JP2000116040A - Salient pole rotor of rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce fluctuating magnetic flux and improve the current and torque response of a rotating electric machine by forming magnetic pole structure where a gap length that is the distance to a stator being located outside a salient pole rotor can be maximized within a range for maintaining the mechanical strength of the salient pole. SOLUTION: End damper bar 5a is arranged so that it is closest to a side surface 2c of a magnetic pole head part within a range for maintaining the mechanical strength of a magnetic pole 2. Further, the gap length between a rotor and a stator is maximized within the range for maintaining the mechanical strength of the magnetic pole 2 at a magnetic pole part 2b being located outside the end damper bar 5a. As a result, by expanding the gap length at the magnetic pole part 2b, magnetic flux ϕdpt that is passed to the magnetic pole part 2b of an adjacent pole through the magnetic pole part 2b being located outside the both end damper bars 5a can be reduced, thus improving the current and torque response characteristics of a rotary electric machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine having a salient pole type rotor having a field winding and a damper bar, and more particularly to a shape of a field pole.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing an example of a conventional salient pole type rotor.

[0003] As shown in FIG. 4, the rotor comprises a magnetic pole 2,
A field winding 4 and a damper bar 5 are provided. Both ends of the head of the magnetic pole 2 support the centrifugal force of the field winding 4. The two ends of the head of the magnetic pole 2 have a structure in which the height of the iron core, which is the distance between the gap side and the field winding side, becomes smaller toward both ends. The gap side surface 2a of the magnetic pole head is
The gap with the stator is gradually changed, and the shape is smooth without any steps, except for small irregularities such as the groove of the damper bar 5. The damper bar 5
A plurality of magnetic poles 2 are provided near the head surface. Each damper bar is conductively connected to each other at the axial end of the rotor to form a short circuit.

[0004]

The short circuit formed by the damper bar 5 shown in FIG. 4 has the effect of suppressing the fluctuation of the magnetic flux passing through the inside of the synchronous machine. If the fluctuation of the magnetic flux at the time of a load change or a speed change is suppressed, the terminal current and torque response characteristics of the rotating electric machine can be improved.

However, in the conventional damper bar arrangement shown in FIG. 4, the fluctuation of the magnetic flux φdpt which passes through the magnetic pole portion 2b located further outside the damper bar 5a at the both ends and to the magnetic pole portion 2b on the adjacent side of the adjacent pole is changed. There is a problem that there is no effect of suppressing the

An object of the present invention is to reduce the magnetic flux φdpt which passes through the magnetic pole portion 2b located further outside the above-mentioned damper bar 5a at the both ends and to the magnetic pole portion 2b on the side adjacent to the adjacent pole to reduce the magnetic flux φdpt. An object of the present invention is to provide a salient pole type rotor capable of improving response characteristics.

[0007]

In order to achieve the above object, the present invention provides a salient pole type rotary electric machine having a magnetic pole, a field winding, and a damper bar on the head gap side of the magnetic pole. The outermost damper bars of the damper bars located at the extreme ends of the magnetic pole are arranged so as to be as close as possible to the side surfaces of the pole head within a range in which the mechanical strength of the magnetic pole can be maintained; In the magnetic pole portion located further outside the extreme end damper bar, the gap length, which is the distance from the stator located outside the salient-pole rotor, is made as wide as possible within a range where the mechanical strength of the magnetic pole can be maintained. A magnetic pole structure was adopted.

[0008]

FIG. 1 is a sectional view of a salient pole type rotor according to an embodiment of the present invention.

In FIG. 1, 2 is a magnetic pole, 4 is a field winding,
5 is a damper bar. Although the figure shows a case where the number of magnetic poles is 4, the present invention may have any number of poles. The figure shows an example in which the rotor is left-right symmetrical with respect to the center of the magnetic pole. The rotor need not be symmetric.

The damper bar 5 is provided with a plurality of conductors near the head surface of the magnetic pole 2 as shown in the figure. Each damper bar is conductively connected to each other at the axial end of the rotor to form a short circuit. Both ends of the head of the magnetic pole 2 support the centrifugal force of the field winding 4. Since the inner diameter surface of the stator facing the outside of the rotor is cylindrical, the distance between the gap surface and the surface on the field winding side decreases at both ends (both sides) of the pole head. It is a growing structure.

According to the present invention, the outermost damper bar 5a is
One of the features is that they are arranged as close as possible to the side surface 2c of the pole head within a range where the mechanical strength of the magnetic pole can be maintained. As a result, the magnetic path of the magnetic flux φdpt passing through the magnetic pole portion 2b located further outside the endmost damper bar 5a and passing to the magnetic pole portion 2b on the adjacent side of the adjacent pole is narrowed.
The magnetic flux φdpt can be reduced. The damper bar 5
It suppresses the fluctuation of the magnetic flux other than the magnetic flux φdpt, but has no effect of suppressing the fluctuation of the magnetic flux φdpt.

Therefore, if the magnetic flux φdpt is reduced, the ratio of the amount of fluctuating magnetic flux to the total magnetic flux is reduced. At the time of a load change or a speed change, the terminal current changes, and a magnetic flux change occurs inside the rotary electric machine according to the change amount. A damper bar plays a role in reducing the magnetic flux fluctuation.

However, as described above, since the damper bar cannot completely eliminate all magnetic flux fluctuations, the magnetic flux inside the rotating electric machine fluctuates, and a terminal voltage proportional to the fluctuation amount and its time change rate is generated. In other words, a larger terminal voltage is generated as the amount of magnetic flux fluctuation increases.

However, as for the terminal voltage of the rotating electric machine, the maximum allowable voltage is limited by the restriction of the power supply capacity.
If the voltage is limited, the amount of change in magnetic flux and the rate of change over time are limited, and therefore the rate of change in terminal current and the rate of change in torque, that is, the response characteristics of the rotating electric machine are also limited.

Therefore, if the magnetic flux φdpt is reduced as described above, the terminal current change rate and the torque change rate can be increased even at the same allowable maximum voltage, and the response characteristics of the rotating electric machine can be improved.

The position of the outermost damper bar 5a is determined in consideration of mechanical strength as described below. That is, if the distance 10 between the extreme end damper bar 5a and the bottom surface 2d of the magnetic pole head on the side of the field winding is too small, the stress applied to this portion by the centrifugal force of the field winding and the like becomes large, so that cracks occur And other mechanical problems. The minimum possible width of the distance 10 is defined as the width at which the maximum stress of the 10 sections calculated using the bending moment due to the centrifugal force acting on the 10 sections and the section modulus of the 10 sections becomes the allowable limit value of the material of the magnetic pole 2. I just need. The allowable limit value is a value obtained by multiplying a stress limit value determined by the mechanical characteristics of the material itself by a safety factor (> 1) according to the usage state of the material. End side damper bar 5a and side surface 2 of magnetic pole head
The distance of c should be as short as possible within the range that satisfies this mechanical constraint caused by the distance 10.

Further, according to the present invention, the gap length between the rotor and the stator in the magnetic pole portion 2b located further outside the endmost damper bar 5a is made as wide as possible as long as the mechanical strength of the magnetic pole can be maintained. Another feature is its structure. In the example of the present invention shown in FIG. 1, the gap between the rotor and the stator is widened by providing a step in the magnetic pole portion 2b.

By increasing the gap length in the portion 2b, the magnetic flux φdpt passing through the magnetic pole portion 2b located further outside the damper bar 5a at the both ends and passing to the magnetic pole portion 2b of the adjacent pole can be reduced. For this reason, the current and torque response characteristics of the rotating electric machine can be improved. However, as described above, the structure of the magnetic pole portion 2b is determined so that mechanical strength due to centrifugal force of rotation can be maintained.

In the example of the present invention shown in FIG. 1, the minimum possible width of the distance 14 between the side surface of the step portion of the magnetic pole and the outermost damper bar is the bending moment due to the centrifugal force acting on the 14 section and the section modulus of the 14 section. The maximum stress of the 14 cross-sections calculated by using the above may be set to a width that is the allowable limit value of the material of the magnetic pole 2b.

Further, the minimum possible width of the distance 12 between the upper surface of the gap portion of the step portion of the magnetic pole on the gap side and the bottom surface 2d of the magnetic pole head on the field winding side is determined by the bending moment due to the centrifugal force acting on the 12 cross section. The maximum stress of the twelve cross sections calculated using the cross section modulus of the cross section may be set to a width that is the allowable limit value of the material of the magnetic pole 2b. The stresses at the sections 10, 12, and 14 may be calculated by a computer using a finite element method or the like.

[0021]

As described above, according to the present invention, the outermost damper bar 5a is arranged as close as possible to both side surfaces 2c of the pole head within a range where the mechanical strength of the pole can be maintained.
Further, the gap length between the rotor and the stator in the magnetic pole portion 2b located further outside the endmost damper bar 5a,
The structure is made as wide as possible as long as the mechanical strength can be maintained. Therefore, it is possible to reduce the magnetic flux φdpt that passes through the magnetic pole portion 2b located further outside the damper bar 5a at the both ends and passes to the magnetic pole portion 2b adjacent to the adjacent pole. Since the magnetic flux φdpt can be reduced, the fluctuating magnetic flux is reduced, so that the current and torque response characteristics of the rotating electric machine can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of a salient pole type rotor according to the present invention.

FIG. 2 is a sectional view of a conventional salient pole type rotor.

[Explanation of symbols]

φdpt ... magnetic flux, 2 ... magnetic pole, 4 ... field winding, 5 ... damper bar.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mika Takahashi 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Yoshitaka Yoshinari 3-chome, Sachimachi, Hitachi City, Ibaraki Prefecture No. 1-1 Inside Hitachi, Ltd.Hitachi Plant (72) Inventor Hiroyuki Nishioka 3-1-1 Sakaicho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Plant (72) Inventor Mitsuhiro Nitobe Hitachi, Ibaraki Prefecture 3-1-1, Sachimachi F-term in Hitachi Works, Ltd. Hitachi Plant (reference) 5H002 AA02 AE07 5H619 AA01 PP02 PP05 PP15

Claims (7)

[Claims] 1. A salient pole type rotor of a rotary electric machine having a magnetic pole and a field winding, and a damper bar on a gap side of the magnetic pole head, the end of the damper bar located at the extreme ends of the magnetic pole. In the magnetic pole portion located further outside the damper bar, the gap length, which is the distance from the stator located outside the salient-pole rotor, is made as wide as possible within a range where the mechanical strength of the magnetic pole can be maintained. A salient pole type rotor for a rotating electric machine having a structure. 2. A salient pole type rotor of a rotary electric machine having a magnetic pole and a field winding and having a damper bar on a gap side of the magnetic pole head, wherein the outermost end of the damper bar located at the both ends of the magnetic pole. In the magnetic pole portion located further outside the damper bar, by providing a step as large as possible in the magnetic pole within a range where the mechanical strength of the magnetic pole can be maintained, the magnetic pole portion can be connected to the stator located outside the salient pole type rotor. A salient pole type rotor for a rotating electric machine, wherein a gap length as a distance is widened. 3. The distance between the side surface of the step portion and the outermost damper bar, the maximum stress in the magnetic pole section formed by the surface connecting the side surface of the step portion and the outermost damper bar, is an allowable value determined by the material of the magnetic pole. 3. The salient pole type rotor of a rotating electric machine according to claim 2, wherein the distance is set as follows. 4. The distance between the gap-side upper surface of the stepped portion and the bottom surface of the magnetic pole head on the field winding side, and the distance between the gap-side upper surface of the stepped portion and the field winding side of the magnetic pole head. 4. The salient pole type rotor of a rotating electric machine according to claim 2, wherein a maximum stress in a magnetic pole section formed by a surface connecting the magnetic poles is set to a distance that is an allowable value determined by a material of the magnetic pole. 5. A salient pole type rotor of a rotary electric machine having a magnetic pole, a field winding and a damper bar on the magnetic pole head gap side, the end of the damper bar located at the extreme ends of the magnetic pole. A salient pole type rotor for a rotating electric machine, wherein a damper bar is arranged so as to be as close as possible to a side surface of the pole head within a range where the mechanical strength of the pole can be maintained. 6. A salient pole type rotor of a rotary electric machine having a magnetic pole and a field winding and having a damper bar on a gap side of the magnetic pole head, the end of the damper bar located at the extreme ends of the magnetic pole. The protrusion of a rotating electric machine according to any one of claims 1 to 4, wherein the damper bar is arranged so as to be as close to the side surface of the pole head as possible within a range where the mechanical strength of the pole can be maintained. Polar rotor. 7. A distance between an outermost damper bar located at the extreme end of the magnetic pole of the damper bar and a side surface of the magnetic pole head is defined by a surface connecting the endmost damper bar and a side surface of the magnetic pole head. 7. The salient pole type rotor of a rotary electric machine according to claim 5, wherein the maximum stress in the magnetic pole cross section is a distance that becomes an allowable limit value determined by the material of the magnetic pole.