JP2008228460A - Rotating machine and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce magnetic saturation in a rotating machine by inserting a permanent magnet between magnetic poles. <P>SOLUTION: A synchronous machine 10 of a salient pole type includes a stator 20 and a rotator 30 having a plurality of salient poles 32. The salient pole 32 is provided with a salient pole barrel part 34 to which field winding 38 is wound and a salient pole head 36 having larger diameter or width compared to the salient pole barrel part 34. The permanent magnet 50 is arranged between salient pole heads 36 of the adjacent salient poles 32 so that the pole which is the same as the magnetized pole of the salient pole 32 is confronted with the pole. The permanent magnets 50 are installed so that they are brought into contact with the salient pole heads 36. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotating machine, and more particularly to a salient pole type synchronous machine.

The salient pole synchronous machine is an important device used in various applications such as a hydroelectric generator, an engine generator, and an industrial motor. The salient pole type synchronous machine is described in detail in a general textbook (for example, see Non-Patent Document 1).
Sakutaro Nonaka, “Electrical Equipment (I)”, 1st edition, 13th edition, Morikita Publishing Co., Ltd., August 1983, p.218-219, p.234

  When a ferromagnetic material such as iron is used as the salient pole of the rotor of the synchronous machine, a large magnetic flux density can be obtained with a smaller current, which is more efficient. However, the iron core has a problem that a magnetic flux density exceeding 2 to 3 Tesla cannot be obtained due to magnetic saturation, and a large field current is required when magnetic saturation occurs. Development of technology capable of reducing the influence of magnetic saturation is desired.

  The present invention has been made in view of the present situation, and an object thereof is to provide a technique for reducing magnetic saturation in a rotating machine.

  One embodiment of the present invention relates to a rotating machine. The rotating machine includes a stator, a rotor, and a salient pole provided on the stator or the rotor, and the salient pole includes a trunk portion around which a field winding is wound, and the trunk portion. A head having a large diameter or width, and further comprising a magnet provided between the heads of adjacent salient poles so that the same pole as the pole on which the salient pole is fielded is opposed. It is characterized by.

  The magnet may be provided in contact with the head. The magnet may be arranged between the heads so that no step is generated between the outer peripheral surface of the magnet and the outer peripheral surface of the head. The magnet may have a shape having a portion wider than the outer peripheral side. The magnet may have a shape whose width is narrowed from the inner peripheral side to the outer peripheral side.

  The salient pole and the magnet may have a plurality of layers stacked with a gap in the axial direction of the rotation axis of the rotor. The salient pole and the magnet may have the gap at the same position. An insulating layer may be formed in the gap.

  A groove may be formed on the head of the salient pole and the outer peripheral surface of the magnet. The groove may be provided along a plane perpendicular to the rotation axis of the rotor.

  Another aspect of the present invention relates to a method for manufacturing a rotating machine. This method is a method for manufacturing any one of the above rotating machines, wherein the step of disposing the magnet between the heads of the salient poles and the polarity opposite to that when the rotor is rotated are provided. A step of exciting a pole, and a step of fixing the magnet between the heads of the salient poles.

  It should be noted that any combination of the above-described constituent elements and a representation of the present invention converted between a method, an apparatus, a system, etc. are also effective as an aspect of the present invention.

  According to the present invention, a technique for reducing magnetic saturation in a rotating machine can be provided.

  FIG. 1 shows a configuration of a conventional salient pole type synchronous machine 10. FIG. 1 schematically shows a cross section of the synchronous machine 10. The synchronous machine 10 includes a cylindrical stator 20 disposed on the outer side, and a rotor 30 disposed coaxially with the stator 20 on the inner side of the stator 20. The rotor 30 has a plurality of salient poles 32 made of a ferromagnetic material such as iron. The salient pole 32 has a salient pole body portion 34 for winding the field winding 38 and a salient pole head portion 36 having a larger diameter or width than the salient pole body portion 34. When a current is supplied to the field winding 38 wound around the salient pole body 34, the salient pole 32 is excited. The rotor 30 is rotated by the electromagnetic force acting between the excited salient pole 32 and the armature 22 of the stator 20.

  FIG. 2 schematically shows the appearance of the salient pole 32. The salient pole head 36 of the salient pole 32 has a larger diameter or width than the salient pole body 34. As a result, the field winding 38 wound around the salient pole body 34 is pressed so as not to jump out in the radial direction by centrifugal force.

  The salient-pole synchronous machine 10 having an iron core has a problem that the terminal voltage of the synchronous machine 10 is limited due to iron magnetic saturation. Magnetic saturation occurs in each part of the iron core. In particular, magnetic saturation is particularly strong in the salient pole body 34 and salient pole head 36 of the rotor 30 in many cases. In order to reduce the field joule loss and heat generation of the field winding 38, it is preferable to increase the cross-sectional area of the field winding 38, but to increase the cross-sectional area of the field winding 38. In addition, it is necessary to reduce the diameter or width of the salient pole body 34 or to reduce the radial thickness of the salient pole head 36, and magnetic field lines tend to concentrate in a narrower region, which easily causes magnetic saturation. . In particular, the salient pole type synchronous machine 10 shown in FIGS. 1 and 2 differs from the claw type magnetic pole synchronizer used in an automobile alternator and the like in the circumferential end portion of the salient pole head 36 at the time of load. Is likely to occur.

  In the present embodiment, a technique is proposed in which a permanent magnet is inserted between the magnetic poles in order to reduce the magnetic saturation of the iron core forming the salient poles 32.

  FIG. 3 shows a configuration of the synchronous machine 10 according to the present embodiment. In the present embodiment, a permanent magnet 50 is provided between the salient pole heads 36 of adjacent salient poles 32 in order to reduce magnetic saturation in the salient poles 32. The permanent magnet 50 is provided such that the same pole as the pole where the salient pole 32 is fielded is opposed. That is, the N pole of the permanent magnet 50 is opposed to the salient pole 32 fielded by the N pole, and the S pole of the permanent magnet 50 is opposed to the salient pole 32 fielded by the S pole. In this way, the permanent magnet 50 generates the magnetic flux 62 in the salient pole 32 in the direction to cancel the magnetic flux 60 generated by the field winding 38 shown in FIG. .

  FIG. 4 schematically shows the appearance of the salient pole 32 according to the present embodiment. A permanent magnet 50 is inserted between the salient pole heads 36 of the adjacent salient poles 32. The permanent magnet 50 is provided in contact with the salient pole head 36. Thereby, since the magnetic flux which comes out of the permanent magnet 50 reaches the salient pole 32 efficiently, the effect of reducing magnetic saturation can be improved. Further, the permanent magnet 50 fills the gap between the salient pole heads 36, and a step is not generated between the outer peripheral surface of the permanent magnet 50 and the outer peripheral surface of the salient pole head 36. By being disposed between the salient pole heads 36, friction loss when the rotor 30 rotates can be reduced.

The inventor has verified the effectiveness of the structure shown in FIGS. 3 and 4 using finite element analysis (FEA). The contents of the analysis will be described below. The analysis target machine is an 8-pole machine having a stator inner diameter of 914 mm, a stator outer diameter of 1240 mm, an axial length of 507 mm, a rated speed of 750 min ⁻¹ , and a Y connection. The operating condition is when no load is applied, and static magnetic field analysis is performed ignoring eddy currents such as damper bars and permanent magnets. The field current is constant. The rotor is rotated at 100 divisions per pole. The residual magnetic flux density of the permanent magnet is 1.2 T, and the recoil relative permeability is 1.05. For the BH characteristics of the stator and the rotor core, the DC magnetization curves of the non-directional electromagnetic steel strips 50A400 and 50A1000 are used, respectively.

  FIG. 5A shows a cross section of the machine A to be analyzed having a conventional structure in which a permanent magnet is not inserted, like the rotating machine shown in FIG. FIG. 6A shows a cross section of the machine B to be analyzed having the structure of the present embodiment shown in FIG. FIG. 7A shows a cross section of the analysis target machine C having a structure in which the salient pole body is 30% thinner than the analysis target machines A and B and the cross-sectional area of the coil region is increased by about 50%. Show.

  FIG. 5B, FIG. 6B, and FIG. 7B show magnetic flux diagrams of the machines A, B, and C to be analyzed at the field current 130A. The magnetic flux density of the salient pole body of the analysis target machine B is 0.28 T smaller than the analysis target machine A. Further, it can be understood that the magnetic flux density of the salient pole body is the same in the analysis object machine C, although the salient pole body part is about 30% thinner than the analysis object machine A.

  FIG. 8 shows a magnetic flux diagram by a permanent magnet. There are no magnetic flux lines that reach the stator side across the gap, and all the magnetic flux lines pass through the salient poles. It is considered that this magnetic flux line cancels out the magnetic flux line caused by the field winding and relaxes magnetic saturation at the salient pole.

  FIG. 9 shows a no-load saturation curve of each analysis target machine. It can be seen that in the analysis object machine A having the conventional structure, the influence of magnetic saturation appears from the vicinity of 90 A of the field current. On the other hand, in the machine B to be analyzed with the permanent magnet inserted, the influence of magnetic saturation appears from around 110A. That is, the unsaturated region is expanded by the insertion of the permanent magnet.

  In FIG. 9, focusing on the region where the terminal voltage is 700 V, it can be seen that the analysis target machine B can reduce the field current by about 40 A than the analysis target machine A. That is, a field current reduction effect can be obtained by inserting a permanent magnet. When attention is paid to the region where the field current is 150 A, it can be seen that the terminal voltage of the analysis target machine A is just over 700 V, whereas the analysis target machine B has a terminal voltage of about 850 V. That is, the effect of improving the terminal voltage can be obtained by inserting the permanent magnet.

  Although the analysis object machine C has a salient pole body portion 30% thinner than the analysis object machine A, an equivalent terminal voltage is obtained. Therefore, by inserting a permanent magnet, the cross-sectional area of the field coil region can be increased by about 50% without reducing the terminal voltage. Thereby, field joule loss and field winding heat generation can be reduced.

  On the other hand, when attention is paid to the region where the field current is 90 A or less, it can be seen that the gap lines of the machines A, B, and C to be analyzed match. That is, it can be seen that the permanent magnet has no effect in a region where magnetic saturation does not occur.

  As described above, it was shown that the magnetic saturation of the machine to be analyzed is remarkably reduced by the insertion of the permanent magnet.

  The above analysis is for no load, but similarly, magnetic saturation is remarkably mitigated by insertion of a permanent magnet. When a salient pole type synchronous machine is used as an electric motor, the polarity of the armature is controlled so that the armature in front of the rotation direction attracts the salient pole in order to rotate the rotor when loaded. More magnetic flux concentrates at the end portion on the front side in the rotation direction, that is, the portion between the field winding and the air gap, and magnetic saturation is particularly likely to occur. This causes a problem that a large field current is required. Similar problems can occur when using a synchronous machine as a generator. However, by inserting a permanent magnet between the salient pole heads, magnetic saturation at the circumferential end of the salient pole head and salient pole body can be significantly reduced, further improving the performance of the synchronous machine. Can be made.

  FIG. 10 shows another configuration example of the synchronous machine 10 according to the embodiment. In the synchronous machine 10 shown in FIG. 10, the permanent magnet 50 has a shape in which the width gradually decreases from the inner peripheral side toward the outer peripheral side.

  FIG. 11 schematically shows the appearance of the salient pole 32 of the synchronous machine 10 shown in FIG. Thus, by arranging the permanent magnet 50 so that the outer peripheral side width of the permanent magnet 50 is smaller than the inner peripheral side width and the salient pole head 36 and the permanent magnet 50 are in contact with each other, A structure can be adopted in which the permanent magnet 50 is pressed by the salient pole head 36 so that the permanent magnet 50 does not jump out due to centrifugal force.

  FIG. 12 shows another configuration example of the synchronous machine 10 according to the embodiment. In the synchronous machine 10 shown in FIG. 12, the permanent magnet 50 has a shape having a portion wider than the outer peripheral side.

  FIG. 13 schematically shows the appearance of the salient pole 32 of the synchronous machine 10 shown in FIG. As described above, the width of the permanent magnet 50 on the outer peripheral side is made narrower than the width near the center, and the permanent magnet 50 is disposed so that the salient pole head 36 and the permanent magnet 50 are in contact with each other. A structure can be adopted in which the magnet 50 is pressed by the salient pole head 36 so that the magnet 50 does not jump out due to centrifugal force. The permanent magnet 50 only needs to have a shape in which at least part thereof has a region whose width becomes narrower toward the outer periphery.

  FIG. 14 shows another configuration example of the conventional synchronous machine 10. In the synchronous machine 10 shown in FIG. 14, the rotor 30 has a structure having a plurality of layers 30 a, 30 b,... Stacked with a gap 40 in the axial direction of the rotation axis of the rotor 30. Thereby, the heat generated in the field winding 38 and the like in the rotor 30 can be efficiently dissipated to the outside.

  FIG. 15 schematically shows the appearance of the salient pole 32 in the synchronous machine 10 of the present embodiment. When the permanent magnet 50 is inserted into the synchronous machine 10 having the structure as shown in FIG. 14, the permanent magnet 50 also has the gap 40 at the same position as the rotor 30 in the axial direction of the rotation axis of the rotor 30. A structure having a plurality of stacked layers is employed. Thus, the heat inside the rotor 30 can be efficiently dissipated to the outside without blocking the gap with the permanent magnet 50.

  An insulating layer may be formed in the gap 40. Thereby, the eddy current generated on the surface of the salient pole head 36 and the permanent magnet 50 can be reduced, and the eddy current loss can be reduced. A plurality of layers of the rotor 30 and the insulating layer may be integrally formed. Further, the insulating layer may be formed only on the salient pole head 36 and the permanent magnet 50.

  FIG. 16 schematically shows the appearance of the salient pole 32 in the synchronous machine 10 of the present embodiment. In this figure, the permanent magnet 50 is omitted for the sake of clarity. In the synchronous machine 10 shown in FIG. 16, a groove 42 is formed on the outer peripheral surface of the salient pole head 36. The groove 42 is provided along a plane perpendicular to the rotation axis of the rotor 30. By adopting such a structure, eddy current loss can be reduced as in the synchronous machine 10 shown in FIG.

  FIG. 17 schematically shows the appearance of the salient pole 32 in the synchronous machine 10 according to the present embodiment. In this figure, a permanent magnet 50 is added to the configuration of the synchronous machine 10 shown in FIG. Grooves 42 are also provided on the outer peripheral surface of the permanent magnet 50. The groove 42 on the surface of the permanent magnet 50 may be provided at the same position as the groove 42 on the surface of the salient pole head 36.

  When the synchronous machine 10 according to the present embodiment is manufactured, after the permanent magnet 50 is disposed between the salient pole heads 36, a current is supplied to the field winding 38 in the opposite direction to the rotation of the rotor 30. The salient pole 32 is excited to the opposite polarity. As a result, the salient pole 32 on the N pole side of the permanent magnet 50 is excited to the S pole, the salient pole 32 on the S pole side is excited to the N pole, and the permanent magnet 50 is fixed to the salient pole head 36 by electromagnetic force. In the meantime, the permanent magnet 50 may be bonded to the salient pole head 36 by welding or a jig. At this time, if it is necessary to magnetize the permanent magnet 50, a current may be supplied to the field winding 38 so that a magnetic force necessary for magnetization is generated.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

  In the embodiment, the rotating field type salient pole type synchronous machine has been described. However, the technique of the present embodiment can be similarly applied to a rotating armature type salient pole type synchronous machine.

It is a figure which shows the structure of the conventional salient pole type synchronous machine. The external appearance of a salient pole is shown typically. It is a figure which shows the structure of the synchronous machine which concerns on this Embodiment. The external appearance of the salient pole concerning this embodiment is shown typically. FIG. 5 (a) is a diagram showing a cross section of an analysis object machine A having a conventional structure in which a permanent magnet is not inserted, as in the rotating machine shown in FIG. 1, and FIG. 5 (b) is an analysis object. 2 is a magnetic flux diagram of machine A. FIG. 6A is a diagram showing a cross section of the analysis object machine B having the structure of the present embodiment shown in FIG. 3, and FIG. 6B is a magnetic flux diagram of the analysis object machine B. FIG. 7A shows a cross section of the analysis target machine C having a structure in which the salient pole body is 30% thinner than the analysis target machines A and B and the cross-sectional area of the coil region is increased by about 50%. FIG. 7B is a magnetic flux diagram of the machine C to be analyzed. It is a figure which shows the magnetic flux diagram by a permanent magnet. It is a figure which shows the no-load saturation curve of each analysis object machine. It is a figure which shows another structural example of the synchronous machine which concerns on embodiment. The external appearance of the salient pole of the synchronous machine shown in FIG. 10 is shown typically. It is a figure which shows another structural example of the synchronous machine which concerns on embodiment. The external appearance of the salient pole of the synchronous machine shown in FIG. 12 is shown typically. It is a figure which shows another structural example of the conventional synchronous machine. An appearance of salient poles in the synchronous machine of the present embodiment is schematically shown. An appearance of salient poles in the synchronous machine of the present embodiment is schematically shown. An appearance of salient poles in the synchronous machine according to the present embodiment is schematically shown.

Explanation of symbols

  10 synchronous machine, 20 stator, 22 armature, 30 rotor, 32 salient pole, 34 salient pole body, 36 salient pole head, 38 field winding, 40 gap, 42 groove, 50 permanent magnet.

Claims (11)

A stator, a rotor, and salient poles provided on the stator or the rotor,
The salient pole is
The body around which the field winding is wound;
Including a head having a larger diameter or width than the trunk,
A rotating machine further comprising a magnet provided between the heads of adjacent salient poles so that the same pole as the pole on which the salient pole is fielded faces.   The rotating machine according to claim 1, wherein the magnet is provided in contact with the head.   The said magnet is arrange | positioned between the said heads so that a level | step difference may not arise between the surface of the outer peripheral side of the said magnet, and the surface of the outer peripheral side of the said head. The rotating machine described.   The rotating machine according to any one of claims 1 to 3, wherein the magnet has a shape having a portion wider than an outer peripheral side.   The rotating machine according to claim 4, wherein the magnet has a shape whose width is narrowed from the inner peripheral side to the outer peripheral side.   6. The rotating machine according to claim 1, wherein the salient pole and the magnet have a plurality of layers stacked with a gap in an axial direction of a rotating shaft of the rotor.   The rotating machine according to claim 6, wherein the salient pole and the magnet have the gap at the same position.   The rotating machine according to claim 6 or 7, wherein an insulating layer is formed in the gap.   The rotating machine according to any one of claims 1 to 8, wherein a groove is formed on a head of the salient pole and a surface on an outer peripheral side of the magnet.   The rotating machine according to claim 9, wherein the groove is provided along a plane perpendicular to a rotation axis of the rotor. A method for manufacturing the rotating machine according to any one of claims 1 to 10,
Disposing the magnet between the salient pole heads;
Exciting the salient poles to a polarity opposite to that when rotating the rotor;
Fixing and adhering the magnet between the heads of the salient poles;
A method comprising the steps of: