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DESCRIPTION
CAPACITOR EMBEDDED BETWEEN BUSBARS, ELECTRIC POWER
DEVICE AND ELECTRIC POWER CONVERSION DEVICE
Technical Field
[0001]
The present invention relates to an inter-bus-bar built-in capacitor, power
equipment and a power converting apparatus.
5 Background Art
[0002]
A capacitor capable of readily supplying electrical energy to an electrical circuit is
used in various kinds of power equipment including an inverter (such as a high-voltage inverter),
an electric current breaker, a transformer and a high-voltage power source. In addition, in
10 accordance with, among others, differences in internal structure between the capacitors, the
voltage ranks of the capacitors, the applications of the capacitors and the types of the power
equipment making use of the capacitors, the specifications of the capacitors are completely
different from each other.
[0003]
15 In a high-voltage inverter for example, normally, inside the inverter (inverter
board) or inside an inverter unit composing the inverter, in accordance with the voltage rank, a
smoothing capacitor such as an aluminum electrolytic capacitor or a film capacitor is provided.
In addition, a snubber capacitor is provided in some cases.
[0004]
20 In general, an inverter such as a high-voltage inverter has an insulated gate
bipolar transistor (properly referred to hereafter as an IGBT) and a smoothing capacitor
electrically connected to the IGBT through a bus bar. In particular, if the inverter is a highvoltage
inverter, the smoothing capacitor has a large size so that the capacitor occupies a large
space in the inverter. In addition, in order to avoid an insulation failure, it is necessary to
25 provide a spatial distance which is long to a certain degree between bus bars, which are normally
provided between the smoothing capacitor and the IGBT, or between a bus bar and a ground
frame (that is, a housing composing the inverter).
[0005]
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On top of that, in order to suppress a surge (that is, in order to decrease a suddenly
rising voltage), a snubber capacitor is usually provided at a location in close proximity to the
IGBT. Since the price of the snubber capacitor is high, however, it is desirable to make the
snubber capacitor cheaper (that is, it is desirable to decrease the capacity of the snubber
5 capacitor). In order to solve this problem, there is provided a capacitor described in Patent
Document 1 to serve as a capacitor composing a snubber circuit. This capacitor is provided so
that a piece of planar resin having a high dielectric constant is in close contact with an area
opposite to bus bar.
Prior Art Document
10 Patent Document
[0006]
Patent Document 1: JP-A-2008-295227
Summary of the Invention
Problems to be Solved by the Invention
15 [0007]
A capacitor described in Patent Document 1 composes a snubber circuit as
explained above to serve as a capacitor for relatively low voltages (specifically, not higher than
about 200 V). Thus, a gap between bus bars composing the capacitor is small. In addition, a
piece of resin is provided between the bus bars. The dielectric constant remains low as before.
20 Thus, even though it is possible to reduce the number of small size capacitors each having a
small capacity and a low voltage and/or downsize the capacitor to serve as a snubber capacitor or
the like in accordance with a technology described in Patent Document 1, the electrical capacity
of the capacitor provided between bus bars remains low as before. That is to say, the
technology described in Patent Document 1 is not sufficient for reducing the number of
25 smoothing-capacitors and/or downsizing the smoothing capacitor which is a typical large size
capacitor having a large capacity and a high voltage.
[0008]
It is therefore an object of the present invention addressing the problems
described above to provide an inter-bus-bar built-in capacitor to serve as a capacitor usable for
30 reducing the number of large-size capacitors used typically in a high-voltage inverter or
downsizing the large-size capacitor, provide power equipment and provide a power converting
apparatus.
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Means for Solving the Problems
[0009]
As a result of intensive studies of the problems to be solved as described above,
inventors of the present invention have discovered that, by providing a high-dielectric-constant
5 material having a specially high dielectric constant between bus bars, it is possible to provide an
inter-bus-bar built-in capacitor, power equipment and a power converting apparatus.
Effect of the Invention
[0010]
In accordance with the present invention, it is possible to provide an inter-bus-bar
10 built-in capacitor to serve as a capacitor usable for reducing the number of large-size capacitors
used typically in a high-voltage inverter or downsizing the large-size capacitor, provide power
equipment and provide a power converting apparatus.
[0011]
Other objects of the present invention, characteristics thereof and its merits
15 perhaps become apparent from the following description of an embodiment of the present
invention with reference to accompanying diagrams.
Brief Description of the Drawings
[0012]
Fig. 1 is a diagram depicting a model of bus bars for an inter-bus-bar built-in
20 capacitor in accordance with a first embodiment of the present invention.
Fig. 2 is a diagram depicting a model of a structure of electrodes used in the interbus-
bar built-in capacitor in accordance with the first embodiment of the present invention.
Fig. 3 is a diagram depicting a model of a typically modified structure of
electrodes used in the inter-bus-bar built-in capacitor in accordance with the first embodiment of
25 the present invention.
Fig. 4 is a diagram depicting a model of a typically modified structure of
electrodes used in the inter-bus-bar built-in capacitor in accordance with the first embodiment of
the present invention.
Fig. 5 is a diagram depicting a model of a typical method for installing the inter-
30 bus-bar built-in capacitor in accordance with the first embodiment of the present invention.
Fig. 6 is a diagram depicting a model of a typically modified inter-bus-bar built-in
capacitor in accordance with the first embodiment of the present invention. 1
i
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Fig. 7 is a diagram depicting a model of an internal structure of an inverter
employing the inter-bus-bar built-in capacitor in accordance with the first embodiment of the
present invention.
Fig. 8 is a diagram depicting a model of an internal structure of an inverter unit
5 employed in the inverter shown in Fig. 7.
Mode for Carrying Out the Invention
[0013]
By referring to diagrams, the following description explains details of a concrete
example of an inter-bus-bar built-in capacitor in accordance with a mode (referred to hereafter as
10 an embodiment) for carrying out the present invention. However, embodiments of the present
invention are by no means limited to this embodiment described below. That is to say, the
embodiment can be further changed arbitrarily in a variety of ways within a range not deviating
from essentials of the present invention.
[0014]
15 1. Inter-Bus-Bar Built-in Capacitor
Fig. 1 is a diagram depicting a model of bus bars for a capacitor built in between
the bus bars in accordance with a first embodiment of the present invention. As shown in Fig.
1, the inter-bus-bar built-in capacitor 3 according to the first embodiment is provided between a
pair of opposing bus bars, that is, an upper bus bar 1 and a lower bus bar 2. In addition, the
20 inter-bus-bar built-in capacitor 3 according to the first embodiment includes a high-dielectricconstant
material which has a relative dielectric constant of at least 50 when a voltage of 1,000 V
is applied to the material at a temperature of 25°C. In the first embodiment shown in Fig. 1, a
plurality of inter-bus-bar built-in capacitors 3 are provided between the pair of opposing bus
bars, that is, the upper bus bar 1 and the lower bus bar 2. In addition, an insulation body 4 is
25 provided between the inter-bus-bar built-in capacitors 3.
[0015]
High-Dielectnc-Constant Material
As described above, the inter-bus-bar built-in capacitor 3 according to the first
embodiment includes a high-dielectric-constant material which has a relative dielectric constant
30 of at least 50 when a voltage of 1,000 V is applied to the material at a temperature of 25°C.
However, a desirable value of the relative dielectric constant is a value not smaller than 500 and
an even more desirable value of the relative dielectric constant is a value not smaller than 2,000.
If the value of the relative dielectric constant is too small, the inter-bus-bar built-in capacitor
•
i.
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including the dielectric material is not capable of withstanding a high voltage so that it is quite
within the bounds of possibility that an insulation failure occurs. In addition, it is also quite
within the bounds of possibility that the number of smoothing capacitors, which are each
normally a large-size capacitor having a large capacity, can no longer be made smaller and/or the
5 capacitors cannot be downsized anymore.
[0016]
Concrete examples of the high-dielectric-constant material are barium titanate
(BaTiOs), zinc oxide supplementation silicon carbide (ZnO supplementation SiC) and strontium
titanate (SrTiCh). That is to say, it is desirable that the inter-bus-bar built-in capacitor 3
10 according to the first embodiment has the same material as the so-called ceramics capacitor. It
is even more desirable that the high-dielectric-constant material is the barium titanate or the zinc
oxide supplementation silicon carbide. It is to be noted that the high-dielectric-constant
material is any one selected from the concrete examples as a material used alone or any ones
selected from the concrete examples as two or more materials combined at an arbitrary
15 combination ratio.
[0017]
Electrodes
The inter-bus-bar built-in capacitor 3 according to the first embodiment normally
has electrodes besides the high-dielectric-constant material. The concrete structure of the
20 electrodes is not prescribed in particular. Usually, however, the inter-bus-bar built-in capacitor
3 according to the first embodiment has an upper electrode brought into contact with the upper
bus bar 1 and a lower electrode brought into contact with the lower bus bar 2. In addition, the
high-dielectric-constant material is held between the upper and lower electrodes. The distance
between the upper and lower electrodes is not prescribed in particular. If the distance between
25 the upper and lower electrodes is too short, however, the upper and lower electrodes are shorted
to each other in some cases. If the distance between the upper and lower electrodes is
excessively too long, on the other hand, it is quite within the bounds of possibility that the
electric capacitance of the inter-bus-bar built-in capacitor decreases. Thus, the distance is
normally set at a value not smaller than 0.02 mm. It is preferable as well as desirable to set the
30 distance at a value not smaller than 0.05 mm but not greater than 0.5 mm. Thus, it is especially
important to have a long distance between the electrodes in order to avoid an insulation failure
because, for example, a voltage applied to a high-voltage inverter or the like is high. If the
distance between the electrodes is long, the electric capacitance of the inter-bus-bar built-in
capacitor decreases. In accordance with the inter-bus-bar built-in capacitor 3 provided by the
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first embodiment, however, the electrical capacitance of the inter-bus-bar built-in capacitor 3 can
be sustained at a sufficiently large value even if the distance between the electrodes is long.
[0018]
In addition, it is desirable to provide the upper and lower electrodes with internal
5 electrodes having a comb-teeth structure. Fig. 2 is a diagram depicting a model of the structure
of preferable electrodes used in the inter-bus-bar built-in capacitor 3 according to the first
embodiment. As shown in Fig. 2, it is desirable that electrodes properly used in the inter-busbar
built-in capacitor 3 according to the first embodiment are electrodes having an upper
electrode 5 brought into contact with the upper bus bar (not shown in Fig. 2), an upper internal
10 electrode 5a connected perpendicularly to the upper electrode 5, a lower electrode 6 brought into
contact with the lower bus bar (not shown in Fig. 2) and a lower internal electrode 6a connected
perpendicularly to the lower electrode 6. In addition, the high-dielectric-constant material 7 is
provided between the upper electrode 5 and the lower electrode 6.
[0019]
15 It is to be noted that the upper internal electrode 5a does not have to be provided
perpendicularly to the upper electrode 5 whereas the lower internal electrode 6a does not have to
be provided perpendicularly to the lower electrode 6. That is to say, the upper internal
electrode 5a can also be provided all but perpendicularly to the upper electrode 5 whereas the
lower internal electrode 6a can also be provided all but perpendicularly to the lower electrode 6.
20 In addition, as shown in Fig. 3, the upper internal electrode 5a can also be provided in parallel to
the upper electrode 5 whereas the lower internal electrode 6a can also be provided in parallel to
the lower electrode 6. In this case, however, the upper internal electrode 5a does not have to be
provided in parallel to the upper electrode 5 whereas the lower internal electrode 6a does not
have to be provided in parallel to the lower electrode 6. That is to say, the upper internal
25 electrode 5a can also be provided approximately in parallel to the upper electrode 5 whereas the
lower internal electrode 6a can also be provided approximately in parallel to the lower electrode
6.
[0020]
By providing the upper internal electrode 5a and the lower internal electrode 6a
30 serving as internal electrodes as described above, the contact area between the internal electrodes
and the high-dielectric-constant material 7 can be increased so that the electrical capacitance of
the inter-bus-bar built-in capacitor 3 can be raised. As a result, a capacitor having a large size
can be made smaller in number or can be downsized. Considering the fact that the length in the
lateral direction (that is, a direction parallel to the contact surface between the bus bars and the
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upper electrode 5 and the lower electrode 6) is larger than the distance between the upper bus bar
1 and the lower bus bar 2, however, it is particularly desirable that the electrodes have a structure
shown in Fig. 2 from a view point that the number of laminations can be increased.
[0021]
5 In addition, as shown in Fig. 4 for example, an insulation body 8 can be provided
between the upper electrode 5 and the lower internal electrode 6a and between the lower
electrode 6 and the upper internal electrode 5a. The insulation body 8 can be the same as the
insulation body 4 to be described later or an insulation body having a type properly determined
in accordance with a voltage applied to the upper bus bar 1 and the lower bus bar 2. An
10 example of an insulation body having a properly determined type is a mixture obtained by
blending barium titanate and manganese. By providing such an insulation body 8 between the
upper electrode 5 and the lower internal electrode 6a and between the lower electrode 6 and the
upper internal electrode 5a, it is possible to avoid short circuits between these electrodes, which
approach each other, with a higher degree of certainty.
15 [0022]
Entire Structure
As shown in Fig. 1, a plurality of inter-bus-bar built-in capacitors 3 according to
the first embodiment are held between the upper bus bar 1 and the lower bus bar 2 and, in
addition, adjacent inter-bus-bar built-in capacitors 3 are sealed against each other by making use
20 of an insulation body 4. The insulation body 4 is not prescribed in particular. That is to say,
the insulation body 4 can be any insulation body provided that the insulation resistance of the
insulation body is high. Atypical material of the insulation body 4 is resin having an insulation
characteristic. To put it concretely, the resin can be epoxy resin, FRP (Fiber Reinforced
Plastics), unsaturated polyester or bakelite, to mention a few. Any single resin material can be
25 used alone. As an alternative, two or more resin materials having different types can be
combined at an arbitrary combination ratio. In addition, by providing the insulation body 4
typically made of resin between inter-bus-bar built-in capacitors 3, surface discharge between the
edges of the inter-bus-bar built-in capacitors 3 can be avoided.
[0023]
30 On top of that, as shown in Fig. 5, for example, capacitor units 9 each composed
of an inter-bus-bar built-in capacitor 3 and an insulation body 4 are created. Then, the capacitor
units 9 are arranged on the lower bus bar 2. After a predetermined number of capacitor units 9
have been arranged on the lower bus bar 2, the upper bus bar 1 is brought into contact (or
bonded) with the capacitor units 9 from a position above the capacitor units 9 in order to hold the
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inter-bus-bar built-in capacitors 3 sealed against each other by the insulation body 4 by
sandwiching the inter-bus-bar built-in capacitors 3 between the upper bus bar 1 and the lower
bus bar 2. In this way, a pair consisting of the upper bus bar 1 and the lower bus bar 2 which
are opposing to each other can be made with ease. In addition, by adopting such a
5 configuration, there are also provided merits that when an inter-bus-bar built-in capacitor 3 fails
for example, only the failing inter-bus-bar built-in capacitor 3 can be replaced so that
maintenance is easy to carry out and the replacement cost is low.
[0024]
In addition, by providing a plurality of inter-bus-bar built-in capacitors as
10 described above, no matter how long and how thick the bus bars are, the number of provided
inter-bus-bar built-in capacitors can be determined properly. Thus, the generality property of
the inter-bus-bar built-in capacitor can be enhanced and the enhanced generality leads to a
reduced manufacturing cost of the inter-bus-bar built-in capacitor. Particularly, in the case of a
bus bar which is long in the lateral direction, it may be difficult to install a single inter-bus-bar
15 built-in capacitor (that is, a single high-dielectric-constant material). Even in such a case, in
accordance with split inter-bus-bar built-in capacitors provided by the first embodiment, the bus
bars and the inter-bus-bar built-in capacitors can be handled with ease so that the inter-bus-bar
built-in capacitors can be installed easily.
[0025]
20 As described before, however, the inter-bus-bar built-in capacitor 3 according to
the first embodiment includes a high-dielectric-constant material which has a relative dielectric
constant of at least 50 when a voltage of 1,000 V is applied to a pair of opposing bus bars at a
temperature of 25°C. Thus, it is not always necessary to provide a plurality of inter-bus-bar
built-in capacitors 3 between the bus bars forming the pair. That is to say, it is possible to
25 provide a configuration in which only one inter-bus-bar built-in capacitor 3 is installed between
the bus bars.
[0026]
Fig. 6 is a diagram depicting a model of a typically modified capacitor built in
between bus bars in accordance with the first embodiment. In the typical configuration shown
30 in Fig. 6, a single inter-bus-bar built-in capacitor 3 is provided throughout the whole area of the
upper bus bar 1 and the lower bus bar 2. In addition, the edges of the inter-bus-bar built-in
capacitor 3 protrude out to the outer side more than the edges of the upper bus bar 1 and the
lower bus bar 2 do. By providing such a layout, surface discharge on the edges of the upper bus
bar 1 and the lower bus bar 2 can be avoided with a higher degree of certainty.
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[0027]
It is to be noted that, in the typical configuration shown in Fig. 6, the edge of the
inter-bus-bar built-in capacitor 3 is the high-dielectric-constant material itself. However, it is
also possible to provide a typical configuration in which an insulation body is provided on the
5 edge of the inter-bus-bar built-in capacitor 3 and the insulation body protrudes out to the outer
side more than the edges of the upper bus bar 1 and the lower bus bar 2 do.
[0028]
In addition, in the typical configurations depicted in Figs. 1 to 6, the upper bus bar
1 and the lower bus bar 2 each are shown to have a curved shape. However, the upper bus bar 1
10 and the lower bus bar 2 do not have to have a curved shape. For example, the upper bus bar 1
and the lower bus bar 2 can also have a flat-plate shape shown in Fig. 8 to be described later.
Even in such a case, it is possible to obtain the same effects as the first embodiment.
[0029]
2. Power Equipment and Power Converting Apparatus
15 Power equipment according to an embodiment is power equipment provided with
a pair of opposing bus bars for supplying electric power. Between the bus bars, a highdielectric-
constant material is provided. The high-dielectric-constant material has a relative
dielectric constant of at least 50 when a voltage of 1,000 V is applied thereto at a temperature of
25°C. The concrete configuration of the power equipment according to the embodiment is not
20 prescribed in particular. However, the bus bars and the high-dielectric-constant material which
are employed in the power equipment according to the embodiment are identical with those
described in the previous chapter with a title of "1. Inter-Bus-Bar Built-in Capacitor". Thus, the
bus bars and the high-dielectric-constant material are not explained again in the following
description.
25 [0030]
On the other hand, a power converting apparatus according to an embodiment is
provided with a switching device and a pair of opposing bus bars for supplying electric power to
the switching device. Between the bus bars, a high-dielectric-constant material is provided.
The high-dielectric-constant material has a relative dielectric constant of at least 50 when a
30 voltage of 1,000 V is applied thereto at a temperature of 25°C.
[0031]
Fig. 7 is a diagram showing a representative internal structure of an inverter board
991 functioning as a concrete example of the power converting apparatus according to the
embodiment. It is to be noted that the external wall of the inverter board 991 shown in Fig. 7 is
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usually a metallic wall which has a nontransparent characteristic. Thus, the internal structure
cannot be observed from the outside. In order to make the explanation easy to give, however,
Fig. 7 shows the internal structure which is deliberately made visible.
[0032]
5 The inverter board 991 functioning as the power equipment shown in Fig. 7 is
provided with an inverter unit 30 inside a unit chamber 992. The inverter unit 30 has the interbus-
bar built-in capacitor according to the embodiment. In addition, the inverter board 991 is
configured to also include at least a fan 993, a ventilation duct 994, a main circuit chamber 995
and a control section 996.
10 [0033]
As described above, the inverter board 991 is usually configured as a metallic
housing. A metal used for making a housing of the inverter board 991 is not prescribed in
particular. However, the housing of the inverter board 991 can be made of typically stainless
steel, iron or the like. It is to be noted that the housing of the inverter board 991 can be made of
15 a single metal or can be made by arbitrarily combining two or more different metals.
[0034]
The unit chamber 992 is provided to allow the inverter unit 30 to be inserted into
and pulled from the unit chamber 992. In the configuration shown in Fig. 7, the number of the
inverter units 30 accommodated in the unit chamber 992 is three. However, the number of the
20 inverter units 30 accommodated in the unit chamber 992 does not have to be three.
[0035]
In addition, in order to blow wind into the inverter unit 30, the unit chamber 992
is provided with an opening (not shown in the figure) linked to the ventilation duct 994 (to be
described later). Air in the ventilation duct 994 is blown into the inverter unit 30 through this
25 opening. In addition, direct-current bus bars, control lines and other components, which are not
shown in the figure, are provided inside the unit chamber 992.
[0036]
The fan 993 blows wind to the inverter unit 30 through the ventilation duct 994.
In addition, the fan 993 blows wind also to the main circuit chamber 995 to be described later.
30 The concrete configuration of the fan 993 is not prescribed in particular. In addition, the
number of the fans 993 is two in the configuration shown in Fig. 3 but it does not have to be two.
On top of that, the installation locations of the fans 993 are not prescribed in particular. For
example, instead of installing a fan 993 for every inverter unit 30, a fan 993 can be placed at one
location above the inverter board 991 so that it is possible to make the apparatus simpler and
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reduce the space. In addition, such a configuration gives a merit that, if a fan is broken, the
broken fan can be replaced with ease.
[0037]
The ventilation duct 994 blows air taken in by the fan 993 to the inverter units 30.
5 In addition, the main circuit chamber 995 and the control section 996 are provided with a variety
of power supplies, a variety of control lines and other components, which are not shown in the
figure. The power supplies, the control lines and the other components drive the inverter units
30.
[0038]
10 Next, the inverter unit 30 is explained by referring to Fig. 8 as follows. Fig. 8 is
a diagram depicting a model of the internal structure of the inverter unit 30 employed in the
inverter board 991 shown in Fig. 7. In the same way as Fig. 7, in order to make the explanation
easy to provide, Fig. 8 also shows the internal structure which is deliberately made visible.
[0039]
15 The inverter unit 30 shown in Fig. 8 is provided with an upper bus bar 1, a lower
bus bar 2, an IGBT 331, a fan 332, an air filter 334 and a smoothing capacitor 339. The upper
bus bar 1 and the fan 32 form a pair of opposing bus bars for holding an inter-bus-bar built-in
capacitor 3 according to the embodiment by sandwiching the inter-bus-bar built-in capacitor 3
between the upper bus bar 1 and the lower bus bar 2. The inter-bus-bar built-in capacitor 3
20 includes a high-dielectric-constant material having a relative dielectric constant of at least 50
when a voltage of 1,000 V is applied thereto at a temperature of 25°C. The IGBT 331 is
connected to the upper bus bar 1 and the lower bus bar 2 whereas the fan 332 is provided below
the IGBT. The smoothing capacitor 339 is also connected to the upper bus bar 1 and the lower
bus bar 2.
25 [0040]
The bus bars composed of the upper bus bar 1 and the lower bus bar 2 are made
of a metal exhibiting a conductive characteristic. The upper bus bar 1 and the lower bus bar 2
serve as a power supplying path for supplying electric power to the IGBT 331 to be described
later from a power-supply source of typically the control section 996 employed in the inverter
30 board 991.
[0041]
The IGBT 331 is a semiconductor switching device receiving electric power
supplied thereto through the bus bars. The IGBT 331 can typically be any arbitrary IGBT
which is commonly known. The fan 332 provided below the IGBT 331 to serve as cooling fins
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is a fan for dissipating heat generated by the IGBT 331.
[0042]
The air filter 334 passes air blowing through the ventilation duct 994 when the air
is flowing to the inside of the inverter unit 30. The air filter 334 is capable of removing dusts or
5 the like from the air flowing to the inside of the inverter unit 30.
[0043]
Between the power-supply source of typically the control section 996 and the
IGBT 331, the smoothing capacitor 339 connected to the bus bars is provided. The smoothing
capacitor 339 accumulates electric charge used for switching the IGBT 331. The smoothing
10 capacitor 339 is typically an aluminum electrolytic capacitor or a film capacitor. The
smoothing capacitor 339 is a commonly known smoothing capacitor. In addition, the
smoothing capacitor 339 can have any arbitrary shape. For example, the smoothing capacitor
339 has a box or cylindrical shape.
[0044]
15 3. Conclusions
In accordance with the inter-bus-bar built-in capacitor provided by the
embodiment, it is possible to reduce the number of large-size capacitors used in a power
converting apparatus such as a high-voltage inverter and/or power equipment and/or make the
capacitors smaller in size. That is to say, since the power converting apparatus and/or the
20 power equipment according to the embodiment include the inter-bus-bar built-in capacitor, it is
possible to reduce the number of large-size capacitors such as smoothing capacitors and/or make
the large-size capacitors smaller in size without decreasing the amount of electric charge
accumulated in the whole power converting apparatus and/or the whole power equipment. As a
result, it is possible to reduce the sizes of the whole power converting apparatus and/or the whole
25 power equipment.
[0045]
Embodiments have been described so far, but implementations of the present
invention are by no means limited to the embodiments. It is obvious that, for a person skilled in
the art, the embodiments can be changed or revised in a variety of ways within the ranges of
30 essentials and appended claims.
Description of Reference Symbols
[0046]
1 Upper bus bar
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2 Lower bus bar
3 Inter-bus-bar built-in capacitor
4 Insulation body
5 Upper electrode
5 a Upper internal electrode (internal electrode)
6 Lower electrode
6a Lower internal electrode (internal electrode)
7 High-dielectric-constant material
8 Insulation body
30 Inverter unit
331 IGBT
332 Cooling fins
334 Air filter
339 Smoothing capacitor
991 Inverter board (inverter)
992 Unit chamber
993 Fan
994 Ventilation duct
995 Main circuit chamber
996 Control section
;;

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CLAIMS
[Claim 1] An inter-bus-bar built-in capacitor provided between a pair of opposing bas bars,
comprising:
a high-dielectric-constant material which has a relative dielectric constant of at
least 50 when a voltage of 1,000 V is appHed at a temperature of 25°C.
[Claim 2] The inter-bus-bar built-in capacitor according to claim 1, wherein internal
electrodes are provided between the opposing bus bars, the internal electrodes each having a
comb-teeth structure and being each electrically connected to one of the opposing bus bars,
vdierein the high-dielectric-constant material is provided between the internal
electrodes.
[Claim 3] The inter-bus-bar built-in capacitor according to claim 1, wherein the highdielectric-
constant material is barium titanate and/or zinc oxide supplementation silicon carbide.
[Claim 4] The inter-bus-bar built-in capacitor according to claim 2, wherein the internal
electrode having a comb-teeth structure is parallel, approximately parallel, perpendicular or
approximately perpendicular to a specific one of the opposing bus bars.
[Claim 5] The inter-bus-bar built-in capacitor according to claim 2, wherein an insulation
body is provided between an edge of the internal electrode having a comb-teeth structure and
another one of the opposing bus bws.
[Claim 6] The inter-bus-bar built-in capacitor according to claim 1, wherein an edge of the
inter-bus-bar built-in capacitor or an insulation-body edge provided at a position more outer than
the edge is provided at a location on the outer side of edges of the bus bars.
[Claim 7] The inter-bus-bar built-in capacitor according to claim 1, wherein a plurality of
the inter-bus-bar built-in capacitors are provided between the opposing bus bars.
[Claim 8] The inter-bus-bar built-in capacitor according to claim 7, wherein an insulation
body is provided between any adjacent ones of the inter-bus-bar buih-in capacitors.
[Claim 9] Power equipment, comprising.
a pair of opposing bus bars for supplying electric power,
wherein a high-dielectric-constant material is provided between the bus bars to
serve as a material which has a relative dielectric constant of at least 50 when a voltage of 1,000
V is applied at a temperature of 25°C.
[Claim 10] A power converting apparatus, comprising:
a switching device; and
a pair of opposing bus bars for supplying electric power to the switching device,
wherein a high-dielectric-constant material is provided between the bus bars to
:
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«
serve as a material which has a relative dielectric constant of at least 50 when a voltage of 1,000
V is applied at a temperature of 25°C.