JP4116631B2 - 3-phase AC rotating machine - Google Patents

Description

  The present invention relates to a three-phase AC rotating machine, and more particularly, to a three-phase AC rotating machine including a stator including a plurality of slots and a rotor including a plurality of magnetic poles.

  A conventional three-phase AC generator includes a rotor and a stator. The rotor includes a bowl-shaped flywheel provided rotatably and two magnetic poles (N pole and S pole) provided on the inner peripheral surface of the flywheel. The N pole and the S pole are arranged at an interval of 180 degrees along the rotation direction of the flywheel. The stator is fixed in the flywheel, and includes three slots arranged opposite to the two magnetic poles, and a three-phase coil wound around each of the three slots. For example, when a flywheel is rotationally driven by an internal combustion engine, a rotating magnetic field is generated at the outer peripheral portion of the stator, and a three-phase AC voltage is generated at a three-phase coil by electromagnetic induction.

There is also a three-phase AC generator multipole type having a four or more magnetic poles. In this three-phase AC generator, if the number of poles is 2n (where n is an integer of 2 or more), the number of slots is 3n. A total of 2n N poles and S poles are alternately arranged at equal angular intervals along the rotation direction of the flywheel. The 3n slots are sequentially assigned to the U phase, the V phase, and the W phase one by one. The U-phase coil is continuously wound around n slots of the U-phase. The V-phase coil is continuously wound around n slots of the V-phase. W-phase coil is-out continuously wound into n slots of the W-phase (for example, see Patent Document 1).
Japanese Patent Application Laid-Open No. 2004-166381

  In such a three-phase AC generator, the output voltage waveform is preferably a sine wave. However, in the conventional three-phase AC generator, the output voltage waveform is a waveform combining a convex in the positive direction and a convex in the negative direction. (See FIG. 7). Further, the conventional three-phase AC generator has a problem that the cogging torque is large.

  Therefore, a main object of the present invention is to provide a three-phase AC rotating machine having an output voltage waveform close to a sine wave and a small cogging torque.

The three-phase AC rotating machine according to the present invention is a three-phase AC rotating machine including a stator including a plurality of slots and a rotor including a plurality of magnetic poles, where 3n + 3 (where n is an integer of 2 or more). Are arranged at equiangular intervals, and the first to third slots arranged at intervals of 120 degrees out of 3n + 3 slots are assigned to the U phase, the W phase, and the V phase, respectively . The n slots between the slots are sequentially assigned to the U phase, the V phase, and the W phase one by one, and the n slots between the second and third slots are sequentially assigned to the W phase, the U phase, and the V phase one by one. Allocate the n slots between the third and first slots one by one to the V phase, W phase and U phase one by one, and the U phase coil is the same in the n + 1 slots allocated to the U phase wound continuously in a direction, n + 1 slots assigned to the V-phase Wound continuous V-phase coil in the same direction, characterized in that the wound continuous W-phase coils in the same direction in the n + 1 slot allocated to W-phase. Accordingly, since the directions of n + 1 voltage vectors generated in the coils in n + 1 slots of each phase are slightly shifted, the output voltage waveform is closer to a sine wave than in the conventional case where the directions of the voltage vectors are uniform.

  Preferably, the number of magnetic poles is an even number of 4 or more and 2n or less. As a result, the least common multiple of the number of magnetic poles and the number of slots becomes larger than before, and the cogging torque becomes smaller.

  As described above, according to the present invention, it is possible to provide a three-phase AC rotating machine having an output voltage waveform close to a sine wave and a small cogging torque.

[Embodiment 1]
1 is a diagram showing a configuration of a three-phase AC generator according to Embodiment 1 of the present invention. In FIG. 1, the three-phase AC generator includes a rotor 1 and a stator 3. The rotor 1 includes a bowl-shaped flywheel 2 that is rotatably provided and 16 magnetic poles P <b> 1 to P <b> 16 that are provided on the inner peripheral surface of the flywheel 2. The 16 magnetic poles P1 to P16 are arranged at equal intervals along the rotational direction of the flywheel. Of the 16 magnetic poles P1 to P16, for example, odd-numbered magnetic poles are N poles, and even-numbered magnetic poles are S poles. The N pole and the S pole may be the same permanent magnet or different permanent magnets.

  The stator 3 is fixed in the flywheel 1 and has 27 slots S1 to S27 disposed facing the magnetic poles P1 to P16, a U-phase coil 4, a V-phase coil 5, and a W-phase coil 6. Including. The 27 slots S1 to S27 are arranged at equiangular intervals. The U-phase coil 4 is continuously wound around nine slots S assigned to the U-phase. The V-phase coil 5 is continuously wound around nine slots S assigned to the V-phase. The W-phase coil 6 is continuously wound around nine slots S assigned to the W-phase. Each of the coils 4 to 6 is wound around the corresponding slot S in the same direction.

  For example, when the flywheel 2 is rotationally driven by an internal combustion engine, a rotating magnetic field is generated on the outer peripheral portion of the stator 3 by the magnetic poles P1 to P16 that are rotationally driven together with the flywheel 2, and three-phase coils 4 to 6 are three-phased by electromagnetic induction. AC voltage is generated.

  FIG. 2 is a diagram schematically illustrating a winding method of the coils 4 to 6. In this winding method, three slots S1, S10, and S19 arranged at intervals of 120 degrees out of 27 slots S1 to S27 are assigned to the U phase, W phase, and V phase, respectively, and the remaining 24 slots. Slots S2 to S9, S11 to S18, and S20 to S27 are sequentially assigned to the U phase, the V phase, and the W phase one by one. The U-phase coil 4 is continuously wound around the nine slots S1, S2, S5, S8, S12, S15, S18, S22, and S25 assigned to the U-phase. The V-phase coil 5 is continuously wound around the nine slots S3, S6, S9, S13, S16, S19, S20, S23, and S26 assigned to the V-phase. The W-phase coil 6 is continuously wound around the nine slots S4, S7, S10, S11, S14, S17, S21, S24, and S27 assigned to the W-phase. One ends of the coils 4, 5 and 6 are connected to the output terminals TU, TV and TW, respectively, and the other ends thereof are commonly connected to the neutral point terminal TO.

  In other words, this three-phase AC generator adds three slots to the conventional 2n pole, 3n slot (n = 8) three-phase AC generator, and assigns the added three slots to the U phase, W phase, and V phase. They are arranged at intervals of 120 degrees. This eliminates the periodicity that three slots are opposed to two magnetic poles and three slots are assigned to the U-phase, V-phase, and W-phase, thereby improving the output voltage waveform and reducing the cogging torque. Can be achieved.

  FIG. 3 is a diagram illustrating voltage vectors of the U phase, the V phase, and the W phase. The U-phase voltage vector is obtained by adding nine unit voltage vectors generated in the U-phase coil 4 in the nine slots S1, S2, S5, S8, S12, S15, S18, S22, and S25 assigned to the U phase. It is a thing. For the V-phase voltage vector, nine unit voltage vectors generated in the V-phase coil 5 in the nine slots S3, S6, S9, S13, S16, S19, S20, S23, and S26 assigned to the V-phase are added. It is a thing. For the W-phase voltage vector, nine unit voltage vectors generated in the W-phase coil 6 in the nine slots S4, S7, S10, S11, S14, S17, S21, S24, and S27 assigned to the W-phase are added. It is a thing.

  FIG. 4 is a diagram in which the nine unit voltage vectors in each phase shown in FIG. 3 are rearranged in the order of the unit voltage vector and the voltage vector angle. In FIG. 4, the U-phase, V-phase, and W-phase voltage vectors are shifted by 120 degrees. The nine unit voltage vectors of each phase are arranged along an arc passing through the base end and the tip end of the arrow indicating the voltage vector of the phase. This is the sum of nine unit voltage vectors whose phases are slightly shifted in direction, and the voltage waveform of each phase is a combination of nine unit voltage waveforms whose phases are shifted slightly. It is shown that.

  FIG. 5 is a diagram illustrating a waveform of the voltage Vuo between the U-phase output terminal TU and the neutral point terminal TO. The unit voltage generated in the coil portion wound around one slot S is large when the entire magnetic pole P overlaps with the slot S during the rotation of the rotor 1, and a part of the magnetic pole P (the tip or the rear in the rotation direction). When only the (end) overlaps the slot S, it is small. Therefore, the unit voltage waveform when one magnetic pole P passes through the slot S becomes convex. Further, the polarity of the voltage is different when the magnetic pole P is an N pole and when it is an S pole. Therefore, a unit voltage having a waveform in which a positive convex and a negative convex are alternately generated in the coil portion wound in one slot S. Since the voltage waveform of each phase is a combination of nine unit voltage waveforms that are slightly shifted in phase, the waveform of the inter-terminal voltage Vou of the U-phase coil 4 is close to a sine wave as shown in FIG. Become. The waveform of the voltage between the terminals of the V-phase coil 5 and the W-phase coil 6 is also close to a sine wave like Vou. As shown in FIG. 6, the waveform of the voltage Vuv between the output terminals TU and TV is closer to a sine wave.

  FIG. 7 is a diagram showing a waveform of the voltage Vuo between terminals of the U-phase coil of the conventional three-phase AC generator, and is a diagram contrasted with FIG. The conventional three-phase AC generator has a periodicity in which three slots are opposed to two magnetic poles, and the three slots are assigned to the U phase, the V phase, and the W phase. Therefore, even in the case of the multipolar type, the voltage waveform of each phase is a combination of a plurality of unit voltage waveforms having the same phase, and is a waveform in which positive and negative convexes appear alternately. Comparing FIG. 5 and FIG. 7, it is clear that the present invention is closer to a sine wave.

  In addition, when 3 slots are added to the conventional 2n pole, 3n slot (n = 1) 3 phase AC generator, and a 3 phase AC generator having 3 × 1 + 3 = 6 slots is configured, the voltage waveform is shown in FIG. The voltage waveform improvement effect is not recognized.

  FIG. 8 is a diagram showing a modification of the first embodiment and is a diagram contrasted with FIG. In FIG. 8, this three-phase alternating current generator is obtained by adding 3 slots to the conventional 2n pole, 3n slot (n = 2) three-phase alternating current generator and providing 3 × 2 + 3 = 9 slots. . In this three-phase AC generator, three slots S1, S4 and S7 arranged at intervals of 120 degrees out of nine slots S1 to S9 are assigned to the U phase, W phase and V phase, respectively, and the remaining 6 The slots S2, S3, S5, S6, S8, and S9 are sequentially assigned to the U phase, V phase, and W phase one by one. The U-phase coil 4 is continuously wound around the three slots S1, S2, and S6 assigned to the U-phase. The V-phase coil 5 is continuously wound around the three slots S3, S7, and S8 assigned to the V-phase. The W-phase coil 6 is continuously wound around the three slots S4, S5, and S9 assigned to the W-phase.

  FIG. 9 is a diagram illustrating voltage vectors of the U phase, the V phase, and the W phase. The U-phase voltage vector is obtained by adding three unit voltage vectors generated in the U-phase coil 4 in the three slots S1, S2, and S6 assigned to the U-phase. The V-phase voltage vector is obtained by adding three unit voltage vectors generated in the V-phase coil 5 in the three slots S3, S7, and S8 assigned to the V-phase. The W-phase voltage vector is obtained by adding three unit voltage vectors generated in the W-phase coil 6 in the three slots S4, S5, and S9 assigned to the W-phase. In this three-phase AC generator, as shown in FIG. 10, the number of steps in the output voltage waveform is increased as compared with the conventional case, and a slight waveform improvement effect is recognized.

  FIG. 11 is a diagram showing another modification of the first embodiment, and is a diagram contrasted with FIG. In FIG. 11, this three-phase alternating current generator is obtained by adding 3 slots to the conventional 2n pole, 3n slot (n = 14) three-phase alternating current generator and providing 3 × 14 + 3 = 45 slots. . In this three-phase AC generator, three slots S1, S16, and S31 arranged at intervals of 120 degrees out of 45 slots S1 to S45 are assigned to the U phase, the W phase, and the V phase, respectively, and the remaining 42 The slots S2 to S15, S17 to S30, and S32 to S45 are sequentially assigned to the U phase, the V phase, and the W phase one by one. The U-phase coil 4 is continuously wound around the 15 slots S1, S2, S5, S8, S11, S14, S18,... Assigned to the U-phase. The V-phase coil 5 is continuously wound around the 15 slots S3, S6, S9, S12, S15, S19,... Assigned to the V-phase. The W phase coil 6 is continuously wound around the 15 slots S4, S7, S10, S13, S16, S17, S20,... Assigned to the W phase.

  FIG. 12 is a diagram illustrating voltage vectors of the U phase, the V phase, and the W phase. The U-phase voltage vector is obtained by adding 15 unit voltage vectors generated in the U-phase coil 4 in the 15 slots S assigned to the U-phase. The V-phase voltage vector is obtained by adding 15 unit voltage vectors generated in the V-phase coil 5 in the 15 slots S assigned to the V-phase. The W-phase voltage vector is obtained by adding 15 unit voltage vectors generated in the W-phase coil 6 in the 15 slots S assigned to the W-phase. Although not shown, the output voltage waveform of the three-phase AC generator is almost a sine wave.

As described above, the relationship between the number of magnetic poles and the number of slots of the three-phase AC generator to which the winding method according to the present invention can be applied is examined. As a result, when the number of magnetic poles is a multiple of 6, the above winding method is realized. It turned out that the number of magnetic poles Np and the number of slots Ns are expressed by the following equations (1) and (2).
Np = (3 × A) ± 1 (1)
Ns = (Np × 3/2) × B + 3 (2)
However, Np is 4 or more, A is an odd number of 1 or more, and B is a natural number.

  FIG. 13 is a diagram showing the relationship between the number of magnetic poles Np and the number of slots Ns. Although FIG. 13 shows the case where the number of magnetic poles Np is 70, it can be realized even when the number of magnetic poles Np is larger. Moreover, although the case where B is 1 and 2 is shown, it can be realized even when B is 3 or more.

  FIG. 14 is a diagram comparing the cogging torque of the conventional three-phase AC generator and the cogging torque of the three-phase AC generator of the present invention. The cogging torque increases as the number of magnetic poles P and slots S overlapping in the same state increases. For example, in a conventional 4-pole, 6-slot three-phase AC generator, the magnetic pole P and the slot S overlap at two locations of 0 degrees and 180 degrees. In contrast, in the four-pole, nine-slot three-phase AC generator of the present invention, the magnetic pole P and the slot S overlap only at a position of 0 degrees. Therefore, the present invention has a smaller cogging torque. Here, if the magnitude of the cogging torque is expressed by the reciprocal of the number of magnetic poles and the least common multiple of the number of slots, the cogging torque of the conventional 4-pole, 6-slot three-phase AC generator is 1/12. The cogging torque of the 4-pole, 9-slot of the invention is 1/36, which is 33.3% of the conventional one. The effect of reducing the cogging torque of the present invention becomes more prominent as the number of magnetic poles increases. In the 16-pole, 27-slot three-phase AC generator shown in FIG. 1, the cogging torque is about 1/10 of the conventional one.

[Embodiment 2]
15 is a diagram showing a configuration of a three-phase AC generator according to Embodiment 2 of the present invention, and is a diagram compared with FIG. Referring to FIG. 15, this three-phase AC generator is different from the three-phase AC generator of FIG. 1 in that the number of slots is reduced from 27 to 21.

  FIG. 16 is a diagram schematically illustrating a winding method of the coils 4 to 6. In this winding method, 24 slots S that are 3/2 times the number of magnetic poles Np = 16 are virtually arranged at equiangular intervals, and the 24 slots S are sequentially arranged one by one in the U phase, V phase, W The three slots S allocated to the phases, arranged at 120 degree intervals among the 24 slots S and respectively allocated to the U phase, the W phase, and the V phase are deleted, and the remaining 21 slots S1 to S21 are deleted. Rearrange at equiangular intervals. The U-phase coil 4 is continuously wound around the seven slots S3, S6, S8, S11, S14, S16, and S19 assigned to the U-phase. The V-phase coil 5 is continuously wound around the seven slots S1, S4, S7, S9, S12, S17, and S20 assigned to the V-phase. The W-phase coil 6 is continuously wound around the seven slots S2, S5, S10, S13, S15, S18, and S21 assigned to the W-phase. One ends of the coils 4, 5 and 6 are connected to the output terminals TU, TV and TW, respectively, and the other ends thereof are commonly connected to the neutral point terminal TO.

  In other words, this three-phase AC generator has three slots removed at 120 degree intervals from the conventional 2n pole, 3n slot (n = 8) three-phase AC generator, and the remaining 21 slots are rearranged at equiangular intervals. It is a thing. This eliminates the periodicity that three slots are opposed to two magnetic poles, and three slots are assigned to the U phase, V phase, and W phase, thereby improving the output voltage waveform and reducing cogging torque. Can do. The voltage vector of each phase is the sum of seven unit voltage vectors that are slightly shifted in direction, and the voltage waveform of each phase is a composite of seven unit voltage waveforms that are slightly shifted in phase, which is close to a sine wave. .

  In addition, when 3 slots are deleted from a conventional 2n pole, 3n slot (n = 2) 3 phase AC generator, and a 3 phase AC generator having 3 × 2-3 = 3 slots is configured, or slot When the number is 6 or less, the voltage waveform is the same as in FIG. 7, and the voltage waveform improvement effect is not recognized.

  FIG. 17 is a diagram showing a modification of the second embodiment, and is a diagram contrasted with FIG. In FIG. 17, this three-phase AC generator has three slots removed from the conventional 2n pole, 3n slot (n = 4) three-phase AC generator, and 3 × 4−3 = 9 slots are provided. It is. In this three-phase AC generator, twelve slots S that are 3/2 times the number of magnetic poles Np = 8 are virtually arranged at equiangular intervals, and the twelve slots S are sequentially arranged in the U phase, V phase, and W phase. Of the 12 slots S, which are arranged at intervals of 120 degrees and are assigned to the U phase, V phase and W phase, respectively, and the remaining 9 slots S1 to S9 are deleted. Rearrange at angular intervals. The U-phase coil 4 is continuously wound around the three slots S3, S5, and S7 assigned to the U-phase. The V-phase coil 5 is continuously wound around the three slots S1, S6, and S8 assigned to the V-phase. The W-phase coil 6 is continuously wound around the three slots S2, S4, S9 assigned to the W-phase. This modified example also improves the voltage waveform.

  FIG. 18 is a diagram showing another modification of the second embodiment and is a diagram contrasted with FIG. In FIG. 18, this three-phase AC generator is obtained by removing 3 slots from the conventional 2n pole, 3n slot (n = 14) three-phase AC generator and providing 3 × 14−3 = 39 slots. It is. In this three-phase AC generator, 42 slots S that are 3/2 times the number of magnetic poles Np = 28 are virtually arranged at equiangular intervals, and the 42 slots S are sequentially arranged in the U phase, V phase, and W phase. Of the 42 slots S, which are arranged at intervals of 120 degrees and are assigned to the U phase, the W phase and the V phase, respectively, and the remaining 39 slots S1 to S39 are deleted. Rearrange at angular intervals. The U-phase coil 4 is continuously wound around the 13 slots S3, S6, S9, S12, S14, S17,... Assigned to the U-phase. The V-phase coil 5 is continuously wound around the 13 slots S1, S4, S7, S10, S13, S15,... Assigned to the V-phase. The W-phase coil 6 is continuously wound around the 13 slots S2, S5, S8, S11, S16, S19, S22,... Assigned to the W-phase. This modified example also improves the voltage waveform.

As described above, the relationship between the number of magnetic poles and the number of slots of the three-phase AC generator to which the winding method according to the present invention can be applied is examined. As a result, when the number of magnetic poles is a multiple of 6, the above winding method is realized. It was found that the number of magnetic poles Np and the number of slots Ns are expressed by the following equations (3) and (4).
Np = (3 × A) ± 1 (3)
Ns = (Np × 3/2) × B-3 (4)
However, Np is 4 or more, Ns is 9 or more, A is an odd number of 1 or more, and B is a natural number.

  FIG. 19 is a diagram illustrating the relationship between the number of magnetic poles Np and the number of slots Ns. FIG. 19 shows the case where the number of magnetic poles Np is 70, but it can be realized even when the number of magnetic poles Np is larger. Moreover, although the case where B is 1 and 2 is shown, it can be realized even when B is 3 or more.

  FIG. 20 is a diagram comparing the cogging torque of the conventional three-phase AC generator and the cogging torque of the three-phase AC generator of the present invention. The cogging torque increases as the number of magnetic poles P and slots S overlapping in the same state increases. For example, in a conventional 20-pole, 30-slot three-phase AC generator, the magnetic pole P and the slot S overlap at six locations of 0 degrees, 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees. On the other hand, in the 20-pole, 27-slot three-phase AC generator of the present invention, the magnetic pole P and the slot S overlap only at the 0 degree position. Therefore, the present invention has a smaller cogging torque. Here, assuming that the magnitude of the cogging torque is expressed by the reciprocal of the least common multiple of the number of magnetic poles and the number of slots, the cogging torque of the conventional 20-pole, 30-slot three-phase AC generator is 1/60. The cogging torque of the 20 poles and 27 slots of the invention is 1/540, which is 11.1% of the conventional. The effect of reducing the cogging torque of the present invention becomes more prominent as the number of magnetic poles increases. In the 28-pole, 39-slot three-phase AC generator shown in FIG.

  In the first and second embodiments, the case where the present invention is applied to a three-phase AC generator has been described. However, the present invention is not limited to this, and the present invention is not limited to any rotating electrical device (generator, Needless to say, the present invention can also be applied to an electric motor).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the structure of the three-phase alternating current generator by Embodiment 1 of this invention. It is a figure which shows typically the winding method of the three-phase alternating current generator shown in FIG. It is a figure which shows the three-phase voltage vector of the three-phase alternating current generator shown in FIG. It is another figure which shows the three-phase voltage vector of the three-phase alternating current generator shown in FIG. It is a figure which shows the voltage waveform of the three-phase alternating current generator shown in FIG. It is another figure which shows the voltage waveform of the three-phase alternating current generator shown in FIG. 6 is a diagram illustrating a comparative example of the first embodiment. FIG. 5 is a diagram illustrating a modification example of the first embodiment. FIG. It is a figure which shows the three-phase voltage vector of the three-phase alternating current generator shown in FIG. It is a figure which shows the voltage waveform of the three-phase alternating current generator shown in FIG. It is a figure which shows the other example of a change of Embodiment 1. FIG. It is a figure which shows the three-phase voltage vector of the three-phase alternating current generator shown in FIG. FIG. 4 is a diagram showing the relationship between the number of magnetic poles and the number of slots in the first embodiment. FIG. 6 is a diagram illustrating an effect of the first embodiment. It is a figure which shows the structure of the three-phase alternating current generator by Embodiment 2 of this invention. It is a figure which shows typically the winding method of the three-phase alternating current generator shown in FIG. It is a figure which shows the example of a change of Embodiment 2. FIG. It is a figure which shows the other example of a change of Embodiment 2. FIG. It is a figure which shows the relationship between the magnetic pole number in Embodiment 2, and the number of slots. It is a figure which shows the effect of Embodiment 2. FIG.

Explanation of symbols

1 rotor, 2 flywheel, 3 stator, 4 U phase coil, 5 V phase coil, 6 W phase coil, P magnetic pole, S slot, TU, TV, TW output terminal, TO neutral point terminal.

Claims (2)

In a three-phase AC rotating machine including a stator including a plurality of slots and a rotor including a plurality of magnetic poles,
3n + 3 slots (where n is an integer of 2 or more) are arranged at equiangular intervals,
Of the 3n + 3 slots, the first to third slots arranged at intervals of 120 degrees are assigned to the U phase, the W phase, and the V phase, respectively.
N slots between the first and second slots are sequentially assigned to the U phase, the V phase, and the W phase one by one,
N slots between the second and third slots are sequentially assigned to W phase, U phase, V phase one by one,
N slots between the third and first slots are sequentially assigned to V phase, W phase, U phase one by one,
A U-phase coil is continuously wound in the same direction in n + 1 slots assigned to the U-phase,
A V-phase coil is continuously wound in the same direction in n + 1 slots assigned to the V-phase,
A three-phase AC rotating machine, wherein a W-phase coil is wound continuously in the same direction in n + 1 slots assigned to the W-phase.   The three-phase AC rotating machine according to claim 1, wherein the number of the magnetic poles is an even number of 4 or more and 2n or less.

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