400 fixed radially inward of the rotor 300 and extending along a central axis J. The stator 200 has a stator core 210 and stator coils 220. The stator core 210 has 48 stator teeth 211 that extend radially inward and are arranged at equal intervals in the circumferential direction. The stator coils 220 are armature windings wound around the stator teeth 211.

[0014] The rotor 300 includes a rotor core 310, rotor coils 320, and magnetic wedges 330. The rotor core 310 has eight rotor teeth 311 that extend radially outward and are arranged at equal intervals in the circumferential direction. The rotor coils 320 are field windings wound around the rotor teeth 311.

[0015] The rotor teeth portion 311 has a root portion 311a around which the rotor coil 320 is wound, and a flange portion 311b that is located radially outward from the root portion 311a and faces the stator 200. The flange portion 311b has a projection 311c that protrudes to one side in the circumferential direction beyond one end in the circumferential direction of the root portion 311a, and a projection 311d that protrudes to the other side in the circumferential direction beyond the other end in the circumferential direction of the root portion 311a, serving as a circumferential salient pole for increasing the magnetic flux linkage with the stator 200.

[0016] When winding the rotor coil 320 onto the rotor teeth 311, for example, nozzle winding is performed, so a space for the winding nozzle is left between a rotor coil 320 wound onto one rotor teeth 311 and a rotor coil 320 wound onto an adjacent rotor teeth 311. When there is a space between adjacent rotor coils 320 in this way, the field winding may bend at high rotational speeds. Therefore, it is conceivable to prevent the field winding from bending by providing a wedge between adjacent rotor coils 320. In this embodiment, a magnetic wedge 330 is provided as the wedge between adjacent rotor coils 320. When the magnetic wedge 330 and the flange 311b are close together, magnetic flux leaks in the circumferential direction of the rotor 300, so a circumferential gap D is provided between the protrusions 311c and 311d of the flange 311b and the magnetic wedge 330.

[0017] FIG. 2 is a side view showing a schematic configuration of a rotor 300 according to Embodiment 1 of the present invention. The magnetic wedge 330 is arranged along the q-axis in the space between the poles of the rotor 300 which is a wound-field type rotor, that is, between adjacent rotor coils 320. The magnetic wedge 330 is, for example, an electromagnetic steel sheet. The magnetic wedge 330 is formed, for example, by axially laminating electromagnetic steel sheets. At least the radially inner end of the magnetic wedge 330 contacts the rotor core 310. The magnetic wedge 330 may contact the rotor core 310 other than at its radially inner end. The magnetic wedge 330 is fixed, for example, by screwing from the axial direction. Note that the magnetic wedge 330 does not necessarily have to contact the rotor core 310. For example, the present embodiment is effective even when there is a slight gap between the magnetic wedge 330 and the rotor core 310.

[0018] According to the present embodiment, by providing the magnetic wedge 330, the reluctance torque of the motor 100 is improved. If importance is attached to the effect of improving the reluctance torque, it is desirable that the radially outer end of the magnetic wedge 330 is at the same radial position as the radially outer end of the rotor core 310, but the magnetic wedge 330 does not necessarily have to extend to the outer periphery of the rotor 300. On the other hand, from the viewpoint of preventing the deflection of the rotor coil 320 which is a field winding, it is desirable that the magnetic wedge 330 is arranged at least at a position facing the rotor coil 320 which is a field winding in the circumferential direction in the radial direction. That is, the length of the magnetic wedge 330 is The dimensions must be such that they cover at least the area facing the rotor coil 320, which is the field winding, in the radial direction. is desirable. Further, the cross-sectional shape of the magnetic wedge 330 cut by a plane orthogonal to the axial direction may be any other shape such as a trapezoid in addition to a rectangular parallelepiped.

[0019] FIG. 3 is a partial side view showing a schematic configuration of a conventional motor 1100. The conventional motor 1100 has a rotor 1300 instead of the rotor 300 as compared with the motor 100 according to Embodiment 1. The rotor 1300 does not have the magnetic wedge 330 according to Embodiment 1. In other respects, the motor 1100 is the same as the motor 100.

[0020] FIG. 4 is a graph showing a comparison of the torque characteristics of the motor 100 of FIG. 1 and the motor 1100 of FIG. 3. FIG. 4 shows the results of obtaining the torques of the motor 100 and the motor 1100 by simulation. In FIG. 4, the horizontal axis represents the phase of the electric current advance angle with respect to the no-load induced voltage, and the vertical axis represents the torque.

[0021] Line 401 is a line showing the characteristics of the field torque of the conventional motor 1100. Line 402 is a line showing the characteristics of the field torque of the motor 100 according to Embodiment 1. Line 403 is a line showing the characteristics of the reluctance torque of the conventional motor 1100. Line 404 is a line showing the characteristics of the reluctance torque of the motor 100 according to Embodiment 1. Line 405 is a line showing the characteristics of the combined torque of the conventional motor 1100. Line 406 is a line showing the characteristics of the combined torque of the motor 100 according to Embodiment 1. The combined torque is the torque obtained by combining the field torque and the reluctance torque.

[0022] As can be seen from referring to FIG. 4, in the motor 100, the negative portion of the reluctance torque is smaller than that of the motor 1100. By providing the magnetic wedge 330, the salient pole ratio of the rotor core 310 is reduced, the negative reluctance torque becomes smaller, and the maximum torque of the combined torque can be increased. In the example of FIG. 4, the maximum torque of the combined torque in the motor 1100 is 192.5 N·m, while the maximum torque of the combined torque in the motor 100 is 198.2 N·m, having an effect of increasing the maximum torque by +3%.

[0023] As described above, in Embodiment 1, by providing the magnetic wedge 330, both the effect of improving the torque of the rotor 300, which is a wound-field type rotor, and the effect of preventing the bending of the field winding are achieved.

[0024] According to Embodiment 1, since the maximum torque can be increased with the same core length, a motor that satisfies the same maximum torque specification can be designed to be smaller than before.

[0025] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention. In addition, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0026] 100...motor 200...Stata 300... Rotor 330...Magnetic wedge 400...shaft

Claims

1. It is a wound-field rotor, It has magnetic wedges arranged along the q-axis in the space between poles, A rotor characterized by the following features.

2. At least the radially inner end of the magnetic wedge is in contact with the rotor core. The rotor according to feature 1.

3. The length of the magnetic wedge is such that it can cover at least the area facing the field winding in the radial direction. The rotor according to feature 1.

4. The rotor core has a rotor teeth portion around which the field winding is wound, The rotor teeth portion has a flange portion that protrudes in the circumferential direction, A circumferential gap is provided between the flange and the magnetic wedge. The rotor according to feature 1.

5. The magnetic wedge is formed by stacking electromagnetic steel sheets in the axial direction. The rotor according to feature 1.

6. A rotating electric machine characterized by having a stator and a rotor as described in claim 1.

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