Reconfigurable power systems and converters

Patent metadata

Field	Value
Publication number	US-9537319-B2
Application number	US-201213433357-A
Country	US
Kind code	B2
Filing date	Mar 29, 2012
Priority date	Apr 15, 2011
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

Reconfigurable power systems and converters and operating methods therefor are disclosed. Reconfigurable power systems may include a DC power source, an electrical energy storage device, an AC power grid connection, and a power converter configured to selectively couple two or more of the DC power source, the electrical energy storage device, and the AC power grid connection.

First claim

What is claimed is:

1. A reconfigurable power system, comprising:
a DC power source;
an electrical energy storage device;
an AC power grid connection; and
a power converter comprising:
a plurality of switching devices,
a first switch interposed between said electrical energy storage device and said plurality of switching devices,
a second switch interposed between said electrical energy storage device and said AC power grid connection,
a third switch interposed between said AC power grid connection and said plurality of switching devices, and
a fourth switch interposed between said DC power source and said plurality of switching devices,
said power converter configured to

selectively couple the DC power source to the electrical energy storage device by closing said fourth switch and maintaining either: said first switch in an open position and said second switch in a closed position; or said first switch in a closed position and said second switch in an open position,
selectively couple the DC power source to the AC power grid connection by maintaining said second switch in an open position, and said third and fourth switches in a closed position, and
selectively couple the electrical energy storage device to the AC power grid connection by maintaining said first and third switches in a closed position,
and wherein the power converter is further configured to:
(1) deliver, during a first time period, power from the DC power source to the electrical energy source but not to the AC power grid connection, the first time period including at least a portion of time in which power outputted by the DC power source is around a power source peak level and a grid demand level of an external AC power grid that is coupled to the reconfigurable power system via the AC power grid connection is below a peak demand level;
(2) deliver, during a second time period, power from the DC power source and the electrical energy source to at least the AC power grid connection, the second time period including at least a portion of time in which the grid demand level is around the peak demand level; and
(3) deliver, during a third time period, power from the electrical energy storage device to the AC power grid connection, the third time period including at least a portion of time in which the power outputted by the DC power source is less than the source peak level and the grid demand level is below the peak demand level.

2. The reconfigurable power system of claim 1 , wherein the DC power source includes at least one solar cell.

3. The reconfigurable power system of claim 1 , wherein the electrical energy storage device includes a battery.

4. The reconfigurable power system of claim 1 , wherein said plurality of switching devices includes at least one semiconductor switching device selected from the group consisting of a power transistor, a power MOSFET, an insulated gate bipolar transistor and a gate turn-off thyristor.

5. The reconfigurable power system of claim 1 , wherein said plurality of switching devices are configured to selectively function as a DC-AC inverter, a DC-DC converter, or an AC-DC converter.

6. The reconfigurable power system of claim 5 , wherein said plurality of switching devices are configured to function as the DC-AC inverter when coupling at least one of the DC power source and the electrical energy storage device to the AC power grid connection to deliver power from at least one of the DC power source and the electrical energy storage device to an AC power grid.

7. The reconfigurable power system of claim 5 , wherein said plurality of switching devices are configured to function as the DC-DC converter when coupling the DC power source to the electrical energy storage device to charge the electrical energy storage device.

8. The reconfigurable power system of claim 5 , wherein said plurality of switching devices are configured to function as the AC-DC converter when coupling the AC power grid connection to the electrical energy storage device to charge the electrical energy storage device.

9. The reconfigurable power system of claim 1 , wherein:
the reconfigurable power system is configured to operate in a selected one of at least three modes;
in a first one of the modes said plurality of switching devices are configured as a DC-DC converter coupling the DC power source to the electrical energy storage device;
in a second one of the modes said plurality of switching devices are configured as a DC-AC inverter coupling at least one of the DC power source and the electrical energy storage device to the AC power grid connection; and
in a third one of the modes said plurality of switching devices are configured as an AC-DC converter coupling the AC power grid connection to the electrical energy storage device.

10. The reconfigurable power system of claim 1 , wherein:
the reconfigurable power system is configured to operate in a selected one of at least three modes;
in a first one of the modes said plurality of switching devices are configured as a DC-DC converter coupling the DC power source to the electrical energy storage device;
in a second one said plurality of switching devices are configured as a DC-AC inverter coupling the DC power source and the electrical energy storage device to the AC power grid connection; and
in a third one of the modes said plurality of switching devices are configured as a DC-AC inverter coupling the electrical energy storage device to the AC power grid connection.

11. The reconfigurable power system of claim 10 , where in a fourth one of the at least three modes said plurality of switching devices are configured as a DC-AC inverter coupling the DC power source to the AC power grid connection.

12. The reconfigurable power system of claim 10 , comprising:
a capacitor connected in parallel with the electrical energy storage device and the DC power source; and
a resistor configured to selectively series-couple the electrical energy storage device to the capacitor.

13. A reconfigurable power converter, comprising:
a power source connection configured to couple with a DC power source;
a storage device connection configured to couple with an electrical energy storage device;
a grid connection configured to couple with an AC power grid; and
a power converter comprising a plurality of switching devices and a plurality of switches, said plurality of switches are selectively interposed between said plurality of switching devices and said power source connection, said storage device connection and said grid connection, said power converter configured to selectively couple two or more of the power source connection, the storage device connection, and the grid connection, wherein the power converter is selectively configured as one of:
a DC-DC converter when coupling the power source connection to the storage device connection, but not to the grid connection, by closing selected switches in said plurality of switches and routing, during a first time period, power from said DC power source through said selected switches that are closed and said plurality of switching devices to said electrical energy storage device, said first time period including at least a portion of time in which power outputted by the DC power source is around a power source peak level and a grid demand level of an external AC power grid that is coupled to the reconfigurable power system via the grid connection is below a peak demand level;
a DC-AC inverter when coupling, during a second time period, at least one of the power source connection and the storage device connection to the grid connection by closing selected switches in said

Assignees

• Parkhideh Babak
• Kim Hongrae
• Univ North Carolina State
• Abb Research Ltd

Inventors

• Parkhideh Babak
• Kim Hongrae

Classifications

• H02J3/38 Primary

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• H02J7/35

  with light sensitive cells · CPC title

• H02J2101/25

  involving maximum power point tracking control for photovoltaic sources · CPC title

• Y02E10/56

  Power conversion systems, e.g. maximum power point trackers · CPC title

• H02J3/385

  Electricity · mapped topic