Power module, power converter device, and electrically powered vehicle

A power module comprising:

• a semiconductor circuit unit for converting direct current power to alternating current power;
• and
• a cylindrical case for accommodating the semiconductor circuit unit, with the cylindrical case including a bottom;
• wherein:
• the cylindrical case further includes two base plates with their main surfaces facing each other;
• the two base plates are connected to each other through a connecting member;
• the connecting member covers a periphery of the base plates;
• a thickness of the connecting member is less than a thickness of each of the base plates;
• fins are formed on a surface of each of the two base plates;
• and
• an outer circumference of the two base plates, viewed from a direction perpendicular to the surface on which the fins are formed, is covered by the connecting member.

The power module according to clam 11, further comprising:

• a first insulating member that is disposed between one of the two base plates and the semiconductor circuit unit;
• and
• a second insulating member that is disposed between another of the two base plates and the semiconductor circuit unit, wherein:
• the semiconductor circuit unit is sandwiched and held between the two base plates through the first insulating member and the second insulating member.