Electric power converter device with improved integration of cooler frame

1. An electric power converter device, comprising:

a first power semiconductor module;

a frame for a closed cooler,

the first power semiconductor module including

a first base plate having a first main side, a second main side opposite the first main side and a lateral side surface extending along a circumferential edge of the first base plate and connecting the first main side and the second main side; and

at least one first die located on the first main side of the first base plate,

wherein the frame is attached to the second main side of the first base plate, and the first base plate has a first step on the second main side along the circumferential edge of the first base plate to form a first recess along the circumferential edge of the first base plate, wherein in the first recess a first portion of the frame is received, wherein the first base plate is made of aluminum silicon carbide (AlSiC), or a combination of copper and aluminum, and the first portion of the frame is fixed to the first base plate by a welding connection which is a butt weld produced by laser welding; and

a molded encapsulation, which encapsulates the first main side and the lateral side surface of the first base plate such that a bottom surface of the encapsulation is flush with the first base plate at the circumferential edge of the first base plate on the second main side.

2. The electric power converter device according to claim 1 , wherein the first portion of the frame is a flange portion that is received in the first recess such that a bottom surface of the flange portion is flush with the second main side of the first base plate adjacent to the first step.

3. The electric power converter device according to claim 2 , wherein the first base plate has a reduced first thickness along its circumferential edge compared to a second thickness of the first base plate in a central area of the first base plate, wherein the central area is laterally surrounded by the first step.

4. The electric power converter device according to claim 2 , comprising a plurality of cooling extensions protruding from the second main side of the first base plate in a central area of the first base plate, wherein the central area is laterally surrounded by the first step.

5. The electric power converter device according to claim 2 , wherein the frame has a plate portion that comprises an opening and wherein an edge portion of the plate portion, which is directly adjacent to the opening and which surrounds the opening, is the first portion of the frame.

6. The electric power converter device according to claim 1 , wherein the first base plate has a reduced first thickness along its circumferential edge compared to a second thickness of the first base plate in a central area of the first base plate, wherein the central area is laterally surrounded by the first step.

7. The electric power converter device according to claim 6 , comprising a plurality of cooling extensions protruding from the second main side of the first base plate in a central area of the first base plate, wherein the central area is laterally surrounded by the first step.

8. The electric power converter device according to claim 6 , wherein the frame has a plate portion that comprises an opening and wherein an edge portion of the plate portion, which is directly adjacent to the opening and which surrounds the opening, is the first portion of the frame.

9. The electric power converter device according to claim 1 , comprising a plurality of cooling extensions protruding from the second main side of the first base plate in a central area of the first base plate, wherein the central area is laterally surrounded by the first step.

10. The electric power converter device according to claim 9 , wherein the frame has a plate portion that comprises an opening and wherein an edge portion of the plate portion, which is directly adjacent to the opening and which surrounds the opening, is the first portion of the frame.

11. The electric power converter device according to claim 1 , wherein the frame has a plate portion that comprises an opening and wherein an edge portion of the plate portion, which is directly adjacent to the opening and which surrounds the opening, is the first portion of the frame.

12. The electric power converter device according to claim 11 , wherein the plate portion has a third thickness which is the same as a depth of the first recess in the first base plate.

13. The electric power converter device according to claim 1 , comprising a cooler cover attached to the frame at a side opposite to the first base plate to form a bottom wall portion of a fluid channel in the closed cooler.

14. The electric power converter device according to claim 1 , comprising at least one second power semiconductor module,

the second power semiconductor module including:

a second base plate having a third main side and a fourth main side opposite the third main side; and

at least one second die located on the third main side of the second base plate,

wherein the frame is attached to the fourth main side of the second base plate, and

wherein the second base plate has a second step on the fourth main side along a circumferential edge of the second base plate to form a second recess along the circumferential edge of the second base plate in which a second portion of the frame is received.