Power system based on current source
A regulated current-fed power system employs power branching units connected in series. Each power branching unit includes a plurality of parallel-redundant converter groups connected in series with each other within a current path for the regulated current. Each parallel-redundant converter group includes at least two direct current (DC)/DC converters connected in parallel with each other, each sharing the power load. A protection device connected in series with each DC/DC converter disconnects the respective DC/DC converter from the regulated current when the respective DC/DC converter short circuits, with the remaining DC/DC converter(s) then receiving more of the power load. An active clamp connected in parallel with all of the DC/DC converters within a parallel-redundant converter group temporarily sinks a portion of the regulated current when one of the DC/DC converters fails in a short-circuit condition. The active clamp shunts the regulated current around all DC/DC converters within the parallel-redundant converter group converters fail in a short-circuit condition.
1. A power branching unit comprising:
an input configured to receive a regulated current;
an output configured to provide the regulated current; and
multiple converter groups coupled between the input and the output, each converter group comprising:
multiple direct current/direct current (DC/DC) converters;
multiple protection devices each configured to selectively prevent one of the DC/DC converters from receiving the regulated current; and
an active clamp configured to (i) temporarily sink a portion of the regulated current in response to one of the DC/DC converters failing and (ii) selectively shunt the regulated current around all of the DC/DC converters in response to all of the DC/DC converters failing.
2. The power branching unit of claim 1 , wherein each protection device comprises a fuse or a switching fuse.
3. The power branching unit of claim 1 , further comprising:
an emergency clamp configured to selectively shunt the regulated current around all of the converter groups; and
an emergency power source coupled in series with the emergency clamp.
4. The power branching unit of claim 1 , wherein, for each converter group:
each DC/DC converter comprises a converter controller configured to selectively adapt operation of the associated DC/DC converter; and
the active clamp comprises a clamp controller configured to transmit signals to the converter controllers to adapt operation of the DC/DC converters.
5. The power branching unit of claim 1 , wherein, for each converter group:
each protection device comprises a current sensor; and
the active clamp comprises a clamp controller configured to receive signals indicating a voltage across the converter group and at least one current sensed by at least one of the protection devices in the converter group.
6. The power branching unit of claim 5 , wherein, for each converter group:
the converter group comprises an additional current sensor; and
the clamp controller is further configured to receive a signal indicating a current flowing through the converter group.
7. The power branching unit of claim 1 , further comprising:
a power branching unit controller configured to cause at least one of the converter groups to increase a voltage across its DC/DC converters when all of the DC/DC converters in another of the converter groups fail.
8. The power branching unit of claim 1 , wherein:
the DC/DC converters in at least one of the converter groups are coupled to a power branching unit controller; and
the DC/DC converters in at least one other of the converter groups are coupled to at least one load.
9. The power branching unit of claim 1 , wherein:
for each converter group, the DC/DC converters in the converter group are coupled in parallel with each other and with the active clamp in the converter group;
for each converter group, each DC/DC converter in the converter group is coupled in series with one of the protection devices in the converter group; and
the converter groups are coupled in series with each other.
10. A system comprising:
an alternating current/direct current (AC/DC) converter configured to be coupled to a power source and generate a regulated current; and
multiple power branching units, each power branching unit comprising:
an input configured to receive the regulated current;
an output configured to provide the regulated current; and
multiple converter groups coupled between the input and the output, each converter group comprising:
multiple direct current/direct current (DC/DC) converters;
multiple protection devices each configured to selectively prevent one of the DC/DC converters from receiving the regulated current; and
an active clamp configured to (i) temporarily sink a portion of the regulated current in response to one of the DC/DC converters failing and (ii) selectively shunt the regulated current around all of the DC/DC converters in response to all of the DC/DC converters failing.
11. The system of claim 10 , wherein each protection device comprises a fuse or a switching fuse.
12. The system of claim 10 , wherein each power branching unit further comprises:
an emergency clamp configured to selectively shunt the regulated current around all of the converter groups; and
an emergency power source coupled in series with the emergency clamp.
13. The system of claim 10 , wherein, for each converter group:
each DC/DC converter comprises a converter controller configured to selectively adapt operation of the associated DC/DC converter; and
the active clamp comprises a clamp controller configured to transmit signals to the converter controllers to adapt operation of the DC/DC converters.
14. The system of claim 10 , wherein, for each converter group:
each protection device comprises a current sensor; and
the active clamp comprises a clamp controller configured to receive signals indicating a voltage across the converter group and at least one current sensed by at least one of the protection devices in the converter group.
15. The system of claim 14 , wherein, for each converter group:
the converter group comprises an additional current sensor; and
the clamp controller is further configured to receive a signal indicating a current flowing through the converter group.
16. The system of claim 10 , wherein each power branching unit further comprises:
a power branching unit controller configured to cause at least one of the converter groups in the power branching unit to increase a voltage across its DC/DC converters when all of the DC/DC converters in another of the converter groups in the power branching unit fail.
17. The system of claim 10 , wherein, for each power branching unit:
the DC/DC converters in at least one of the converter groups are coupled to a power branching unit controller; and
the DC/DC converters in at least one other of the converter groups are coupled to at least one load.
18. The system of claim 10 , wherein, for each power branching unit:
for each converter group, the DC/DC converters in the converter group are coupled in parallel with each other and with the active clamp in the converter group;
for each converter group, each DC/DC converter in the converter group is coupled in series with one of the protection devices in the converter group; and
the converter groups are coupled in series with each other.
19. The system of claim 10 , further comprising:
a power bus configured to provide the regulated current from the AC/DC converter to the power branching units.
20. A method comprising:
receiving a regulated current at an input of a power branching unit;
providing the regulated current from an output of the power branching unit; and
passing the regulated current through multiple converter groups, each converter group comprising:
multiple direct current/direct current (DC/DC) converters;
multiple protection devices each configured to selectively prevent one of the DC/DC converters from receiving the regulated current; and
an active clamp configured to (i) temporarily sink a portion of the regulated current in response to one of the DC/DC converters failing and (ii) selectively shunt the regulated current around all of the DC/DC converters in response to all of the DC/DC converters failing.