Hatem Allagui

Design, Modeling and Energy Management of a PEM Fuel Cell / Supercapacitor Hybrid Vehicle

This work concerns the study and the modeling of hybrid Proton Exchange Membrane (PEM) Fuel Cell electric vehicle. In fact, the paper deals with the model description of the powertrain which includes two energy sources: a PEM Fuel Cell as a primary source and a supercapacitor as a secondary source. The architecture is two degrees of freedom permitting a stability of the DC bus voltage. The hybridation of primary source with an energy storage system can improve vehicle dynamic response during transients and hydrogen consumption. The proposed energy management algorithm allows us to have a minimum hydrogen consumption. This algorithm is based on supercapacitor state of charge (SOC) control and acceleration/deceleration phases making possible braking energy recovery. The proposed model is simulated and tested using Matlab/Simulink software allowing rapid transitions between sources. The obtained results with the New European Driving Cycle (NEDC) cycle demonstrate a 22% gain in hydrogen consumption.

Study of an electronic load for measuring the internal impedance of a PEM fuel cell

In order to further understanding the behavior of PEM fuel cell and optimize their performance, it is necessary to perform measurements in real time. The measure of internal impedance of a fuel cell in load is of great importance. In this work, we present the impedance measurement method of a PEM fuel cell by electrochemical impedance spectroscopy method (EIS), as well the study of an electronic load for the implementation of the measurement technique. The theoretical results are obtained by a simulation with PSPICE software.

Bond graph modeling and control of a single PEM cell

This paper addresses the problem of bond graph methodology as a graphical approach for modeling renewable and electrochemical sources, particularly fuel cells. The purpose is to highlight the bond graph approach in order to model a PEM cell model, as a first step, and to control the incoming hydrogen and oxygen flows to its electrodes as a second step. The adapted control is conventional based on a PID regulator.

Study of a boost converter for PEM fuel cell

This work concerns the study and the modeling of a static converter step-up fuel cell, in order to understand the behavior of this type of energy source in power electronics. After an overview of its operation, this paper proposes a model fuel cell PEMFC supplied with pure hydrogen and oxygen. This model takes into account of the different physicochemical phenomena in a fuel cell. This paper presents a proposed model for a PEM fuel cell: the static model with undissociated electrodes which involves classical laws to describe the different phenomena in a stack. In essence, this model is directly implemented under Matlab-Simulink and can therefore be connected to the static converter model which is regulated in voltage; this model is used as a voltage source for the static converter. The type of the conversion structure is a boost, increasing the voltage delivered by the fuel cell and controlled by a PWM signal. After modeling the converter, it is connected to the fuel cell model. The control regulation system is then defined based on the use of a PID controller. Then, the system formed by the fuel cell and the converter is compared to that formed by the same converter but powered with single power-supplied with a classical generator battery.

The Identification of Randles Impedance Model Parameters of a PEM Fuel Cell by the Least Square Method

One of the problems of industrial development of fuel cells is the reliability of their performances with time. The solution of this problem is through by the development of improved diagnostic methods such as the identification of parameters. This work focuses on the modeling and the identification of the impedance model parameters of a Proton Exchange Membrane (PEM) fuel cell. It is based on the Randles model represented by specific complex impedance at each cell. We have used the “Least square” method to determine the parameters model using measured reference values. The proposed authentication method is valid for Randles model, but it can be generalized to be applied to others.

Parameters identification of the complex impedance model of the PEM fuel cell using Matlab/Simulink

In this work, we present a new technical method for identifying the complex impedance model parameters of a Proton Exchange Membrane (pEM) Fuel Cell for on-board diagnosis in real time. The study of the PEM Fuel Cell modelling is important in order to understand the physical phenomena that occurring in this green renewable energy source. A diagnosis method is presented by analyzing the behavior of the complex impedance. For this, we present the identification method of the various complex impedance parameters; this identification is based on mathematical methods using the least squares method and the interpolation analysis method. The results are obtained using Matlab/Simulink tools and allow us to validate the electrical model of the complex impedance. These results validate a modelling method for a rapid and real-time diagnosis of the PEM Fuel Cell complex impedance.

The frequency behavior of the electrochemical model fuel cell by impedance spectroscopy

This paper discusses the frequency behavior of the impedance model fuel cell using the spectroscopy method. We used the “EIS Spectrum Analyser” software to view the influence of the different electrochemical components in the frequency domain. The frequency behavior is deducted by the Bode diagram or by the Nyquist plot. In this work, I focused on the impedance spectrum found by the Nyquist diagram. The form of the different models used in this work is found based on the deducted results for a certain frequency range and other defined parameters.

The effects of the different auxiliaries on the performance of PEM fuel cell

The work presents in this paper concerns the studies of the effects of the different auxiliaries on the performance of PEMFC and to control this auxiliaries (incoming hydrogen and oxygen flows to its electrodes, the temperature, the humidifier....). The aim is to highlight the bond graph approach to present a PEM fuel cell model. The adopted control is conventional based on a PID and PI regulator. This approach tries to describe the presented simulation results mathematically in order to develop control strategies for incoming gas flows, optimal temperature and performance improvement.

The bond graphs to the study of interactions between the PEM fuel cell and static converters

The fuel cells are commonly used in many applications. A deep knowledge of the fuel cells functioning system is a necessity for power electronics engineers. This paper offers a theoretical and experimental study of the fuel cells behavior connected to static Converter. The aim of this work is to highlight the bond graph representation in order to study the interactions between the fuel cell type Proton Exchange Membrane (PEMFC) and static Converters (boost and buck converter) based on models developed under 20-sim.

A comparative study between a 20-sim and a Simulink single PEM cell model

This paper presents the development of a cell models for proton exchange membrane (PEM) fuel cell. The models have been implemented in MATLAB/SIMULINK and 20-sim environments. A comparative study was carried out in this manuscript between a Simulink and bond graph model of a 200-W stack (Electrochem Inc.) PEM cell, in order to understand its voltage behavior. After an overview of its operation, this paper proposes a PEM cell model supplied with pure hydrogen and oxygen. This model takes into account physico-chemical, electrochemical and thermal phenomena that can be found in a PEMFC. We propose a static model with dissociated electrodes which involves classical laws to describe the different phenomena in a stack. In essence, this model is directly implanted, firstly, under Matlab-Simulink, secondly under 20-sim software. The implementations are described. The given comparative study between the different modeling approaches is given to show the great advantages of the bond graph approach in the design process of fuel cell systems.