JP5129034B2 - AC excitation rotating electric machine - Google Patents

Description

  The present invention relates to an AC excitation rotating electric machine such as an AC excitation variable speed generator motor, and more particularly to improvement of a rotor wedge thereof.

  As is well known, an AC excitation rotating electric machine includes a stator coil housed in a stator slot and a rotor coil housed in the rotor slot. The rotor slot is an open slot opened on the outer peripheral surface of the rotor core. For this reason, in the gap between the inner peripheral surface of the stator core and the outer peripheral surface of the rotor core, pulsation of magnetic resistance due to the stator slot and the rotor slot occurs, and the output voltage induced in the stator coil Waveform distortion (harmonic) occurs. This phenomenon is called slot harmonic.

  Since the magnitude of this waveform distortion largely depends on the combination of the number of stator slots and the number of rotor slots, the selection of the number of slots is a very important design item. However, the selection of the number of slots cannot be determined by considering only waveform distortion, but also by taking into account optimization of electrical design such as magnetic flux density, excitation current, excitation voltage, etc. of each part and miniaturization. Need to be done.

  On the other hand, in conventional rotating electrical machines such as water turbine generators, in order to suppress slot harmonics, a method of providing a magnetic wedge in a stator slot to improve waveform distortion has been employed (for example, Patent Documents). 1). In this conventional rotating electric machine, by using a magnetic wedge in the stator slot, there is an effect of reducing the pulsation of the magnetic resistance in the gap and suppressing the slot harmonic. In addition, although the rotary electric machine shown by patent document 1 is a permanent magnet type rotary electric machine, the same effect is acquired also about the rotary electric machine which does not use a permanent magnet.

Japanese Patent Laid-Open No. 11-252835

  As described above, in the AC rotating electrical machine, the selection of the number of slots cannot be determined considering only waveform distortion, but optimization of the electrical design such as magnetic flux density, excitation current, excitation voltage, etc. of each part, miniaturization, etc. Therefore, even if the number of slots is optimal in terms of electrical design, if the waveform distortion is large, the number of slots cannot be adopted, or the electrical design and waveform distortion Even if the number of slots satisfies the above, there are problems such as an increase in cost such as an increase in the size of the rotating electrical machine.

  On the other hand, in the conventional rotating electric machine shown in Patent Document 1, electromagnetic force acts on the magnetic wedge because the magnetic flux passes through the magnetic wedge of the stator. There is a problem that the force acts on the magnetic wedge of the stator, and the magnetic wedge may be fatigued by vibration.

  The present invention has been made to solve the above-described problems, and an AC rotating electrical machine that can supply high-quality electric power by reducing distortion of a voltage waveform due to slot harmonics of the AC excitation rotating electrical machine. It is intended.

An AC-excited rotating electrical machine according to the present invention includes a stator having an annular stator core configured by laminating magnetic thin plates in an axial direction, and an opening provided on an inner peripheral surface of the stator core. And a stator coil housed in the stator slot, and a magnetic thin plate laminated in the axial direction, and the outer peripheral surface of the stator core is opposed to the inner peripheral surface through a gap. A rotor having a rotor core disposed in an inner space of the stator core, a rotor slot provided in the rotor core and having an opening on the outer peripheral surface, and housed in the rotor slot A rotor coil, a non-magnetic wedge positioned on the outer peripheral surface side of the rotor core with respect to the rotor coil and installed in the rotor slot, and the rotor core with respect to the non-magnetic wedge On the outer surface side An AC excitation electric rotating machine and a magnetic wedge movement is prevented in the radial direction outer side of at least the rotor core engaged with the rotor core is disposed in the rotor slot and the magnetic The wedge includes an engaging portion that engages with the non-magnetic wedge at an end portion in the length direction thereof and prevents movement in the length direction .

  In the AC excitation rotating electric machine according to the present invention, preferably, the rotor core includes a rotor ventilation duct extending from a radially inner side to a radially outer side, and the magnetic wedge is the rotor ventilation duct. Is provided with a cutout portion connected to the rotor ventilation duct in a portion corresponding to.

  Furthermore, in the AC-excited rotating electrical machine according to the present invention, preferably, the notch portion is formed on a side portion of the magnetic wedge, in a width direction of the radially outer surface from the radially inner surface of the magnetic wedge. An inclined surface inclined inward is provided.

According to the AC excitation electric rotating machine according to the invention, the magnetic wedge is pressed in the radially outward on the rotor core by the centrifugal force generated by the rotation of the rotating rotor, the electromagnetic force is magnetic wedge vibrates also act on the magnetic wedge Therefore, the magnetic wedge does not cause fatigue failure due to vibration. Also, the magnetic wedge reduces the magnetoresistance pulsation in the gap between the stator and the rotor, so that slot harmonics can be improved, distortion of the voltage waveform due to slot harmonics is reduced, and high quality An AC excitation rotating electric machine that can supply electric power can be obtained.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of a part of an AC-excited rotating electrical machine according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged view of a portion A in FIG. In the first embodiment, an AC excitation variable speed generator motor is shown as an example of the AC excitation rotating electric machine, and in the following description, the AC excitation variable speed generator motor will be described.

  1 and 2, the stator of the AC excitation variable speed generator motor includes an annular stator core 1 made of a laminate in which thin steel plates that are magnetic thin plates are laminated in the axial direction. The stator slot 2 installed on the inner peripheral side of the stator core 1 has an opening on the inner peripheral surface of the stator core 1. The stator slot 2 accommodates a three-phase stator coil (not shown). The stator slot 2 is provided with a nonmagnetic wedge (not shown) for holding the stator coil, and the opening of the stator slot 2 is closed by this nonmagnetic wedge.

The rotor of the AC excitation variable speed generator motor includes a rotor core 3 made of a laminate in which a plurality of thin steel plates, which are magnetic thin plates, are laminated in the axial direction. The rotor slot 4 installed on the outer peripheral side of the rotor core 3 has an opening on the outer peripheral surface of the rotor core 3. The rotor slot 4 houses a lower coil 6 and an upper coil 7 of a rotor coil that constitute a three-phase AC exciting winding. The lower opening coil 6 is disposed at the bottom of the rotor slot 4, and the upper opening coil 7 is positioned on the outer peripheral surface side of the rotor core 3 with respect to the lower opening coil 6 and is accommodated in the rotor slot 4. The rotor core 3 is inserted into the inner space of the stator core 1, and the outer peripheral surface thereof faces the inner peripheral surface of the stator core 1 via a predetermined gap portion 5.

  A nonmagnetic wedge 8 made of a nonmagnetic material is located on the outer peripheral surface side of the rotor core 3 with respect to the upper opening coil 7 and is installed in the rotor slot 4. The nonmagnetic wedge 8 has a side surface engaged with a recess provided on the side wall of the rotor slot 4, and the movement of the rotor core 3 in the radial direction and the circumferential direction is prevented.

  The side surface of the magnetic wedge 9 has a triangular cross section, and the cross section provided on the side wall in the vicinity of the opening of the rotor slot 4 is firmly engaged with the triangular recess. Thereby, the nonmagnetic wedge 9 is prevented from moving in the radial direction and in the circumferential direction of the rotor core 3. The magnetic wedge 9 is configured so as to close the opening of the rotor slot 4 and its outer surface is substantially flush with the outer peripheral surface of the rotor core 3. The lower coil 6 and the upper coil 7 are firmly held in the rotor slot 4 by a nonmagnetic wedge 8 via a wedge lower spacer 11 and an inter-coil spacer 10.

  When the AC excitation variable speed generator motor configured as described above operates as a generator, a three-phase AC excitation current is applied to the rotor coil to generate a rotating magnetic field, and the rotating magnetic field is rotated by the rotor. In combination with this, a three-phase AC voltage is generated across the stator coil. The frequency of the voltage applied to the rotor coil is, for example, about 2 to 6 [Hz], but the frequency of the voltage induced in the stator coil is, for example, a commercial frequency depending on the setting of the rotation speed of the rotor.

  Magnetoresistive pulsation due to the rotor slot 4 in the gap 5 between the stator core 1 and the rotor core 3 is reduced by the magnetic wedge 9. For this reason, slot harmonics can be suppressed. In addition, the centrifugal force generated by the rotation of the rotor acting on the lower coil 6 and the upper coil 7, which are the rotor coils in the rotor slot 4, and the insulators provided on them, is caused by the nonmagnetic wedge 8. Taken firmly. Therefore, the magnetic wedge 9 need only hold its own centrifugal force.

  Further, during operation of the AC excitation variable speed generator motor, centrifugal force always acts on the outer side in the radial direction of the rotor, and the magnetic wedge 9 is pressed against the rotor core 3 and firmly fixed. In this case, the electromagnetic vibration generated in the magnetic wedge provided in the stator slot is hardly generated. Further, as described above, the frequency on the rotor side of the AC excitation variable speed generator motor is generally several [Hz], and the frequency is lower than that on the stator side. Therefore, a magnetic wedge is provided in the stator slot 2. Fatigue failure is less likely to occur than in the case. Thus, an AC excitation variable speed generator motor having a structure that can easily improve the voltage waveform without changing the electrical design, such as changing the number of slots, and that does not easily cause breakage of the magnetic wedge due to electromagnetic vibration. Can be obtained.

Embodiment 2. FIG.
Next, an AC excited rotating electrical machine according to Embodiment 2 of the present invention will be described. 3 is a longitudinal sectional view of a part of an AC excitation rotating electric machine according to Embodiment 2 of the present invention, and corresponds to a cross section taken along line BB in FIG. In the second embodiment, an AC excitation variable speed generator-motor is shown as an example of an AC excitation rotating electric machine. In the following description, an AC excitation variable-speed generator motor will be described.

  In the AC excitation variable speed generator motor shown in FIG. 3, the central shaft 12 is installed in the vertical direction. The central axis 12 forms the central axis of the rotor core 3 and the stator core (not shown), and is also the central axis of a rotor axis (not shown) provided at the center of the rotor core 3. . The non-magnetic wedge 8 installed in the rotor slot of the rotor core 3 protrudes radially outward on the radially outer surface at the axial end, that is, the lower end which is the longitudinal end. An engaging portion composed of an annular convex portion 81 is formed. In addition, the magnetic wedge 9 installed in the rotor slot of the rotor core 3 has an engagement portion composed of an annular recess 91 on the radially inner surface which is the end in the axial direction, that is, the end in the length direction. Is formed.

  As shown in FIG. 3, the concave portion 91 of the magnetic wedge 9 and the convex portion 81 of the non-magnetic wedge 8 are engaged with each other to form an engagement structure 13 that prevents the magnetic wedge 9 from moving off in the axial direction. It is composed. The non-magnetic wedge 8 is held and prevented in the axial direction by a method similar to that of the prior art, such as by winding a tape for preventing dropping at the lower end of the axial end portion. Other configurations are the same as those in the first embodiment.

  According to the AC excitation variable speed generator-motor according to the second embodiment of the present invention configured as described above, the same effect as in the first embodiment can be obtained, and the non-magnetic wedge and the magnetic wedge are shafts. Since it is engaged in the direction, it is possible to prevent the magnetic wedge from falling off.

  In the above description, the case where the engaging portion 13 is formed only at the lower end in the axial direction of the magnetic wedge 8 and the nonmagnetic wedge 9 is shown, but it may be formed in the same manner at the upper end in the axial direction. In this case, the magnetic wedge 9 can be prevented from falling off due to expansion and contraction of the magnetic wedge 9 due to heat.

Embodiment 3 FIG.
Next, an AC excitation rotating electric machine according to Embodiment 3 of the present invention will be described. 4 is a longitudinal sectional view of a part of an AC excited rotating electric machine according to Embodiment 3 of the present invention, FIG. 5 is a transverse sectional view taken along the line CC of FIG. 4, and FIG. 6 is an embodiment of the present invention. 3 is a plan view of a magnetic wedge of the AC excitation rotating electric machine at No. 3. In the third embodiment, an AC excitation variable speed generator motor is shown as an example of the AC excitation rotating electric machine, and in the following description, the AC excitation variable speed generator motor will be described.

  4, 5, and 6, the rotor core 3 includes a plurality of rotor ventilation ducts 14 that extend from the radially inner side to the radially outer side. The plurality of rotor ventilation ducts 14 are installed in the stacking direction of the rotor core 3 via a predetermined interval. The nonmagnetic wedge 8 includes ventilation cutout portions 82 connected to the rotor ventilation duct 14 on both sides of the portion corresponding to the rotor ventilation duct 14. Further, the magnetic wedge 9 includes ventilation notches 92 connected to the rotor ventilation duct 14 on both sides of the portion corresponding to the rotor ventilation duct 14.

  The bottom surface of the notch portion 82 provided in the non-magnetic wedge 8 and the bottom surface of the notch portion 92 provided in the magnetic wedge 9 each have a radius of the rotor core 3 that is the same as the direction of the rotor ventilation duct 14. It is formed to be in the direction. Other configurations are the same as those in the first or second embodiment.

  According to the AC excitation type variable speed generator-motor according to Embodiment 3 of the present invention configured as described above, as shown in FIG. 5, the cooling air 16 passes through the ventilation duct 14 from the inner diameter side of the rotor core 3. Although it flows in the radial direction toward the outer diameter side, the cooling air 16 impedes ventilation by the notch portions 82 provided on both sides of the nonmagnetic wedge 8 and the notches 92 provided on both sides of the magnetic wedge 9. It can flow without receiving. Therefore, the same effect as in the first embodiment or the second embodiment can be obtained, and the ventilation characteristics are not inhibited by the nonmagnetic wedge 8 and the magnetic wedge 9.

Embodiment 4 FIG.
Next, an AC excited rotating electric machine according to Embodiment 4 of the present invention will be described. 7 is a cross-sectional view of a rotor ventilation duct portion of an AC excited rotating electrical machine according to Embodiment 4 of the present invention, and FIG. 8 is a plan view of a magnetic wedge of the AC excited rotating electrical machine according to Embodiment 4 of the present invention. FIG. In the fourth embodiment, an AC excitation variable speed generator motor is shown as an example of an AC excitation rotating electric machine. In the following description, an AC excitation variable speed generator motor will be described.

  7 and 8, the magnetic wedge 9 includes notches 93 on both sides of the portion corresponding to the rotor ventilation duct 14. The notch 93 includes an inclined surface 931 that is inclined from the lower surface side of the magnetic wedge 9, that is, the radially inner surface of the rotor core 3, to the upper surface side, that is, the radially outer surface of the rotor core 3. Yes. Other configurations are the same as those of the third embodiment.

  As shown in FIG. 7, the cooling air 16 flowing in the rotor ventilation duct 14 flows in the radial direction from the inner diameter side to the outer diameter side of the rotor core 3, but is fixed to the rotor in the rotor ventilation duct 14. At the exit to the gap with the child, the cooling air 16 has a component 161 that is directed toward the rotor in the direction of rotation delay. According to the AC excitation variable speed generator-motor according to the fourth embodiment of the present invention, as described above, the magnetic wedge 9 is provided on both sides of the magnetic wedge 9 on the lower surface side of the magnetic wedge 9, that is, the radius of the rotor core 3. Since the notched portion 93 is provided with the inclined surface 931 inclined from the inner surface in the direction to the upper surface side, that is, the outer surface in the radial direction of the rotor core 3 in the width direction, the cooling air 161 directed toward the rotational direction delay side is provided. Ventilation resistance when exiting the gap can be reduced.

  Further, when the cooling air 16 is emitted from the rotor ventilation duct 14 to the gap, a pressure loss occurs due to a sudden expansion of the cross section of the ventilation path. In order to reduce the pressure loss, the cross sectional area of the ventilation space is rapidly increased. According to the fourth embodiment, the magnetic wedge notch 93 is formed on the lower surface side of the magnetic wedge 9, that is, from the radially inner surface of the rotor core 3. Since the inclined surface 931 that is inclined inward in the width direction of the radially outer surface of the rotor core 3 is provided, rapid expansion of the cross-sectional area of the ventilation path from the rotor ventilation duct 14 to the gap can be suppressed, and ventilation characteristics are improved. can do.

  In the AC excitation variable speed generator motor, since the rotor generally rotates in both directions, the magnetic wedge notches 92 need to be provided on both the left and right sides, but the rotor rotates only in one direction. If it is an electric machine, you may provide the notch part which extends from the lower surface side of a magnetic wedge to an upper surface side, and inclines toward the width direction center part of a magnetic wedge only in the side part of the rotation direction advance side of a magnetic wedge.

  In the first to fourth embodiments described above, the AC excitation variable speed generator motor has been described as an example. However, the present invention is not limited to the AC excitation variable speed generator motor, and the rotor is provided with an AC excitation coil. It can be applied to all exciting rotating electrical machines.

It is a cross-sectional view of a part of the AC excitation rotating electric machine according to Embodiment 1 of the present invention. It is an enlarged view of the A section of FIG. It is a longitudinal cross-sectional view of a part of an AC excitation rotating electric machine according to Embodiment 2 of the present invention. It is a longitudinal cross-sectional view of a part of an AC excitation rotating electric machine according to Embodiment 3 of the present invention. It is a cross-sectional view which follows CC of FIG. It is a top view of the magnetic wedge of the alternating current excitation rotary electric machine in Embodiment 3 of this invention. It is a cross-sectional view of the rotor ventilation duct part of the alternating current excitation rotary electric machine which concerns on Embodiment 4 of this invention. It is a top view of the magnetic wedge of the alternating current excitation rotary electric machine which concerns on Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator core 2 Stator slot 3 Rotor core 4 Rotor slot 5 Air gap 6 Lower coil 7 Upper coil 8 Nonmagnetic wedge 9 Magnetic wedge 10 Inter-coil spacer 11 Wedge lower spacer 12 Central shaft 13 Engagement structure 14 Cooling Duct 16, 161 Cooling air 17 Notch 81, 91 Engagement part 92, 93 Notch part 931 Inclined surface

Claims (3)

A stator having an annular stator core configured by laminating magnetic thin plates in the axial direction, a stator slot provided in the stator core and having an opening on an inner peripheral surface of the stator core, and the fixed A stator coil housed in a child slot and a magnetic thin plate laminated in the axial direction, and the inner surface of the stator core so that the outer peripheral surface faces the inner peripheral surface of the stator core with a gap therebetween A rotor having a rotor core disposed in the space; a rotor slot provided in the rotor core having an opening in the outer peripheral surface; a rotor coil housed in the rotor slot; and the rotation A non-magnetic wedge disposed on the outer peripheral surface side of the rotor core with respect to the rotor coil and installed in the rotor slot, and an outer peripheral surface side of the rotor core with respect to the non-magnetic wedge. Installed in the rotor slot Serial engage the rotor core and an AC excitation electric rotating machine and a magnetic wedge which moves radially outward of at least the rotor core is prevented,
The magnetic wedge includes an engaging portion that engages with the non-magnetic wedge at an end portion in the length direction thereof and prevents movement in the length direction.
AC excitation rotating electrical machine characterized by that. The rotor core includes a rotor ventilation duct extending from a radially inner side to a radially outer side, and the magnetic wedge includes a notch portion connected to the rotor ventilation duct at a portion corresponding to the rotor ventilation duct. ,
The alternating current excitation rotating electric machine according to claim 1 characterized by things. The notch includes an inclined surface that is inclined at the side of the magnetic wedge from the radially inner surface of the magnetic wedge to the inner side in the width direction of the radially outer surface.
The alternating current excitation rotating electric machine according to claim 2 characterized by things.

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