Abdoul N'Diaye

Energy efficiency and fault tolerance comparison of DC/DC converters topologies for fuel cell electric vehicles

Due to low DC voltage generated from fuel cell, a DC/DC converter must be used to interface fuel cell and DC bus in automotive applications such as fuel cell electric vehicles (FCEVs). Furthermore, the occurrence of power semiconductors failures in DC/DC converter has negative effects both for fuel cell and DC/DC converter and consequently on the whole powertrain. The purpose of this paper is to show and analyze the impacts of power semiconductors faults on energy efficiency and waveforms (e.g. FC and DC bus voltages, FC current) without modifying the topology and control. Besides, it has been chosen to focus this study on two topologies of interleaved DC/DC converters enabling to take into consideration the requirements of FCEV applications. These topologies have the capacity compared with the boost topology to operate even in case of faults, ensuring consequently a continuity of service.

Interactions between fuel cell and DC/DC converter for fuel cell electric vehicle applications: Influence of faults

Over the last few decades, the proton exchange membrane fuel cell (PEMFC) has been named by public and private researchers as excellent candidate for automotive applications with a high degree of autonomy and zero pollutant emissions (gases, noise). However, before the commercialization of fuel cell electric vehicles (FCEV), some challenging issues remain to be solved, especially the reliability of power trains in case of faults. In this perspective, the purpose of this paper is to study the influence of faults on the interactions between fuel cell and DC/DC converter. The main contribution of this work is to study different faults which could occur during the operation both for FC and DC/DC converter.

Equivalent consumption minimization strategy for hybrid electric vehicle powered by fuel cell, battery and supercapacitor

This paper describes a novel equivalent consumption minimization strategy (ECMS) for a fuel cell hybrid electric vehicle. The vehicle is composed of a fuel cell as main energy source, batteries and supercapacitors as peaking power sources. Through using fuel cell efficiency penalty coefficient, battery SOC coefficient and supercapacitor SOC coefficient, the designed new strategy aims to operate the fuel cell system at its best efficiency point, the battery as a long term energy buffer and supercapacitor to supply peak power. Considering the characteristic differences between battery and supercapacitor, different SOC penality coefficients are set to full play the potential of batterys large storage ability and supercapacitors fast charge/discharge power. The proposed energy management is validated by simulation using driving cycle with urban pattern.

Fault-tolerant control for PEMFC and its DC/DC converter

Over the last decade, fault-tolerance has gained a growing interest from the scientific community, particularly for Proton Exchange Membrane Fuel Cell (PEMFC) and its DC/DC converter. Fault-tolerance has two main objectives: provide high-level improvement in system availability and lead to substantial reduction in maintenance costs. Generally, fault-tolerance refers to a Fault-Tolerant System (FTS) and/or Control (FTC). PEMFC and its DC/DC converter must respond to challenging issues for stationary and automotive applications, in terms of reliability. Indeed, the unavailability of the current Fuel Cell System (FCS) stops to market these components on a large scale. In PEMFCs, the Membrane Electrode Assembly (MEA) can be subjected to different failures: membrane break, internal gas leakage, cell flooding or drying, poisoning of the catalyst areas... By comparison, in DC/DC converters, power switches ranked the most delicate components. Once the failure has been detected, FCS stop must be avoided. In order to ensure the availability of the FCS and/or to minimize the undesirable effects of degraded operating mode on FCS, FTS and FTC must be used. This paper presents a FTC applied to the DC/DC converter in case of drying membrane failure in PEMFC. The FTC consists in degrading the converter performances through its control in order to bring back the PEMFC in an optimum operating condition. The developed FTC is implemented experimentally on a MicroAutoBox. The obtained experimental results demonstrate the efficiency of the FTC to improve the performances of the PEMFC.