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

1. 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.

2. The rotating electrical machine unit according to claim 1 , wherein the rotating electrical machine is an alternating current rotating electrical machine driven by a three-phase alternating current power, and includes an inverter circuit for converting a direct current power into an alternating current power, and

the inverter circuit has first to third power modules provided for each phase,

the first to third power modules are provided by connecting a pair of transistors of upper and lower arm circuits in series,

the heat radiation unit has first and second radiation surfaces radiating heat from the pair of transistors, and

the heat radiation unit is configured such that each of the first and second radiation surface is inserted into the first coolant path to face inner and outer peripheries of the first coolant path formed in the ring shape.

3. The rotating electrical machine unit according to claim 2 , wherein, on the first and second radiation surfaces of the heat radiation unit of the first to third power modules, a plurality of heat radiation fins are vertically provided to protrude to the coolant path.

4. The rotating electrical machine unit according to claim 3 , wherein each of the first to third power modules has a metal case having a rectangular parallelepiped shape, and

surfaces of two side plates arranged to face each other in the metal case having the rectangular parallelepiped shape are the first and second radiation surfaces, respectively.

5. The rotating electrical machine unit according to claim 3 , wherein the first power module is arranged near an inlet of the coolant path of the power inverter, and the second power module is arranged at an interval of a predetermined angle from the first power module around a center axis in an axial direction of the rotator along flow of the cooling medium introduced from the inlet of the coolant path, and the third power module is arranged at an interval of a predetermined angle from the second power module around a center axis in the axial direction of the rotator along the flow of the cooling medium.

6. The rotating electrical machine unit according to claim 3 further comprising:

a bearing that rotatably holds the ring-shaped second casing and the rotator; and

a rotator holding unit integrally formed with the rotating electrical machine by being stacked in such a manner that the lower surface of the stator is in contact with the upper surface of the second casing.

7. The rotating electrical machine unit according to claim 2 , wherein each of the first to third power modules has a metal case having a rectangular parallelepiped shape, and

surfaces of two side plates arranged to face each other in the metal case having the rectangular parallelepiped shape are the first and second radiation surfaces, respectively.

8. The rotating electrical machine unit according to claim 7 , wherein the first power module is arranged near an inlet of the coolant path of the power inverter, and the second power module is arranged at an interval of a predetermined angle from the first power module around a center axis in an axial direction of the rotator along flow of the cooling medium introduced from the inlet of the coolant path, and the third power module is arranged at an interval of a predetermined angle from the second power module around a center axis in the axial direction of the rotator along the flow of the cooling medium.

9. The rotating electrical machine unit according to claim 7 further comprising:

a bearing that rotatably holds the ring-shaped second casing and the rotator; and

a rotator holding unit integrally formed with the rotating electrical machine by being stacked in such a manner that the lower surface of the stator is in contact with the upper surface of the second casing.

10. The rotating electrical machine unit according to claim 2 , wherein the first power module is arranged near an inlet of the coolant path of the power inverter, and the second power module is arranged at an interval of a predetermined angle from the first power module around a center axis in an axial direction of the rotator along flow of the cooling medium introduced from the inlet of the coolant path, and the third power module is arranged at an interval of a predetermined angle from the second power module around a center axis in the axial direction of the rotator along the flow of the cooling medium.

11. The rotating electrical machine unit according to claim 10 further comprising:

a bearing that rotatably holds the ring-shaped second casing and the rotator; and

a rotator holding unit integrally formed with the rotating electrical machine by being stacked in such a manner that the lower surface of the stator is in contact with the upper surface of the second casing.

12. The rotating electrical machine unit according to claim 2 further comprising:

a bearing that rotatably holds the ring-shaped second casing and the rotator; and

a rotator holding unit integrally formed with the rotating electrical machine by being stacked in such a manner that the lower surface of the stator is in contact with the upper surface of the second casing.

13. The rotating electrical machine unit according to claim 1 further comprising:

a bearing that rotatably holds the ring-shaped second casing and the rotator; and

a rotator holding unit integrally formed with the rotating electrical machine by being stacked in such a manner that the lower surface of the stator is in contact with the upper surface of the second casing.

14. The rotating electrical machine unit according to claim 13 , wherein the rotator holding unit includes a second coolant path formed to have a ring shape in the second casing.

15. The rotating electrical machine unit according to claim 14 , wherein the second coolant path is formed in such a manner that a second space concavely formed to have a ring shape from the upper surface of the second casing is closed by the lower surface of the stator.

16. The rotating electrical machine unit according to claim 15 , wherein the stator includes a rib extending to an outer side, and a penetrating hole allowing communication between the first coolant path of the power inverter and the second coolant path of the rotator holding unit is provided as a communication flow channel in the rib.

17. The rotating electrical machine unit according to claim 14 , wherein the stator includes a rib extending to an outer side, and a penetrating hole allowing communication between the first coolant path of the power inverter and the second coolant path of the rotator holding unit is provided as a communication flow channel in the rib.