Power conversion device

1 . A power conversion device, comprising:

semiconductor modules forming a power conversion circuit including upper-and-lower arm circuits operable in three phases, the semiconductor modules including power terminals and midpoint terminals, the midpoint terminals forming midpoints of the upper-and-lower arm circuits; and

midpoint conductors electrically connecting common-phase terminals of the midpoint terminals, wherein

the semiconductor modules include

first modules forming a first-phase circuit of the upper-and-lower arm circuits and successively arranged in a first direction so as to form a part of a first row of the semiconductor modules, the first row extending in the first direction,

second modules forming a second-phase circuit of the upper-and-lower arm circuits and successively arranged in the first direction so as to form a part of a second row of the semiconductor modules, the second row extending in the first direction, the second modules facing the first modules in a second direction perpendicular to the first direction such that the first row and the second row are shifted from each other in the second direction, and

third modules forming a third-phase circuit of the upper-and-lower arm circuits and arranged in the second direction such that at least one of the third modules forms a part of the first row and a rest of the third modules forms a part of the second row,

the midpoint conductors include a first conductor electrically connecting midpoint terminals of the first modules, a second conductor electrically connecting midpoint terminals of the second modules, and a third conductor electrically connecting midpoint terminals of the third modules,

semiconductor modules forming the first row have surfaces facing the second row and from which midpoint terminals protrude toward the second row,

semiconductor modules forming the second row have surfaces facing the first row and from which midpoint terminals protrude toward the first row, and

each of the midpoint conductors extends in the first direction from a connected portion of a corresponding midpoint terminal, the first direction being a direction from the third modules toward the first modules and the second modules.

2 . The power conversion device according to claim 1 , wherein

a portion of the third conductor extending in the first direction is disposed between the first conductor and the second conductor in the second direction.

3 . The power conversion device according to claim 2 , wherein

the midpoint conductors have plate shapes and have surfaces facing each other in the second direction.

4 . The power conversion device according to claim 1 , wherein

the power terminals protrude from surfaces of the semiconductor modules opposite from the surfaces from which the midpoint terminals protrude.

5 . The power conversion device according to claim 1 , further comprising

a cooler facing the semiconductor modules in a third direction perpendicular to the first direction and the second direction, the cooler being configured to cool each of the semiconductor modules, wherein

the cooler is disposed to collectively cool the semiconductor modules in each of the first row and second row.

6 . The power conversion device according to claim 5 , wherein

the cooler includes a first cooler configured to cool the semiconductor modules forming the first row, and a second cooler configured to cool the semiconductor modules forming the second row.

7 . The power conversion device according to claim 1 , further comprising:

a capacitor overlapped with at least part of each of the semiconductor modules in planar view along a third direction perpendicular to the first direction and the second direction; and

power conductors electrically connecting the capacitor and the power terminals of the semiconductor modules.

8 . The power conversion device according to claim 5 , further comprising:

a capacitor; and

power conductors electrically connecting the capacitor and the power terminals of the semiconductor modules, wherein

each phase circuit of the upper-and-lower arm circuits includes series circuits connected in parallel to each other,

each of the semiconductor modules forms one of the series circuits,

the midpoint conductors each connect semiconductor modules of a corresponding phase circuit of the upper-and-lower arm circuits in parallel, and

the cooler is disposed between the capacitor and the semiconductor modules such that the cooler faces at least a part of each of the midpoint conductors in the third direction.

9 . The power conversion device according to claim 1 , wherein

each phase circuit of the upper-and-lower arm circuits includes series circuits connected in parallel to each other,

each of the semiconductor modules forms one of the series circuits, and

the midpoint conductors each connect semiconductor modules of a corresponding phase circuit of the upper-and-lower arm circuits in parallel.

10 . The power conversion device according to claim 1 , wherein

the first module, the second module, and the third module each include an upper arm module forming an upper arm of a corresponding phase circuit of the upper-and-lower arm circuits, and a lower arm module forming a lower arm of the corresponding phase circuit of the upper-and-lower arm circuits, and

the midpoint conductors each connect the upper arm module and the lower arm module of the corresponding phase circuit in series.