FIELD OF INDUSTRIAL APPLICATION
[0001] This invention relates to a vehicle mounting transformer and, more particularly,
to a vehicle mounting transformer for use in a vehicle operating electric system for
achieving the power and regenerative running control by means of a power conversion
system such as a pulse width modulation control conversion system.
PRIOR ART
[0002] Fig. 9 is a schematic diagram illustrating one example of a conventional shell-type
vehicle mounting transformer 4 disclosed in Japanese Patent Laid-Open No. 1-133311
and Japanese Patent Laid-Open No. 2-184007. The vehicle mounting transformer 4 comprises
a shell-type iron core 5, an input side winding 6 wound on the iron core 5 and a plurality
of output side windings 7 disposed in a magnetic inductance relationship with respect
to the iron core 5 and the input side winding 6. The vehicle mounting transformer
4 further comprises a magnetic member assembly 17 including a plurality of magnetic
elements 13 disposed between the input side winding 6 and the output side windings
7 and arranged in a space surrounded by the iron core 5 with air gaps therebetween
and insulating material 14 insulatingly supporting the magnetic elements 13 relative
to each other and relative to the iron core 5 and the windings 6 and 7. The magnetic
elements 13 are insulatingly supported with air gaps formed by the insulating material
14, so that a magnetic member with air gap is generally constructed.
[0003] Fig. 10 is a circuit diagram illustrating a vehicular operating electric system using
the vehicle mounting transformer illustrated in rig. 9. In Fig. 10, the electric power
is supplied to the input side windings 6 wound on the iron core 5 of the vehicle mounting
transformer 4 through an interrupter 3. Four output side windings 7 of the vehicle
mounting transformer 4 are related to the magnetic member 13 and directly connected
respectively to the inputs of the pulse width modulation (PWM) converter 9. The output
of the PWM converter 9 is connected to the input of the VVVF inverter 11 through a
capacitor 10. The output of the VVVF inverter 11 is connected to a three-phase induction
motor 12 for driving wheels of an electric vehicle.
[0004] The leakage flux generated during the operation of the vehicle mounting transformer
4 under the load increases since a magnetic member assembly 17 which is a magnetic
member with air gap, whereby the leakage impedance increases.
PROBLEM TO BE SOLVED BY THE INVENTION
[0005] The conventional vehicle mounting transformer thus constructed is desirable in that
the requisite reactive voltage can be obtained with a light-weight and compact structure.
However, while it is required that the respective windings divided from the output
side windings 7 in view of the load control or the like are magnetically loosely coupled
to each other when it is used as a vehicle mounting transformer, it has been difficult
to realize a winding arrangement which satisfies the need of the loose coupling between
the output side windings.
[0006] That is, in the power conversion system of the PWM inverter control used in a vehicle
electric system, a multi-phase PWM converter control, which is a circuit system in
which the converter units controlled at the different phases are connected to the
output winding of the transformer. For example, in the four-phase PWM converted control
system, the output winding of the transformer is divided into four, each is connected
by the converter units, and the GTO thyristor gate control is achieved at the different
phases.
[0007] In this case, if the magnetic coupling between the output windings are strong, one
converted unit may be subjected to a magnetic interference by the operation of another
converter unit whereby the wave form of the converter input current is disturbed,
resulting in increase of the noise flow to the trolley line due to the increase in
the harmonic current component and the increase of the peak of the current ripples,
whereby the current interrupting capacity of the GTO element is exceeded and the GTO
will be destroyed.
[0008] For these reasons, it is required that the magnetic coupling between the output windings
of the transformer used in the PWM converter control is loose, i.e., the transformer
is required to have loose coupling characteristics in which load conditions of one
output winding does not magnetically interfere the other output windings.
[0009] Accordingly, the object of the present invention is to provide a vehicle mounting
transformer in which magnetically loose coupling characteristics between each of the
output side windings can be stably obtained.
MEASURE FOR SOLVING THE PROBLEM
[0010] With the above object in view, the vehicle mounting transformer of the present invention
comprises a shell-type iron core, an input side winding wound around the iron core,
a plurality output side windings wound around the iron core and disposed in a magnetic
induction relationship with respect to the input side winding, and a loose coupling
magnetic member assembly including a gap-less magnetic member disposed between the
neighboring out of the output side windings and within a space surrounded by the iron
core.
[0011] If desired, an air-gap reactor magnetic material assembly may be provided between
the input side and the output side windings.
[0012] According to the present invention, necessary stable loose coupling between each
of the output side windings can be obtained by the gap-less magnetic core inserted
between the output side windings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will become more readily apparent from the following detailed
description of the embodiment of the present invention taken in conjunction with the
accompanying drawings, in which:
Fig. 1 is a schematic sectional side view illustrating a vehicle mounting transformer
of one embodiment of the present invention;
Fig. 2 is a sectional front view of the vehicle mounting transformer taken along line
II - II of Fig. 1;
Fig. 3 is a perspective view illustrating the reactor magnetic member assembly of
the vehicle mounting transformer illustrated in Fig. 1;
Fig. 4 is a sectional front view of the vehicle mounting transformer taken along line
III - III of Fig. 1;
Fig. 5 is a perspective view illustrating the loose coupling magnetic member assembly
of the vehicle mounting transformer illustrated in Fig. 1;
Fig. 6 is a schematic diagram illustrating the vehicle operating electric system employing
the vehicle mounting transformer illustrated in Figs. 1 to 5;
Fig. 7 is a vector diagram illustrating the phase relationship of the vehicle mounting
transformer of the present invention;
Fig. 8 is a schematic sectional side view illustrating the vehicle mounting transformer
of another embodiment of the present invention;
Fig. 9 is a schematic sectional side view illustrating a conventional vehicle mounting
transformer; and
Fig. 10 is a schematic diagram illustrating the vehicle operating electric system
employing, the conventional vehicle mounting transformer illustrating in Fig. 9.
EMBODIMENTS
[0014] Fig. 1 is a schematic diagram illustrating one embodiment of the shell-type vehicle
mounting transformer of the present invention. In Fig. 1, the general arrangement
of the iron core 5 and the windings 6 and 7 of the vehicle mounting transformer 4A
is similar to that of the conventional vehicle mounting transformer 4 illustrated
in Fig. 9. That is, the iron core 5 comprises a main core 5a of a width 2W, legs 5b
of width W disposed in parallel at the both sides of the main core 5a and yokes 5c
of width W connecting the main core 5a and the legs 5b. The main core 5a has wound
thereon, in a space 5d surrounded by the iron core 5, input side windings 6a and 6b,
which are spaced in the direction of axis of the windings and connected in parallel
to each other. The main core 5a has also wound thereon, in a space 5d surrounded by
the iron core 5, four output side windings 7a to 7d, and while the output side windings
7a and 7b are disposed at the both sides of the input side winding 6a to sandwich
it in the axial direction, the output side windings 7c and 7d are disposed at the
both sides of the input side winding 6b to sandwich it in the axial direction.
[0015] The vehicle mounting transformer 4A comprises a reactor magnetic member assembly
17 disposed within an axial space between the input side windings 6a and 6b and the
output side windings 7a to 7d. The transformer also comprises a loose coupling magnetic
member assembly 18 disposed within an axial space between the neighboring output side
windings 7b and 7c.
[0016] The reactor magnetic member assembly 17 comprises, as illustrated in detail in Figs.
2 and 3, a substantially rectangular, suitably rigid insulator 14 having a substantially
rectangular central opening 17a for accommodating the main core 5a of the iron core
5 and a plurality of magnetic member elements 13b embedded within the insulator 14
and disposed in parallel with air gaps 13a therebetween so that an air gap magnetic
member 13 is constituted within the, space 5d surrounded by the iron core 5. Each
magnetic member element 13b is a lamination in which an elongated rectangular magnetic
plates are stacked in the same direction as the direction of stack (arrow A of Fig.
1) of the rectangular pancake coils, and this lamination is arranged in parallel to
the direction of extension of the coil conductors (arrow B of Fig. 2). In the illustrated
embodiment, four magnetic member elements 13b are disposed at each side of the main
core 5a and three air gaps are defined. As shown in Fig. 3, the insulator 14 comprises
two insulating plates 14b and 14c sandwiching the magnetic member elements 13b therebetween
to securely support by means of insulating pins 14a, insulations 14d for filling the
spaces defined between the insulating plates 14b and 14c at each end which is not
occupied by the magnetic member elements 13b and insulations 14e inserted between
the magnetic member elements 13b to define air gaps 13a therebetween, thereby to generally
insulatingly support the magnetic member elements 13b with air gaps therebetween relative
to each other and to the windings 6 and 7.
[0017] The loose coupling magnetic member assembly 18 comprises, as shown in detail in Figs.
4 and 5, a substantially rectangular, suitably rigid insulator 16 having a substantially
rectangular central opening 18a for accommodating the main core 5a of the iron core
5 and gap-less magnetic member 15 embedded within the insulator 16 and disposed within
the space 5d surrounded by the iron core 5. The gap-less magnetic member 15 comprises
a plurality of (four in the illustrated embodiment) magnetic member elements 15b which
are disposed in the direction perpendicular to the direction of extension of the coil
conductors (arrow B) and spaced from each other by insulators 16e in the direction
of extension of the coil conductors. Each magnetic member element 15b is also spaced
from each other by the insulations 16e made such as of glass epoxy in a manner similar
to the magnetic member elements 13b of the reactor magnetic member assembly 17. However,
this spaced arrangement of the magnetic member elements 15b is for the purpose of
minimizing the eddy losses generated in the magnetic member 15 due to the leakage
flux intruding perpendicularly to the surface of the magnetic member 15 and has the
orientation different from those in the reactor magnetic member assembly 17, so that
the magnetic member 15 may be considered as an air-gap-less magnetic member in a magnetic
sense. Each magnetic member element 15b is a lamination in which rectangular magnetic
plates are stacked in the direction parallel to the direction of stack (arrow A) of
the rectangular pancake coils.
[0018] As illustrated in Fig. 5, the insulator 16 comprises two insulating plates 16b and
16c sandwiching the magnetic member elements 15b therebetween to securely support
them by means of insulating pins 16a, insulations 16d for filling the spaces defined
between the insulating plates 16b and 16c at each end which is not occupied by the
magnetic member elements 15b and insulations 16e inserted between the magnetic member
elements 15b, thereby to generally insulatingly support the magnetic member elements
15 relative to the iron core 5 and the windings 6 and 7. The insulating pins 16a are
inserted into holes formed in the magnetic member elements 15b as well as the insulating
plates 16b and 16c. The loose coupling magnetic member assembly 18 thus assembled
is varnish impregnated into a unitary structure.
[0019] The outer shape of the insulator 16 of the loose coupling magnetic member assembly
18 is similar to that of the insulator 14 of the reactor magnetic member assembly
17 and is adapted to be stacked between the windings 6 and 7 to constitute a coil
group to be supported by the iron core 5. Accordingly, in manufacturing the coil group,
the loose coupling magnetic member assembly 18 and the reactor magnetic member assembly
17 can be handled and stacked in the same way as the coils, so that the iron core
assembly and the coil group assembly can be easily carried out by the same transformer
assembling process as that heretofore has been used.
[0020] As illustrated in Fig. 1, each reactor magnetic member assembly 17 is sandwiched
and supported between the output side winding 7a and the input side winding 6a, the
input side winding 6a and the output side winding 7b, the output side winding 7c and
the input side winding 6b and between the input side winding 6b and the output side
winding 7d. The magnetic member elements 13b of each assembly 17 are embedded and
supported within the rigid insulating plate 14, so that they are electrically insulated
relative to the charged portion while they are mechanically supported at places within
the iron core 5 by the iron core 5 and the windings 6 and 7. The loose coupling magnetic
member assembly 18 is inserted and supported between the output side winding 7b and
the neighboring output side winding 7c. The magnetic members 15 of the loose coupling
magnetic member assembly 18 are also electrically insulated by the rigid insulator
16 and mechanically supported by the iron core 5 and the windings 6 and 7 at the predetermined
position within the iron core 5.
[0021] In other respects, the arrangement may be identical to that of the conventional vehicle
mounting transformer illustrated in Fig. 9.
[0022] Fig. 6 is a circuit diagram illustrating the vehicle operating electric system partly
in block diagram employing the vehicle mounting transformer of the present invention
illustrated in Figs. 1 to 5. In Fig. 4, the electric power is supplied from the trolley
line 1 through a pantograph 2 and is supplied to the input side windings 6 wound on
the iron core 5 of the vehicle mounting transformer 4 through an interrupter 3. Four
output side windings 7a to 7d of the vehicle mounting transformer 4A are related to
the first and the second magnetic members 17 and 18 and directly connected respectively
to the inputs of the pulse width modulation (PWM) converter 9. The output of the PWM
converter 9 is connected to the input of the VVVF inverter 11 through a capacitor
10. The output of the VVVF inverter 11 is connected to a three-phase induction motor
12 for driving wheels of an electric vehicle.
[0023] In the vehicle operating electric system of Fig. 4 employing the vehicle mounting
transformer 4A of the present invention, the voltage supplied from the trolley line
1 through the pantograph 2 and the interrupter 3 is inputed into the input side winding
6 of the vehicle mounting transformer 4A and transformed therein to be outputed to
the output side windings 7 of the vehicle mounting transformer 4A. The outputs from
the output side windings 7 are supplied to the PWM converter 9 through the AC reactor
8, where the single phase AC power is converted into DC power. This DC power, after
smoothed by the capacitor 10, is supplied to the VVVF inverter 11, where it is converted
into three-phase AC power. This three-phase AC power drives the three-phase induction
motor 12 to drive the wheels of the vehicle (not shown)
[0024] The leakage flux generated during the operation under the load of the vehicle mounting
transformer 4A is increased by the reactor magnetic member assembly 17 which is an
air-gap magnetic member and, as its result, the leakage impedance increases. By suitably
selecting the numbers and the dimensions of the magnetic member elements 13b and the
air gaps 13a of the reactor magnetic member assembly 17, a suitable leakage impedance
Z
TA capable of providing a necessary reactive voltage V
L.
[0025] Therefore, the phase relationship between the input side terminal voltage (which
is referred to converter voltage) V
C of the PWM converter 9 and the input voltage V of the vehicle mounting transformer
4A as converted in the equal transforming ratio is as illustrated in Fig. 5. That
is, the input voltage V of the vehicle mounting transformer 4A is a vector sum of
the converter voltage V
C and the reactive voltage V
L which is generated during the power running operation at the power factor = 1 at
the product (Z
TA · I) of the leakage impedance Z
TA of the vehicle mounting transformer 4A and the input current I of the PWM converter
9.
[0026] Also, the loose coupling magnetic member assembly 18 which is an gap-less iron core
disposed between the output side windings 7b and 7c magnetically isolates the output
side windings 7b and 7c, whereby the loose coupling suitable for the pulse width modulation
control can be realized.
[0027] Fig. 8 illustrates a vehicle mounting transformer 4C of another embodiment of the
present invention in which six output side windings 37a to 37f are provided and two
loose coupling magnetic member assemblies 18 are employed. Thus, while the output
side winding is divided into four in the embodiment illustrated in Figs. 1 to 5, it
is to be understood that the present invention is equally applicable where the output
side winding is divided into more than four windings, and that similar advantageous
results can be obtained.
ADVANTAGEOUS RESULTS OF THE INVENTION
[0028] As has been described, according to the present invention, a loose coupling magnetic
member assembly inserted between the neighboring output side windings and having a
magnetic member supported by an insulator is provided, so that magnetic loose coupling
characteristics necessary for the pulse width modulation converter control can be
electrically and mechanically stably obtained.
[0029] Also, by providing a reactor magnetic member assembly disposed between the input
side winding and the output side windings and having a plurality of magnetic member
elements with air gaps therebetween and disposed within a space surrounded by the
iron core, a reactive voltage necessary for the pulse width modulation control can
at the same time be obtained.
[0030] The loose coupling magnetic member assembly and the reactive magnetic member assembly
are both supported by the plate-shaped insulators having the substantially rectangular
central opening for accommodating the iron core therein and insulatingly supporting
the magnetic members. Therefore, these magnetic member assemblies can be stacked together
with the coils in the same assembling process as that heretofore used to constitute
coil groups, so that the transformer assembly process can be carried out in the same
manner as that heretofore done without the need for any change in assembly equipments
and facilities.
1. A vehicle mounting transformer comprising a shell-type iron core, an input side winding
wound on said iron core and a plurality of output side windings disposed in a magnetically
inductive relationship relative to said iron core and said input side winding, characterized
by a loose coupling magnetic member assembly disposed between the neighboring output
side windings out of said output side windings and having an air gap-less magnetic
member disposed within a space surrounded by said iron core, said loose coupling magnetic
member assembly magnetically loosely coupling said neighboring output side windings
to each other.
2. A vehicle mounting transformer as claimed in claim 1, wherein said loose coupling
magnetic member assembly comprises an insulating member for insulatingly supporting
said gap-less magnetic member relative to said iron core and said windings.
3. A vehicle mounting transformer as claimed in claim 2, wherein said insulating member
of said loose coupling magnetic member assembly is a substantially rectangular plate
member having a substantially rectangular central opening for accommodating said iron
core, and said gap-less magnetic member comprises a plurality of magnetic member elements
embedded within said insulating member and arranged in the direction perpendicular
to the direction of extension of the coil conductors and spaced from each other in
the direction of extension of the coil conductors by said insulating member.
4. A vehicle mounting transformer as claimed in claim 1, wherein each of said magnetic
member elements is a lamination body of rectangular magnetic plates stacked in the
same direction as the direction of stack of rectangular pancake coils.
5. A vehicle mounting transformer as claimed in claim 2, wherein said insulating member
comprises two insulating plates sandwiching and securely supporting said magnetic
member elements therebetween by insulating pins, insulators filling spaces between
said insulating plates at both ends not occupied by the magnetic member elements and
insulators inserted between said magnetic member elements, thereby to generally insulatingly
support said magnetic member relative to said iron core and said windings.
6. A vehicle mounting transformer as claimed in claim 1, further comprising a rector
magnetic member assembly disposed between said input side winding and said output
side windings and having a magnetic member including a plurality of magnetic member
elements arranged with air gaps therebetween within a space surrounded by said iron
core.
7. A vehicle mounting transformer as claimed in claim 6, wherein said reactor magnetic
member assembly comprises an insulating member insulatingly supporting said magnetic
member relative to said iron core and said windings.
8. A vehicle mounting transformer as claimed in claim 7, wherein said insulating member
of said reactor magnetic member assembly is a substantially rectangular plate member
having a substantially rectangular central opening for accommodating said iron core,
and said magnetic member elements are embedded within said insulating member and arranged
in the direction parallel to the direction of extension of the coil conductors and
spaced from, each other in the direction perpendicular to the direction of extension
of the coil conductors by said insulating member.
9. A vehicle mounting transformer as claimed in claim 7, wherein each of said magnetic
member elements is a lamination body of rectangular magnetic plates stacked in the
same direction as the direction of stack of rectangular pancake coils.
10. A vehicle mounting transformer as claimed in claim 7, wherein said insulating member
comprises insulating plates sandwiching and holding said magnetic member elements
therebetween, insulating pins for securing said magnetic member elements and said
insulating plates together, insulators filling spaces between said insulating plates
not occupied by the magnetic member elements and insulators inserted between said
magnetic member elements, thereby to generally insulatingly support said magnetic
member relative to said iron core and said windings.
11. A vehicle mounting transformer as claimed in claim 6, wherein the outer configuration
of said loose magnetic member assembly is substantially the same as that of said reactor
magnetic member assembly, said loose magnetic member assembly and said reactor magnetic
member assembly are stacked between said windings to constitute a coil group to be
supported by said iron core.
12. A coil group comprising an input side winding to be wound on a shell-type magnetic
iron core, a plurality of output side windings disposed in a magnetically inductive,
stacked relationship relative to said input side winding, a loose coupling magnetic
member assembly having air gap-less magnetic member disposed between the neighboring
output side member insulatingly supporting said air gap-less magnetic member, for
magnetically loosely coupling said neighboring output side windings to each other,
and a rector magnetic member assembly having a plurality of magnetic member elements
disposed between said input side winding and said output side windings and an insulating
member insulatingly supporting said magnetic member elements relative to each other
and to said windings.