AU2021386717A1

AU2021386717A1 - Rotary electric machine and electric vehicle rotary electric machine system using same

Info

Publication number: AU2021386717A1
Application number: AU2021386717A
Authority: AU
Inventors: Katsuhiko Fujii; Daisuke Kori; Misato Sato; Shinji Sugimoto; Osamu Tsuchitani
Original assignee: Hitachi Industrial Products Ltd
Current assignee: Hitachi Industrial Products Ltd
Priority date: 2020-11-26
Filing date: 2021-06-08
Publication date: 2023-06-22
Anticipated expiration: 2041-06-08
Also published as: AU2021386717B2; WO2022113405A1; JP2022084270A

Abstract

Disclosed is a rotary electric machine that, even while having three-phase alternating-current windings of two systems having different configurations, enables improved efficiency without an increase in the complexity of the configuration of the windings. This rotary electric machine comprises a rotor (2) and a stator (3) having a three-phase alternating-current winding, wherein: the three-phase alternating-current winding includes a first system winding (15) and a second system winding (16) which are independent of each other; a plurality of first slots (18) in which the first system winding (15) is located and a plurality of second slots (19) in which the second system winding (16) is located are provided; the number of first slots (18) is greater than or equal to the number of second slots (19); and the first system winding (15) is positioned more radially inward than the second system winding (16) in the stator (3).

Description

DESCRIPTION

Title of Invention

ROTARY ELECTRIC MACHINE AND ROTARY ELECTRIC MACHINE SYSTEM FOR ELECTRIC VEHCLE USING SAME

Technical Field

[0001]

This invention relates to a rotary electric machine,

and a rotary electric machine system for an electric vehicle

using the rotary electric machine.

Background Art

[0002]

With respect to an electric system for an automobile

(for example, an electric power steering system) and a wind

power generation system, there has been a demand for a

system that has redundancy for allowing the system to

continue its operation even when an abnormality occurs in

the system. In such a system, two sets of windings are

disposed in one rotary electric machine, and the respective

windings are connected to power supplies or power converters

that are independent from each other. The respective

windings of two systems have the same configuration (such as

the number of turns), and they output 50% of a whole system

output respectively. Accordingly, even when an abnormality occurs in one system, although an output of the electric system is decreased than a usual operation, an operation of the electric system can be continued by the other system without stopping the electric system.

[00031

On the other hand, in a rotary electric machine system

for supplying electricity in an electric vehicle such as a

dump truck, to realize the downsizing and the reduction of

weight of the system, it is considered to adopt a rotary

electric machine that has two sets of windings in place of a

main generator and a sub generator. In this case, one set

of windings is provided for supplying electricity to a

traction motor that drives a vehicle body and the other set

of windings is provided for supplying electricity to

peripheral equipment such as a cooler and hence, it is

necessary to mount the two set of windings having different

configurations on one rotary electric machine.

[0004]

As a prior art relating to a rotary electric machine

having two set of windings of two systems that differ in

configuration from each other, a technique described in

patent literature 1 is known. In this technique, to enable

simultaneous outputting of a single-phase alternating

current and a three-phase alternating current in an

alternating current generator, the three-phase alternating windings adopt the Y-connection where one end of a single phase alternating current winding having a voltage that is

1/2 of an induced voltage of a U-phase winding and having a

phase difference with respect to the induced voltage of the

U-phase winding is connected to a neutral point of the Y

connection. Further, an intermediate tap is provided to the

U-phase winding, and a single-phase current is outputted

from the other end of the single-phase alternating current

winding and the intermediate tap.

Citation List

Patent Literature

[00051

Patent Literature 1: Japanese Unexamined Patent

Application Publication No. 2015-201918

Summary of Invention

Technical Problem

[00061

In the above-mentioned prior art, a circulating

current attributed to a three-phase unbalance flows into a

three-phase electric circuit and a single-phase alternating

current electric circuit via the intermediate point and

hence, efficiency of the system is lowered. Further, the

configuration of the three-phase alternating current

windings becomes complicated and hence, a manufacturing cost is increased. Still further, in a case where the prior art is applied to the rotary electric machine system for an electric vehicle described above, although both of two sets of windings are formed of a three-phase alternating current winding, substantially the same problem arises.

[0007]

Accordingly, the present invention provides a rotary

electric machine that can enhance efficiency without making

the configuration of windings complicated while having two

sets of three-phase alternating current windings having

different configurations, and a rotary electric machine

system for an electric vehicle that uses such a rotary

electric machine.

Solution to Probrem

[0008]

In order to solve the above problem, a rotary electric

machine according to the invention comprises: a rotor; and a

stator having a three-phase alternating current winding. In

the rotary electric machine, the three-phase alternating

current winding includes first windings and second windings

that are independent from each other, the rotary electric

machine includes: a plurality of first slots in which the

first windings are provided; and a plurality of second slots

in which the second windings are provided, the number of the

first slots is equal to or larger than the number of the second slots, and the first windings are provided more inward than the second windings in the stator.

[00091

Further, in order to solve the above problem, a rotary

electric machine system for an electric vehicle comprises: a

rotary electric machine that supplies power to a main

machine and an auxiliary machine mounted on an electric

vehicle; and a prime mover that drives the rotary electric

machine. In the rotary electric machine system for an

electric vehicle, the rotary electric machine is the rotary

electric machine according to the invention, power is

supplied to the main machine from the first windings via a

first power converter, and power is supplied to the

auxiliary machine from the second windings via a second

power converter.

[0010]

Further, in order to solve the above problem, a rotary

electric machine system for an electric vehicle comprises: a

rotary electric machine that drives an electric vehicle; and

a battery that supplies power to the rotary electric machine

via a first power converter. In the rotary electric machine

system for an electric vehicle, a rotary electric machine is

the rotary electric machine according to the invention,

power is supplied to the first windings from the battery via

the first power converter, and regenerative power is charged into the battery from the second windings via the second power converter.

Advantageous Effects of Invention

[0011]

According to the invention, the rotary electric

machine is capable of enhancing efficiency without making

the configuration of windings complicated while having two

sets of three-phase alternating current windings having

different configurations.

[0012]

Objects, features, and effects other than the above

will be apparent from the description of the following

embodiments.

Brief Description of Drawings

[0013]

Figure 1 is a cross-sectional view of a rotary

electric machine according to an example 1 of the present

invention as viewed in a rotation axis direction.

Figure 2 is a partial cross-sectional view of the

rotary electric machine according to the example 1 as viewed

in a direction perpendicular to the rotation axis.

Figure 3 is a developed view of a stator in the

example 1.

Figure 4 is a developed view of a stator of a rotary

electric machine according to a modification 1.

Figure 5 is a developed view of a portion of a stator

of a rotary electric machine according to a modification 2.

Figure 6 is a developed view of a stator of a rotary

electric machine according to a modification 3.

Figure 7 is a developed view of a stator of a rotary

electric machine according to an example 2.

Figure 8 is a developed view of a stator in this

example 1 (picking up Figure 3 again).

Figure 9 is a view expressing three-phase voltages on

rotational coordinates in a case where magnetic pole centers

of windings of respective phases differ from each other by a

phase difference angle of u.

Figure 10 is a voltage vector view expressing

directions of d-q axes voltage vectors when a dq conversion

is performed on three-phase voltages of first windings and

second windings using the first windings as the reference.

Figure 11 is a voltage vector view expressing a

voltage (VI) of the first windings where a dq axes voltage

components are expressed by an expression (3).

Figure 12 is a developed view of a stator of a rotary

electric machine according to an example 3.

Figure 13 is a developed view of a stator indicating a

first example of stepped portions on a side wall in a slot.

Figure 14 is a developed view of a stator indicating a

second example of stepped portions on the side wall in the

slot.

Figure 15 is a developed view of a stator indicating a

third example of stepped portions on the side wall in the

slot.

Figure 16 is a developed view of the stator expressing

a first example of the winding configurations of the first

windings, the second windings and the third windings.

Figure 17 is a developed view of the stator expressing

a second example of the winding configurations of the first

windings, the second windings and the third windings.

Figure 18 is a developed view of the stator expressing

a third example of the winding configurations of the first

windings, the second windings and the third windings.

Figure 19 is a block diagram illustrating the

configuration of a rotary electric machine system for a dump

truck according to an example 6.

Figure 20 is a block diagram illustrating the

configuration of a rotary electric machine system for an

electric bus according to an example 7.

Description of Embodiments

[0014]

Hereinafter, embodiments of the present invention are

described in conjunction with the following examples 1 to 7

with reference to drawings. In the respective drawings,

parts having the same reference numbers indicate identical

features or features having similar functions.

Example 1

[0015]

Figure 1 is a cross-sectional view of a rotary

electric machine according to an example 1 of the present

invention as viewed in a rotation axis direction. The

rotary electric machine according to this example 1 is a

field-winding-type synchronous rotating electric machine.

[0016]

The rotary electric machine 100 according to this

example is applicable as a generator having an output of

several thousand kVA and a rotational speed of several

thousand min-' that is used a power source for a large-sized

dump truck. The rotary electric machine according to this

example 1 is rotatably driven by a prime mover such as an

engine.

[0017]

As illustrated in Figure 1, a rotor 2 and a stator 3

are arranged in a frame 1. From end portions of the rotor 2

and the stator 3 in an axial direction, a coil end 6 and a

coil end 7 protrude respectively. A bearing 4 mounted on the frame 1 rotatably supports one end portion of a shaft 5 that is fixed to the rotor 2 and forms a rotary shaft. The other end portion of the shaft 5 is connected to the prime mover not illustrated in the drawings, and is supported by a bearing on a prime mover side. The other end portion of the shaft 5 may be rotatably supported by a bearing that the rotary electric machine 100 includes.

[0018]

An inflow port 8 into which a refrigerant 9 flows is

disposed in the frame 1. The refrigerant 9 is supplied to

the rotary electric machine 100 by a blower or the like not

illustrated in a drawing. The refrigerant 9 that flows into

the frame 1 flows in a right direction in Figure 1, that is,

in a rotational axis direction of the rotary electric

machine 100, and flows out to an atmosphere outside the

frame 1.

[0019]

Figure 2 is a partial cross-sectional view of the

rotary electric machine 100 according to this example 1

illustrated in Figure 1 in a direction perpendicular to a

rotational axis of the rotary electric machine 100.

[0020]

As illustrated in Figure 2, the rotor 2 includes a

rotor core 10, a field winding 11, a dumper bar 12 (braking

winding), and a rotor wedges 13. The stator 3 includes a stator core 14, first windings 15 and second windings 16 that are three-phase alternating current windings, and a stator wedges 17. The rotor 2 and the stator 3 face each other with an air gap 22 formed therebetween. The first windings 15 are disposed in first slots 18, and the second windings 16 are disposed in second slots 19. A passage for refrigerant 9 in the frame 1 includes back surface ducts 20, axial ducts 21, and an air gap 22. The back surface ducts

20 and the axial ducts 21 are arranged at a fixed interval

in a circumferential direction.

[0021]

The first slot 18 in which the first winding 15 is

disposed is formed of a groove where the groove extends in a

radial direction in the stator core 14 from an inner

peripheral surface of the stator core 14 that faces a

surface of the rotor 2, uses a radial direction as a depth

direction and a rotary axis direction as a longitudinal

direction. Further, the second slot 19 in which the second

system winding 16 is disposed is disposed adjacent to the

first slot 18 in the depth direction. In this example 1, as

illustrated in Figure 2, a portion of the first slot 18

extending in the depth direction is set as a second slot 19.

[0022]

The plurality of the first slots 18 and the plurality

of the second slots 19 are arranged at an equal interval along the circumferential direction of the stator core 14.

A slot interval between the second slots 19 is larger than a

slot interval between the first slots 18. In this example

1, an amount of two slots of the first slot 18 corresponds

to the second slot 19. Accordingly, the slot number of the

second slots 19 is smaller than the slot number of the first

slots 18. That is, in this example 1, the slot number of

the second slots 19 is half of the slot number of the first

slots 18. Accordingly, in this example 1, in the first

winding 15 and the second winding 16, the slot in which only

the first system winding 15 is disposed and the slot which

is deeper than the slot and in which both windings are

disposed are alternately arranged along the circumferential

direction in the stator core 14.

[0023]

The slot number of the second slots 19 is smaller than

the slot number of the first slots 18 and hence, as

described later, an induced voltage of the second windings

16 can be set smaller than an induced voltage of the first

windings 15. Accordingly, in a case where the rotary

electric machine 100 is operated by a generator, an output

voltage of the second windings 16 can be set smaller than an

output voltage of the first windings 15.

[0024]

In this example 1 illustrated in Figure 2, the slot

number of the second slots 19 is half of the slot number of

the first slots 18. However, the present invention is not

limited to such a configuration, and the number of the

second slots 19 can be suitably set corresponding to a

desired characteristic (an induced voltage, an output

voltage or the like).

[0025]

The second winding 16 is, as illustrated in Figure 2,

disposed on the first winding 15 in an overlapping manner in

the depth direction of the slot. Accordingly, it is

sufficient to set the slot number with respect to the first

windings 15, and to use a part of the slot number as the

slot number of the second windings 16. As a result,

although the rotary electric machine 100 has two sets of the

windings, it is possible to prevent the configuration of the

slots of the rotor from becoming complicated.

[0026]

In the stator 3, the first windings 15 and the second

windings 16 are not electrically coupled to each other and

are independent from each other. Accordingly, in a case

where the first windings 15 and the second windings 16 are

respectively connected to external circuits, a circulating

current can be suppressed and hence, lowering of the

efficiency due to a circulating current is prevented.

Further, although the stator 3 includes the first windings

15 and the second windings 16, the configuration of the

windings does not become complicated.

[0027]

Figure 3 is a developed view illustrating the cross

sectional configuration of the stator 3 according to this

example 1 illustrated in Figure 2 by extending the cross

sectional configuration in a straight shape. The air gap 22

(Figure 2) is positioned on a lower side of Figure 3, the

frame 1 (Figure 2) is positioned on an upper side of Figure

3.

[0028]

The first windings 15 and the second windings 16 are

respectively formed of distributed winding. In this example

1, the number of poles of the rotary electric machine 100 is

10 poles, and the number of slots of the first slots 18 and

the number of slots of the second slots 19 are respectively

90 slots and 45 slots.

[0029]

As illustrated in Figure 3, the first windings 15 and

the second windings 16 are formed of an upper coil

(indicated by "up" in Figure 3) and a bottom coil (indicated

by "bottom" in Figure 3) that are arranged in an overlapping

manner along the depth direction of the slots.

[0030]

Three phases of the first windings 15 are expressed as

Ul, V1, W1, and three phases of the second windings 16 are

expressed as U2, V2, W2. A numeral with a parenthesis is

given to each slot as a slot number. Furter, positive and

negative symbols (+, -) indicate the directions along which

an electric current flows (current polarities), wherein the

direction that is directed to a depth side with respect to a

paper on which the drawing is depicted is indicated by "+",

and the direction toward front side is indicated by "-".

[0031]

Since the number of poles (10) and the number of slots

(the first slot: 90, the second slot: 45) as described

previously, in this example 1, the number of slots for each

pole and each phase (= the number of slots/ the number of

poles/ the number of phases) is 3 in the first windings 15

and 1.5 in the second windings 16.

[0032]

That is, in the first windings 15, the number of coils

for each phase and each pole becomes 3. Accordingly, as

illustrated in Figure 3, the respective phase windings each

formed of three coils that are arranged continuously (UUU,

VVV, WWW) are repeatedly arranged at a fixed phase order

(UUU-VVV-WWW...).

[0033]

Further, in the second windings 16, in each phase, the

phase winding formed of one coil and the phase winding

formed of two coils are alternatively arranged.

Accordingly, the number of slots for each pole and each

phase, that is, the number of coils of one phase and one

pole becomes 2.5 in average. Further, in the stator 3, the

phase winding formed of one coil and the phase winding

formed of two coils are arranged at a fixed phase order.

The phase winding formed of one coil (U, V, W) and the phase

winding formed of two coils (UU, VV, WW) are repeatedly

arranged at a fixed phase order (U-VV-W-UU-V-WW...) by making

the number of coils of two phase windings disposed

adjacently to each other differ from each other so as to

make the phase windings having the different number of coils

are uniformly distributed along the circumferential

direction of the stator 3.

[0034]

In this example 1 illustrated in Figure 3, the number

of slots in which crossover wires that form a coil loop by

connecting the coils (upper and bottom coils) in the slots

(hereinafter referred to as "the number of crossover") is 7

(slots) in the first windings 15 and 5 (slots) in the second

windings 16. With these crossover wires, for example, as

illustrated in Figure 3, the upper coil (1) and the bottom

coil (7) of the first windings 15 are connected to each other and the upper coil (1) and the bottom coil (5) of the second windings 16 are connected to each other. With respect to the number of crossover wires of the first windings 15, the crossover wires are connected to 7 slots from the upper coil (1) to the bottom coil (7) and hence, the number of crossover wires is 7 (slots). With respect to the number of crossover of the second windings 16, the crossover wires are connected to 5 slots from the upper coil

(1) to the bottom coil (5) and hence, the number of

crossover is 5 (slots). The number of crossover is not

limited to the above-mentioned 7 and 5, and can be suitably

set.

[00351

In this example 1 illustrated in Figure 3, the three

phase connection of the first windings 15 and the second

windings 16 are formed of a Y-connection. The number of

parallel connections of the Y-connection is 5 parallels in

the first windings 15, and is 10 parallels in the second

wirings 18. The number of parallel connections is suitably

set corresponding to the specification of the rotary

electric machine.

[00361

By setting the number of the second slots smaller than

the number of the first slots as in the case of this example

1, winding man-hours of the distributed winding can be reduced compared to a case where the number of the second slots smaller is set equal to the number of the first slots and hence, a manufacturing cost can be reduced. According to the studies that the inventors of the present invention have made, in this example 1, the winding man-hours can be reduced by 25%.

[0037]

Further, as described hereinafter, this example 1 is

suitable in a case where an induced electromotive voltage of

the first windings 15 is higher than an induced

electromotive voltage of the second windings 16.

[0038]

The size of the rotary electric machine depends on

magnitude of an induced electromotive voltage. Accordingly,

in this example 1, out of the first windings 15 and the

second windings 16, a field magnetic flux amount of the

rotor 2 is set in conformity with the first windings 15

having a large induced electromotive voltage. Further, to

set an induced electromotive voltage of the second windings

16 smaller than an induced electromotive voltage of the

first windings 15, the number of turns of the second

windings 16 is set smaller than the number of turns of the

first windings 15.

[0039]

In this case, as described above, a field magnetic

flux amount of the rotor 2 is set in conformity with the

first windings 15 and hence, the field magnetic flux amount

of the rotor 2 is excessively large for the second windings

16. Accordingly, to set an induced electromotive voltage of

the second windings 16 to a predetermined value smaller than

an induced electromotive voltage of the first windings 15,

some means is necessary to lower an induced electromotive

voltage of the second windings 16 while maintaining an

induced electromotive voltage of the first windings 15.

[0040]

According to the studies made by the inventors of the

present invention, as a means that lowers an induced

electromotive voltage of the second windings 16 while

maintaining the induced electromotive voltage of the first

windings 15, the increase of the number of parallel

circuits, the reduction of the number of turns, a change of

the number of crossover lines and the reduction of the

number of slots are effective. According to the studies

made by the inventors of the present invention, even in a

case where it is difficult to reduce an induced

electromotive voltage by the increase of the number of

parallel circuits, the reduction of the number of turns, and

a change of the number of crossover, the reduction of the

number of slots is effective to reduce an induced electromotive voltage. The larger the difference between an induced electromotive voltage of the first windings 15 and an induced electromotive voltage of the second windings, the higher an effect of the reduction of slots becomes.

Accordingly, in the example 1, the number of the second

slots 19 is set smaller than the number of the first slots

18.

[0041]

Further, in this example 1, in the stator 3, the first

windings 15 is positioned on a more inner diameter side than

the second windings 16. That is, the first windings 15 are

disposed closer to the air gap 22 than the second windings

16. Accordingly, magnetic fluxes that interlink the first

windings 15 become larger than magnetic fluxes that

interlink the second windings 16 in number and hence, the

difference in the number of flux interlinkage can be easily

set. As a result, the difference in an induced

electromotive voltage can be surely set between the first

windings 15 and the second windings 16 such that an induced

electromotive voltage of the first windings 15 becomes

larger than an induced electromotive voltage of the second

windings 16.

[0042]

Further, the first windings 15 are disposed closer to

the air gap 22 than the second windings 16 and hence, the first winding 15 faces two inner wall surfaces of the stator core 14 that extends in the depth direction in the first slot 18, and the second winding 16 faces two inner wall surfaces of the stator core 14 that extends in the depth direction in the second slot 19 and one surface of the stator core 14 that forms a bottom surface of the second slot 19. That is, the number of opposedly facing surfaces of the stator core 14 with the winding is smaller in the first winding 15 than in the second winding 16.

Accordingly, the number of core surfaces of the stator core

14 in the slot that form discharge surfaces when corona

discharge occurs is smaller in the first windings 15 having

a large induced electromotive voltage than in the second

windings 16. As a result, lowering of an insulation life of

the rotary electric machine caused by an effect of corona

discharge can be suppressed.

[0043]

A formed coil where the first windings 15 and the

second windings 16 have the same wire size and have

different number of turns may be formed by molding in

advance, and the formed coil may be inserted into the slots

from an inner diameter side (the air gap 22 side) of the

stator core 14. With such a configuration, it is possible

to enhance the efficiency of the manufacture of the stator 3

that includes the first windings 15 and the second windings

16. Accordingly, it is possible to reduce a manufacturing

cost of a rotary electric machine having two sets of

windings that have different configurations.

[0044]

Next, a modification 1 of this example 1 is described.

[0045]

Figure 4 is a developed view of a stator of a rotary

electric machine according to the modification 1.

[0046]

In the modification 1, the number of first slots 18 is

90 slots, which is the same number as the example 1

described above. However, the number of second slots 19 is

30 slots, which is smaller than the number of second slots

19 in the example 1 (45 slots). Further, in the first

windings 15, the number of slots for each pole and each

phase is 3, which is the same number as the example 1, and

the number of slots for each pole and each phase in the

second windings 16 is 1, which is smaller than the number of

slots for each pole and each phase in the example 1.

[0047]

A slot pitch angle (= 360/the number of slots) is 4

degrees with respect to the first slots 18, and is 12

degrees with respect to the second slots 19. With such

setting of the angles, the positions of the second slots 19

can be aligned with the positions of the first slots 18.

Accordingly,at portions where the positions of both slots

are aligned with each other, the first slot 18 and the

second slot 19 form one continuous slot that has

substantially the same rectangular cross section as the

first slot 18 and is deeper than the first slot 18.

Accordingly, it is possible to efficiently mount the two

sets of windings having the different configurations on the

stator core 14.

[0048]

Figure 5 is a developed view of a portion of a stator

of a rotary electric machine according to a modification 2.

[0049]

In the modification 2, the number of first slots 18 is

90, which is the same number of slots as the example 1

described above. However, the number of second slots 19 is

60 slots, which is larger than the number of second slots 19

in the example 1 (45 slots). Further, in the first windings

15, the number of slots for each pole and each phase is 3,

which is the same number of slots for each pole and each

phase in the example 1. However, in the second windings 16,

the number of slots for each pole and each phase is 2, which

is larger than the number of slots for each pole and each

phase in the example 1.

[0050]

A slot pitch angle (360/the number of slots) is 4

degrees with respect to the first slots 18, and is 6 degrees

with respect to the second slots 19. With such setting of

the angles, as illustrated in Figure 5, although the

positions of the second slots 19 can be aligned with the

positions of the first slots 18 at some portions, the second

slots 19 are displaced from portions disposed adjacently to

the first slots 18.

[0051]

Mounting of the windings to the stator core in the

modification 2 can be performed by setting a wire shape of

the winding to a round line shape.

[0052]

According to the studies made by the inventors, as in

the case of the modification 1, the condition that the

respective positions of the second slots 19 agree with the

first slots 18 are expressed by an expression (1) and an

expression (2). In the expressions, P indicates the number

of poles, Ns 1 indicates the slot number of the first slots

18, and Ns 2 indicates the slot number of the second slots

19.

[0053]

[Math 1]

k = Nsi/(PxNx3 (number of phases)x0.5) .. (1)

[0054]

[Math 2]

Ns2 = Nsi /N ... (2)

[0055]

According to the studies made by the inventors of the

present invention, in a case where a value of k takes a

positive integer with respect to a positive integer (natural

number) N for setting N2s with respect to Nsi, the respective

positions of the second slots 19 are aligned with the first

slots 18. For example, in a case where P =10 and Nsi= 90,

when N = 2, 3, k takes an integer (3, 2). Accordingly, N =2

and Ns 2 = 45 in the example 1, and N =3 and Ns 2 = 30 in the

modification 1.

[0056]

Figure 6 is a developed view of a stator of a rotary

electric machine according to a modification 3.

[0057]

In the modification 3, the number of first slots 18 is

90 slots, which is the same number as the example 1

described above. However, the number of second slots 19 is

15 slots, which is smaller than the number of second slots

19 in the example 1 (45 slots).

[0058]

A slot pitch angle (= 360/the number of slots) is 4

degrees with respect to the first slots 18, and is 24

degrees with respect to the second slots 19. Further, in the expression (1) and the expression (2), N = 6 and k = 1.

Accordingly, as illustrated in Figure 6, the positions of

the second slots 19 and the positions of the first slots 18

can be aligned with each other.

[00591

Further, in the modification 3, although the first

windings 15 are wound by distributed winding in the same

manner as the example 1, the second windings 16 are wound by

concentrated winding.

[00601

According to the example 1 described above, it is

possible to realize the rotary electric machine having the

two sets of windings having different configurations without

making the configuration of the windings complicated.

[00611

The application of the configuration of the stator in

the example 1 is not limited to a field winding type

synchronous machine, and such configuration of the stator is

also applicable to a squirrel cage induction machine, a

wound-rotor induction machine, a permanent magnet

synchronous machine and the like.

Example 2

[00621

Figure 7 is a developed view illustrating a state

where the cross-sectional configuration of a stator of a rotary electric machine according to an example 2 of the present invention is expanded linearly. The configurations other than the stator are substantially equal to the corresponding configuration of the rotary electric machine according to the example 1. In the same manner as Figure 3, an air gap 22 (Figure 2) is positioned on a lower side of

Figure 7, and a frame 1 (Figure 2) is positioned on an upper

side of Figure 7.

[00631

As illustrated in Figure 7, in the example 2, the

position of the magnetic pole center generated by U-phase

winding of the first windings 15 and the position of the

magnetic pole center generated by U-phase winding of the

second windings 16 are aligned with each other.

[0064]

Figure 8 is a developed view of the stator according

to the stator of the example 1 described above (Figure 3

being used again).

[00651

As illustrated in Figure 8, in the example 1 described

above, the position of a magnetic pole center 23 generated

by the U-phase winding of the first windings 15 and the

position of a magnetic pole center 24 generated by the U

phase winding of the second windings 16 are different from

each other by a phase difference angle u.

[0066 ]

Accordingly, in the example 2, the windings are

disposed such that the phase difference angle u in Figure 8

becomes 0. To be more specific, without changing the

position of the second windings 16 in Figure 8, the winding

of the first windings 15 is displaced by 1 slot.

[0067]

Next, the electric characteristic of the rotary

electric machine according to the example 2 is described.

[0068]

Figure 9 is a view illustrating three phase voltages

on rotational coordinates with respect to a case where

magnetic pole centers genarated by the respective phase

windings differ from each other by a phase difference angle

a between the first windings 15 and the second windings 16.

[0069]

In Figure 9, 0 is a phase difference angle between a d

axis of rotational coordinates and the U-phase (U 1 ) of the

first windings.

[0070]

Figure 10 is a view illustrating the direction of d-q

axes voltage vectors in a case where a dq transformation is

applied to three phase voltages of each of the first

windings 15 and the second windings 16 based on a two- reaction theory using the first windings 15 as the reference.

[0071]

In Figure 10, the di-qi axes vectors indicate the

three phase voltages of the first windings 15, and the d2-q2

axes vectors indicate the three phase voltages of the second

windings 16.

[0072]

The d-axis voltage and the q-axis voltage are

orthogonal to each other and hence, mutual inductance

between d-q axes can be ignored. However, as illustrated in

the same drawing, in the case of the three-phase alternating

current windings of two systems arranged at the phase

difference angle a, mutual inductance (Maia2, Ma2ai, Mqiq2,

Mg2qi) between the same axes are (between di - d 2 axes,

between qi - q2 axes) is generated. To use the mutual

reactance X obtained by multiplying the mutual inductance by

"2ixfrequency", the following voltage expressions (3) are

obtained.

[0073]

[Math 3]

Vd1 = R1'1d - Xq1lq1 - Xqlq2!q2 Vqi = RIqi + E1 + XaIai + Xala2Id2 (3) Va2 = Rzlaz - Xq2lq2 - Xq2qlfql Vq2 = R212 + E2 + Xa2I2 + Xd2z1Id1

[00741

In the expression (3) , Vai, Dd2, Vqi, Va2, Iai, Ia2, Iqi

and Iq2 respectively indicate a d axis voltage of the first

windings, a d axis voltage of the second windings, a q axis

voltage of the first windings, a q axis voltage of the

second wirings, a d axis current of the first windings, a d

axis current of the second windings, a q axis current of the

first windings, and a q axis current of the second windings.

Further, Xai, Xa2, Xqi, Xq2, R1, R2 , Ei, E2 , Xaia2, Xd2dl, and Xqiq2

and Xq2q1 respectively indicate a d-axis reactance of the

first windings, a d-axis reactance of the second windings, a

q-axis reactance of the first windings, a q-axis reactance

of the second windings, a winding resistance of the first

windings, a winding resistance of the second windings, an

induced electromotive voltage of the first windings, an

induced electromotive voltage of the second windings, a

mutual reactance between d axes (di - d2 axes), and a mutual

reactance between q axes (qi - q2 axes).

[0075]

Four expressions that are the voltage equations

respectively contain mutual reactance. Accordingly, a

voltage of the first windings 15 and a voltage of the second

windings 16, change when a parameter of one windigs changes

even when a parameter of the other windings does not change.

That is, although the first windings 15 and the second windings 16 are independent from each other as electric circuits, the first windings 15 and the second windings 16 are magnetically coupled to each other via a mutual reactance.

[0076]

Figure 11 is a voltage vector view indicating a

voltage (VI) of the first windings where dq axes voltage

components are expressed by the expression (3).

[0077]

In Figure 11, i indicates a current phase angle, #1 5 indicates a power factor, and 1 indicates a load angle.

Further, in Figure 11, voltage components affixed with an

underline indicate parameters depending on the mutual

reactance between the same axes. Voi indicates a voltage

vector in a case where mutual inductance is not generated.

[0078]

As shown in Figure 11, V1 advances compared to Voi by

the mutual reactance between the same axes. That is, a

power ratio angle is increased by the mutual reactance

between the same axes and hence, a power factor is

decreased.

[0079]

Accordingly, by setting the phase difference angle u

(Figure 8) between the position of the magnetic pole center

23 generated by the U-phase winding of the first windings 15 and the position of the magnetic pole center 24 generated by the U-phase winding of the second windings 16 to 0 as in the case of the example 2, the generation of the mutual reactance between the same axes can be suppressed and hence, lowering of a power factor can be suppressed. Accordingly, the rotary electric machine can prevent lowering of its efficiency while having the first windings 15 and the second windings 16.

[00801

As described above, in the example 2, due to the

reason set forth above, by making the magnetic pole

generated by the first windings 15 and the magnetic pole

generated by the second windings 16 aligned with each other,

it is possible to prevent lowering of efficiency of the

rotary electric machine that includes the first windings 15

and the second windings 16.

Example 3

[0081]

Figure 12 is a developed view of a stator of a rotary

electric machine according to an example 3 of the present

invention. The configurations other than a stator are

substantially equal to the corresponding configurations of

the example 1. In the same manner as Figure 3, an air gap 22

(Figure 2) is positioned on a lower side of Figure 12, and a frame 1 (Figure 2) is positioned on an upper side of Figure

12.

[0082]

As illustrated in Figure 12, in the example 3, all

slots formed in the stator 3 have the same shape. That is,

in a cross section of the illustrated stator, cross

sectional shapes of all slots on which the winding is wound

have a rectangular cross-sectional shape of the same depth.

[0083]

In the example 3, the configuration of the first

windings 5 and the configuration of the second windings 6

have the substantially same corresponding configuration of

the example 1 (Figure 3) described above. Accordingly, out

of the first windings 15 and the second windings 16, in the

slot in which only the first windings 15 is disposed, a

cavity portion 25 is formed on a radially outer diameter

side of the first windings 15.

[0084]

In the same manner as the example 1 (Figure 1 and

Figure 2) described above, also in this example 3, a

refrigerant 9 for cooling flows in the axial direction of

the rotary electric machine using a back surface duct 20, an

axial duct 21 and an air gap 22 as passages. Further, in

the example 3, the cavity portion 25 disposed in the slot in

which only the first windings 15 is disposed forms a passage for the refrigerant 9. With such a configuration, the first windings 15 are brought into direct contact with the refrigerant 9 that flows through the cavity portion 25.

Accordingly, a heat transfer area of the stator core 14 is

increased.

[00851

According to the example 3, a cooling performance of

the stator 3 is enhanced and hence, the rise of a

temperature of the first windings 15 can be suppressed with

certainty. Further, the first windings 15 can be

efficiently cooled by a refrigerant that passes through the

cavity portion 25 and hence, in a case that a type of

insulation that allows a large rise of temperature is

applied as an insulation type of the windings, the rotary

electric machine may have neither the back surface duct 20

nor the axial duct 21. In this case, the configuration of

the rotary electric machine can be made compact.

Example 4

[00861

Next, a rotary electric machine according to an

example 4 is described with reference to Figure 13 to Figure

15.

[0087]

In the example 4, a stepped portion is formed on a

side wall of a stator core 14 in a slot between a first slot

18 and a second slot 19. The configurations of the first

windings 15 and the second windings 16 are substantially

equal to the corresponding configurations of the example 1

(Figure 3). Further, in the same manner as the example 1,

the positions of the second slots 19 are aligned with the

positions of the first slots 18.

[00881

Figure 13 is a developed view of a stator illustrating

a first example of the stepped portion formed on a side wall

in the slot.

[00891

As illustrated in Figure 13, in the first example, a

slot width of the first slot 18 is larger than a slot width

of the second slot 19.

[00901

According to the slot shape illustrated in Figure 13,

the difference in an inductive electromotive voltage between

the first windings 15 and the second windings 16 can be

increased by increasing the number of turns of the first

windings 15.

[0091]

Also in the first example, in the same manner as the

example 1, the stator can be manufactured easily and

efficiently by applying a method of manufacturing where a

formed coil is inserted into the slots.

[00921

Figure 14 is a developed view of a stator illustrating

a second example of the stepped portion formed on a side

wall in the slot.

[0093]

As illustrated in Figure 14, in the second example, a

slot width of the second slot 19 is larger than a slot width

of the first slot 18.

[0094]

According to the slot shape illustrated in Figure 14,

a current density of the second system winding 16 can be

reduced by increasing a size of a wire or the number of

parallelly arranged wires.

[0095]

Figure 15 is a developed view of a stator illustrating

a third example of the stepped portion formed on a side wall

in the slot.

[0096]

As illustrated in Figure 15, in the third example, a

stepped portion that narrows a slot width and a stepped

portion that widens a step width are continuously formed.

That is, between the first slot 18 and the second slot 19,

an inner wall surface of the slot of the stator core 14 has

a protruding portion 26 that protrudes in a circumferential direction, that is, in a direction that the slot width is narrowed.

[0097]

According to the slot shape illustrated in Figure 15,

the protruding portions 26 become stoppers for the second

windings 16 and hence, it is possible to prevent the removal

of the second windings 16 toward an inner diameter side.

Further, the first windings 15 and the second windings 16

are disposed in a spaced apart manner due to the protruding

portions 26 and hence, it is possible to prevent the

occurrence of short-circuiting between the first windings 15

and the second windings 16 in the slot.

[0098]

The stator core having a slot shape illustrated in

Figure 15 can be manufactured by integral forming of

electromagnetic steel plates.

Example 5

[0099]

Next, a rotary electric machine according to an

example 5 is described with reference to Figure 16 to Figure

18.

[0100]

The rotary electric machine according to the example 5

includes third windings 27 in addition to the first windings

15 and the second windings 16. The configuration of first windings 15 and the configuration of second windings 16 are substantially equal to the configurations of the first windings 15 and the configuration of the second windings 16 of the example 1 (Figure 3). Further, in the same manner as the example 1, the positions of second slots 19 are aligned with the positions of the first slots 18.

[0101]

Figure 16 is a developed view of the stator 3

illustrating a first example of the winding configurations

of the first windings 15, the second windings 16 and the

third windings 27.

[0102]

As illustrated in Figure 16, in the first example,

although the configurations of the first windings 15 and the

second windings 16 are substantially equal to the

corresponding configuration of the modification 1 (Figure 4)

of the example 1 as described above, the rotary electric

machine according to the example 5 further includes: on an

outer profile side of the second windings 16, the third

windings 27 in an overlapping manner with the second

windings 16 along the depth direction of the slot. The

positions of the third windings 27 are aligned with the

positions of the first windings 15 and the second windings

16. Accordingly, the number of slots for the third windings

27 is equal to the number of slots for the second windings

16.

[0103]

Figure 17 is a developed view of the stator 3

illustrating a second example of the winding configurations

of the first windings 15, the second windings 16 and the

third windings 27.

[0104]

As illustrated in Figure 17, in the second example,

although the number of slots for the third windings 27 is

equal to the corresponding number of slots for the first

example (Figure 16) described above, the number of slots for

the second windings 16 is equal to the corresponding number

of slots for the first windings 15.

[0105]

Figure 18 is a developed view of the stator 3

illustrating a third example of the winding configurations

of the first windings 15, the second windings 16 and the

third windings 27.

[0106]

As illustrated in Figure 18, in the third example, the

number of slots for the second windings 16 is 2/3 of the

number of slots for the first windings 15, and the number of

slots for the third windings 27 is 1/3 of the number of

slots for the first windings 15.

[01071

In the rotary electric machine according to the

example 5, the first windings 15, the second windings 16 and

the third windings 27 are not electrically connected with

each other and are independent from each other.

[0108]

In the example 5, the first windings 15, the second

windings 16 and the third windings 27 are disposed in this

order from an inner diameter side to an outer diameter side

of the stator. However, the arrangement is not limited to

such arrangement, and the first windings, the second

windings, .. the n-th windings (n (integer) > 3) may be

sequentially arranged. In this case, assuming the number of

slots for the first windings 15 (1 i(integer) n) as Nsi,

the number of slots for respective windings are set so as to

take the arrangement of Ns1i Ns2 > Ns3_ Nsn.

[0109]

According to the example 5, it is possible to form the

stator having windings of three or more systems.

Example 6

[0110]

Figure 19 is a block diagram illustrating the

configuration of a rotary electric machine system for a dump

truck that is an example 6 of the present invention.

[0111]

As illustrated in Figure 19, a rotary shaft of the

rotary electric machine 100 according to any one of the

examples 1 to 5 described above is directly connected to a

rotary shaft of an engine 200 that is a prime mover by means

of a coupling 31. When the rotary electric machine 100 is

rotated by the engine 200, the rotary electric machine

generates a three-phase alternating current power.

[0112]

Three-phase alternating current powers that the first

windings 15 and the second windings 16 that the rotary

electric machine 100 includes are respectively supplied to a

power converter 201a and a power converter 201b.

[0113]

The power converter 201a converts three-phase

alternating current power from the first windings 15, and

converted power is supplied to rotary electric machines 300

for driving that becomes a main machine for rotatably

driving wheels of the dump truck. On the other hand, the

power converter 201b converts three-phase alternating

current power from the second windings 16, and converted

power is supplied to a blower 301 that supplies a

refrigerant 9 for cooling the rotary electric machine 100 to

the rotary electric machine 100.

[0114]

According to the example 6, using one rotary electric

machine 100, it is possible to supply power for driving the

rotary electric machine 300 and the blower 301.

Accordingly, it is possible to realize downsizing and the

reduction of weight of a rotary electric machine system for

a dump track.

[0115]

The supply destination of power from the second

windings 16 is not limited to the blower 300, and the power

from the second windings 16 may be used as power for driving

other electric auxiliary machines.

Example 7

[0116]

Figure 20 is a block diagram illustrating the

configuration of a rotary electric machine system for an

electric bus that is an example 7 according to the present

invention.

[0117]

As illustrated in Figure 20, a rotary shaft of the

rotary electric machine 100 according to any one of the

examples 1 to 5 described above is directly connected to a

speed reducing device 202 by means of a coupling 31.

[0118]

In making the electric bus perform traveling, a switch

205 connects a battery 204 to a power converter 203a. The power converter 203a converts direct-current power from the battery 204 to a three-phase alternating-current power by power conversion, and supplies the three-phase alternating current power to first system windings 15 of a rotary electric machine 100. Accordingly, the rotary electric machine 100 is operated as an electric machine, and power of the rotary electric machine 100 is transmitted to wheels through the speed reducing device 202.

[0119]

In case of stopping the electric bus, the switch 205

connects the battery 204 to a power converter 203b. The

power converter 203b converts regenerated power from second

windings 16 of the rotary electric machine 100 in a

regenerative state into direct-current power, and outputs

the direct-current power. The direct-current power is

charged in the battery 204.

[0120]

According to the example 7, with the use of the second

windings 16 that is independent of the first windings 15,

charging of the battery by the regenerated power can be

controlled with accuracy.

[0121]

It should be noted that the present invention is not

limited to the examples described above, and includes

various modification examples. For example, the examples described above have been described in detail to simply describe the present invention, and are not necessarily required to include all the described configurations. In addition, part of the configuration of each of the examples can be subjected to addition, deletion, and replacement with respect to other configurations.

[0122]

For example, the configuration of the stators in the

respective examples are applicable to various types of

rotary electric machines such as a field winding type

synchronous machine, a squirrel case induction machine, a

wound induction machine, a permanent magnet synchronous

machine.

[0123]

Further, the drive-use rotary electric machines in the

respective examples are applicable to various devices and

systems that make use of an output of the rotary electric

machine (generated electric power, rotary drive force).

[0124]

Further, the rotary electric machine systems according

to the example 6 and 7 described above are not limited to a

dump truck and an electric bus, and may be applied to other

electric vehicles and electric ship and the like. Further,

the rotary electric machine system according to the example

7 may be applied to an elevator (particularly, a high-speed large-capacity elevator). In this case, the rotary electric machine 100 is used as a traction machine.

[0125]

Reference Signs List

1... frame,

2... rotor,

3... stator

4... bearing

5... shaft

6, 7... coil end

8. inlet port

9... refrigerant

10... rotor core

11... field winding

12... damper bar

13... rotor wedge

14... stator core

15... first windings

16... second windings

17... stator wedge

18... first slot

19... second slot

20... back surface duct

21... axial duct

22... air gap

23, 24: magnetic pole center

25... cavity portion

26... protruding portion

27: third windings

31... coupling

100... rotatory electric machine

200... engine

201a, 201b... power converter

202: speed reducing device

203a. 203b... power converter

204... battery

205... switch

300... rotary electric machine for driving

301... blower

Claims

Claim 1

A rotary electric machine comprising:

a rotor; and

a stator having a three-phase alternating current

winding, wherein

the three-phase alternating current winding includes

first windings and second windings that are independent from

each other,

the rotary electric machine includes:

a plurality of first slots in which the first windings

are provided; and

a plurality of second slots in which the second

windings are provided,

the number of the first slots is equal to or larger

than the number of the second slots, and

the first windings are provided more inward than the

second windings in the stator.
Claim 2

The rotary electric machine according to claim 1,

wherein an induced electromotive voltage of the first windings is larger than an induced electromotive voltage of the second windings.
Claim 3

The rotary electric machine according to claim 1,

wherein positions of the second slots are aligned with

positions of the first slots.
Claim 4

The rotary electric machine according to claim 3,

wherein assuming the number of poles of the rotary electric

machine as P and the number of the first slots as Nsi, a

value of Ns 1 / (PxNx3 (the number of phases)x 0.5) is an

integer and the number of slots of the second slots is Ns 1 /N

with respect to an integer N.
Claim 5

The rotary electric machine according to claim 1,

wherein a position of a magnetic pole generated by the first

windings and a position of a magnetic pole generated by the

second windings are aligned with each other.
Claim 6

The rotary electric machine according to claim 1,

wherein the plurality of first slots include the first slots having cavities on an outer diameter side of the first windings.
Claim 7

The rotary electric machine according to claim 3,

wherein a side wall of the stator has a stepped portion

between the first slot and the second slot.
Claim 8

The rotary electric machine according to claim 7,

wherein the stepped portion is formed such that a width of

the second slot is smaller than a width of the first slot.
Claim 9

The rotary electric machine according to claim 7,

wherein the stepped portion is formed such that a width of

the second slot is larger than a width of the first slot.
Claim 10

The rotary electric machine according to claim 7,

wherein the stepped portion is formed such that the side

wall of the stator protrudes between the first slot and the

second slot.
Claim 11

The rotary electric machine according to claim 1,

wherein the three-phase alternating current winding further

has third to n-th windings (n (integer) > 3), and the first

windings to the n-th windings are sequentially disposed from

an inner diameter side to an outer diameter side of the

stator
Claim 12

A rotary electric machine system for an electric

vehicle, the rotary electric machine system comprising:

a rotary electric machine that supplies power to a

main machine and an auxiliary machine mounted on an electric

vehicle;

a prime mover that drives the rotary electric machine,

wherein

the rotary electric machine is the rotary electric

machine according to claim 1,

power is supplied to the main machine from the first

windings via a first power converter, and

power is supplied to the auxiliary machine from the

second windings via a second power converter.
Claim 13

The rotary electric machine system for an electric

vehicle according to claim 12, wherein the electric vehicle is a dump truck; the main machine is a rotary electric machine for driving, and the auxiliary machine is a cooling blower.
Claim 14

A rotary electric machine system for an electric

vehicle comprising:

a rotary electric machine that drives an electric

vehicle; and

a battery that supplies power to the rotary electric

machine via a first power converter, wherein

a rotary electric machine is the rotary electric

machine described in claim 1,

power is supplied to the first windings from the

battery via the first power converter, and

regenerative power is charged into the battery from

the second windings via the second power converter.
Claim 15

The rotary electric machine system according to claim

14, wherein the electric vehicle is an electric bus.