Electrical apparatus, cooling system therefor, and electric vehicle

A direct cooling inverter comprising:

• a plurality of semiconductor chips;
• a substrate for mounting said plurality of semiconductor chips;
• a copper base for mounting said substrate;
• a fin formed integrally with said copper base;
• and
• a case having an opening part;
• wherein a liquid path of a cooling medium is formed by mounting said copper base on the opening part of said case;
• wherein said copper base and said fin are directly cooled by the cooling medium;
• wherein said fin is formed in parallel with a longitudinal direction of the liquid path;
• wherein the liquid path comprises a cooling part formed at a bottom of said plurality of semiconductor chips and an introducing part for introducing the cooling medium supplied from an outside to the cooling part;
• and
• wherein a cross-sectional area of the liquid path extending from the introducing part up to the cooling part is substantially constant.