Direct current power system

Patent metadata

Field	Value
Publication number	US-2016226251-A1
Application number	US-201514609991-A
Country	US
Kind code	A1
Filing date	Jan 30, 2015
Priority date	Jan 30, 2015
Publication date	Aug 4, 2016
Grant date	—

Abstract

A direct current (DC) power system includes a plurality of energy sources supplying power to a plurality of loads and a common DC bus having at least one positive rail. The common DC bus is coupled between the plurality of energy sources and the plurality of loads. The common DC bus includes at least two DC bus subsections with DC power transfer capability therebetween and at least one DC bus separator coupled between the at least two DC bus subsections. The DC bus separator includes at least one positive rail controllable switching with at least one of its terminals coupled with at least one terminal of a positive rail inductor to provide a current path between the at least two DC bus subsections during normal operation via the positive rail inductor. The at least one positive rail controllable switch is controlled to be switched off to break the current path when a fault on the positive rail is detected. Furthermore, the DC bus separator includes at least one positive rail diode connected in parallel to the at least one positive rail inductor and arranged to provide a circulating current path to dissipate an inductor current in the at least one positive rail inductor when the at least one positive rail controllable switch is switched off.

First claim

1 . A direct current power system comprising:
a plurality of energy sources supplying power to a plurality of loads; a common direct current (DC) bus having at least one positive rail, the common DC bus coupled between the plurality of energy sources and the plurality of loads, wherein the common DC bus comprises:
at least two DC bus subsections with DC power transfer capability therebetween;
at least one DC bus separator coupled between the at least two DC bus subsections, wherein the DC bus separator comprises:
at least one positive rail controllable switch with at least one of its terminals coupled with at least one terminal of a positive rail inductor to provide a current path between the at least two DC bus subsections during normal operation via the positive rail inductor, wherein the at least one positive rail controllable switch is controlled to be switched off to break the current path when a fault on the positive rail is detected;
at least one positive rail diode connected in parallel to the at least one positive rail inductor and arranged to provide a circulating current path to dissipate an inductor current in the at least one positive rail inductor when the at least one positive rail controllable switch is switched off.

2 . The DC power system of claim 1 , wherein the plurality of loads include marine or subsea equipment.

3 . The DC power system of claim 1 , wherein the plurality of energy sources include generators, energy storage devices, power grid or combinations thereof.

4 . The DC power system of claim 1 , wherein the positive rail controllable switch comprises a switching device based on semiconductor technology.

5 . The DC power system of claim 4 , wherein the switching device include an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a field effect transistor (FET), a gate turn-off thyristor, an insulated gate commutated thyristor (IGCT), an injection enhanced gate transistor (IEGT), a silicon carbide based switch, a gallium nitride based switch, a gallium arsenide based switch, or equivalents thereof.

6 . The DC power system of claim 1 , wherein the positive rail controllable switch comprise a plurality of switching devices connected in series or in parallel or combinations thereof.

7 . The DC power system of claim 1 , wherein the common DC bus includes a negative rail or a ground rail or combinations thereof.

8 . The DC power system of claim 7 , wherein the DC bus separator further includes a negative rail controllable switch having at least one of its terminals coupled with at least one terminal of a negative rail inductor to provide the current path between the at least two DC bus subsections during normal operation via the negative rail inductor, wherein the negative rail controllable switch is controlled to be switched off to break the current path when a fault on the negative rail is detected.

9 . The DC power system of claim 8 , wherein the DC bus separator further includes a negative rail diode connected in parallel to the negative rail inductor and arranged to provide a circulating current path to dissipate an inductor current in the negative rail inductor when the negative rail controllable switch is switched off.

10 . The DC power system of claim 9 , wherein the common DC bus is configured for unidirectional power flow or bidirectional power flow.

11 . The DC power system of claim 10 , wherein when the common DC bus is configured for bidirectional power flow, the DC power system includes at least two DC bus separators connected in series with opposite polarity, each DC bus separator configured to isolate the healthy DC bus subsection from the faulty DC bus subsection depending on the direction of the DC bus current.

12 . The DC power system of claim 7 , wherein a plurality of DC capacitors are connected between the positive and the negative rail or between the ground rail and the positive rail or between the ground rail and the negative rail of the DC bus.

13 . The DC power system of claim 7 , wherein the plurality of loads are connected between the positive rail and the negative rail or between the positive rail and the ground rail or between the negative rail and the ground rail.

14 . A method of supplying direct current (DC) power comprising:
providing a plurality of energy sources to supply DC power to a plurality of loads; coupling the plurality of energy sources and the plurality of loads by a common DC bus having at least one positive rail, wherein the coupling comprises:
providing at least two DC bus subsections with DC power transfer capability therebetween;
coupling at least one DC bus separator between the at least two DC bus subsections, wherein coupling the at least one DC bus separator comprises:
coupling at least one terminal of a positive rail to at least one terminal of a positive rail inductor to provide a current path between the at least two DC bus subsections during normal operation via the positive rail inductor;
controlling the at least one positive rail controllable switch to be switched off to break the current path when a fault on the positive rail is detected;
connecting at least one positive rail diode in parallel to the at least one positive rail inductor and arranged to provide a circulating current path to dissipate an inductor current in the at least one positive rail inductor when the at least one positive rail controllable switch is switched off.

15 . The method of claim 14 further comprising providing a negative rail or a ground rail or both in the common DC bus.

16 . The method of claim 15 further comprising coupling one terminal of a negative rail controllable s switch to one terminal of a negative rail inductor to provide the current path between the at least two DC bus subsections during normal operation via the negative rail inductor.

17 . The method of claim 16 further comprising controlling the negative rail switch to be switched off to break the current path when a fault on the negative rail is detected.

18 . The method of claim 17 further comprising connecting a negative rail diode in parallel to the negative rail inductor and arranged to provide a circulating current path to dissipate an inductor current in the negative rail inductor when the negative rail controllable switch is switched off.

19 . The method of claim 18 comprising at least two DC bus separators connected in series with opposite polarity when the common DC bus is configured for bidirectional power flow, each DC bus separator configured to isolate the healthy DC bus subsection from the faulty DC bus subsection depending on the direction of the DC bus current.

20 . The method of claim 15 comprising connecting a plurality of DC capacitors between the positive and the negative rail or between the ground rail and the positive rail or between the ground rail and the negative rail of the DC bus.

21 . The method of claim 15 comprising connecting the plurality of loads between the positive rail and the negative rail or between the positive rail and the ground rail or between the negative rail and the ground rail.

22 . The method of claim 14 , wherein providing DC power to the plurality of loads comprises providing DC power to marine or subsea equipment.

Assignees

• Gen Electric

Inventors

• Tenca Pierluigi
• Sihler Christof Martin

Classifications

• H02H7/262

  involving transmissions of switching or blocking orders · CPC title

• H03K17/08

  Modifications for protecting switching circuit against overcurrent or overvoltage · CPC title

• H02H3/087

  for DC applications · CPC title

• H02H7/267

  for parallel lines and wires · CPC title

• H02H7/268 Primary

  for DC systems · CPC title