Power conditioning system and control method therefor

Patent metadata

Field	Value
Publication number	US-10166884-B2
Application number	US-201515750950-A
Country	US
Kind code	B2
Filing date	Aug 11, 2015
Priority date	Aug 11, 2015
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

A power conditioning system that includes a fuel cell to be connected to a load, a fuel cell converter connected between the fuel cell and the load, the fuel cell converter converting an output voltage of the fuel cell at a predetermined required voltage ratio, a battery connected in parallel with the fuel cell with respect to the load, the battery serving as a power supply source different from the fuel cell, a battery converter connected between the battery and the load, the battery converter converting an output voltage of the battery at a predetermined required voltage ratio. The power conditioning system includes a converter direct coupling unit configured to directly couple an input side and an output side of the fuel cell converter during startup of the power conditioning system and a fuel cell output voltage increasing unit configured to increase the output voltage of the fuel cell to a predetermined voltage by supplying oxidant gas during startup of the fuel cell.

First claim

The invention claimed is:

1. A power conditioning system with two converters, comprising:
a fuel cell to be connected to a load;
a fuel cell converter connected between the fuel cell and the load, the fuel cell converter converting an output voltage of the fuel cell at a predetermined required voltage ratio;
a battery connected in parallel with the fuel cell with respect to the load, the battery serving as a power supply source different from the fuel cell;
a battery converter connected between the battery and the load, the battery converter converting an output voltage of the battery at a predetermined required voltage ratio;
a converter direct coupling unit configured to directly couple an input side and an output side of the fuel cell converter during startup of the power conditioning system; and
a fuel cell output voltage increasing unit configured to increase the output voltage of the fuel cell to a predetermined voltage by supplying oxidant gas during startup of the fuel cell.

2. The power conditioning system according to claim 1 , further comprising:
a converter input voltage adjusting unit configured to adjust an input-side voltage of the fuel cell converter to the predetermined voltage before the output voltage of the fuel cell is increased to the predetermined voltage by the fuel cell output voltage increasing unit.

3. The power conditioning system according to claim 2 , wherein:
the converter input voltage adjusting unit adjusts the input-side voltage of the fuel cell converter to the predetermined voltage using stored power of the battery by the battery converter and the converter direct coupling unit.

4. The power conditioning system according to claim 2 , wherein:
the converter input voltage adjusting unit stops a function of the converter direct coupling unit and adjusts the input-side voltage of the fuel cell converter to the predetermined voltage using stored power of the battery by the battery converter and the fuel cell converter.

5. The power conditioning system according to claim 1 , further comprising:
a current sensor configured to detect an output current of the fuel cell during the startup of the fuel cell; and
an output current determining unit configured to determine whether or not the output current detected by the current sensor has been increased to a predetermined value or larger after the startup of the fuel cell,
wherein a voltage control gain of the battery converter is increased more when the output current is determined to have been increased to the predetermined value or larger by the output current determining unit than when the output current is below the predetermined value.

6. The power conditioning system according to claim 1 , wherein:
the converter direct coupling unit directly couples the fuel cell converter and simultaneously increases an input-side voltage and an output-side voltage of the fuel cell converter to the predetermined voltage using stored power of the battery during the startup of the power conditioning system.

7. The power conditioning system according to claim 1 , wherein:
the fuel cell converter includes a plurality of switching elements configured to step up and down the output voltage of the fuel cell; and
the converter direct coupling unit directly couples the fuel cell converter by setting an output-side voltage of the fuel cell converter to the predetermined voltage by the battery converter and setting an input-side voltage to a voltage value higher than the output-side voltage of the fuel cell converter by the fuel cell converter.

8. A control method for a power conditioning system with:
a fuel cell to be connected to a load;
a fuel cell converter connected between the fuel cell and the load, the fuel cell converter converting an output voltage of the fuel cell at a predetermined required voltage ratio;
a battery serving as a power supply source different from the fuel cell; and
a battery converter connected between the battery and the load, the battery converter converting an output voltage of the battery at a predetermined required voltage ratio;
the control method comprising:
directly coupling an input side and an output side of the fuel cell converter; and
increasing the output voltage of the fuel cell to a predetermined voltage by supplying oxidant gas during startup of the fuel cell.

Assignees

• Nissan Motor

Inventors

• Matsumoto Michihiko

Classifications

• H02M3/155

  using semiconductor devices only · CPC title

• H01M8/04888

  of auxiliary devices, e.g. batteries, capacitors · CPC title

• B60L58/31

  for starting of fuel cells · CPC title

• B60L2240/547

  Voltage · CPC title

• H01M8/04302

  applied during start-up · CPC title