Rotating electrical machine unit with a power inverter having a ring-shaped casing

A rotating electrical machine unit comprising:

• a rotating electrical machine including a ring-shaped stator and a rotator provided inside of the stator;
• and
• a power inverter including a ring-shaped first casing and a power module accommodated in the first casing, and integrated with the rotating electrical machine by being stacked in such a manner that a lower surface of the first casing is in contact with an upper surface of a stator core of the stator in an axial direction,
• wherein the power inverter has a first coolant path formed to have a ring shape in the first casing,
• wherein the power module has a heat radiation unit arranged in the first coolant path and exchanging heat with a cooling medium flowing in the first coolant path,
• wherein the first coolant path is formed in such a manner that a first space concavely formed to have a ring shape from the lower surface of the first casing is closed by the upper surface of the stator core, and
• wherein the cooling medium is water.