JP7159800B2 - Rotating electric machine - Google Patents

Description

The present invention relates to a rotating electric machine having two stators.

Conventionally, a rotor in which a rotor core and permanent magnets are alternately arranged in a circumferential direction to form an annular shape, a first stator provided on the outer peripheral side of the rotor with an air gap, and an air gap on the inner peripheral side of the rotor. A rotary electric machine including a second stator provided with a gap is known.

In Patent Document 1, the above configuration is provided, the permanent magnets are magnetized in the circumferential direction of the rotor, and the magnetization directions of the adjacent permanent magnets are opposite, and the first stator is magnetized in the circumferential direction on the surface facing the rotor. a plurality of first slots formed at equal intervals in the rotor and windings housed in each of the first slots; and a second stator formed at equal intervals in the circumferential direction on a surface facing the rotor. A vernier motor is disclosed having a plurality of interleaved secondary slots and a winding housed in each secondary slot. When the number of the first slots and the number of the second slots are the same, and the period of the slots is a, the circumferential position of the first slots and the circumferential position of the second slots are relative. The second stator is arranged with respect to the first stator so as to be shifted by half the period a of the slots (a/2).

JP 2016-5412 A

A motor generates rotational torque by synchronizing a rotational magnetic flux component produced by a stator and a magnetic flux component produced by a rotor. In a vernier motor or a fractional slot motor, there are a plurality of rotating magnetic flux components created by the stator. While there are rotating magnetic flux components that contribute to torque generation, there are rotating magnetic flux components that do not contribute to torque generation. A rotating magnetic flux component that does not contribute to the generation of torque generates a loss and deteriorates the rotational efficiency of the motor.

In Patent Document 1, the main purpose is to increase the number of interlinking magnetic fluxes in the windings of each stator by effectively using the magnetic flux generated by the permanent magnet of the rotor. No countermeasures have been taken against the occurrence of loss due to rotating magnetic flux components that do not rotate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotating electrical machine having two stators, which rotates with high efficiency by suppressing loss due to a rotating magnetic flux component that does not contribute to torque generation.

A rotary electric machine according to the present invention employs the following means to achieve the above objects.

A rotary electric machine according to the present invention includes a rotor formed in an annular shape by alternately arranging rotor cores and permanent magnets in a circumferential direction, and a first end surface of the rotor facing a first end face, with an air gap provided with respect to the rotor. and a second stator facing a second end face opposite to the first end face of the rotor and provided with an air gap with respect to the rotor, wherein the permanent magnets are magnetized in the circumferential direction of the rotor such that the magnetization directions of the adjacent permanent magnets are opposite; It has a plurality of first slots formed at equal intervals in the circumferential direction and first windings housed in each of the first slots, and the second stator includes the second stator of the rotor. a plurality of second slots formed at regular intervals in the circumferential direction on a surface facing the end surface of the first slot; the number of the second slots is the same as the number of the second slots, the first slots and the second slots are arranged to face each other, and the first winding and the A plurality of phases of alternating current is supplied to the second winding, and the first winding housed in the first slot and the second slot facing the first slot The currents supplied to the second winding have a phase difference of 180 degrees, the number of pole pairs Z formed by the permanent magnets of the rotor, the number n of the first slots, and the number n of the first slots. The pole pair number p formed by applying a current to the winding of satisfies the relationship of the following formula (1),
Z=n±p (1)
This is the gist of it.

In one aspect of the present invention, the number of pole pairs Z formed by the permanent magnets of the rotor and the number n of the first slots may satisfy the relationship of the following formula (2).
Z=n±1 (2)

In one aspect of the present invention, the first winding and the second winding are three-phase windings, and the first winding housed in the first slot and the first winding are three-phase windings. The second windings housed in the second slots facing the slots may be composed of windings of the same phase.

In one aspect of the present invention, the first stator may be arranged radially outside the rotor, and the second stator may be arranged radially inside the rotor.

In one aspect of the present invention, the first winding is wound around the first stator by distributed winding, and the second winding is wound around the second stator by distributed winding. You can say that there is.

According to the present invention, the fundamental wave magnetic flux component that does not contribute to the generation of torque among the rotating magnetic flux components produced by the first stator, and the fundamental wave magnetic flux component that does not contribute to the generation of torque among the rotating magnetic flux components produced by the second stator. and cancel each other out, the loss due to those magnetic flux components does not occur or is suppressed. On the other hand, the harmonic magnetic flux component that contributes to torque generation among the rotating magnetic flux components produced by the first stator and the harmonic magnetic flux component that contributes to torque generation among the rotating magnetic flux components produced by the second stator cancel each other. It generates a magnetic flux without causing a rotor to generate torque. As a result, the rotating electric machine rotates with high efficiency.

1 is a radial cross-sectional view of a rotating electrical machine; FIG. 1 is an axial cross-sectional view of a rotating electrical machine; FIG. It is a figure which shows an example of the connection relationship of an outer winding and an inner winding. FIG. 2 is a simplified diagram showing a rotating magnetic flux component produced by a W-phase outer winding of a rotating electric machine; FIG. 2 is a diagram showing a simplified rotating magnetic flux component produced by a W-phase inner winding of a rotating electric machine; FIG. 4 is a diagram showing phase current-torque characteristics of the rotary electric machine of the embodiment and a conventional motor; It is a radial cross-sectional view of a rotating electric machine of another embodiment.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. The shapes and the like described below are examples for explanation, and can be changed as appropriate according to the specifications of the rotating electric machine. The same reference numerals are given to the same elements in all the drawings, and redundant explanations are omitted.

FIG. 1 is a radial cross-sectional view of a rotating electric machine 10 according to an embodiment of the present invention, showing a cross section of 180 degrees. FIG. 2 is an axial cross-sectional view of the rotating electric machine 10 according to the embodiment of the present invention, showing a cross section of the upper half. As shown in FIG. 1, the rotary electric machine 10 includes a rotor 12 formed in an annular shape by alternately arranging rotor cores 30 and permanent magnets 32 in the circumferential direction, and an air gap 50 formed radially outwardly of the rotor 12. The provided outer stator 14 (also referred to as a first stator; hereinafter, the term is similarly expressed in parentheses), and the inner stator 16 ( second stator).

The permanent magnets 32 are magnetized in the circumferential direction of the rotor 12, and the magnetization directions of adjacent permanent magnets 32 are opposite. In FIG. 1, the direction of magnetization of some of the permanent magnets 32 is indicated by arrows. The adjacent permanent magnet 32b is magnetized to have an S pole on the upper side and an N pole on the lower side, and the permanent magnet 32c adjacent to the permanent magnet 32b is magnetized to have an N pole on the upper side and an S pole on the lower side. The number of permanent magnets 32 is 46 in total, and the number of pole pairs Z formed by the permanent magnets 32 is 23.

The outer stator 14 is provided to face the outer end surface 46 (first end surface) of the rotor 12, and includes an outer stator core 15 (first stator core) and an outer winding 38 (first winding). The outer stator core 15 includes an annular outer yoke 33 (first yoke) and a plurality of outer teeth 36 (first yoke) protruding radially inward from the inner peripheral surface of the outer yoke 33 and spaced apart in the circumferential direction. 1 tooth) and an outer slot 34 (first slot) formed between each outer tooth 36 . As shown in FIG. 1 , the plurality of outer slots 34 are formed at regular intervals in the circumferential direction on the surface facing the outer end surface 46 of the rotor 12 .

The outer winding 38 is a winding (three-phase winding) through which a three-phase alternating current flows, and is inserted (stored) in each of the outer slots 34 and wound around the outer stator core 15 by distributed winding. FIG. 1 shows a simplified view of the outer winding 38 in each outer slot 34 and a portion of the W-phase outer winding 38w. The outer winding 38 with a dot in the center of the circle in each outer slot 34 indicates a winding through which current flows from the back of the paper to the front, and the outer winding 38 with an X in the circle indicates It shows the windings through which the current flows from the front to the back of the paper. Since AC current flows through the outer winding 38, the direction of the current in the outer winding 38 within each outer slot 34 naturally changes with time.

The inner stator 16 is provided facing an inner end face 48 (second end face) of the rotor 12, and includes an inner stator core 17 (second stator core) and an inner winding 44 (second winding). The inner stator core 17 includes an annular inner yoke 39 (second yoke) and a plurality of inner teeth 42 (second yoke) projecting radially outward from the outer peripheral surface of the inner yoke 39 and spaced apart in the circumferential direction. teeth) and inner slots 40 (second slots) formed between each inner tooth 42 . As shown in FIG. 1 , the plurality of inner slots 40 are formed on the surface facing the inner end surface 48 of the rotor 12 at regular intervals in the circumferential direction.

Like the outer winding 38 described above, the inner winding 44 is a winding (three-phase winding) through which a three-phase alternating current flows, and is inserted (stored) in each inner slot 40 and distributed in the inner stator core 17. It is wound in rolls. FIG. 1 shows a simplified view of the inner winding 44 in each inner slot 40 and part of the W-phase inner winding 44w. The inner windings 44 with a dot in the center of the circle in each inner slot 40 indicate the windings in which the current flows from the back to the front of the paper surface, and the inner windings 44 with an X in the circle are It shows the windings through which the current flows from the front to the back of the paper. It should be noted that, like the outer winding 38, an alternating current flows through the inner winding 44, so naturally the direction of current flow in the inner winding 44 within each inner slot 40 changes with time.

The number n of outer slots 34 of the outer stator 14 and the number n of inner slots 40 of the inner stator 16 are the same, 24 each. Each outer slot 34 and each inner slot 40 are arranged at opposing positions.

FIG. 3 is a diagram showing an example of the connection relationship between the outer winding 38 of the outer stator 14 and the inner winding 44 of the inner stator 16. As shown in FIG. U-, V-, and W-phase windings 38u, 38v, and 38w of the outer winding 38, and U-, V-, and W-phase windings 44u, 44v, and 44w of the inner winding 44 are connected for each phase. They are connected in series to form a set of U-, V-, and W-phase windings, which are star-connected. The windings 38u, 38v, 38w and the windings 44u, 44v, 44w may be connected in parallel for each phase, and the paired windings of each phase may be delta-connected. .

As shown in FIG. 1, the outer winding 38 housed in the outer slot 34 and the inner winding 44 housed in the inner slot 40 facing the outer slot 34 are composed of windings of the same phase. . However, the winding direction of the outer winding 38 to the outer stator core 15 and the winding direction of the inner winding 44 to the inner stator core 17 are opposite. Therefore, the current supplied to the outer winding 38 housed in the outer slot 34 and the current supplied to the inner winding 44 housed in the inner slot 40 facing the outer slot 34 have a phase difference of 180 degrees. That is, they have an electrical angle phase difference of 180 degrees. Here, the pole pair number p formed by applying current to the outer winding 38 and the pole pair number p formed by applying current to the inner winding 44 are the same, ie, 1, respectively.

The rotary electric machine 10 of this embodiment functions as a vernier motor and satisfies the magnetic pole relationship of the vernier motor. Namely, the number of pole pairs Z formed by the permanent magnets 32 of the rotor 12, the number n of the outer slots 34 or inner slots 40, and the number p of pole pairs formed by applying current to the outer windings 38 or inner windings 44. satisfies the relationship of the following formula (1).

Z=n±p (1)

As described above, in this embodiment, Z=23, n=24, and p=1. Also, in the present embodiment, p=1, so the relationship of the following expression (2) is satisfied.

Z=n±1 (2)

As shown in FIG. 2, the rotor core 30 is supported by a support portion 20 connected to the rotating shaft 18. As shown in FIG. The rotary shaft 18 is rotatably held by the case 22 via a bearing 24 and protrudes outside the case 22 to output the rotational force of the rotor 12 to the outside of the case 22 . The outer stator 14 and the inner stator 16 are fixed to the inner surface of the case 22 and arranged with an air gap with respect to the rotor 12 . A three-phase alternating current is supplied to the outer winding 38 of the outer stator 14 and the inner winding 44 of the inner stator 16, and each stator generates rotating magnetic flux. Rotational torque is generated.

Next, the effects of the rotary electric machine 10 of this embodiment will be described. FIG. 4 is a simplified diagram showing the rotating magnetic flux components MA1 and MA2 produced by the W-phase outer winding 38w of the rotating electrical machine 10. FIG. It is a figure which shows simply the magnetic flux components MB1 and MB2. As described above, the currents supplied to the outer winding 38 housed in the outer slot 34 and the inner winding 44 housed in the inner slot 40 facing the outer slot 34 have a phase difference of 180 degrees. Therefore, in FIGS. 4 and 5, a current flows through the W-phase outer winding 38w from the back to the front of the paper, while the W-phase inner winding 44w opposite thereto flows from the front to the back of the paper. There is a current flowing towards

As shown in FIG. 4, when a current flows through the W-phase outer winding 38w from the back to the front of the paper, counterclockwise rotating magnetic flux components MA1 and MA2 are generated according to the right-handed screw rule. The rotating magnetic flux component MA1 is a fundamental wave magnetic flux component that does not contribute to the rotating torque of the rotor 12. It is a rotating magnetic flux component that crosses the rotor 12 again after passing through and returns to the outer yoke 33 of the outer stator 14 . On the other hand, the rotating magnetic flux component MA2 is a harmonic magnetic flux component that contributes to the rotating torque of the rotor 12, and rotates through the outer yoke 33 of the outer stator 14 and the vicinity of the air gap 50 between the outer stator 14 and the rotor 12. is the rotating magnetic flux component.

As shown in FIG. 5, when a current flows through the W-phase inner winding 44w from the front to the back of the paper, clockwise rotating magnetic flux components MB1 and MB2 are generated according to the right-handed screw rule. The rotating magnetic flux component MB1 is a fundamental wave magnetic flux component that does not contribute to the rotating torque of the rotor 12, passes through the inner yoke 39 of the inner stator 16, across the rotor 12, reaches the outer yoke 33 of the outer stator 14, and reaches the outer yoke 33. It is a rotating magnetic flux component that crosses the rotor 12 again and returns to the inner yoke 39 of the inner stator 16 after passing through. On the other hand, the rotating magnetic flux component MB2 is a harmonic magnetic flux component that contributes to the rotating torque of the rotor 12, and rotates through the inner yoke 39 of the inner stator 16 and the vicinity of the air gap 52 between the inner stator 16 and the rotor 12. is the rotating magnetic flux component.

As shown in FIGS. 4 and 5, the fundamental wave magnetic flux component MA1 produced by the outer stator 14 and the fundamental wave magnetic flux component MB1 produced by the inner stator 16 are opposite direction magnetic flux components passing through the same route, so they cancel each other out. It will be. As a result, the loss due to the fundamental wave magnetic flux components MA1 and MB1 does not occur, or the loss can be suppressed. On the other hand, the harmonic magnetic flux component MA2 produced by the outer stator 14 and the harmonic magnetic flux component MB2 produced by the inner stator 16 generate magnetic flux without canceling each other, causing the rotor 12 to generate rotational torque. As a result, the rotary electric machine 10 rotates with high efficiency. Note that the W-phase outer winding 38w and the inner winding 44w have been described here, but the U-phase outer and inner windings and the V-phase outer and inner windings also generates a similar rotating magnetic flux component.

FIG. 6 is a graph showing changes in torque with respect to phase current (torque characteristics TC1) in the rotary electric machine 10 of the present embodiment and changes in torque with respect to phase currents (torque characteristics TC2) in the conventional motor. Here, the motor of the prior art is the motor described in Patent Document 1. In the motor of the prior art, as shown in the torque characteristic TC2, when the effective value of the current flowing through each phase of the three-phase winding is increased, the torque value saturates halfway and large rotational torque cannot be obtained. . This is because when the effective value of the current flowing in each phase of the three-phase winding is increased, the fundamental wave magnetic flux component created by the outer stator (first stator) and the inner stator (second stator) This is due to magnetic saturation, particularly in the outer yoke of the outer stator and the inner yoke of the inner stator, due to the generated fundamental wave magnetic flux component. Magnetic saturation causes loss and deteriorates the conversion efficiency from electrical energy to mechanical energy.

On the other hand, in the rotary electric machine 10 of the present embodiment, magnetic saturation is suppressed because the fundamental wave magnetic flux component produced by the outer stator 14 and the fundamental wave magnetic flux component produced by the inner stator 16 cancel each other out. Therefore, as indicated by the torque characteristic TC1, by increasing the effective value of the current flowing through each phase of the three-phase winding, a large rotational torque can be obtained without saturating the torque value.

Next, a rotating electric machine according to another embodiment will be described. FIG. 7 is a radial cross-sectional view of a rotating electric machine 80 of another embodiment. 7 and the rotating electric machine 10 of FIG. The number of pole pairs formed by line 44, otherwise the same. That is, in the rotating electrical machine 80, the number n of the outer slots 34 of the outer stator 14 and the number n of the inner slots 40 of the inner stator 16 are each 24, like the rotating electrical machine 10 described above. As in the rotating electrical machine 10 described above, the outer winding 38 is wound around the outer stator core 15 with distributed winding, and the inner winding 44 is also wound around the inner stator core 17 with distributed winding.

However, unlike the rotating electrical machine 10 described above, the rotating electrical machine 80 has 44 permanent magnets 32 and the number of pole pairs Z formed by the permanent magnets 32 is 22. As shown in FIG. Further, unlike the rotating electrical machine 10 described above, the rotating electrical machine 80 has a pole pair number p formed by applying a current to the outer winding 38 and a pole pair number p formed by applying a current to the inner winding 44. , respectively 2. In this way, the rotary electric machine 80 has Z=22, n=24, and p=2, and, like the rotary electric machine 10, satisfies the magnetic pole relationship of the vernier motor of the above equation (1), and functions as a vernier motor. do. In the rotating electric machine 80 as well, the same effects as those of the rotating electric machine 10 can be obtained.

In the rotating electric machines of the embodiments described above, the outer winding 38 is wound around the outer stator core 15 by distributed winding, and the inner winding 44 is also wound around the inner stator core 17 by distributed winding. However, the outer winding 38 may be wound around the outer stator core 15 with concentrated winding, and the inner winding 44 may also be wound around the inner stator core 17 with concentrated winding.

Further, the rotary electric machine of each embodiment described above is a radial gap motor in which an outer stator 14 (first stator) and an inner stator 16 (second stator) are arranged with air gaps on both sides of the rotor 12 in the radial direction. Met. However, it may be an axial gap motor in which the first stator 14 and the second stator 16 are arranged with air gaps on both sides of the rotor 12 in the axial direction.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to such respective embodiments in any way, and can of course be embodied in various forms without departing from the gist of the present invention. is.

10, 80 rotary electric machine, 12 rotor, 14 outer stator (first stator), 15 outer stator core (first stator core), 16 inner stator (second stator), 17 inner stator core (second stator core), 18 Rotating shaft 20 Support part 22 Case 24 Bearing 30 Rotor core 32, 32a, 32b, 32c Permanent magnet 33 Outer yoke (first yoke) 34 Outer slot (first slot) 36 Outer teeth ( first tooth), 38, 38u, 38v, 38w outer winding (first winding, winding), 39 inner yoke (second yoke), 40 inner slot (second slot), 42 inner tooth (second teeth), 44, 44u, 44v, 44w inner winding (second winding, winding), 46 outer end face (first end face), 48 inner end face (second end face), 50, 52 air gap, MA1, MA2, MB1, MB2 rotating magnetic flux component, TC1, TC2 torque characteristic.

Claims (5)

a rotor formed in an annular shape by alternately arranging rotor cores and permanent magnets in a circumferential direction;
a first stator facing a first end surface of the rotor and provided with an air gap with respect to the rotor;
a second stator facing a second end face opposite to the first end face of the rotor and provided with an air gap with respect to the rotor;
the permanent magnets are magnetized in the circumferential direction of the rotor, and the magnetization directions of the adjacent permanent magnets are opposite;
The first stator includes a plurality of first slots formed at equal intervals in a circumferential direction on a surface of the rotor facing the first end surface, and first slots housed in the respective first slots. and a winding;
The second stator includes a plurality of second slots formed at equal intervals in a circumferential direction on a surface of the rotor facing the second end surface, and second slots housed in the respective second slots. and a winding;
the number of the first slots and the number of the second slots are the same;
Each of the first slots and each of the second slots are arranged at opposing positions,
A multi-phase alternating current is supplied to the first winding and the second winding,
The current supplied to the first winding housed in the first slot and the second winding housed in the second slot opposite to the first slot is 180 degrees. having a phase difference,
The number of pole pairs Z formed by the permanent magnets of the rotor, the number n of the first slots, and the number p of pole pairs formed by applying a current to the first winding are expressed by the following equation (1): satisfy the relationship of
Z=n±p (1)
A rotating electrical machine characterized by: The rotating electric machine according to claim 1,
The number of pole pairs Z formed by the permanent magnets of the rotor and the number n of the first slots satisfy the relationship of the following formula (2):
Z=n±1 (2)
A rotating electrical machine characterized by: The rotating electric machine according to claim 1 or 2 ,
The first winding and the second winding are three-phase windings,
The first winding housed in the first slot and the second winding housed in the second slot facing the first slot are composed of windings of the same phase. Ru
A rotating electrical machine characterized by: The rotating electric machine according to any one of claims 1 to 3 ,
The first stator is arranged radially outward of the rotor,
The second stator is arranged radially inward of the rotor,
A rotating electrical machine characterized by: The rotating electrical machine according to claim 3 ,
The first winding is wound around the first stator by distributed winding,
The second winding is wound around the second stator with distributed winding,
A rotating electrical machine characterized by:

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