Cooling of wide bandgap semiconductor devices

1. A power device, comprising:

at least one power semiconductor module comprising a wide bandgap semiconductor element;

a cooling system for actively cooling the wide bandgap semiconductor element with a cooling medium, wherein the cooling system comprises a refrigeration device for lowering a temperature of the cooling medium below an ambient temperature of the power device;

wherein the cooling system is adapted for lowering the temperature of the cooling medium in such a way that a temperature of the wide bandgap semiconductor element is below 100° C.

2. The power device of claim 1 , wherein the wide bandgap semiconductor element comprises a unipolar semiconductor switch and/or is based on SIC.

3. The power device of claim 2 , wherein the wide bandgap semiconductor element comprises an SiC MOSFET.

4. The power device of claim 1 , wherein the wide bandgap semiconductor element comprises an SiC MOSFET.

5. The power device according to claim 1 , wherein the power semiconductor element comprises a combination of a unipolar wide bandgap switch and a bipolar switch.

6. The power device according to claim 1 , wherein the voltage rating of the power device is above 2 kV.

7. The power device according to claim 1 , wherein the refrigeration device is based on vapor compression.

8. The power device according to claim 1 , wherein the cooling system comprises a first cooling circuit for cooling the at least one power semiconductor module;

wherein the cooling system comprises a second cooling circuit for cooling the first cooling circuit, which is in thermal contact with the second cooling circuit via an internal exchanger.

9. The power device of claim 8 , wherein the second cooling circuit comprises the refrigeration device.

10. The power device of claim 9 , wherein the second cooling circuit comprises an external heat exchanger adapted for heat exchanging with ambient air of the power device.

11. The power device of claim 1 , wherein the power semiconductor element comprises a combination of a unipolar wide bandgap switch and a bipolar switch;

wherein the voltage rating of the power device is above 2 kV; and

wherein the refrigeration device is based on vapor compression.

12. The power device of claim 1 , wherein the cooling system comprises a first cooling circuit for cooling the at least one power semiconductor module;

wherein the cooling system comprises a second cooling circuit for cooling the first cooling circuit, which is in thermal contact with the second cooling circuit via an internal exchanger.

13. A method for cooling at least one power semiconductor module comprising a wide bandgap semiconductor element, the method comprising:

lowering, with a refrigeration device, a temperature of a cooling medium below an ambient temperature of a power device comprising the wide bandgap semiconductor element;

cooling the wide bandgap semiconductor with the cooling medium such that a temperature of the wide bandgap semiconductor element is below 100° C.

14. The method of claim 13 , wherein the wide bandgap element is cooled such that its temperature is above 20° C.

15. The method of claim 14 , wherein the cooling medium is cooled below 0° C.

16. The method of claim 13 , wherein the cooling medium is cooled below 0° C.

17. A method for operating a power device, the method comprising:

operating a wide bandgap semiconductor element with a switching frequency below 500 Hz;

cooling the wide bandgap semiconductor element below a temperature of 100° C. by lowering, with a refrigeration device, a temperature of a cooling medium below an ambient temperature of the wide bandgap semiconductor element; and

cooling the wide bandgap semiconductor with the cooling medium.

18. A power device comprising:

at least one power semiconductor module comprising a wide bandgap semiconductor element;

a cooling system for actively cooling the wide bandgap semiconductor element with a cooling medium, wherein the cooling system comprises a refrigeration device for lowering a temperature of the cooling medium below an ambient temperature of the power device, the cooling system is adapted for lowering the temperature of the cooling medium in such a way that a temperature of the wide bandgap semiconductor element is below 100° C.;

a controller for controlling a switching frequency of the wide bandgap semiconductor element, wherein the power device is adapted for performing the operations under the control of the controller comprising:

operate the wide bandgap semiconductor element with a switching frequency below 500 Hz;

cool the wide bandgap semiconductor element below 100° C. by lowering, with the refrigeration device, a temperature of the cooling medium below the ambient temperature of the wide bandgap semiconductor element; and

cool the wide bandgap semiconductor with the cooling medium.

19. The power device of claim 18 being an electrical converter.