JP2019122183A - Stator of rotating electric machine and rotating electric machine - Google Patents

Abstract

To provide a stator of a rotating electrical machine which has high reliability by suppressing inter-turn dielectric breakdown in a motor stator due to an increase in surge sharing voltage.SOLUTION: A stator of a rotating electrical machine includes a stator core 121, a plurality of slots 123 provided in the stator core 121, a plurality of three-phase segment coils 200 disposed in each of the plurality of slots 123, and a first insulating member 210 disposed between the stator core 121 and the plurality of segment coils 200, and a second insulating member 211 is provided between different phases of a plurality of segment coils 200b and 200c disposed in the respective slots 123, and between the same phases of the segment coils 200a and 200b from among the plurality of segment coils 200.SELECTED DRAWING: Figure 6A

Description

  The present invention relates to a stator of a rotating electrical machine and a rotating electrical machine.

  Electric rotating machines closely connected to industry and life are the basic devices that support modern society. In particular, in hybrid vehicles and electric vehicles, which are spreading from the viewpoint of global environment protection, the motor as a power source is required to be smaller and lighter in view of securing a mounting space and improving fuel consumption by reducing the weight.

  As a means to cope with this, the drive motor tends to rotate at high speed, and the inverter that controls the rotation number is required to increase the frequency of the drive voltage fundamental wave. Conventionally, IGBTs have been used as inverter elements, but practical applications of next-generation inverters that operate at higher speeds and use low-loss silicon carbide (SiC) and gallium nitride (GaN) as elements are progressing .

  On the other hand, in the inverter-driven motor, surge voltage is generated at the input end by switching of the inverter. Due to the high-speed switching of the drive inverter, the surge voltage is increased, and the shared voltage in the coil of the motor stator is increased accordingly. In the prior art, it is expected that the inter-turn dielectric breakdown due to the application of the sharing voltage, which has not been a problem at the sharing voltage level of the inverter, will be manifested, and a highly reliable insulation system design corresponding to high speed inverter / switching is required.

  Generally, an enameled insulation coated wire is used for a stator coil of a motor for a hybrid car or an electric car, and the insulation protection against the voltage sharing is carried by the enameled insulation layer of the coil. Therefore, it is conceivable to thicken the enamel insulating coating layer so as to withstand the increased sharing voltage against the increase of the surge sharing voltage by the next-generation inverter.

  As a technique for increasing the insulation thickness of the coil, for example, Patent Document 1 is proposed. Patent Document 1 discloses a technique in which the insulation thickness of the upper coil having a high load ratio of the surge voltage is made thicker than the insulation thickness of the lower coil to secure the insulation strength against the surge voltage.

JP 11-89148 A

  However, as described in Patent Document 1, there is a problem that the increase in coil insulation thickness reduces the ratio of the conductor occupied in the coil, and the motor output decreases due to the decrease in coil current density.

  In addition, a decrease in coil current density due to an increase in coil insulation thickness causes a problem that the coil temperature increases when the motor is in operation, and thermal degradation of the insulation system accelerates and the motor breaks down.

  An object of the present invention is to provide a stator of a rotating electrical machine and a rotating electrical machine in which the above-mentioned problems are solved and insulation between coils in the motor stator is prevented from breakdown due to increase in surge sharing voltage. is there.

  In order to achieve the above object, the present invention is characterized in that the rotor, the stator, the plurality of slots provided in the stator core of the stator, and the slots of the plurality of slots are provided. A rotating electrical machine comprising: a plurality of segmented coils; and a first insulating member disposed between the stator core and the plurality of segmented coils, wherein the plurality disposed in the respective slots A second insulating member is disposed between the segment coils, and the second insulating members are disposed to have different numbers depending on the respective slots.

  According to the present invention, it is possible to provide a stator for a rotating electrical machine and a rotating electrical machine that can ensure high reliability by suppressing dielectric breakdown between coils in a motor stator due to an increase in surge sharing voltage.

1 is a cross-sectional view of a rotating electrical machine according to an embodiment of the present invention cut along a rotation axis direction. It is an appearance perspective view of a stator core concerning one example of the present invention. It is an appearance perspective view of a stator concerning one example of the present invention. FIG. 7 is a diagram showing one segment coil according to an embodiment of the present invention. It is a figure which shows the state which integrated the segment coil which concerns on one Example of this invention in a stator core. It is a V-V cross-sectional view in FIG. 4A. It is a figure which shows the structure which interposed the 2nd insulation member between the in-phase segment coils based on one Example of this invention. It is a figure which shows the structure which does not interpose a 2nd insulation member between in-phase segment coils based on one Example of this invention. It is a comparative example which shows the relation between a segment coil and an insulating member. It is a schematic diagram of a surge simulation voltage waveform concerning one example of the present invention.

  Hereinafter, embodiments of the present invention will be described based on the drawings. The present invention is not limited to the following embodiments, and includes various modifications and applications within the technical concept of the present invention.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a cross-sectional view of a rotating electrical machine according to an embodiment of the present invention cut along the rotation axis direction. In FIG. 1, a rotating electrical machine 100 is configured of a housing 110, a stator 120, a stator core 121, a stator coil 122, and a rotor 130.

  A stator 120 is fixed to the inner circumferential side of the housing 110. A rotor 130 is rotatably supported on the inner peripheral side of the stator 120. The housing 110 is formed in a cylindrical shape by pressing or the like.

  A liquid cooling jacket 112 is fixed to the outer peripheral side of the housing 110. The inner peripheral wall of the liquid cooling jacket 112 and the outer peripheral wall of the housing 110 constitute a refrigerant passage 113 of liquid refrigerant such as oil, and the refrigerant passage 113 is formed so as to prevent liquid leakage. The liquid cooling jacket 112 accommodates bearings 114 and 115 for rotatably supporting the rotation shaft 131 of the rotor 130.

  In the case of direct liquid cooling, the liquid refrigerant accumulated in the refrigerant storage space 116 passes through the refrigerant passage 113 and flows out from the refrigerant outlets 117 and 118 toward the stator 120 to cool the stator 120.

  The rotor 130 is configured of a rotor core 132 configured by laminating electromagnetic steel sheets, a permanent magnet 133 embedded in the rotor core 132, and a rotating shaft 131. The rotor 130 of this embodiment has a surface magnet type rotor using a general permanent magnet or an embedded magnet type structure.

  Next, the configuration of the stator core will be described with reference to FIG. FIG. 2 is an external perspective view of a stator core according to an embodiment of the present invention.

  In FIG. 2, the stator core 121 is formed such that a plurality of slots 123 parallel to the axial direction of the stator core 121 are equally spaced in the circumferential direction. In the present embodiment, the number of slots 123 is 72. The stator coil 122 is incorporated in the slot 123. A plurality of teeth 124 are formed between the slots 123. The shape of the slot 123 is a substantially rectangular shape having a constant width, and in the present embodiment, the width and the parallel part depth are respectively about 4.2 mm and 11.5 mm.

  The stator core 121 is formed by punching an electromagnetic steel plate equivalent to 35A300 of Japanese Industrial Standard JIS C 2552 by punching, laminating a plurality of annular magnetic steel plates formed, and welding and fixing them. The welding portion 125 formed by TIG welding, laser welding or the like is provided in parallel with the axial direction of the stator core 121 at the outer peripheral portion of the cylindrical stator core 121. In the present embodiment, the dimensions of the stator core 121 are an outer diameter of 245 mm, an inner diameter of 200 mm, and a core area thickness of 94 mm.

  Next, the configuration of the stator will be described with reference to FIG. FIG. 3 is an external perspective view of a stator according to an embodiment of the present invention.

  The stator 120 has a stator coil 122 formed by a segment winding method and a cylindrical stator core 121 on which the stator coil 122 is mounted. The stator coil 122 is wound in a distributed winding manner and connected in a star connection configuration. The distributed winding is a winding method in which the phase winding is wound around the stator core 121 such that the phase winding is accommodated in two slots 123 spaced apart across a plurality of slots 123 described later. In this embodiment, since the distributed winding is adopted as the winding method, the magnetic flux distribution formed is closer to a sine wave as compared with the concentrated winding, and has a feature of easily generating reluctance torque. Therefore, the controllability of field-weakening control and control utilizing reluctance torque is improved, and this rotary electric machine 100 can be used over a wide rotational speed range from low rotational speed to high rotational speed. It is possible to obtain excellent motor characteristics suitable for automobiles.

  The stator coil 122 constitutes a three-phase star-connected phase coil, which may be round or square in cross section, but the cross section inside the slot 123 is used as effectively as possible. Since a structure in which the space in the slot is reduced tends to lead to an improvement in efficiency, it is preferable in terms of the improvement in efficiency that the cross section has a rectangular shape. The rectangular shape of the cross section of the stator coil 122 may have a shape in which the circumferential direction of the stator core 121 is short and the radial direction is long, and conversely, the circumferential direction is long and the radial direction is short. It may be

  Next, the configuration of the stator coil will be described using FIGS. 4 and 5. FIG. 4A is a diagram showing one segment coil according to an embodiment of the present invention. FIG. 4B is a view showing a state in which a segment coil according to an embodiment of the present invention is incorporated in a stator core. FIG. 5 is a V-V cross-sectional view of FIG. 4A.

  As shown in FIG. 4A, in the present embodiment, a linear coil is formed into a substantially U-shaped segment coil 200 having an apex 201 as a turning point and having oblique portions 202 on both sides thereof. In the segment coil 200 of this embodiment, as shown in FIG. 5, a substantially rectangular sectional shape in which a copper conductor 301 having a width of 3.3 mm and a height of 2.4 mm is covered with a polyimide insulating layer 302 having a thickness of 0.1 mm. A flat wire with The segment coil 200 has a shape in which the rectangular cross section of the segment coil 200 in each slot 123 is long in the circumferential direction of the stator core 121 and short in the radial direction of the stator core 121. In the present embodiment, a plurality of segment coils 200 are used to form a stator coil.

  The segment coil 200 is inserted into the slot 123 from the direction of the rotational axis of the stator core 121 via an insulating member (not shown), as shown in FIG. 4B. The linear portion 203 of the segment coil 200 is accommodated in the slot 123, and the portion protruding from the end face of the stator core 121 is bent toward the other segment coil 200 to be connected, and the welding side inclined portion 204 is formed. . Furthermore, the end 205 of the welding-side inclined portion is bent. The bent ends 205 of the segment coil 200 are welded and electrically connected.

  In this embodiment, four (several) segment coils 200 are incorporated in each slot 123 of a plurality of slots, and the stator coil 122 is a three-phase coil (U1, U2, V1, V2, W1, W2). Each coil was connected by 2Y connection. The number of turns of each phase coil is 48 turns. Attach the input terminals 126 (U), 127 (V), and 128 (W) of the stator coil 122 of each of the three UVW phases to the stator coil 122 (see FIG. 3), and finally, the slot 123 with epoxy varnish. The segment coil 200, the first insulating member 210, and the second insulating member 211 disposed inside are fixed.

  Next, the configuration in the slot will be described using FIG. FIG. 6A is a view showing a configuration in which the second insulating member is interposed between the in-phase segment coils according to an embodiment of the present invention. FIG. 6B is a diagram illustrating a configuration in which the second insulating member is not interposed between the in-phase segment coils according to an embodiment of the present invention.

  As shown in FIGS. 6A and 6B, a substantially O-shaped first insulating member 210 is disposed between the segment coil 200 and the teeth 124 (the stator core 121), and the segment coil 200 and the stator core 121. And are isolated.

  Of the segment coils of three phases (U phase, V phase, W phase), two slots U (200a, 200b) and two phase coils 200 (200c, 200d) of V phase are provided in the slot 123. ) Are arranged. The two U-phase segment coils 200 (200a, 200b) are located on the opening side of the slot 123, and this U-phase side is the turn near the input end where the shared voltage is high.

  A second insulating member 211a is disposed between the different phase coils in the slot 123, that is, between the U-phase segment coil 200b and the V-phase segment coil 200c, and the segment coil between different phases is isolated.

  Furthermore, in the present embodiment, as shown in FIG. 6A, the second insulating member 211b is disposed between the adjacent in-phase (U-phase) segment coils 200a and 200b. However, the second insulating member 211b is not disposed in all the slots 123, and as shown in FIG. 6B, there are slots 123 in which the second insulating member 211b is not disposed. That is, in the stator 120 of the present embodiment, the slot 123 in which the second insulating member 211b is disposed and the slot 123 in which the second insulating member 211b is not disposed are mixed. When viewed across the slots 123 of the stator 120, the second insulating members 211 disposed in the slots 123 are disposed in different numbers by the slots 123. In other words, the second insulating member 211b is disposed between different phases of the plurality of segment coils disposed in the respective slots and between the same phases of some of the plurality of segment coils. As described above, the arrangement of the second insulating members 211 is different in this embodiment.

  The slot 123 in which the second insulating member 211 b is disposed is disposed unevenly at the voltage input end (motor voltage input end). In the present embodiment, as an example, the coils from the motor voltage input end to the three turns and the adjacent in-phase (U-phase) segment coils 200a and 200b are used. Depending on the voltage, the second insulating member 211b may be provided only at the motor voltage input terminal. The second insulating member 211 b may not be disposed in the other slots 123. This takes into consideration that the surge sharing voltage is applied only to the turn near the voltage input terminal. In addition, since the cost increases if the second insulating member 211b is disposed more than necessary, in the present embodiment, the second insulating member 211b is disposed in the predetermined slot 123 in order to suppress the increase in cost.

  A comparative example is shown in FIG. FIG. 7 is a comparative example showing the relationship between the segment coil and the insulating member. In FIG. 6, the insulating member 220 is disposed in the slot 123 in a generally B-shape. The in-phases of the segment coils 200a and 200b and the segment coils 200c and 200d are in contact with each other, and an insulating member 220 is disposed between the segment coil 200 and the teeth 124 (the stator core 121). Further, the end of the insulating member 220 is disposed so as to overlap between the U-phase segment coil 200 b and the V-phase segment coil 200 c.

  In recent years, with the speeding up of switching in the inverter, the shared voltage between turns in the segment coil tends to increase. In such a situation, when the configuration shown in FIG. 7 is arranged in all the slots 123 of the stator 120, a surge voltage is applied between the segment coils 200a and 200b located in the turn on the motor voltage input end side. As a result, dielectric breakdown occurs. In the present embodiment, the second insulating member 211b is disposed between the segment coils 200a and 200b in order to prevent the dielectric breakdown.

  In the present embodiment, an insulating member obtained by previously forming a three-layer laminate paper in which an aramid paper-polyethylene naphthalate (PEN) -aramid paper having a thickness of 0.2 mm is adhesively laminated is used as the first insulating member 210. In order to facilitate the insertion into the slot 123, the first insulating member 210 may be tapered so that the thickness on the insertion side is reduced. In addition, as the second insulating member, an adhesive aramid tape having a width of 3.4 mm and a thickness of 0.19 mm was attached to the linear portion 203 of the segment coil 200 before the segment coil 200 was inserted into the slot.

  Next, verification in which the inverter / surge simulation voltage is applied by the test power supply will be described with reference to FIG. FIG. 8 is a schematic view of a surge simulation voltage waveform according to an embodiment of the present invention.

  For the stator 120 of the present embodiment described above, an inverter / surge simulation voltage having a schematic waveform shown in FIG. 8 is applied by the test power supply to the input terminal 126 (see FIG. 3) of the U-phase coil, It was verified whether there would be a difference in behavior. At this time, the V-phase coil and the stator core 121 were at ground potential, and the W-phase coil was open.

  As for the surge simulation voltage, the surge voltage peak Vp in FIG. 8 is 1.5 kVp, the surge voltage rise time tr is 50 ns, the pulse width tw is 120 ns, and the pulse frequency f is 10 kHz. As a result, in the configuration of the comparative example shown in FIG. 7, the dielectric breakdown occurred between the turn closest to the voltage input end of the U-phase coil and the turn in the in-phase coil adjacent to it in about 3 hours. On the other hand, in the configuration of the present embodiment in which the insulation is reinforced by the second insulating member, no dielectric breakdown occurs even after 10 hours of continuous charging.

  In this example, an aramid tape in which aramid fibers having a glass transition temperature exceeding 200 ° C. and sufficient heat resistance are formed into a tape shape is used as the second insulating member. This is because in the motor for hybrid vehicles and electric vehicles, the temperature rise of the stator can not be avoided, and the heat resistance of the insulating member is considered. If the heat resistance of the insulating member is low, insulation breakdown during operation may occur due to the heat and mechanical deterioration of the insulating member due to the temperature rise of the motor. In order to prevent this, it is necessary to use a resin having a glass transition temperature of 50 ° C. or higher.

  Moreover, although the molded object (tape-like body) to which the adhesive agent was apply | coated was used as a 2nd insulation member in a present Example, the tape shape which an adhesive agent is not apply | coated as a 2nd insulation member after insertion of a segment coil. The molded body of may be inserted and mounted. In addition to this, an air gap of a predetermined width is provided between a turn requiring insulation strengthening after insertion (after placement) of the segment coil 200 and an adjacent turn using the air gap provided for inserting the segment coil 200, and the air gap A second insulating member can be provided, for example, by injecting and thermosetting a thermosetting resin.

  In addition, in the present example, a single-leaf aramid tape was used as the second insulating member. The shared voltage is known to decrease with distance from the voltage input, and the second insulating member can be graded according to the shared voltage level. For example, in the first turn adjacent to the voltage input terminal having a high shared voltage level, two layers of insulating members may be used, and in the second and subsequent turns, the second insulating member may be used as one layer. In other words, the thickness of the second insulating member disposed in the first turn is made thicker than the thickness of the second insulating member disposed in the second and subsequent turns. When the second insulating member is arranged from the first turn to the third turn, the thickness of the second insulating member arranged in the first turn is the second insulating member arranged in the second turn and the third tongue Make it thicker than the thickness of

  As described above, according to the present embodiment, it is possible to provide a rotating electrical machine in which high reliability is ensured by suppressing the inter-turn dielectric breakdown in the motor stator due to the increase of the surge sharing voltage.

  The present invention is not limited to the embodiments described above, and includes various modifications. The above-described embodiments are described in detail to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described.

Reference Signs List 100 rotating electric machine 110 housing 112 liquid cooling jacket 113 refrigerant passage 114 bearing 115 bearing 116 refrigerant storage space 117 refrigerant outlet 118 refrigerant outlet 120 stator 121 stator core 122 stator core 123 stator coil 123 slot 124 teeth 125 welding part 126 input terminal 130 Example rotor 130 Rotor 131 Rotor shaft 132 Rotor core 133 Permanent magnet 200 Segment coil 200a Segment coil 200b Segment coil 200c Segment coil 200d Segment coil 201 Peak 202 Slope portion 203 Straight portion 204 Weld side slope portion 205 End portion 210 First insulating member 211 second insulating member 211 a second insulating member 211 b second insulating member 220 insulating member 301 copper conductor 302 polyimide insulating layer

Claims (17)

Between a stator core, a plurality of slots provided in the stator core, a plurality of segment coils disposed in each slot of the plurality of slots, and between the stator core and the plurality of segment coils A stator of a rotating electrical machine, comprising: a first insulating member disposed;
A second insulating member is disposed between the plurality of segment coils disposed in the respective slots,
The stator of a rotary electric machine, wherein the second insulating members are arranged to have different numbers according to the respective slots. A stator core, a plurality of slots provided in the stator core, a plurality of three-phase segment coils disposed in each of the plurality of slots, the stator core, and the plurality of segment coils A stator of a rotating electrical machine comprising a first insulating member disposed between
A second insulating member is disposed between different phases of the plurality of segment coils disposed in the respective slots, and between in-phase portions of some of the plurality of segment coils. Stator of rotating electric machine. In claim 2,
A stator of a rotating electrical machine, wherein the second insulating member disposed between the same phase is disposed eccentrically on the voltage input end side. In claim 3,
The stator of a rotating electrical machine, wherein the second insulating member is disposed only at a voltage input end. In claim 3,
The stator of a rotating electrical machine, wherein the second insulating member is disposed in a first turn, a second turn, and a third turn that are voltage input terminals. In claim 5,
A stator of a rotating electrical machine, wherein a thickness of the second insulating member is thicker than the first turn than the second turn and the third turn. In claim 1 or 2,
The stator of a rotating electrical machine, wherein the segment coil is a flat wire in cross section. In claim 7,
The segment coil is formed by covering a copper conductor with a polyimide insulating layer. In claim 1 or 2,
A stator for a rotating electrical machine, wherein the segment coil, the first insulating member, and the second insulating member are fixed in the slot by an epoxy-based varnish. In claim 1 or 2,
A stator of a rotating electrical machine, wherein the second insulating member is a resin having a glass transition temperature of 50 ° C. or higher. In claim 1 or 2,
The stator of a rotating electrical machine, wherein the second insulating member is an aramid fiber. In claim 11,
The stator of a rotating electrical machine, wherein the aramid fiber is in the form of a tape. In claim 2,
The second insulating member is a tape-shaped aramid fiber, and before arranging the plurality of segment coils in the slot, the second insulating member may be disposed between different phases of the plurality of segment coils and a part of the plurality of segment coils. A stator of a rotating electrical machine characterized in that the stator coil is attached to segment coils between in-phase segments. In claim 1 or 2,
A stator for a rotating electrical machine, wherein the second insulating member is formed by injecting a thermosetting resin after arranging the plurality of segment coils in the slot. In claim 1 or 2,
The stator of a rotating electrical machine, wherein the first insulating member is a three-layer laminated paper in which aramid paper-polyethylene naphthalate-aramid paper is adhesively laminated. In claim 15,
The stator of a rotating electrical machine, wherein the first insulating member is tapered such that the thickness on the side to be inserted into the slot is reduced. A rotating electrical machine comprising a rotor and a stator,
The said stator is a rotary electric machine characterized by being a claim 1 or 2.

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