Semiconductor device for hybrid energy storage systems

1. A method for semiconductor device selection, comprising:

identifying a worst operation condition for a plurality of semiconductor devices in a Modular Multilevel Converter (MMC), the identifying comprising:

determining power losses for each of the semiconductor devices under a plurality of operation conditions, and

calculating a maximum junction temperature for each of the plurality of semiconductor devices at each of the plurality of operation conditions;

determining a maximum junction temperature under the identified worst operation condition for each of a plurality of commercially available semiconductor devices which satisfy a threshold voltage rating;

comparing all semiconductor devices which satisfy the threshold voltage rating and a maximum junction temperature threshold condition to identify a semiconductor device with a lowest system cost; and

selecting and installing the semiconductor device with the lowest system cost in the MMC.

2. The method as recited in claim 1 , wherein the determining power losses further comprises:

separately determining transistor conduction, transistor switching, diode conduction, and diode switching losses; and

combining the determined losses to identify total power losses of each of the semiconductor devices.

3. The method as recited in claim 1 , wherein the identifying the worst operation condition further comprises:

analyzing a plurality of combinations of battery power (P batt ) and UltraCapacitor power (P uc ) in the MMC, the analyzing comprising:

setting output power (P out ) as a positive maximum (P out _ max ) and battery power equal to −P out _ max );

iteratively comparing P batt with P out _ max ;

setting P uc equal to P out −P batt if P batt is smaller than P out _ max ;

adjusting P batt by a threshold step amount (P step ) until P batt is larger than P out _ max to generate a plurality of operation conditions for different combinations of P out , P batt , and P uc ;

setting output power (P out ) as a negative maximum (−P out _ max ) and battery power equal to −P out _ max );

iteratively comparing P batt with P out _ max ;

setting P uc equal to P out −P batt if P batt is smaller than P out _ max ; and

adjusting P batt by a threshold step amount (P step ) until P batt is larger than P out _ max to generate a plurality of operation conditions for different combinations of P out , P batt , and P uc .

4. The method as recited in claim 3 , wherein the maximum junction temperature for each of the plurality of semiconductors is iteratively calculated each time P batt is adjusted by P step .

5. The method as recited in claim 1 , wherein the identifying a worst operation condition further comprises determining power losses for each of a plurality of submodules (SMs) in the MMC.

6. The method as recited in claim 1 , wherein the worst operating condition is present when output power (P out ) is a positive maximum or a negative maximum.

7. The method as recited in claim 1 , wherein the plurality of commercially available semiconductor devices includes all commercially available semiconductor devices that satisfy the threshold voltage rating.

8. A system for semiconductor device selection, comprising:

an operation condition determiner for identifying a worst operation condition for a plurality of semiconductor devices in a Modular Multilevel Converter (MMC), the operation condition determiner being further configured to:

determine power losses for each of the semiconductor devices under a plurality of operation conditions, and

calculate a maximum junction temperature for each of the plurality of semiconductor devices at each of the plurality of operation conditions;

a junction temperature determiner for calculating a maximum junction temperature under the identified worst operation condition for each of a plurality of commercially available semiconductor devices which satisfy a threshold voltage rating; and

a device selector for comparing all semiconductor devices which satisfy the threshold voltage rating and a maximum junction temperature threshold condition to identify a semiconductor device with a lowest system cost, the semiconductor device with the lowest system cost being selected and installed in the MMC.

9. The system as recited in claim 8 , wherein the operation condition determiner is configured to calculate the power losses by separately determining transistor conduction, transistor switching, diode conduction, and diode switching losses, and combining the determined losses to identify total power losses of each of the semiconductor devices.

10. The system as recited in claim 8 , wherein the identifying the worst operation condition using the operation condition determiner further comprises:

analyzing a plurality of combinations of battery power (P batt ) and UltraCapacitor power (P uc ) in the MMC, the analyzing comprising:

setting output power (P out ) as a positive maximum (P out _ max ) and battery power equal to −P out _ max );

iteratively comparing P batt with P out _ max ;

setting P uc equal to P out −P batt if P batt is smaller than P out _ max ;

adjusting P batt by a threshold step amount (P step ) until P batt is larger than P out _ max to generate a plurality of operation conditions for different combinations of P out , P batt , and P uc ;

setting output power (P out ) as a negative maximum (−P out _ max ) and battery power equal to −P out _ max );

iteratively comparing P batt with P out _ max ;

setting P uc equal to P out −P batt if P batt is smaller than P out _ max ; and

adjusting P batt by a threshold step amount (P step ) until P batt is larger than P out _ max to generate a plurality of operation conditions for different combinations of P out , P batt , and P uc .

11. The system as recited in claim 10 , wherein the maximum junction temperature for each of the plurality of semiconductors is iteratively calculated each time P batt is adjusted by P step .

12. The system as recited in claim 8 , wherein the operation condition determiner is further configured to determine power losses for each of a plurality of submodules (SMs) in the MMC.

13. The system as recited in claim 8 , wherein the worst operating condition is present when output power (P out ) is a positive maximum or a negative maximum.

14. The system as recited in claim 8 , wherein the plurality of commercially available semiconductor devices includes all commercially available semiconductor devices that satisfy the threshold voltage rating.

15. A non-transitory computer-readable storage medium including a computer-readable

program for semiconductor device selection, wherein the computer-readable program when executed on a computer causes the computer to perform the steps of:

identifying a worst operation condition for a plurality of semiconductor devices in a Modular Multilevel Converter (MMC), the identifying comprising:

determining power losses for each of the semiconductor devices under a plurality of operation conditions, and

calculating a maximum junction temperature for each of the plurality of semiconductor devices at each of the plurality of operation conditions;

determining a maximum junction temperature under the identified worst operation condition for each of a plurality of commercially available semiconductor devices which satisfy a threshold voltage rating;

comparing all semiconductor devices which satisfy the threshold voltage rating and a maximum junction temperature threshold condition to identify a semiconductor device with a lowest system cost; and

selecting and installing the semiconductor device with the lowest system cost in the MMC.

16. The non-transitory computer-readable storage medium as recited in claim 15 , wherein the determining power losses further comprises:

separately determining transistor conduction, transistor switching, diode conduction, and diode switching losses; and

combining the determined losses to identify total power losses of each of the semiconductor devices.

17. The non-transitory computer-readable storage medium as recited in claim 15 , wherein the identifying the worst operation condition further comprises:

analyzing a plurality of combinations of battery power (P batt ) and UltraCapacitor power (P uc ) in the MMC, the analyzing comprising:

setting output power (P out ) as a positive maximum (P out _ max ) and battery power equal to −P out _ max );

iteratively comparing P batt with P out _ max ;

setting P uc equal to P out −P batt if P batt is smaller than P out _ max ;

adjusting P batt by a threshold step amount (P step ) until P batt is larger than P out _ max to generate a plurality of operation conditions for different combinations of P out , P batt , and P uc ;

setting output power (P out ) as a negative maximum (−P out _ max ) and battery power equal to −P out _ max );

iteratively comparing P batt with P out _ max ;

setting P uc equal to P out −P batt if P batt is smaller than P out _ max ; and

adjusting P batt by a threshold step amount (P step ) until P batt is larger than P out _ max to generate a plurality of operation conditions for different combinations of P out , P batt , and P uc .

18. The computer-readable storage medium as recited in claim 17 , wherein the maximum junction temperature for each of the plurality of semiconductors is iteratively calculated each time P batt is adjusted by P step .

19. The non-transitory computer-readable storage medium as recited in claim 15 , wherein the identifying a worst operation condition further comprises determining power losses for each of a plurality of submodules (SMs) in the MMC.

20. The non-transitory computer-readable storage medium as recited in claim 15 , wherein the worst operating condition is present when output power (P out ) is a positive maximum or a negative maximum.