Fuel cell power plant with real and reactive power modes

Patent metadata

Field	Value
Publication number	US-2018181154-A1
Application number	US-201715832860-A
Country	US
Kind code	A1
Filing date	Dec 6, 2017
Priority date	Mar 4, 2016
Publication date	Jun 28, 2018
Grant date	—

Abstract

An illustrative example fuel cell power plant includes a cell stack assembly having a plurality of fuel cells configured to generate electricity based on an electrochemical reaction. The power plant includes a capacitor, a plurality of inverters, and at least one controller that is configured to control the plurality of inverters in a first mode and a second mode. The first mode includes the cell stack assembly associated with at least one of the inverters. A cell stack assembly and the associated inverter provide real power to a load external to the fuel cell power plant in the first mode. The second mode includes at least a second one of the inverters associated with the capacitor. The capacitor and the second one of the inverters selectively provide reactive power to or receive reactive power from a grid external to the fuel cell power plant in the second mode.

First claim

We claim:

1 . A fuel cell power plant, comprising:
a cell stack assembly including a plurality of fuel cells configured to generate electricity based on an electrochemical reaction; a capacitor; a plurality of inverters; and at least one controller that is configured to control the plurality of inverters in a first mode and a second mode, the first mode including the cell stack assembly associated with at least one of the inverters, the cell stack assembly and the at least one of the inverters providing real power to a load external to the fuel cell power plant, the second mode including at least a second one of the inverters associated with the capacitor, the second one of the inverters and the capacitor selectively providing reactive power to or receiving reactive power from a grid external to the fuel cell power plant.

2 . The fuel cell power plant of claim 1 , wherein the reactive power of the second mode is the only power output from the fuel cell power plant of the second mode that is external to the fuel cell power plant.

3 . The fuel cell power plant of claim 1 , wherein more than one of the inverters is associated with the capacitor in the second mode.

4 . The fuel cell power plant of claim 1 , wherein the capacitor is charged by the reactive power received from the grid in the second mode.

5 . The fuel cell power plant of claim 1 , wherein
the first mode includes the capacitor associated with at least one of the inverters; and the first mode includes the capacitor providing supplemental power output from the fuel cell power plant when there is an increase in a load demand on the fuel cell power plant.

6 . The fuel cell power plant of claim 1 , wherein the real power is a low voltage power less than or equal to 600 kilowatts.

7 . The fuel cell power plant of claim 1 , comprising
a DC bus between the cell stack assembly and the plurality of inverters; and a switching device that is controlled by the controller to selectively couple the cell stack assembly, the capacitor, and selected ones of the plurality of inverters respectively to the DC bus.

8 . The fuel cell power plant of claim 8 , comprising
an output configured to be coupled to a load external to the fuel cell power plant; an AC bus between the plurality of inverters and the output; and at least one switching device that is controlled by the controller to selectively couple selected ones of the inverters to the output.

9 . The fuel cell power plant of claim 1 , wherein the capacitor is the only source of power supplied by the fuel cell power plant external to the fuel cell power plant in the second mode.

10 . The fuel cell power plant of claim 1 , wherein the second mode includes at least a first one of the inverters associated with the cell stack assembly, the first one of the inverters and the cell stack assembly providing power to at least one other component of the fuel cell power plant.

11 . A method of operating a fuel cell power plant including a cell stack assembly, a capacitor, and a plurality of inverters, the method comprising:
controlling the plurality of inverters in a first mode and a second mode; using the cell stack assembly and at least one associated one of the inverters for providing real power to a load external to the fuel cell power plant in the first mode; and using the capacitor and at least a second one of the inverters for selectively providing reactive power to or receiving reactive power from a grid external to the fuel cell power plant in the second mode.

12 . The method of claim 11 , wherein the reactive power of the second mode is the only power output from the fuel cell power plant in the second mode that is external to the fuel cell power plant.

13 . The method of claim 11 , wherein more than one of the inverters is associated with the capacitor in the second mode.

14 . The method of claim 11 , comprising charging the capacitor using the reactive power received from the grid in the second mode.

15 . The method of claim 11 , comprising providing supplemental power output from the fuel cell power plant using the capacitor and at least one of the inverters associated with the capacitor in the first mode when there is an increase in a load demand on the fuel cell power plant.

16 . The method of claim 11 , wherein the real power is a low voltage power less than or equal to 600 kilowatts.

17 . The method of claim 11 , wherein the capacitor is the only source of power supplied by the fuel cell power plant external to the fuel cell power plant in the second mode.

18 . The method of claim 11 , comprising using the cell stack assembly and at least one associated one of the inverters for providing power to at least one other component of the fuel cell power plant in the second mode.

Assignees

• Doosan Fuel Cell America Inc

Inventors

• Philhower Jason W

Classifications

• H02J3/381

  Dispersed generators · CPC title

• H02J2101/30

  Fuel cells · CPC title

• H01M2250/10

  Fuel cells in stationary systems, e.g. emergency power source in plant · CPC title

• H02J3/38

  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

• H01M16/003

  of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers · CPC title