Patent attributes
Provided is a power conversion device including: power semiconductor elements, a support case, a heat sink, in which a plurality of boss portions are formed; a smoothing capacitor including a case member having a plurality of leg portions; and a bus bar configured to connect the smoothing capacitor and the DC input terminal, wherein, in the power conversion device in which the plurality of leg portions of the case member being respectively fixed to the plurality of boss portions of the heat sink, wherein materials and dimensions of the respective boss portions, the respective leg portions, the support case, and the bus bar are determined so that a total thermal expansion/contraction amount of the respective boss portions and the respective leg portions falls within a range of 0.9 to 1.1 relative to a total thermal expansion/contraction amount of the support case and the bus bar.