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International audience; The device-level description of power switches is an emerging topic that enhances the real-time simulation (RTS) accuracy of power electronic converters. However, device-level RTS (DLRTS) is challenging due to contradictions between the additional computing amounts introduced by nonlinear switch models and the nanosecond-level simulation time step required by fast switching transients. Therefore, much research has sought the tradeoff between the accuracy and speed in DLRTSs. In this article, we review state-of-the-art DLRTS technologies, in particular for device-level switch models and efficient network solvers. Moreover, we summarize different applications of DLRTSs and crosswise compare their performances. We also give some outlooks on future research. This review not only provides a comprehensive overview of DLRTSs for general audiences but also provides a technical reference for practitioners. See "A List of Acronyms Used in This Article" for relevant acronyms and their definitions.

International audience; This paper presents a multi-physical modeling of a 2D reversible tubular solid oxide cell. The developed model can represent both a solid oxide electrolysis cell (SOEC) and solid oxide fuel cell (SOFC) operations. By taking into account of the electrochemical, fluidic and thermal physical phenomena, the presented model can accurately describe the multi-physical effects inside a cell for both fuel cell and electrolysis cell operation under entire working range of cell current and temperature. In addition, an iterative solver is proposed which is used to solve the 2D distribution of physical quantities along the tubular cell. The proposed model is suitable for embedded applications such as real-time simulation or online diagnostic control. The reversible solid oxide cell model is then validated experimentally in both SOEC and SOFC configurations under different species partial pressures, operating temperatures and current densities conditions.

International audience; This paper presents a multi-physical model for a micro tubular solid oxide fuel cell (SOFC) using syngas as fuel. The proposed control oriented syngas fuel cell model includes both hydrogen and carbon monoxide co-oxidation phenomena and is demonstrated through the electrochemical, fluidic and thermal dynamic characteristics of the fuel cell. The developed model is validated experimentally under different operating conditions regarding different reaction temperatures, species partial pressures and entire working range of current densities. As an important part of the model, the co-oxidation phenomenon of hydrogen and carbon monoxide is discussed in details. The developed model can be used in embedded applications like real-time simulation, which can help to design and test the control and online diagnostic strategy for fuel cell power generation system in the industrial applications

International audience; This paper presents a computationally efficient 2-D steady-state model for fuel cell real-time control implementation. Both the fluid and electrochemical physical domains are considered in the proposed real-time model. The fuel cell under-rib convection is fully described by considering the geometry of serpentine channel. In addition, in order to solve the implicit activation voltage loss, and further explore the computational performance, three numerical root-searching algorithms: bisection, secant and Newton-Raphson methods are respectively applied to the proposed implicit iterative solver and compared. The preferred secant method has been proven to effectively improve both the efficiency and robustness performance of the proposed real-time fuel cell model. Moreover, a CFD-based COMSOL fuel cell model is used to validate the calculation accuracy. Furthermore, the practical feasibility of the presented real-time model has been verified using a RT-LAB simulator platform from Opal-RT.

International audience; This paper presents a novel 2-D real-time modeling approach for a proton exchange membrane fuel cell (PEMFC) based on a tridiagonal matrix algorithm (Thomas algorithm). The Thomas algorithm consists of a forward elimination and a backward substitution, its arithmetic complexity of computations being much lower than the Gaussian elimination. In order to use this advanced numerical solver, the differential equations of reactant gas convection and diffusion phenomena in serpentine channels are transformed into a tridiagonal equations system. In addition, a three levels bisection algorithm has been developed to solve spatial physical quantities distribution for electrochemical domain. The real-time computing methods developed in this paper are then implemented in C language for a fast execution time in real-time processor. The proposed real-time model is experimentally validated using a 1.2kW Ballard NEXA fuel cell system, and its practical feasibilities in advanced real-time control for PEMFC systems have been experimentally demonstrated in a RT-LAB real-time simulator.

FDFC 2017, 7th International Conference on Fundamentals & Development of Fuel Cells,, STUTTGART, ALLEMAGNE, 31-/01/2017 - 02/02/2017; In automotive application, polymer electrolyte membrane fuel cells (PEMFCs) are operated through dynamic working conditions. Dynamic driving cycles are mainly composed by cold starting, sudden load variations, continuous load running, idle running, full power running, overload running, and start-stop repetitions [1-2]. These conditions if operated for long-time can severely impact the PEMFC lifetime. To solve this problem, a power balance strategy related to a PEMFC-battery hybrid structure is usually considered to improve the PEMFC durability [3]. As a result of the power balance strategy based on the battery state of charge optimization, a more beneficial quasi-static load profile is commonly obtained for the PEMFC operations. The aim of this work is to observe the effects of the quasi-static load profile on the PEMFC degradation. To this purpose a quasi-static reference profile was developed to separately investigate the impacts of both stationary conditions and load variations (from 0 h to 408 h) and start-stop conditions (from 408 h to 792 h) on the stack voltage degradation. A stack voltage reduction was observed after 408 h of operation, where the impact of the load variation was tested. Subsequently, the first recovering was found. Test results after 792 h also showed the start-stop impact on the stack voltage degradation. Particularly, considering the voltage variation with respect to the cumulated energy an higher voltage slope can be observed. An accelerated load profile was finally developed to study the influence of the number of repetitions in both load and start-stop cycles on the PEMFC voltage degradation; the results are then compared. Both reference and accelerated load profiles are reported below.

International audience; A current-fed full-bridge bidirectional voltage doubler with secondary-assisted device voltage clamping and zero current commutation is proposed for fuel cell vehicles (FCVs). The proposed topology is suitable for interfacing energy storage and/or fuel cell stack with dc bus in FCVs. Voltage doubler on secondary side is selected to enhance the gain by 2x, reduce transformer size, and efficiently reduce the low frequency dc current harmonics. Parasitics based zero voltage switching (ZVS), secondary based zero current switching (ZCS) of low voltage side devices and ZVS of secondary devices are achieved. Proposed secondary modulation technique naturally clamps the voltage across the primary side devices with zero current commutation, thus eliminating the necessity for traditional active-clamp or passive snubbers. Switching losses are reduced owing to softswitching of all semiconductor devices. Steady state analysis and design are studied and explained. Experimental results of a 1kW proof-of-concept hardware prototype are shown to demonstrate the performance and confirm the proposed claims.