Diode clamped solid-state circuit breaker without dynamic voltage balancing issues

1. A diode clamped solid-state circuit breaker (SSCB), comprising:

a series of N source-side switches connected in series between a first DC source connection and a common connection point, the series of N source-side switches comprising a first source-side switch connected to the first DC source connection and a second source-side switch connected adjacent to the first source-side switch;

a series of N line-side switches connected in series between a line-side connection and the common connection point, the series of N line-side switches comprising a first line-side switch connected to the line-side connection and a second line-side switch connected adjacent to the first line-side switch;

a series of N clamping capacitors connected in series between a second DC source connection and the common connection point, the series of N clamping capacitors comprising a first clamping capacitor connected to the second DC source connection and a second clamping capacitor connected adjacent to the first clamping capacitor;

a source-side surge protector connected across the first source-side switch;

a line-side surge protector connected across the first line-side switch;

a source-side clamping diode connected at a first end between the first and second source-side switches and at a second end between the first and second clamping capacitors; and

a line-side clamping diode connected at a first end between the first and second line-side switches and at a second end between the first and second clamping capacitors.

2. The SSCB of claim 1 , comprising control circuitry configured to control switching of the series of N source-side switches in response to a detected source-side fault and the series of N line-side switches in response to a detected line-side fault.

3. The SSCB of claim 2 , wherein the control circuitry comprises gate drivers associated with the series of N source-side switches and the series of N line-side switches.

4. The SSCB of claim 2 , wherein the control circuitry sequentially turns off the series of N source-side switches from an N-th source-side switch to the first source-side switch in response to the detected source-side fault.

5. The SSCB of claim 4 , wherein the control circuitry turns off the second source-side switch before turning off the first source-side switch.

6. The SSCB of claim 2 , wherein the control circuitry sequentially turns off the series of N line-side switches from an N-th line-side switch to the first line-side switch in response to the detected line-side fault.

7. The SSCB of claim 6 , wherein the control circuitry turns off the second line-side switch before turning off the first line-side switch.

8. The SSCB of claim 2 , wherein N is greater than two.

9. The SSCB of claim 1 , comprising a second source-side clamping diode connected at a first end between the second source-side switch and a third source-side switch connected adjacent to the second source-side switch, and at a second end between the second clamping capacitor and a third clamping capacitor of the series of N clamping capacitors, the third clamping capacitor connected adjacent to the second clamping capacitor; and

a second line-side clamping diode connected at a first end between the second line-side switch and a third line-side switch connected adjacent to the second line-side switch, and at a second end between the second clamping capacitor and the third clamping capacitor.

10. The SSCB of claim 9 , comprising control circuitry configured to sequentially turn off the series of N source-side switches in response to the detected source-side fault, wherein the control circuitry turns off the third source-side switch before turning off the second source-side switch, and turns off the second source-side switch before turning off the first source-side switch.

11. The SSCB of claim 9 , comprising control circuitry configured to sequentially turn off the series of N line-side switches in response to the detected line-side fault, wherein the control circuitry turns off the third line-side switch before turning off the second line-side switch, and turns off the second line-side switch before turning off the first line-side switch.

12. The SSCB of claim 1 , wherein the first and second clamping capacitors have equal capacitance.

13. The SSCB of claim 1 , wherein the first and second clamping capacitors have different capacitances.

14. The SSCB of claim 13 , wherein the capacitance of the first clamping capacitor is greater than the capacitance of the second clamping capacitor.

15. A method, comprising:

supplying DC voltage through a diode clamped solid-state circuit breaker (SSCB) by turning on a series of N source-side switches and a series of N line-side switches of the SSCB, the series of N source-side switches connected in series between a first DC source connection and a common connection point and the series of N line-side switches connected in series between a line-side connection and the common connection point, the series of N source-side switches comprising a first source-side switch connected to the first DC source connection and a second source-side switch connected adjacent to the first source-side switch and the series of N line-side switches comprising a first line-side switch connected to the line-side connection and a second line-side switch connected adjacent to the first line-side switch, the SSCB further comprising a series of N clamping capacitors connected in series between a second DC source connection and the common connection point, N−1 source-side clamping diodes each connected between different pairs of adjacent source-side switches in the series of N source-side switches and different pairs of adjacent clamping capacitors in the series of N clamping capacitors, and N−1 line-side clamping diodes each connected between different pairs of adjacent line-side switches in the series of N line-side switches and the different pairs of adjacent clamping capacitors;

detecting a source-side fault or a line-side fault; and

sequentially turning off the series of N source-side switches from an N-th source-side switch to the first source-side switch in response to the detected source-side fault, where the second source-side switch is turned off before the first source-side switch is turned off to direct current flow through a first clamping capacitor of the series of N clamping capacitors and one of the N−1 source-side clamping diodes and the first source-side switch is turned off to direct current flow through a surge protector connected across the first source-side switch; or

sequentially turning off the series of N line-side switches from an N-th line-side switch to the first line-side switch in response to the detected line-side fault, where the second line-side switch is turned off before the first line-side switch is turned off to direct current flow through the first clamping capacitor and one of the N−1 line side clamping diodes and the first line-side switch is turned off to direct current flow through a surge protector connected across the first line-side switch.

16. The method of claim 15 , wherein N equals two and the series of N clamping capacitors comprises the first clamping capacitor and a second clamping capacitor, wherein the first and second clamping capacitors have equal capacitance.

17. The method of claim 15 , wherein N equals two and the series of N clamping capacitors comprises the first clamping capacitor and a second clamping capacitor, wherein a capacitance of the first clamping capacitor is greater than a capacitance of the second clamping capacitor.

18. The method of claim 15 , wherein sequentially turning off the series of N source-side switches comprises turning off a third source-side switch before the second source-side switch is turned off to direct current flow through the first clamping capacitor and a second clamping capacitor and another one of the N−1 source-side clamping diodes.

19. The method of claim 15 , wherein sequentially turning off the series of N line-side switches comprises turning off a third line-side switch before the second line-side switch is turned off to direct current flow through the first clamping capacitor and a second clamping capacitor and another one of the N−1 line-side clamping diodes.

20. The method of claim 15 , wherein each clamping capacitor of the series of N clamping capacitors has a different capacitance.