Patent Publication Number: US-2023163693-A1

Title: Power conversion device

Description:
TECHNICAL FIELD 
     The present invention relates to a power conversion device. 
     BACKGROUND ART 
     A power conversion device, when performing quick switching operations for performing DC/AC power conversion, becomes a generation source of electromagnetic noise. To suppress generation of electromagnetic noise, conventionally, a measures of disposing a noise filter circuit has been taken as a countermeasure against electromagnetic noise (to provide electromagnetic compatibility, that is, EMC). 
     However, to employ the countermeasure, a power conversion device needs to have a space in which components such as a capacitor and a core constituting a noise filter circuit are disposed. Furthermore, it is necessary to consider that heating of a bus bar and components of the noise filter circuit has an effect on degrading and damaging other components. Therefore, improvement in cooling performance is necessary to suppress the temperature of the components of the noise filter within an allowable range. 
     As a background art of the present invention, the following PTL 1 is known. PTL 1 discloses a configuration in which a noise filter assembly  20 A includes a resin member  22  and is fixed to a bottom portion  7   a  of a case  7  via a flexible insulating sheet  26  made of a silicon-based material or the like. 
     CITATION LIST 
     Patent Literature 
     PTL 1: WO2019/064833 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     In a configuration in PTL 1, when downsizing a power conversion device, there is an issue in fixing of components which may deteriorate reliability of the power conversion device. Thus, there lies a problem in downsizing the power conversion device while improving cooling efficiency of the components to improve reliability of the power conversion device. 
     Solution to Problem 
     A power conversion device according to the present invention includes a power conversion circuit unit which converts DC power into AC power, a flow path including body for letting a refrigerant for cooling the power conversion circuit unit flow, a filter circuit unit which suppresses electric noise from a wire for transmitting the DC power, and a filter case portion which houses the filter circuit unit, where the filter case portion is formed integrally with the flow path including body, and a gap between the filter case portion and the filter circuit unit is filled with a first resin. 
     Advantageous Effects of Invention 
     According to the present invention, a power conversion device that achieves both downsizing and improvement in cooling efficiency to have improved reliability can be provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view illustrating an overall configuration of a power conversion device. 
         FIG.  2    is an explanatory view of the power conversion device in  FIG.  1   . 
         FIG.  3    is an exploded view of the power conversion device in  FIG.  2   . 
         FIG.  4    is a view of a connector and its surroundings in  FIG.  1   . 
         FIG.  5    is a view illustrating a mold bus bar disposed in a filter case portion. 
         FIG.  6    is an exploded view of the inside of the filter case portion. 
         FIG.  7    is an exploded view of a mold bus bar (filter circuit). 
         FIG.  8    is a cross-sectional view illustrating a structure of the power conversion device according to a first embodiment of the present invention. 
         FIG.  9    is a view for explaining arrangement of capacitors inside the filter case portion. 
         FIG.  10    is a view for explaining an inner wall surface, provided around a core, of the filter case portion. 
         FIG.  11    is an exploded view of the power conversion device according to a second embodiment of the present invention. 
         FIG.  12    is for explaining the mold bus bar in  FIG.  11   . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, a configuration of a power conversion device according to a first embodiment of the present invention will now be described with reference to  FIGS.  1  to  10   . 
     Configuration of First Embodiment and Power Conversion Device 
       FIG.  1    illustrates an overall configuration of a power conversion device  1 . The power conversion device  1  is housed in a housing  2  and is integrally fixed to the housing  2  by a connector  23 . The connector  23  and its surroundings will be described later in detail with reference to  FIG.  4   . 
     The housing  2  is grounded to a ground potential, has a bottom portion, and is formed in a box shape with an open top. There is a space for housing the power conversion device  1  in the housing  2 . The housing  2  is formed of a metal such as aluminum and iron, and the entire structure can be formed by casting, for example, aluminum die casting. Although not illustrated, a high-voltage battery connected to the power conversion device  1  is disposed outside the housing  2 , and is electrically connected to the mold bus bar  4  from the outside of the filter case portion  3  described later with reference to  FIG.  2   . 
       FIG.  2    is an explanatory view of the power conversion device  1  in  FIG.  1   . Note that an arrow R is a looking direction for explaining  FIG.  3    to be described later. 
     The power conversion device  1  includes a filter case portion  3 , a mold bus bar  4 , a power semiconductor module  9  that converts DC power into AC power, a flow path including body  10 , a smoothing capacitor  11 , a Y capacitor  13 , and a DC mold bus bar  14 . The filter case portion  3  has a shape integrated with the flow path including body  10 , and the flow path including body  10  is entirely housed inside the housing  2 . 
     The mold bus bar  4  is housed inside the filter case portion  3  integrated with the flow path including body  10 , and is electrically connected to the power semiconductor module  9 . The mold bus bar  4  includes a first capacitor  6 , a second capacitor  7 , a magnetic core member  8  (hereinafter, core  8 ), and electronic components (with no reference sign) such as an EMC filter circuit and a discharge resistor. Details will be described later. 
       FIG.  3    is an exploded view of the power conversion device  1 , and illustrates the power conversion device  1  as viewed along a direction indicated by the arrow R shown in  FIG.  2   . 
     The flow path including body  10  is formed of a metal such as aluminum and iron, and can be formed by casting, for example, aluminum die casting. 
     The flow path including body  10  has a structure that houses therein the power semiconductor module  9 , and includes a power semiconductor module mounting port  26  for housing the power semiconductor module  9 . The power semiconductor module attachment port is provided at one of side surface portions of the flow path including body  10 . The power semiconductor module mounting port  26  is provided by the same number as the number of the power semiconductor module  9 . 
     The flow path including body  10  includes inside a housing portion for housing the power semiconductor module  9 , and the housing portion has a shape extending in a substantially horizontal direction deeper into the flow path including body  10  from the power semiconductor module mounting port  26 . As illustrated in  FIG.  2   , the power semiconductor module  9  is fixed in the flow path including body  10  by a fixing member (not illustrated) with an input/output terminal portions protruding to the outside of the flow path including body  10 . 
     The flow path including body  10  includes a smoothing capacitor housing portion  24  and a Y capacitor housing portion  25  to respectively house the smoothing capacitor  11  and the Y capacitor  13 . A gap between the smoothing capacitor  11  and the Y capacitor  13 , which are components of a power conversion circuit unit to be described later, and a housing portion is filled with a potting resin  15  (hereinafter, resin  15 ) and the resin  15  is cured therein. Accordingly, the heat generated by the components of the power conversion circuit unit is released via the resin  15  into a refrigerant, described later, flowing in the flow path including body  10 . 
     The resin  15  is a thermally conductive resin, and is capable of suppressing vibration of the smoothing capacitor  11  and the Y capacitor  13  to contribute to fixing of circuit components together with the ground bus bar  5 , described later, to the power conversion device  1 . Thus, the number of dedicated components required for fixing such as screws can be reduced, and a fixing space required for placing the components is also reduced. 
     The DC mold bus bar  14  is held by the flow path including body  10  and disposed so as to extend in parallel with the power semiconductor module mounting port  26  and a surface of the smoothing capacitor  11  where connection terminals exist. The DC mold bus bar  14  is electrically connected to the power semiconductor module  9  and the smoothing capacitor  11 . The DC mold bus bar  14  is molded with an insulating resin. 
     The power conversion circuit unit (not illustrated) included in the power conversion device  1  will now be described. The power conversion circuit unit includes a switching element and a diode, such as insulated gate bipolar transistors (IGBTs), that operate as an upper arm and a switching element and a diode, such as IGBTs, that operate as a lower arm. The switching element of the upper arm and the switching element of the lower arm convert DC power into AC power. 
     The power conversion circuit unit includes the power semiconductor module  9  that converts DC power into AC power, the smoothing capacitor  11  that smooths the DC power supplied to the power semiconductor module  9 , and the Y capacitor  13 . The smoothing capacitor  11  is connected between a high-voltage battery and the power semiconductor module  9 , smooths DC power, and supplies the smoothed DC power to the power semiconductor module  9 . That is, the smoothing capacitor  11  electrically connects the high-voltage battery to the power conversion circuit unit. The Y capacitor  13  is connected between the power semiconductor module  9  and the ground potential, and suppresses noise generated by the power semiconductor module  9 . 
       FIG.  4    is a view of the connector  23  and its surroundings in  FIG.  1   . Note that  FIG.  4    is a view of the connector  23  and its surroundings as viewed from the open surface side of the upper portion of the housing  2  with the power conversion device  1  housed in the housing  2 . 
     The connector  23  is fixed to the housing  2  by a fastening member  28 . The connector bus bar  27  is electrically connected to the connector  23 . The mold bus bar  4  integrated with the filter case portion  3  is electrically connected to the connector bus bar  27 . Accordingly, the filter case portion  3  is electrically connected to the housing  2  via the mold bus bar  4 , the connector bus bar  27 , the connector  23 , and the fastening member  28 . 
     The connector  23  is electrically connected through an opening provided on a side surface of the housing  2  to the high-voltage battery disposed outside the housing  2 . The connector  23  is electrically connected also to the power semiconductor module  9 . Accordingly, the bus bar members such as the connector bus bar  27  and the mold bus bar  4  are also electrically connected to the power semiconductor module  9  via the connector  23  in a similar manner. 
       FIG.  5    is a view illustrating a mold bus bar disposed in a filter case portion. 
     The filter case portion  3  is provided with a space in which the mold bus bar  4  is housed. Part of the internal space is a housing portion for the core  8  which is part of the mold bus bar  4 . The housing portion for the core  8  has a form of a bottom surface having a round shape along the circumferential shape of the core  8 . 
     The mold bus bar  4 , the first capacitor  6 , and the second capacitor  7  housed in the filter case portion  3  are placed so as to be in contact with bottom surfaces (in the depth side in the drawing in  FIG.  5   ) of the filter case portion  3 . Gaps between the mold bus bar  4  and the capacitors  6  and  7  are filled with the resin  15  and the resin  15  is cured therein. Accordingly, part of the mold bus bar  4  is fixed together with the first capacitor  6 , the second capacitor  7 , and the core member  8  by resin  15 . Part of the mold bus bar  4  runs above across an upper portion (in a viewer&#39;s side in the drawing) of first capacitor  6 . Components other than the mold bus bar  4  may be housed as long as the space in the filter case portion  3  allows. 
       FIG.  6    is an exploded view of the inside of the filter case portion. Note that an arrow S indicates a viewing direction for explaining  FIG.  8   . 
     The first capacitor  6  and the second capacitor  7  function as part of the mold bus bar  4  as a filter circuit. The first capacitor  6  is disposed such that a longitudinal direction thereof is parallel to a longitudinal direction of the filter case portion  3 . The second capacitor  7  is disposed such that a longitudinal direction thereof is parallel to a lateral direction of the filter case portion  3 . The core  8  is held by the mold bus bar  4  and housed so as to be concentric with the circular bottom surface of the filter case portion  3  described later. 
     Each of the first capacitor  6 , the second capacitor  7 , and the core  8  is a filter circuit having an effect of suppressing noise, but they all disadvantageously generate heat. When a current flows in a bus bar, represented by the mold bus bar  4 , used in the power conversion device  1 , the electrical resistance of the bus bar material causes heat loss, and heat transfers from connection portions to the first capacitor  6  and the second capacitor  7 . The transferred heat may cause damage or deterioration of the first capacitor  6  and the second capacitor  7 . Thus, it is necessary to suppress heat in order to maintain the function of suppressing noise. That is, since the mold bus bar  4  housed in the filter case portion  3  generates heat by a current flowing therein, it is necessary to actively transfer the heat to the wall surface of the filter case portion  3 . Thus, releasing heat by heat conduction via the resin  15  is necessary. 
     Gaps between the filter case portion  3  and the mold bus bar  4 , the core member  8 , the first capacitor  6 , and the second capacitor  7  the resin  15  are filled with the resin  15  and the resin  15  is cured therein. Accordingly, heat generated by the mold bus bar  4 , the first capacitor  6 , and the second capacitor  7  is thermally conducted to the filter case portion  3  via the resin  15 . As a result, the mold bus bar  4 , the first capacitor  6 , and the second capacitor  7  are cooled by the refrigerant flowing in the flow path including body  10  integrated with the filter case portion  3 . 
     The resin  15  is a resin member having thermal conductivity and electrical insulation properties, and not only improves cooling efficiency but also fixes a relative position of the mold bus bar  4  placed in the filter case portion  3 . Although the filling rate of the resin  15  with respect to the volume of the housing portion of the filter case portion  3  is not specified, a high filling rate of the resin  15  is preferable from the viewpoint of efficient cooling. 
       FIG.  7    is an exploded view of the mold bus bar  4 . 
     The mold bus bar  4  is provided between the high-voltage battery and the smoothing capacitor  11  as a filter circuit unit that suppresses noise from a wire for transmitting DC power. The electromagnetic noise generated by the power conversion circuit unit when converting power is suppressed by the core  8 , the first capacitor  6 , and the second capacitor  7 . 
     The mold bus bar  4  includes a positive electrode bus bar  18 , a negative electrode bus bar  19 , a ground bus bar  5 , a first capacitor  6 , a second capacitor  7 , and a core  8  which are disposed along an inner wall of the filter case portion  3 . The mold bus bar  4  includes a ground bus bar  5  as a component constituting a noise filter. At least one of the positive electrode bus bar  18  and the negative electrode bus bar  19 , described later, and its surroundings are molded and sealed with resin to secure insulation between the bus bars of the respective phases and to integrate the bus bars as a part. This insulating resin is a second resin different from the resin  15  used to fill the filter case portion  3 . Accordingly, the mold bus bar  4  is reliably kept insulated, and its components are integrally held together. 
     The mold bus bar  4  is provided as an integrated part by molding and fixing with the second resin to avoid assembling becoming complicated which happens when the positive electrode bus bar  18  and the negative electrode bus bar  19  unfixed to each other are housed in the filter case portion  3 . This facilitates assembling in the filter case portion  3 . Furthermore, insert molding can be employed by using the bus bar portion as an insert member, which makes assembling easy. 
     Although the positive electrode bus bar  18 , the negative electrode bus bar  19 , and the ground bus bar  5  are integrated in the mold bus bar  4 , a method may be employed that only one or two of the positive electrode bus bar  18 , the negative electrode bus bar  19 , and the ground bus bar  5  are integrally formed with the second resin as an insert member. In addition, each of those bus bars may be formed separately from each other as a single member. 
     As described above, the first capacitor  6  and the second capacitor  7  suppress the electromagnetic noise of a current flowing in the filter circuit unit  4 . The first capacitor  6  and the second capacitor  7  are disposed at the connection terminal surfaces of the positive electrode bus bar  18  and the negative electrode bus bar  19  so as the longitudinal directions of the first capacitor  6  and the second capacitor  7  to be perpendicular to each other. 
     One end of the first capacitor  6  is electrically connected to the positive electrode bus bar  18  and the other end of the first capacitor  6  is electrically connected to the negative electrode bus bar  19 . One end of the second capacitor  7  is connected to the positive electrode bus bar  18  or the negative electrode bus bar  19  and the other end of the second capacitor  7  is grounded to the ground potential by the ground bus bar  5 . 
     The second capacitor  7  is connected to the filter case portion  3  to be connected to the metal housing  2  grounded to the ground potential. This sets the filter case portion  3  to the ground potential. Realizing the connection of the second capacitor  7  to the ground potential by connecting the second capacitor  7  to the filter case portion  3  makes an attaching work easy. Furthermore, positioning a connection point between the filter case portion  3  and the metal housing  2  grounded to the ground potential in the vicinity of the second capacitor  7  is suitable for taking measures against electromagnetic noise from the viewpoint of a wiring length. 
     The core  8  is made of a magnetic material and has a hollow cylindrical shape of which inner circumference forms a through hole. The positive electrode bus bar  18  and the negative electrode bus bar  19  are configured to pass through the through hole in the center of the core  8 , and this configuration realizes integrally fixing the positive electrode bus bar  18  and the negative electrode bus bar  19  to the mold bus bar  4 . The core  8  is disposed so as to surround the positive electrode bus bar  18  and the negative electrode bus bar  19 , whereby the core  8  absorbs electromagnetic noise of currents flowing in the bus bars to suppress electromagnetic noise. The positive electrode bus bar  18  and the negative electrode bus bar  19  penetrating the core  8  are electrically connected to the DC mold bus bar  14 . A GND bus bar (with no reference sign) of the Y capacitor  13  is also fixed to the DC mold bus bar  14 . 
     The positive electrode bus bar  18  and the negative electrode bus bar  19  are electrically connected to the first capacitor  6 , the second capacitor  7 , and the DC mold bus bar  14  by the connection described above. The positive electrode bus bar  18  and the negative electrode bus bar  19  are electrically connected also to the connector bus bar  27  described above. The positive electrode bus bar  18  and the negative electrode bus bar  19  include terminal portions for electrically connecting to the first capacitor  6  and the second capacitor  7 . Note that the connection may be made by any general way of electric connection, such as connection by welding, caulking, and screw-fastening. 
     The ground bus bar  5  will now be described. The ground bus bar  5  is connected to one of terminals of the second capacitor  7 . The ground bus bar  5  is fixed to a rim surface of the filter case portion  3  by screw-fastening, and is electrically connected to the same potential as the ground potential of the housing  2  fastened to the flow path including body  10  via the filter case portion  3 . The ground bus bar  5  may be directly connected to the housing  2 . The second capacitor  7  is thereby connected to the ground potential. A fastening element such as a screw is used for connecting the ground bus bar  5  to the filter case portion  3 . This functions to fix the position of the mold bus bar  4 , which contributes to improvement of vibration resistance of the components. 
       FIG.  8    is a cross-sectional view of the power conversion device  1  according to the first embodiment of the present invention. Note that  FIG.  8    is a view of the power conversion device  1  as viewed along the direction indicated by the arrow S in  FIG.  6   . 
     As described above, the power conversion device  1  is configured that the flow path including body  10  is integrated with the filter case portion  3  to be downsized. The flow path including body  10  includes the power semiconductor module  9  and a refrigerant flow path  16  around the power semiconductor module  9 . A refrigerant is made to flow in the refrigerant flow path  16  for cooling. The resin  15  that has filled the filter case portion  3  and is cured therein fixes the mold bus bar  4  and the capacitors  6  and  7 . This allows heat generated by the mold bus bar  4  and the capacitors  6  and  7  to be released to the refrigerant in the refrigerant flow path  16  via the resin  15 , the filter case portion  3 , and the flow path including body  10 . Accordingly, both downsizing and improvement in cooling efficiency of the power conversion device  1  can be achieved, thereby facilitating reliability. 
     In  FIG.  8   , the mold bus bar  4  is schematically illustrated to have an L-shaped cross-sectional view. The upper surface side (upper side in the drawing) of the L shape is necessary for welding to the terminals of the capacitors  6  and  7 . However, it is not expectable that this portion releases heat to the filter case integrally formed with the flow path including body  10 . To release heat generated by this bus bar portion, such a portion that is intentionally provided along a wall surface is necessary. Such a portion that runs along the inner peripheral wall surface to release heat is disposed in parallel along the rim surface of the filter case portion  3 . With the capacitors  6  and  7 , the magnetic core  8 , and the mold bus bar  4  embedded and fixed in the potting resin  15 , the effect of cooling the EMC components can be improved and this also improves the reliability of the power conversion device. 
     The first capacitor  6  and the second capacitor  7 , which are disposed as described above in the present embodiment, may instead be disposed so as the longitudinal directions thereof to be parallel or to have an angle with respect to each other. Furthermore, the first capacitor  6  and the second capacitor  7 , which are disposed so as bottom surfaces thereof to be in contact with the bottom surface of the filter case portion  3 , may instead be disposed so as side surfaces thereof to be in contact with each other. Although two first capacitors and two second capacitors are placed in  FIGS.  6  and  7   , a single first capacitor and a single second capacitor may be placed. 
     In addition, such a method may be employed that the resin  15  in a molten state is injected to fill a gap between the capacitors  6  and  7  and the capacitor housing portion of the filter case portion  3  and cured, or the capacitors  6  and  7  may be immersed in the resin  15  in a molten state previously injected in the capacitor housing portion and then the resin  15  may be cured to fix the capacitors  6  and  7 . 
       FIG.  9    is a view for explaining the arrangement of the capacitors  6  and  7  inside the filter case portion  3 . 
     The filter case portion  3  is formed integrally with the flow path including body  10  to have a surrounded space with an opening in an upper portion (in a viewer&#39;s side in the drawing) and a rim surface surrounding the opening, so that the space houses the components of the mold bus bar  4  as a filter circuit unit. 
     The first capacitor  6  and the second capacitor  7  are separated from each other by a first partition wall  20  which is part of the filter case portion  3  provided between the first capacitor  6  and the second capacitor  7 . Similarly, a second partition wall  21  is provided between the core  8  and the second capacitor  7 . The first partition wall  20  and the second partition wall  21  are part of the filter case portion  3 . This increases the number of surfaces by which the capacitors  6  and  7  are in proximity to the filter case portion  3 , and thereby causes heat transfer  22  of the heat generated by the capacitors  6  and  7  to the filter case portion  3  of which temperature is relatively low, whereby the cooling performance can be enhanced. Furthermore, the partition walls provided partially around the capacitors  6  and  7  can also enhance fixing of the capacitors  6  and  7 . The first partition wall  20  and the second partition wall  21  for fixing the capacitors  6  and  7  are not necessarily provided. 
       FIG.  10    is a perspective view for explaining an inner wall surface  17 , of the filter case portion  3 , that houses the core  8 . 
     As described above, the core  8  suppresses the electromagnetic noise by absorbing fluctuation of the current flowing in the mold bus bar  4  penetrating the core  8 . During this absorption, the core  8  self-generates heat and raises its temperature. Thus, the cooling performance around the core  8  needs to be enhanced. 
     The inner wall surface  17  is part of the filter case portion  3 , and is curved into a circular circumferential surface along the shape of the outer surface of the core  8 . The resin  15  described above fills a gap between the core  8  and the inner wall surface  17  and is cured therein (not illustrated). This makes, with the mold bus bar  4  housed, the distance between the inner wall surface  17  of the filter case portion  3  and the outer circumferential portion of the core  8  constant, and thus the thickness of the filled resin  15  can be made thin and uniform. As a result, the heat of the core member  8  can be efficiently transferred to the filter case portion  3  of which temperature is relatively low, and the cooling performance of the core  8  can be enhanced. Note that such a configuration in which cooling efficiency is improved by forming the shape of the inner wall surface  17  to be further closer along the core  8  may be employed. 
     According to the first embodiment of the present invention described above, the following operational effects are obtained. 
     (1) The power conversion device  1  includes the power conversion circuit unit which converts DC power into AC power, the flow path including body  10  for letting the refrigerant for cooling the power conversion circuit unit flow, the filter circuit unit  4  which suppresses electric noise from a wire for transmitting DC power, and the filter case portion  3  which houses the filter circuit unit  4 , where the filter case portion  3  is formed integrally with the flow path including body  10 , and a gap between the filter case portion  3  and the filter circuit unit  4  is filled with the first resin  15 . With this configuration, a power conversion device that achieves both downsizing and improvement in cooling efficiency to have improved reliability can be provided. 
     (2) The filter circuit unit  4  of the power conversion device  1  includes the positive electrode bus bar  18 , the negative electrode bus bar  19 , the core member  8  which is a magnetic body and disposed to surround the positive electrode bus bar  18  and the negative electrode bus bar  19 , the first capacitor  6  having one end connected to the positive electrode bus bar  18  and another end connected to the negative electrode bus bar  19 , and the second capacitor  7  having one end connected to the positive electrode bus bar  18  and the negative electrode bus bar  19  and another end grounded to the ground potential, where the positive electrode bus bar  18 , the negative electrode bus bar  19 , the core member  8 , the first capacitor  6 , and the second capacitor  7  are disposed along the inner wall surface of the filter case portion  3 . With this configuration, both downsizing and improvement in cooling efficiency of the power conversion device  1  can be achieved. 
     (3) The filter case portion  3  of the power conversion device  1  has an inner wall surface  17  that is along an outer shape of the core member  8 . With this configuration, the cooling efficiency of the core  8  that easily generates heat can be improved. 
     (4) The filter case portion  3  of the power conversion device  1  includes a first partition wall  20  that separates the first capacitor  6  and the second capacitor  7  from each other. With this configuration, the cooling efficiency of the capacitor that is easily affected by generated heat can be improved. 
     (5) The filter case portion  3  of the power conversion device  1  includes a second partition wall  21  that separates the second capacitor  7  and the core member  8  from each other. With this configuration, both improvement in cooling efficiency of the capacitor portion which is easily affected by generated heat and improvement in cooling efficiency of the bus bar portion which easily generates heated can be achieved. 
     (6) The power conversion device  1  includes the housing  2  made of metal and grounded to the ground potential, where the filter case portion  3  is electrically connected to the housing  2 , and the second capacitor  7  is electrically connected to the filter case portion  3 . This also contributes to downsizing of the entire configuration while facilitating assembling. 
     (7) The power conversion device  1  includes the ground bus bar  5  which connects the second capacitor  7  to the filter case portion  3 , where at least one of the positive electrode bus bar  18  and the negative electrode bus bar  19 , and the ground bus bar  5  are integrally molded and sealed with the second resin member, and the filter case portion  3  has the rim surface surrounding the opening, and the ground bus bar  5  is fixed to the rim surface. This configuration enhances fixing of the components. 
     Note that the above description is merely of examples. When interpreting the invention, there is no limitation nor restriction on the corresponding relationship between the matters described in the above embodiments and the matters described in the claims. For example, a configuration like that of a power conversion device  1 A according to a second embodiment illustrated in  FIG.  11    may be adopted. 
     Second Embodiment 
     A power conversion device  1 A illustrated in  FIG.  11    has the same basic configuration as the power conversion device  1  of the first embodiment. The structural difference from the first embodiment is that a housing portion of a filter case portion  3 A is continuous to a housing portion of a Y capacitor  13 A of a flow path including body  10 A. A resin  15 A fills a housing portion integrated with a portion from the filter case portion  3 A to the housing portion for the Y capacitor, and is cured therein. This eliminates the need of dividing the portion filled with the resin  15 A. Furthermore, similarly to the first embodiment, fixing the noise filter circuit components with the resin  15 A eliminates the need of an additional component necessary for fixing. Furthermore, heat transfer  22  via the resin  15 A to the flow path including body  10 A of which temperature is relatively low is caused, so that, similarly, the cooling performance can be improved by the refrigerant flowing in the flow path including body  10 A. 
       FIG.  12    illustrates a mold bus bar  4 A placed in the power conversion device  1 A in  FIG.  11   . Even when the positions of the positive electrode bus bar  18 , the negative electrode bus bar  19 , and a ground bus bar  5 A and shapes or the like thereof are different from those of the power conversion device  1  according to the first embodiment, there is no difference in the state of the filled resin  15 A as illustrated in  FIG.  11   . Thus, the same effect as that of the first embodiment can be obtained. 
     As described above, deletion, replacement with a different configuration, and addition of a different configuration can be made without departing from the technical idea of the invention, and aspects of the invention are also included in the scope of the present invention. 
     REFERENCE SIGNS LIST 
       1  power conversion device 
       2  housing 
       3 ,  3 A filter case portion 
       4 ,  4 A mold bus bar 
       5 ,  5 A ground bus bar 
       6 ,  6 A first capacitor 
       7 ,  7 A second capacitor 
       8 ,  8 A magnetic core member 
       9 ,  9 A power semiconductor module 
       10 ,  10 A flow path including body 
       11  smoothing capacitor 
       13 ,  13 A Y capacitor 
       14 ,  14 A DC mold bus bar 
       15 ,  15 A first resin 
       16  refrigerant flow path 
       17  inner wall surface 
       18  positive electrode bus bar 
       19  negative electrode bus bar 
       20  first partition wall 
       21  second partition wall 
       22  heat transfer 
       23  connector 
       24  smoothing capacitor housing portion 
       25  Y capacitor housing portion 
       26  power semiconductor module mounting port 
       27  connector bus bar 
       28  fastening member