Control by state observer of PEMFC anodic purges in dead-end operating mode

Abstract

International audienceA Proton Exchange Membrane Fuel Cell (PEMFC) needs an active system to control all the ancillaries and ensure optimal operating conditions, especially in a fuel cell vehicle. For the fuel cell system architecture, dead-end anode is the cheapest architecture for the hydrogen line and also the one that leads to important reversible and irreversible degradations if not appropriately managed. To address the cost and durability issues on fuel cell vehicles, this study proposes a state observer which aims at estimating online the nitrogen saturation in the anode side in order to trigger the purge at a given criterion. This observer is based on a simple set of equations extracted from a detailed 2D-meshed model. Nitrogen buildup is evaluated in simulation with different road profiles with less than 5% error. Moreover the fuel cell system efficiency increases compared to the other existing purge strategies, so as the mileage. The observer can also be used to develop other optimal strategies to minimize the irreversible degradations of the fuel cell

PEMFC purging at low operating temperatures: An experimental approach

“…The nitrogen cross-over and accumulation in the anode depends on membrane temperature and hydration level and the current density. 43,54,55 Mittlesteadt and Umbrell 56 have devised a simple method to measure nitrogen crossover as a function of temperature, RH, and the equivalent weight (EW) of the membrane material. They found that nitrogen crossover could be represented as two parallel processes representing nitrogen transport through the polymer and nitrogen transport through the water phase of the ionomer.…”

A nonlinear control strategy for fuel delivery in PEM fuel cells considering nitrogen permeation

“…where zðtÞb  eðtÞ T ;x 2 ðtÞ;x 4 ðtÞ Ã T , and the coefficient matrix H ¼ fh ij g2ℝ 5Â5 ði; j ¼ 1; 2; …; 5Þ and the vector L2ℝ 5Â1 can be obtained and expressed as follows by substituting (26) into (13), (27) into (15), and (20) into the derivative of (19), respectively: …”

“…Then, based on the fact that Q v is positive definite, (30), and (31), _ VðtÞ is negative. Therefore, from the previous facts, the errors  eðtÞ T ;x 2 ðtÞ;x 4 ðtÞ Ã are uniformly ultimately bounded under the regulation of the control law (26) and (27) [34].…”

“…A state observer was proposed in Ref. [27] for anode nitrogen saturation estimation to optimize the anodic purge strategy of dead-end operating mode of PEM fuel cells. However, these control strategies focus more on the optimized interval purge operations for less voltage reduction with adequate hydrogen supply.…”

Sliding mode observer for proton exchange membrane fuel cell: automotive application

“…A previous work with the same purpose has been presented in [13] with the UKF technique (Unscented Kalman Filter) for the observer instead of sliding mode. This UKF observer is difficult to tune for a specific (P,T) couple with no theoretical proof of convergence.…”