Hybrid ac and dc distribution system and method of use

Patent metadata

Field	Value
Publication number	US-2016352105-A1
Application number	US-201514725949-A
Country	US
Kind code	A1
Filing date	May 29, 2015
Priority date	May 29, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A hybrid AC and DC distribution system includes a doubly fed induction generator (DFIG), a DC distribution bus, an AC/DC converter, an AC distribution bus, and a DC/AC converter. The DFIG includes a rotor and a stator, and is configured to generate a first AC power at the rotor and a second AC power at the stator. The AC/DC converter is coupled to the rotor and the DC distribution bus. The AC/DC converter converts the first AC power to a first DC power at a first node for delivery to a first load through the DC distribution bus. The DC/AC converter is coupled between the first node and a second node coupled to the stator and the AC distribution bus. The DC/AC converter converts the first DC power to the second AC power at the second node for delivery to a second load through the AC distribution bus.

First claim

What is claimed is:

1 . A hybrid alternating current (AC) and direct current (DC) distribution system comprising:
a doubly fed induction generator (DFIG) comprising a rotor and a stator, said DFIG configured to generate a first AC power at said rotor and a second AC power at said stator; a DC distribution bus configured to be coupled to a first load; an AC-to-DC converter coupled to said rotor and further coupled to said DC distribution bus at a first node, said AC-to-DC converter configured to convert the first AC power to a first DC power at the first node for delivery through said DC distribution bus; an AC distribution bus configured to be coupled to a second load; and a DC-to-AC converter coupled between the first node and a second node, the second node coupled to said stator and said AC distribution bus, said DC-to-AC converter configured to convert the first DC power to the second AC power for delivery to said stator and through said AC distribution bus.

2 . The hybrid AC and DC distribution system in accordance with claim 1 further comprising:
an energy store configured to receive a second DC power; and
a DC-to-DC converter coupled between the first node and said energy store, said DC-to-DC converter configured to convert the first DC power to the second DC power,
wherein said energy store is further configured to provide said second AC power to said second node through said DC-to-DC converter and said DC-to-AC converter.

3 . They hybrid AC and DC distribution system in accordance with claim 1 , wherein the first load comprises a drive load.

4 . The hybrid AC and DC distribution system in accordance with claim 3 further comprising a load-side DC-to-AC converter coupled between said DC distribution bus and the drive load, said load-side DC-to-AC converter configured to convert the first DC power to a third AC power for delivery to the drive load.

5 . The hybrid AC and DC distribution system in accordance with claim 1 , wherein the second load comprises a drive load.

6 . The hybrid AC and DC distribution system in accordance with claim 5 further comprising:
a load-side AC-to-DC converter coupled to said AC distribution bus, said load-side AC-to-DC converter configured to convert the second AC power to a third DC power; and
a load-side DC-to-AC converter coupled between said load-side AC-to-DC converter and the drive load, said load-side DC-to-AC converter configured to convert the third DC power to a third AC power for delivery to the drive load.

7 . The hybrid AC and DC distribution system in accordance with claim 1 , wherein said DC distribution bus comprises a DC ring bus coupled to a second power source and a DC load.

8 . The hybrid AC and DC distribution system in accordance with claim 7 , wherein said DC ring bus couples to the first node through a protection tie and a DC circuit breaker.

9 . The hybrid AC and DC distribution system in accordance with claim 1 , wherein said AC distribution bus comprises an AC ring bus.

10 . The hybrid AC and DC distribution system in accordance with claim 9 , wherein said AC ring bus couples to the second node through an AC circuit breaker and a choke.

11 . A method of operating a hybrid alternating current (AC) and direct current (DC) distribution system, said method comprising:
generating a first AC power at a rotor and a second AC power at a stator for a doubly fed induction generator (DFIG); converting the first AC power to a first DC power at a first node; coupling the first DC power to a DC distribution bus; delivering the first DC power to a first load coupled to the DC distribution bus; converting the first DC power to the second AC power at a second node; coupling the second node to an AC distribution bus and a stator for the DFIG; and delivering the second AC power to a second load coupled to the AC distribution bus.

12 . The method in accordance with claim 11 further comprising converting the first DC power to a second DC power for delivery to an energy store.

13 . The method in accordance with claim 11 , wherein delivering the first DC power to a first load comprises:
converting the first DC power to a third AC power; and supplying the third AC power to the first load.

14 . The method in accordance with claim 11 , wherein delivering the second AC power to a second load comprises:
converting the second AC power to a second DC power; converting the second DC power to a third AC power; and supplying the third AC power to the second load.

15 . An islanded electrical system comprising:
a doubly fed induction generator (DFIG) comprising a rotor and a stator, said DFIG configured to generate a first alternating current (AC) power at said rotor and a second AC power at said stator; a direct current (DC) ring bus directly couplable to a DC electronic load and configured to be coupled to a first drive load through a first load-side DC-to-AC converter; an AC-to-DC converter coupled to said rotor and further coupled to said DC ring bus at a first node, said AC-to-DC converter configured to convert the first AC power to a first DC power at the first node for delivery to said DC ring bus; an AC ring bus directly couplable to an AC auxiliary load and configured to be coupled to a second drive load through a load-side AC-to-DC converter and a second load-side DC-to-AC converter; a DC-to-AC converter coupled between the first node and a second node, the second node coupled to said stator and said AC ring bus, said DC-to-AC converter configured to convert the first DC power to the second AC power for delivery to said stator and said AC ring bus; and an energy store coupled to the first node through a DC-to-DC converter.

16 . The islanded electrical system in accordance with claim 15 , wherein said DC ring bus couples to the first node through a DC circuit breaker and a protection tie.

17 . The islanded electrical system in accordance with claim 16 , wherein said AC ring bus couples to the second node through an AC circuit breaker and a choke.

18 . The islanded electrical system in accordance with claim 17 , wherein said DC circuit breaker and said AC circuit breaker are independently controllable by a controller.

19 . The islanded electrical system in accordance with claim 15 further comprising an engine having a drive shaft coupled to said DFIG and configured to turn said rotor at a variable speed.

20 . The islanded electrical system in accordance with claim 19 , wherein said engine is configured to turn said rotor at a speed determined based on a variable load level and a fuel efficiency of said engine, the variable load level at least partially defined by said first drive load, said second drive load, said DC electronic load, and said AC auxiliary load.

21 . The islanded electrical system in accordance with claim 20 further comprising a controller configured to determine the variable speed at which said rotor turns according to the variable load level and the fuel efficiency.

22 . The islanded electrical system in accordance with claim 21 further comprising a second DFIG coupled to a second engine and configured to turn at a second variable speed.

23 . The islanded electrical system in accordance with claim 22 , wherein said controller is further configured to determine the second variable speed according to the variable load level and a second fuel efficiency of the second engine.

24 . The islanded electr

Assignees

• Gen Electric

Inventors

• Tiwari Arvind Kumar
• Kolhatkar Yashomani Y
• Agrawal Neeraj

Classifications

• H02J4/25 Primary

  for transfer of electric power between AC and DC networks, e.g. for supplying the DC section within a load from an AC mains system · CPC title

• H02J1/14

  Balancing load and power generation in DC networks · CPC title

• H02J3/02 Primary

  using a single network for simultaneous distribution of AC power at different frequencies · CPC title

• H02J1/102

  being switching converters (H02J1/108, H02J1/12 take precedence) · CPC title

• H02M3/04

  by static converters · CPC title