Arnaud Gaillard

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.

Part-load control stategy of a 20kW SiC power converter for embedded PEMFC multi-stack architectures

This paper deals with the integration of the electric power-conditioning interface to the Fuel Cell (FC) module for embedded electric power generation. Specifically, the current study aims to propose an adequate control strategy to achieve a high efficiency of a compact 20kW DC/DC PEMFC output multiphase converter based on new wide-bandgap technology devices. The proposed control strategy is based on the part-load approach fulfilling demanding specifications such as low input current ripple, high performances of the converter over the load power range and small losses enabling the simplification of the cooling circuit.

6-Phase Soft-Switching Interleaved Boost Converter Based on SiC Semiconductor for Fuel Cell Vehicles

This paper deals with the design of a DC/DC boost converter aimed at Fuel Cell Vehicle (FCV) application. In order to extend the FC lifespan and to increase the reliability, efficiency and power density, a DC/DC boost converter should be designed with the following features: low current ripple, low weight, low volume, and high redundancy. In this study, a 6-phase Interleaved Boost Converter (IBC) is firstly chosen to satisfy the above requirements. Then, in order to further decrease the power losses of the system, power switches based on Silicon Carbide semiconductors and simple auxiliary circuits for soft-switching have been adopted.

Switch short-circuit fault detection algorithm based on drain-to-source voltage monitoring for a fault tolerant DC/DC converter

Switch Short-Circuit Fault (SSCF) is one of the most harmful failure mode in a DC-DC Converter. As a consequence, the earliest identification should be ensured in order to avoid the shutdown of the whole system. In this paper, a fast and simple method is introduced for detecting and identifying the faulty leg caused by a SSCF in a six-phase Interleaved Boost Converter (IBC) for Fuel Cell Vehicle application. The proposed detection technique is based on a comparison between the power MOSFET Drain-to-Source Voltage VDS in ON state with an adjustable threshold voltage VDS-ON-TH by using only control pulses and driver information. After the fault detection, and its isolation, remedial actions by control reconfiguration methodology are applied to allow the DC-DC converter to operate in pre-fault conditions. To confirm the effectiveness of the suggested approach, simulation tests are reported using Matlab/Simulink© and ANSYS/Simplorer©. Also, comparative study between the developed voltage-based method and current-based method is provided by numerical simulations. The results obtained by the proposed method indicate that the SSCF can be detected not only in switch ON state but also in OFF state by adding some modifications to the proposed algorithm. In switch OFF state, the results prove similar behavior detection time for both the methods which detects fault occurrence in less than one switching period. By contrast, for the ON state, the proposed method detects the failure for a 100 kHz frequency using the voltage information provided by the driver. The advantage of this method is that the detections are valid in both states (ON and OFF), the suggested algorithm is simple, and easily configurable.