Abstract:
A power conversion apparatus comprising a base  110  which includes a first fixation portion  110   a  and a second fixation portion  110   b  that are coupled to each other at a desired angle, wherein power modules IPM 1 , IPM 2  and IPM 3  are fixed on the first fixation portion  110   a  of the base  110 , a control circuit board  10  is fixed with its first principal surface  10   a  held in direct or indirect touch with the second fixation portion  110   b  of the base  110 , and components constituting a control circuit are packaged on the second principal surface  10   b  of the control circuit board  10 . Owing to the configuration, a versatility for the installation of the power conversion apparatus on a vehicle becomes high, the vibration-proofness of the control circuit board is enhanced, and heats generated by the electronic components, etc. packaged on the control circuit board are sufficiently emitted.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to a power conversion apparatus which controls an AC motor for driving, for example, a vehicle, and more particularly to the mechanical configuration thereof. 
         [0003]    2. Description of the Related Art 
         [0004]    In general, a power conversion apparatus for controlling the driving motor of a vehicle in a hybrid automobile, an electric automobile or the like includes as its principal constituents, power modules each of which includes power semiconductor elements for converting powers between DC and AC, a control circuit board on which components constituting a control circuit for controlling the power semiconductor elements of the power modules are packaged, a smoothing capacitor, and bus bars which electrically connect the power modules and the motor. The constituents are arranged and fixed in correspondence with the mounting structure of the vehicle. 
         [0005]    In such a power conversion apparatus, there has been a prior-art apparatus wherein, in view of increase in the number of the power modules (IPMs) to-be-installed in which the power semiconductor elements for converting the powers are included, the IPMs are vertically erected and are arranged and fixed so that they can be arranged without enlarging a floor area. (Refer to, for example, JP-A-2004-215340 which shall be called “Patent Document 1” below.) 
         [0006]    Further, there has been a prior-art apparatus wherein the resin-molded plate portion of a plate having built-in bus bars is provided with a central support post, and the central support post is held in abutment on the tentative surface of a printed circuit board on which the control circuit is packaged, so as to suppress the vibrations of the printed circuit board. (Refer to, for example, JP-A-2003-324903 which shall be called “Patent Document 2” below.) 
         [0007]    In addition, there has been a prior-art apparatus wherein pins for the control signals of the switching semiconductor element modules are formed with crooked portions each of which is endowed with a flexibility by a bending work, so as to absorb displacements developing due to vibrations or the difference of thermal expansions, by the crooked portions. (Refer to, for example, JP-A-2005-85958 which shall be called “Patent Document 3” below.) 
         [0008]    Regarding an equipment which is installed on a vehicle, however, a space allowed for the installation is severely restricted. A versatility for the installation on the vehicle is not always high, merely by the contrivance in which the elements constituting the equipment are arranged substantially vertically as in the prior-art apparatus stated in Patent Document 1. Further, in the prior-art apparatus, the control circuit board for controlling the drives of the power modules (IPM drive circuit board) is fixed on a base side through a cover member, and any configurational consideration for enhancing vibration-proofness is not made. 
         [0009]    Besides, according to the prior-art apparatus stated in Patent Document 2, the printed circuit board is not supported at any part other than its peripheral edge part and the part abutting on the central support post. Accordingly, a resonance point ascribable to the vibrations is inevitably existent, and displacements caused by the resonance of the printed circuit board attributed to the resonance frequency of the resonance point develop, so that electric components and electronic components packaged on the printed circuit board, or structural components are apprehended to damage or fall off. Further, the prior-art apparatus has not a structure which emits heats generated by the electronic components, etc. packaged on the control circuit board, and it is problematic in durability and reliability. 
         [0010]    Besides, in the prior-art apparatus stated in Patent Document 3, the pins for the control signals as are disposed in the power modules including the switching semiconductor elements include the crooked portions each of which has been subjected to the bending work so as to ensure the flexibility. In general, however, it is difficult to perform a work of high precision by the bending work. In an assembling structure which requires a comparatively minute dimensional precision as in case of inserting the control signal pins of the power modules into holes provided in a printed circuit board, as in the power conversion apparatus which is installed on the vehicle, there is the problem that all the pins cannot be inserted due to dimensional deviations in some cases. 
       SUMMARY OF THE INVENTION 
       [0011]    This invention has been made in order to solve the above problems in the prior-art apparatuses, and has for its object to obtain a power conversion apparatus which is installed on the mounting location of a vehicle or the like at a high versatility, and whose vibration-proofness and cooling effect are high. 
         [0012]    A power conversion apparatus according to this invention consists in a power conversion apparatus including power modules which include semiconductor elements constituting a power conversion circuit for converting powers between DC and AC, a control circuit board on which components constituting a control circuit for driving and controlling the semiconductor elements are packaged, bus bars which connect the power conversion circuit and an external equipment, and a base on which, at least, the power modules and the control circuit board are fixed; wherein the base includes a first fixation portion and a second fixation portion which are coupled to each other at a desired angle, the power modules are fixed on the first fixation portion of the base, the control circuit board is fixed with its first principal surface held in direct or indirect touch with the second fixation portion of the base, and the components are packaged on a second principal surface of the control circuit board. 
         [0013]    In this invention, the “desired angle” signifies an angle which is set in consideration of the structural restrictions etc. of an installation space or installation location where the power conversion apparatus is installed, in a vehicle by way of example. Although the angle is optional, it should desirably be an angle other than 180 degrees. 
         [0014]    Besides, a power conversion apparatus according to this invention consists in a power conversion apparatus including a plurality of pairs of power modules which include semiconductor elements constituting a power conversion circuit for converting powers between DC and AC, a plurality of control circuit boards on which components constituting control circuits for driving and controlling the semiconductor elements are packaged, bus bars which connect the power conversion circuit and an external equipment, and a base on which, at least, the power modules and the control circuit boards are fixed; wherein the base includes a first fixation portion, a second fixation portion which is coupled to one end of the first fixation portion, and a third fixation portion which is coupled to the other end of the first fixation portion; the first fixation portion and the second fixation portion, and the first fixation portion and the third fixation portion are respectively coupled to each other at desired angles; the plurality of pairs of power modules are fixed on the first fixation portion of the base; at least one of the plurality of control circuit boards is fixed with its first principal surface held in direct or indirect touch with the second fixation portion of the base; the components are packaged on a second principal surface of such one control circuit board; at least one other control circuit board is fixed with its first principal surface held in direct or indirect touch with the third fixation portion of the base; and the components are packaged on a second principal surface of such other control circuit board. 
         [0015]    In this invention, the “desired angles” signify angles which are set in consideration of the structural restrictions etc. of an installation space or installation location where the power conversion apparatus is installed, in a vehicle by way of example. Although the angles are optional, they should desirably be angles other than 180 degrees. 
         [0016]    In accordance with the power conversion apparatus according to this invention, the base includes the first fixation portion and second fixation portion which are respectively flat, and which are coupled to each other at the desired angle. Therefore, the power conversion apparatus can be endowed with the optimum configuration corresponding to the situation of the mounting space, and it is permitted to increase the versatility of the installation of the apparatus in the vehicle of many spatial restrictions, especially an engine room or the like. Moreover, the control circuit board is fixed with its first principal surface held in direct or indirect touch with the second fixation portion of the base. Therefore, the rigidity of the control circuit board becomes high, and the vibration-proofness and cooling effect thereof can be enhanced. 
         [0017]    Besides, in accordance with the power conversion apparatus according to this invention, even in the case where the plurality of pairs of power modules and the plurality of control circuit boards are included, the power conversion apparatus can be endowed with the optimum configuration corresponding to the situation of the mounting space, and it is permitted to increase the versatility of the installation of the apparatus in the vehicle of many spatial restrictions, especially an engine room or the like. In addition, the rigidities of the control circuit boards become high, and the vibration-proofness and cooling effects thereof can be enhanced. 
         [0018]    The foregoing and other object, features, and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is an explanatory diagram showing the schematic circuit arrangement of a power conversion apparatus according to Embodiment 1 of this invention; 
           [0020]      FIG. 2  is a plan view of the power conversion apparatus according to Embodiment 1 of this invention; 
           [0021]      FIG. 3  is a side view of the power conversion apparatus according to Embodiment 1 of this invention; 
           [0022]      FIG. 4  is a plan view of a power conversion apparatus according to Embodiment 2 of this invention; 
           [0023]      FIG. 5  is a side view of the power conversion apparatus according to Embodiment 2 of this invention; 
           [0024]      FIG. 6  is a plan view of a power conversion apparatus according to Embodiment 3 of this invention; and 
           [0025]      FIG. 7  is a side view of the power conversion apparatus according to Embodiment 3 of this invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment 1 
       [0026]      FIG. 1  is an explanatory diagram showing the schematic arrangement of a power conversion circuit. Referring to  FIG. 1 , a semiconductor element (Insulated Gate Bipolar Transistor: hereinbelow, abbreviated to “IGBT”)  1   a  in which a MOS field effect transistor and a bipolar transistor are combined into one chip, and a flywheel diode  1   b  are connected in parallel, thereby to constitute a pair of power semiconductor elements  1 . Likewise, IGBTs  2   a ,  3   a ,  4   a ,  5   a  and  6   a  and flywheel diodes  2   b ,  3   b ,  4   b ,  5   b  and  6   b  corresponding to the IGBTs are connected in parallel, thereby to constitute pairs of power semiconductor elements  2 ,  3 ,  4 ,  5  and  6 , respectively. 
         [0027]    The power semiconductor elements  1 ,  3  and  5  form the upper arms of three-phase bridge circuits constituting the power conversion circuit, and the power semiconductor elements  2 ,  4  and  6  form the lower arms thereof, respectively. Besides, the power semiconductor elements  1  and  2 ,  3  and  4 , and  5  and  6  are respectively connected in series, and the series connection points are respectively connected to the stator windings U, V and W of a brushless DC motor  8  through bus bars  106 AC,  105 AC and  107 AC. The power semiconductor elements  1  and  2 ,  3  and  4 , and  5  and  6  are respectively integrated, thereby to constitute power modules IPM 1 , IPM 2  and IPM 3  which are the minimum units performing the powering and regeneration of the AC motor  8 . Incidentally, signs IPM 1 B, IPM 2 B and IPM 3 B denote the bottom surfaces of the respectively corresponding power modules IPM 1 , IPM 2  and IPM 3 . 
         [0028]    The power modules IPM 1 , IPM 2  and IPM 3  have their P-electrode side main terminals connected to the P-electrode of a battery  7  being a DC power source, through a bus bar by screws  151 ,  152  and  153 , and have their N-electrode side main terminals connected to the N-electrode of the battery  7  through a bus bar by screws  161 ,  162  and  163 , respectively, as will be explained later. Besides, a smoothing capacitor  9  is connected between the P-electrode and N-electrode of the battery  7  by connection parts  91  and  92 . The smoothing capacitor  9  absorbs those ripple fluctuations of the DC power of the battery  7  which develop when the power semiconductor elements  1  and  2 ,  3  and  4 , and  5  and  6  perform switching operations. 
         [0029]    A control circuit board  10  is disposed in a manner to be mechanically independent of the power modules IPM 1 , IPM 2  and IPM 3 , and electric components, electronic components, etc. which constitute a control circuit not shown are packaged on the control circuit board  10 . The control circuit provided on the control circuit board  10  is electrically connected to all of the signal electrode terminals  101 S 1  and  101 S 2 ,  102 S 1  and  102 S 2 , and  103 S 1  and  103 S 2  of the respectively corresponding power modules IPM 1 , IPM 2  and IPM 3 , so as to subject the power semiconductor elements  1  and  2 ,  3  and  4 , and  5  and  6  to switching controls. The AC side main terminals  101 AC,  102 AC and  103 AC of the power modules IPM 1 , IPM 2  and IPM 3  are respectively connected to the bus bars  105 AC,  106 AC and  107 AC by screws  181 ,  182  and  183  as will be explained later. 
         [0030]    The power modules PM 1 , PM 2  and PM 3  which include the three-phase bridge circuits consisting of the power semiconductor elements  1  and  2 ,  3  and  4 , and  5  and  6 , respectively, and the control circuit board  10  which includes the control circuit, constitute a power conversion apparatus which performs the power conversion between DC and AC. 
         [0031]    The power conversion apparatus shown in  FIG. 1  is such that the three power modules IMP 1 , IMP 2  and IMP 3  are connected in parallel so as to drive one brushless DC motor  8 . More specifically, the IGBTs  1   a  and  2   a ,  3   a  and  4   a , and  5   a  and  6   a  of the power modules IPM 1 , IPM 2  and IPM 3  are respectively subjected to switching controls by control signals from the control circuit provided on the control circuit board  10 , whereby the brushless DC motor  8  is rotated forward or reversely at a desired speed by, for example, a PWM (Puls Wide Modulation) control. 
         [0032]    When the IGBTs  1   a  and  2   a ,  3   a  and  4   a , and  5   a  and  6   a  of the respective power modules IPM 1 , IPM 2  and IPM 3  repeat ON and OFF operations in accordance with the PWM control, ripple powers being the drifts of currents develop in the DC power systems on the sides of the battery  7 , of the three-phase bridge circuits respectively composed of the power semiconductor elements  1  and  2 ,  3  and  4 , and  5  and  6 , thereby to incur degradation in the lifetime of the battery  7 . For the purpose of suppressing the ripple powers of the drifts, therefore, the smoothing capacitor  9  is connected in parallel between the P- and N-electrodes of the battery  7  so as to prolong the lifetime of the battery  7 . 
         [0033]      FIGS. 2 and 3  show the power conversion apparatus according to Embodiment 1 of this invention as includes the principal portions of the power conversion circuit shown in  FIG. 1 .  FIG. 2  is a plan view of the power conversion apparatus, and  FIG. 3  is a side view thereof. Parts corresponding to those in  FIG. 1  are assigned the same numerals and signs as in  FIG. 1 . 
         [0034]    Referring to  FIGS. 2 and 3 , a base  110  includes a first flat fixation portion  110   a  and a second flat fixation portion  110   b  which are coupled defining an angle of 90 degrees, and it is formed having a substantially L-shaped section as seen from  FIG. 3 . Although both the fixation portions  110   a  and  110   b  of the base  110  are formed of a unitary metal plate, the base  110  may well be configured in such a way that the respective fixation portions  110   a  and  110   b  formed of separate metal plates are coupled by welding or the like. The bottom surface of the first fixation portion  110   a  of the base  110  is unitarily provided with a plurality of radiation fins  200  made of protuberant bars, while the side part of the second fixation portion  110   b  is unitarily provided with a plurality of radiation fins  190  made of protuberant bars. 
         [0035]    The radiation fins  200  provided unitarily with the first fixation portion  110   a  of the base  110 , chiefly emit heats generated by the power modules IPM 1 , IPM 2  and IPM 3  as have been conducted to the first fixation portion  110   a  of the base  110 , by bringing them into touch with a coolant such as water, liquid or air, not shown. Besides, the radiation fins  190  provided unitarily with the second fixation portion  110   b  of the base  110 , chiefly emit heats generated by the electronic components, the electric components, etc. packaged on the control circuit board  10 , to a coolant such as water, liquid or air, not shown. 
         [0036]    The power modules IPM 1 , IPM 2  and IPM 3  are respectively fixed by screws  141 ,  142  and  143  with their bottom surfaces held in touch with the first fixation portion  110   a  of the base  110 . The screws  141 ,  142  and  143  are clamped in threadable engagements with threaded holes (not shown) machined in the first fixation portion  110   a  of the base  110 . The power modules IPM 1 , IMP 2  and IMPS are respectively provided with the P-electrode side main terminals  101 P,  102 P and  103 P, as well as the N-electrode side main terminals  101 N,  102 N and  103 N, and the AC side main terminals  101 AC,  102 AC and  103 AC. Further, the power modules IPM 1 , IMP 2  and IMPS are respectively provided with the pairs of signal electrode terminals  10151  and  101 S 2 ,  102 S 1  and  102 S 2 , and  103 S 1  and  103 S 2  for conducting the control signals which control the pairs of included power semiconductor elements. 
         [0037]    The control circuit board  10  has its first principal surface  10   a  bonded to the second fixation portion  110   b  of the base  110  over the whole area thereof by an adhesive  180 , and it is fixed to the second fixation portion  110   b  of the base  110  by screws  171 ,  172  and  173 . The respective screws  171 ,  172  and  173  are clamped in threadable engagements with threaded holes machined in the second fixation portion  110   b  of the base  110 . Besides, the components such as electronic components and electric components (not shown) which constitute the control circuit for the switching controls of the power semiconductor elements included in the power modules IPM 1 , IPM 2  and IPM 3  are packaged on the second principal surface  10   b  of the control circuit board  10 . 
         [0038]    Terminal members  101 T 1  and  101 T 2 ,  102 T 1  and  102 T 2 , and  103 T 1  and  103 T 2  are packaged on the second principal surface  10   b  of the control circuit board  10 . Each of the terminal members  101 T 1  and  101 T 2 ,  102 T 1  and  102 T 2 , and  103 T 1  and  103 T 2  is formed of four pieces of electrically conductive material, and the four pieces of the electrically conductive material are unitarily secured by the corresponding one of insulating members  10121  and  101 Z 2 ,  102 Z 1  and  102 Z 2 , and  103 Z 1  and  103 Z 2  which are fixed to the first fixation portion  110   a  of the base  110 . The insulating members  10121  and  101 Z 2 ,  102 Z 1  and  102 Z 2 , and  103 Z 1  and  103 Z 2  are formed by, for example, insert-molding a resin material. 
         [0039]    The four pieces of the electrically conductive material as constitute the corresponding one of the terminal members  101 T 1  and  101 T 2 ,  102 T 1  and  102 T 2 , and  103 T 1  and  103 T 2  are formed substantially in the shape of letter L. Each of the four pieces is formed with a crooked portion  109  on one side thereof, whereby a mechanical displacement developing in the electrically conductive material due to vibrations or the difference of thermal expansions is absorbed by the crooked portion  109 . 
         [0040]    The crooked portion  109  is formed by any working method other than bending, such as punching, laser cutting, wire discharging, or turret punch pressing. In the case where the crooked portion  109  is formed by such a working method other than the bending, a dimensional deviation after the working can be much more suppressed than in the working by the bending (that is, a dimensional precision can be enhanced). Therefore, the step of adjustments which are required in the insertion of the terminal into a joint part and the positioning of the terminal in the ordinary assembling process of the terminal is dispensed with, and the facilitation and high efficiency of the assembling job of the terminal can be realized. 
         [0041]    The signal electrode terminals  101 S 1  and  101 S 2 ,  102 S 1  and  102 S 2 , and  103 S 1  and  103 S 2  of the power modules IPM 1 , IPM 2  and IMP 3  are secured by brazing  108  and electrically connected to the respectively corresponding terminal members  101 T 1  and  101 T 2 ,  102 T 1  and  102 T 2 , and  103 T 1  and  103 T 2 . Incidentally, soldering or welding may well be employed instead of the brazing. 
         [0042]    The P-electrode side main terminals  101 P,  102 P and  103 P of the power modules IPM 1 , IPM 2  and IPM 3  are respectively fixed by co-clamping and electrically connected to a bus bar  104 P, by screws  151 ,  152  and  153 , thereby to be connected to the P-electrode of the battery. Likewise, the N-electrode side main terminals  101 N,  102 N and  103 N are respectively fixed by co-clamping and electrically connected to a bus bar  104 N, by screws  161 ,  162  and  163 , thereby to be connected to the N-electrode of the battery. 
         [0043]    In addition, the AC side main terminals  101 AC,  102 AC and  103 AC of the power modules IPM 1 , IPM 2  and IPM 3  are respectively fixed and electrically connected to the bus bars  105 AC,  106 AC and  107 AC by the screws  181 ,  182  and  183 . The bus bars  105 AC,  106 AC and  107 AC are connected to the stator windings U, V and W of the brushless DC motor  8  as shown in  FIG. 1 . 
         [0044]    As seen from  FIG. 3 , the respective screws  151 ,  152 ,  153 ,  161 ,  162 ,  163 ,  181 ,  182  and  183  are clamped in threadable engagements with nuts  193 . The nuts  193  are unitarily assembled and arranged in a terminal bed, not shown, which is made of an electrically insulating material. 
         [0045]    The first fixation portion  110   a  and second fixation portion  110   b  of the base  110  are coupled at the angle of 90 degrees as stated before. In Embodiment 1, the angle of 90 degrees is the optimum angle suitable for the shape, etc. of an installation location where the power conversion apparatus is arranged, for example, an installation location in the engine room of a vehicle. 
         [0046]    If the shape, etc. of the installation location where the power conversion apparatus is installed are more suitable when the first fixation portion  110   a  and second fixation portion  110   b  of the base  110  are coupled at any angle other than 90 degrees, the base in which the first fixation portion  110   a  and the second fixation portion  110   b  are connected at the suitable angle is formed. In this case, by way of example, a plurality of bases in which the angles defined between the first fixation portion  110   a  and second fixation portion  110   b  of the base  110  are different may be prepared so as to select the base having the optimum angle, from among the bases. Alternatively, the coupling between the first fixation portion  110   a  and second fixation portion  110   b  of the base  110  may be mechanically adjusted or changed so as to adjust the angle. 
         [0047]    The power conversion apparatus according to Embodiment 1 of this invention configured as described above is mounted in the predetermined location of the vehicle or the like. In this regard, the first fixation portion  110   a  and second fixation portion  110   b  of the base  110  are coupled at 90 degrees being the angle which is suitable for the condition of the space part of the mounting location, other structures, or the like, so that the apparatus can be mounted in the optimum arrangement suitable for the mounting location. Besides, if the power conversion apparatus is mounted in a location of different mechanical condition, the base in which the first fixation portion and the second fixation portion are connected at a desired angle suitable for the condition is configured, whereby the optimum arrangement suitable for the condition can be established. In the case of Embodiment 1, the base  110  is configured of the first fixation portion  110   a  and second fixation portion  110   b  which have the simple flat shapes, so that the base  110  can be altered very easily. 
         [0048]    Moreover, in accordance with the power conversion apparatus according to Embodiment 1, the control circuit board  10  has its first principal surface bonded to the second fixation portion  110   b  of the base  110  over the whole area by the adhesive  180 , and it is fixed by the screws  171 ,  172  and  173 , so that the control circuit board  10  does not incur resonance as in the prior art and does not exert evil influence on the packaged components. Furthermore, the heat dissipation of the control circuit board  10  proceeds very effectively, and the influences of heats on the packaged components, etc. can be lessened. 
       Embodiment 2 
       [0049]      FIGS. 4 and 5  show a power conversion apparatus according to Embodiment 2 of this invention, and  FIG. 4  is a plan view of the apparatus, while  FIG. 5  is a side view thereof. 
         [0050]    Embodiment 2 consists in that two power modules IPM 11  and IPM 12 , IPM 21  and IPM 22 , or IPM 31  and IPM 32  forming one set are electrically connected in parallel, for each phase of the stator winding U, V or W of a three-phase brushless DC motor, so as to drive the motor which is a load of higher power. 
         [0051]    Referring to  FIGS. 4 and 5 , the power modules IPM 11  and IPM 12 , IPM 21  and IPM 22 , and IPM 31  and IPM 32  form pairs, and they are fixed by screws  1411  and  1412 ,  1421  and  1422 , and  1431  and  1432  with their bottom surfaces held in touch with the first fixation portion  110   a  of a base  110 , respectively. The respective screws are clamped in threadable engagements with threaded holes which are provided in the first fixation portion  110   a  of the base  110 . 
         [0052]    The base  110  is configured of the first flat fixation portion  110   a , a second flat fixation portion  110   b  which is coupled to one end of the first fixation portion  110   a , and a third flat fixation portion  110   c  which is coupled to the other end of the first fixation portion  110   a . The first fixation portion  110   a  and the second fixation portion  110   b  are coupled at an angle of 90 degrees, while the first fixation portion  110   a  and the third fixation portion  110   c  are similarly coupled at the angle of 90 degrees. Although all the fixation portions  110   a ,  110   b  and  110   c  of the base  110  are formed of a unitary metal plate, the base  110  may well be configured in such a way that the respective fixation portions  110   a ,  110   b  and  110   c  formed of separate metal plates are coupled by welding or the like. 
         [0053]    The bottom surface of the first fixation portion  110   a  of the base  110  is unitarily provided with radiation fins  2001  and  2002  made of pluralities of protuberant bars, the side part of the second fixation portion  110   b  is unitarily provided with radiation fins  1901  made of a plurality of protuberant bars, and the side part of the third fixation portion  110   c  is unitarily provided with radiation fins  1902  made of a plurality of protuberant bars. 
         [0054]    The radiation fins  2001  and  2002  provided unitarily with the first fixation portion  110   a  of the base  110 , chiefly emit heats generated by the power modules IPM 11  and IPM 12 , IPM 21  and IPM 22 , and IPM 31  and IPM 32  as have been conducted to the first fixation portion  110   a  of the base  110 , by bringing them into touch with a coolant such as water, liquid or air, not shown. Besides, the radiation fins  1901  and  1902  provided unitarily with the second fixation portion  110   b  and third fixation portion  110   c  of the base  110 , chiefly emit heats generated by electronic components, electric components, etc. packaged on a first control circuit board  111  and a second control circuit board  112 , to a coolant such as water, liquid or air, not shown, respectively. 
         [0055]    The power modules IPM 11  and IPM 12 , IMP 21  and IPM 22 , and IMP 31  and IPM 32  are respectively provided with P-electrode side main terminals  101 P 1  and  101 P 2 ,  102 P 1  and  102 P 2 , and  103 P 1  and  103 P 2 , as well as N-electrode side main terminals  101 N 1  and  101 N 2 ,  102 N 1  and  102 N 2 , and  103 N 1  and  103 N 2 , and AC side main terminals  101 AC 1  and  101 AC 2 ,  102 AC 1  and  102 AC 2 , and  103 AC 1  and  103 AC 2 . Further, the power modules IPM 11  and IPM 12 , IMP 21  and IPM 22 , and IMP 31  and IPM 32  are respectively provided with pairs of signal electrode terminals  101 S 11  and  101 S 12 ,  101 S 21  and  101 S 22 ,  102 S 11  and  102 S 12 ,  102 S 21  and  102 S 22 ,  103 S 11  and  103 S 12 , and  103 S 21  and  103 S 22  for conducting control signals which control pairs of included power semiconductor elements. 
         [0056]    The first control circuit board  111  has its first principal surface  111   a  bonded to the second fixation portion  110   b  of the base  110  over the whole area thereof by an adhesive  180 , and it is fixed to the second fixation portion  110   b  of the base  110  by screws  1711 ,  1721  and  1731 . The respective screws  1711 ,  1721  and  1731  are clamped in threadable engagements with threaded holes machined in the second fixation portion  110   b  of the base  110 . Besides, the components such as electronic components and electric components (not shown) which constitute a control circuit for the switching controls of the power semiconductor elements included in the power modules IPM 11 , IPM 21  and IPM 31  are packaged on the second principal surface  111   b  of the first control circuit board  111 . 
         [0057]    Likewise, the second control circuit board  112  has its first principal surface  112   a  bonded to the third fixation portion  110   c  of the base  110  over the whole area thereof by an adhesive  180 , and it is fixed to the third fixation portion  110   c  of the base  110  by screws  1712 ,  1722  and  1732 . The respective screws  1712 ,  1722  and  1732  are clamped in threadable engagements with threaded holes machined in the third fixation portion  110   c  of the base  110 . Besides, the components such as electronic components and electric components (not shown) which constitute a control circuit for the switching controls of the power semiconductor elements included in the power modules IPM 12 , IPM 22  and IPM 32  are packaged on the second principal surface  112   b  of the second control circuit board  112 . 
         [0058]    In addition, terminal members  101 T 11  and  101 T 12 ,  102 T 11  and  102 T 21 , and  103 T 11  and  103 T 21  are packaged on the second principal surface  111   b  of the first control circuit board  111 . Each of the terminal members  101 T 11  and  101 T 12 ,  102 T 11  and  102 T 12 , and  103 T 11  and  103 T 12  is formed of four pieces of electrically conductive material, and the four pieces of the electrically conductive material are unitarily secured by the corresponding one of insulating members  101 Z 11  and  101 Z 12 ,  102 Z 11  and  102 Z 12 , and  103 Z 11  and  103 Z 12  which are fixed to the first fixation portion  110   a  of the base  110 . 
         [0059]    Likewise, terminal members  101 T 21  and  101 T 22 ,  102 T 21  and  102 T 22 , and  103 T 21  and  103 T 22  are packaged on the second principal surface  112   b  of the second control circuit board  112 . Each of the terminal members  101 T 21  and  101 T 22 ,  102 T 21  and  102 T 22 , and  103 T 21  and  103 T 22  is formed of four pieces of electrically conductive material, and the four pieces of the electrically conductive material are unitarily secured by the corresponding one of insulating members  101 Z 21  and  101 Z 22 ,  102 Z 21  and  102 Z 22 , and  103 Z 21  and  103 Z 22  which are fixed to the first fixation portion  110   a  of the base  110 . The insulating members  101 Z 21  and  101 Z 22 ,  102 Z 21  and  102 Z 22 , and  103 Z 21  and  103 Z 22  are formed by, for example, insert-molding a resin material. 
         [0060]    The four pieces of the electrically conductive material as constitute the corresponding one of the terminal members  101 T 11  and  101 T 12 ,  102 T 11  and  102 T 12 , and  103 T 11  and  103 T 12  are formed substantially in the shape of letter L, and each of the four pieces is formed with a crooked portion  1091  on one side thereof. Likewise, the four pieces of the electrically conductive material as constitute the corresponding one of the terminal members  101 T 21  and  101 T 22 ,  102 T 21  and  102 T 22 , and  103 T 21  and  103 T 22  are formed substantially in the shape of letter L, and each of the four pieces is formed with a crooked portion  1092  on one side thereof. Mechanical displacements developing in the electrically conductive material due to vibrations or the difference of thermal expansions are absorbed by the crooked portions  1091  and  1092 . 
         [0061]    The crooked portions  1091  and  1092  are formed by any working method other than bending, such as punching, laser cutting, wire discharging, or turret punch pressing. In the case where the crooked portions are formed by such a working method other than the bending, dimensional deviations after the working can be much more suppressed than in the working by the bending (that is, dimensional precisions can be enhanced). Therefore, the step of adjustments which are required in the insertion of the terminal into a joint part and the positioning of the terminal in the ordinary assembling process of the terminal is dispensed with, and the facilitation and high efficiency of the assembling job of the terminal can be realized. 
         [0062]    The signal electrode terminals  101 S 11  and  101 S 12 ,  102 S 11  and  102 S 12 , and  103 S 11  and  103 S 12  of the power modules IPM 11 , IPM 21  and IMP 31  are secured by brazing  1081  and electrically connected to the respectively corresponding terminal members  101 T 11  and  101 T 12 ,  102 T 11  and  102 T 12 , and  103 T 11  and  103 T 12 . Incidentally, soldering or welding may well be employed instead of the brazing. 
         [0063]    Likewise, the signal electrode terminals  101 S 21  and  101 S 22 ,  102 S 21  and  102 S 22 , and  103 S 21  and  103 S 22  of the power modules IPM 12 , IPM 22  and IMP 32  are secured by brazing  1082  and electrically connected to the respectively corresponding terminal members  101 T 21  and  101 T 22 ,  102 T 21  and  102 T 22 , and  103 T 21  and  103 T 22 . Incidentally, soldering or welding may well be employed instead of the brazing. 
         [0064]    The P-electrode side main terminals  101 P 1 ,  102 P 1  and  103 P 1  of the power modules IPM 11 , IPM 21  and IPM 31  are respectively fixed by co-clamping and electrically connected to a bus bar  104 P 1 , by screws  1511 ,  1521  and  1531 , thereby to be connected to the P-electrode of a battery. In like fashion, the N-electrode side main terminals  101 N 1 ,  102 N 1  and  103 N 1  are respectively fixed by co-clamping and electrically connected to a bus bar  104 N 1 , by screws  1611 ,  1621  and  1631 , thereby to be connected to the N-electrode of the battery. 
         [0065]    Likewise, the P-electrode side main terminals  101 P 2 ,  102 P 2  and  103 P 2  of the power modules IPM 12 , IPM 22  and IPM 32  are respectively fixed by co-clamping and electrically connected to a bus bar  104 P 2 , by screws  1512 ,  1522  and  1532 , thereby to be connected to the P-electrode of the battery. In like fashion, the N-electrode side main terminals  101 N 2 ,  102 N 2  and  103 N 2  are respectively fixed by co-clamping and electrically connected to a bus bar  104 N 2 , by screws  1612 ,  1622  and  1632 , thereby to be connected to the N-electrode of the battery. 
         [0066]    In addition, the AC side main terminals  101 AC 1 ,  102 AC 1  and  103 AC 1  of the power modules IPM 11 , IPM 21  and IPM 31  are respectively fixed and electrically connected to bus bars  105 AC,  106 AC and  107 AC by screws  1811 ,  1821  and  1831 . The bus bars  105 AC,  106 AC and  107 AC are connected to the stator windings U, V and W of the brushless DC motor  8  as shown in  FIG. 1 . 
         [0067]    Likewise, the AC side main terminals  101 AC 2 ,  102 AC 2  and  103 AC 2  of the power modules IPM 12 , IPM 22  and IPM 32  are respectively fixed and electrically connected to the bus bars  105 AC,  106 AC and  107 AC by screws  1812 ,  1822  and  1832 . 
         [0068]    As seen from  FIG. 5 , the respective screws  1511 ,  1521 ,  1531 ,  1611 ,  1621 ,  1631 ,  1811 ,  1821  and  1831 , and  1512 ,  1522 ,  1532 ,  1612 ,  1622 ,  1632 ,  1812 ,  1822  and  1832  are clamped in threadable engagements with nuts  1931  and  1932 . The nuts  1931  and  1932  are unitarily assembled and arranged in a terminal bed, not shown, which is made of an electrically insulating material. 
         [0069]    The first fixation portion  110   a  and second fixation portion  110   b , and the first fixation portion  110   a  and third fixation portion  110   c  of the base  110  are respectively coupled at the angles of 90 degrees as stated before. In Embodiment 2, the angles of 90 degrees are the optimum angles suitable for the shape, etc. of an installation location where the power conversion apparatus is arranged, for example, an installation location in the engine room of a vehicle. 
         [0070]    If the shape, etc. of the installation location where the power conversion apparatus is installed are more suitable when the first fixation portion  110   a  and second fixation portion  110   b  of the base  110  are coupled at any angle other than 90 degrees, the base in which the first fixation portion  110   a  and the second fixation portion  110   b  are connected at the suitable angle is formed. Besides, if the shape, etc. are more suitable when the first fixation portion  110   a  and third fixation portion  110   c  of the base  110  are coupled at any angle other than 90 degrees, the base in which the first fixation portion  110   a  and the third fixation portion  110   c  are connected at the suitable angle is formed. 
         [0071]    In this case, by way of example, a plurality of bases in which the angles defined between the first fixation portion  110   a  and second fixation portion  110   b  of the base  110 , and the angles defined between the first fixation portion  110   a  and third fixation portion  110   c  are different may be prepared so as to select the base having the optimum angles, from among the bases. Alternatively, the coupling between the first fixation portion  110   a  and second fixation portion  110   b  of the base  110 , and the coupling between the first fixation portion  110   a  and third fixation portion  110   c  may be mechanically adjusted or changed so as to adjust the angles. 
         [0072]    The power conversion apparatus according to Embodiment 2 of this invention configured as described above is mounted in the predetermined location of the vehicle or the like. In this regard, the first fixation portion  110   a  and second fixation portion  110   b  of the base  110  are coupled at 90 degrees being the angle which is suitable for the condition of the space part of the mounting location, other structures, or the like, so that the apparatus can be mounted in the optimum arrangement suitable for the mounting location. Besides, if the power conversion apparatus is mounted in a location of different mechanical condition, the base in which the first fixation portion  110   a  and second fixation portion  110   b , and the first fixation portion  110   a  and third fixation portion  110   c  are connected at desired angles suitable for the condition is configured, whereby the optimum arrangement suitable for the condition can be established. In the case of Embodiment 2, the base  110  is configured of the first fixation portion  110   a , second fixation portion  110   b  and third fixation portion  110   c  which have the simple flat shapes, so that the base  110  can be altered very easily. 
         [0073]    Furthermore, in accordance with the power conversion apparatus according to Embodiment 2, even in a case where a power conversion circuit is configured by combining a large number of power modules, control circuit boards on which the corresponding power modules and control circuits therefor are packaged can be dispersedly arranged on the plurality of fixation portions of a base. Also, the respective control circuit boards  111  and  112  have their first principal surfaces bonded to the second fixation portion  110   b  and third fixation portion  110   c  of the base  110  over the whole areas by the adhesives  180 , and they are fixed by the screws  1711 ,  1721  and  1731 , and  1712 ,  1722  and  1732 . Therefore, the control circuit boards  111  and  112  do not incur resonances as in the prior art and do not exert evil influences on the packaged components. Moreover, the heat dissipations of the control circuit boards  111  and  112  proceed very effectively, and the influences of heats on the packaged components, etc. can be lessened. 
       Embodiment 3 
       [0074]      FIGS. 6 and 7  show a power conversion apparatus according to Embodiment 3 of this invention, and  FIG. 6  is a plan view of the apparatus, while  FIG. 7  is a side view thereof. Embodiment 3 consists in that one power module IPM 1 , IPM 2  or IPM 3  is arranged for the corresponding one of the stator windings of a three-phase brushless DC motor. 
         [0075]    Referring to  FIGS. 6 and 7 , a control circuit board  10  has its first principal surface  10   a  bonded to the outer side of the second fixation portion  110   b  of a base  110  over the whole area by an adhesive  180 , and it is fixed by screws  171 ,  172  and  173 . Electronic components, electric components, etc. which constitute a control circuit for the switching controls of power semiconductor elements included in the power modules IPM 1 , IPM 2  and IPM 3  are packaged on the second principal surface  10   b  of the control circuit board  10 . 
         [0076]    Terminals  101 T 1  and  101 T 2 ,  102 T 1  and  102 T 2 , and  103 T 1  and  103 T 2  which are packaged on the second principal surface  10   b  of the control circuit board  10 , penetrate through penetrating holes  300  provided in the second fixation portion  110   b  of the base  110  and are led onto the inner side of the second fixation portion  110   b  of the base  110 , so as to be connected by brazing to the corresponding signal electrode terminals  101 S 1  and  101 S 2 ,  102 S 1  and  102 S 2 , and  103 S 1  and  103 S 2  of the power modules IPM 1 , IPM 2  and IPM 3 , respectively. 
         [0077]    The inner side of the second fixation portion  110   b  of the base  110  is unitarily provided with radiation fins  190  which are made of a plurality of protuberant bars. The radiation fins  190  chiefly emit heats generated by the electronic components, the electric components, etc. packaged on the control circuit board  10 , to a coolant such as water, liquid or air, not shown. 
         [0078]    Incidentally, the remaining configuration is the same as in Embodiment 1, and identical numerals and signs indicate identical or corresponding portions, respectively. 
         [0079]    The power conversion apparatus according to Embodiment 3 of this invention configured as described above is mounted in the predetermined location of a vehicle or the like, similarly to the power conversion apparatus according to Embodiment 1. In this regard, the first fixation portion  110   a  and second fixation portion  110   b  of the base  110  are coupled at 90 degrees being an angle which is suitable for the condition of the space part of the mounting location, other structures, or the like, so that the apparatus can be mounted in the optimum arrangement suitable for the mounting location. Besides, if the power conversion apparatus is mounted in a location of different mechanical condition, the base in which the first fixation portion  110   a  and second fixation portion  110   b  are connected at a desired angle suitable for the condition is configured, whereby the optimum arrangement suitable for the condition can be established. In the case of Embodiment 3, the base  110  is configured of the first fixation portion  110   a  and second fixation portion  110   b  which have simple flat shapes, so that the base  110  can be altered very easily. 
         [0080]    In addition, the control circuit board  10  has its first principal surface bonded to the second fixation portion  110   b  of the base  110  over the whole area by the adhesive  180 , and it is fixed by the screws  171 ,  172  and  173 , so that the control circuit board  10  does not incur resonance as in the prior art and does not exert evil influence on the packaged components. Furthermore, the heat dissipation of the control circuit board  10  proceeds very effectively, and the influences of heats on the packaged components, etc. can be lessened. 
         [0081]    Incidentally, two such power conversion apparatuses according to Embodiment 3 as shown in  FIGS. 6 and 7  may well be arranged in opposition as one set, so as to arrange two power modules for the corresponding phase of the stator windings of a motor for the purpose of driving the motor being a load of high power, as illustrated in Embodiment 2. 
         [0082]    Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this is not limited to the illustrative embodiments set forth herein.