Apparatus for diagnosing a state of a fuel cell stack and method thereof

Patent metadata

Field	Value
Publication number	US-9494655-B2
Application number	US-201414566121-A
Country	US
Kind code	B2
Filing date	Dec 10, 2014
Priority date	Aug 29, 2014
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

Disclosed are an apparatus and a method for diagnosing a state of a fuel cell stack with high accuracy by reducing the deviation of a harmonic component although the voltage variation of the fuel cell stack is substantial. According to the present invention, a harmonic component is detected by converting the difference between the voltage of the fuel cell stack and a moving average voltage to a frequency and the state of the fuel cell stack is diagnosed based on the size of the detected harmonic component.

First claim

What is claimed is:

1. An apparatus for diagnosing a state of a fuel cell stack, comprising:
an alternating current applying device configured to apply an alternating current to a direct current of the fuel cell stack;
a voltage measurer configured to measure a voltage of the fuel cell stack;
a moving average voltage calculator configured to calculate a moving average voltage based on the voltage measured by the voltage measurer;
a voltage difference calculator configured to calculate a difference between the measured voltage of the fuel cell stack and the calculated moving average voltage;
a VF (Voltage-Frequency) converter configured to convert a calculated result to a frequency: and
a diagnosis device configured to diagnose the state of the fuel cell stack based on a size of harmonic components in the converted frequency.

2. An apparatus of claim 1 , wherein the diagnosis device is configured to determine the state of the fuel cell stack as an abnormal state when the size of the harmonic components is greater than a first threshold value, and determine the state of the fuel cell stack as a normal state when the size of the harmonic components is equal to or less than a second threshold value.

3. An apparatus of claim 2 , wherein the first threshold value has a value greater than the second threshold value.

4. A method for diagnosing a state of a fuel cell stack, comprising:
applying, by a controller, an alternating current to a direct current of the fuel cell stack;
measuring, by the controller, a voltage of the fuel cell stack;
calculating, by the controller, a moving average voltage based on the measured voltage;
calculating, by the controller, a difference between the measured voltage of the fuel cell stack and the calculated moving average voltage;
converting, by the controller, the calculated voltage difference to a frequency; and
diagnosing, by the controller, the state of the fuel cell stack based on a size of harmonic components in the converted frequency.

5. A method of claim 4 , further comprising:
determining, by the controller, the state of the fuel cell stack as an abnormal state when the size of the harmonic components is greater than a first threshold value; and
determining, by the controller, the state of the fuel cell stack as a normal state when the size of the harmonic components is equal to or less than a second threshold value.

6. A method of claim 5 , wherein the first threshold value has a value greater than the second threshold value.

7. A fuel cell system comprises an apparatus of claim 1 to diagnose a state of the fuel cell stack.

8. A vehicle comprises a fuel cell system of claim 7 to diagnose a state of the fuel cell stack.

9. A non-transitory computer readable medium containing program instructions executed by a controller, the computer readable medium comprising:
program instructions that apply an alternating current to a direct current of the fuel cell stack;
program instructions that measure a voltage of the fuel cell stack;
program instructions that calculate a moving average voltage based on the measured voltage;
program instructions that calculate a difference between the measured voltage of the fuel cell stack and the calculated moving average voltage;
program instructions that convert the calculated voltage difference to a frequency; and
program instructions that diagnose the state of the fuel cell stack based on a size of harmonic components in the converted frequency.

Assignees

• Hyundai Motor Co Ltd

Inventors

• Jeong Kwi Seong
• Won Sang Bok
• Kum Young Bum
• Ko Jae Jun

Classifications

• G01R31/3637 Primary

  Physics · mapped topic

• H01M8/04649

  of fuel cell stacks · CPC title

• H01M8/04559 Primary

  of fuel cell stacks · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title