Method and device for observing a state of a fuel-cell electrochemical system

Patent metadata

Field	Value
Publication number	US-10359477-B2
Application number	US-201815862838-A
Country	US
Kind code	B2
Filing date	Jan 5, 2018
Priority date	Jan 9, 2017
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A method for observing a state of an electrochemical system including a fuel cell including the following steps: measuring parameters that are representative of the fuel cell in operation; forming a control vector; forming a measurement vector; calculating a temporal variation, referred to as a non-corrected temporal variation; calculating a corrective term in sliding mode; calculating an estimate of the state of the electrochemical system; reiterating above steps while incrementing the measurement time.

First claim

The invention claimed is:

1. A method for observing a state (X) of an electrochemical system comprising a fuel cell that is formed from at least one electrochemical cell comprising an anode and a cathode separated from each other by a membrane, further comprising an anodic distribution circuit for distributing hydrogen that is linked to an anodic fluid discharge line provided with a purge valve controlled on the basis of a purge signal (Q ao ), and a cathodic distribution circuit for distributing oxygen, said method comprising the following steps:
a) measuring, at a measurement time (t k ), an electric current (I) of the fuel cell, a voltage (V) of the fuel cell, an anodic pressure (P a ) of the anodic distribution circuit, a cathodic pressure (P c ) of the cathodic distribution circuit, and a temperature (T) of the fuel cell;
b) forming a control vector (U) on the basis of the purge signal (Q ao ) and of the measurements of the electric current (I), of the temperature (T) and of the cathodic pressure (P c );
c) forming a measurement vector (Y) on the basis of an ohmic resistance value (Rm) of the membrane deduced from the measurements of the electric current (I) and of the voltage (V), and on the basis of the measurement of the anodic pressure (P a );
d) calculating a non-corrected temporal variation ({circumflex over ({dot over (X)})} nc ), on the basis of a prior estimate ({circumflex over (X)}) of the state (X) and of the control vector (U), based on a predetermined representation (f) of the state of the electrochemical system, the state (X) being formed from state variables that are representative of the amounts of nitrogen (n N 2 a ) and of hydrogen (n H 2 a ) at the anode, and of the amounts of water at the anode (n H 2 O a ), at the cathode (n H 2 O c ), and in the membrane (λ m );
e) calculating a corrective term (ε) in sliding mode on the basis of a difference (S) between the measurement vector (Y) and a measurement estimate (Ŷ) of the measurement vector (Y) obtained on the basis of a prior estimate ({circumflex over (X)}) of the state (X);
f) calculating an estimate ({circumflex over (X)}) of said state (X) of the electrochemical system for the measurement time (t k ), on the basis of the non-corrected temporal variation ({circumflex over ({dot over (X)})} nc ) and of the corrective term (ε);
g) reiterating steps a) to f) while incrementing the measurement time, the prior estimate ({circumflex over (X)}) of steps d) and e) then corresponding to the state estimate ({circumflex over (X)}) calculated in the preceding iteration.

2. The method according to claim 1 , wherein the difference (S) is equal to the difference between the measurement vector (Y) and the measurement estimate (Ŷ).

3. The method according to claim 1 , wherein the measurement estimate (Ŷ) is calculated on the basis of the state estimate ({circumflex over (X)}) calculated at the preceding measurement time (t k-1 ), based on a predetermined model (h) expressing a relationship between the measurement vector (Y), the state (X) and the control vector (U).

4. The method according to claim 1 , wherein the corrective term (ε) is equal to the product of a predetermined gain parameter (K) and a sign function applied to the difference (S).

5. The method according to claim 1 , wherein the state vector (X) is defined such that X=[n N 2 a ; n H 2 O a ; n H 2 O c ; λ m ; n H 2 a ], the control vector (U) is defined such that U=[Q ao ; I; T; P c ], and the measurement vector (Y) is defined such that Y=[R m ; P a ].

6. The method according to claim 1 , wherein step f) of calculating the state estimate ({circumflex over (X)}) comprises a step of calculating a state estimate variation term ({circumflex over ({dot over (X)})}), the terms of which are written as:

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Assignees

• Commissariat Energie Atomique

Inventors

• Piffard Maxime
• Bideaux Eric
• Gerard Mathias
• Massioni Paolo
• Naiff Da Fonseca Ramon

Classifications

• H01M8/04895

  Current · CPC title

• H01M8/04641

  of the individual fuel cell · CPC title

• G01R31/387 Primary

  Determining ampere-hour charge capacity or SoC · CPC title

• H01M8/04305

  Modeling, demonstration models of fuel cells, e.g. for training purposes · CPC title

• H01M8/04231 Primary

  Purging of the reactants · CPC title