Patent ID: 7876563

Claim:
A cooling structure of a power semiconductor device, comprising: a cooling water passage that is formed opposite to a mounting surface where the power semiconductor device is mounted, a cooling water for cooling said power semiconductor device flowing through the cooling water passage; and a plurality of fins provided on a path of said cooling water passage and set up with a spacing therebetween in a direction orthogonal to a flow direction of the cooling water to promote heat exchange between said power semiconductor device and the cooling water, said plurality of fins having ends facing an upstream side of a cooling water flow, and said end of at least one fin among said plurality of fins being arranged so as to be displaced to a more upstream side of the cooling water flow than said ends of the fins adjacent to both sides of said fin, wherein said cooling water passage is formed at a position between a pair of inner walls that are arranged on both sides of said plurality of fins and face each other, said cooling water passage meanders on said mounting surface, and at a straight portion of said cooling water passage extending straight, said ends are arranged so as to be displaced from a downstream side to the upstream side of the cooling water flow as a distance from each of said pair of inner walls increases.