Design and experimental verification of a fuel cell/supercapacitor passive configuration for a light vehicle

The fuel cell/supercapacitor passive configuration without using any DC/DC converters is promising in auto-motive applications as it can downsize the fuel cell stack, maintain the peak power capability, improve the system efficiency, and remove the need of additional control. This paper presents the design and characterization of a fuel cell/supercapacitor passive hybrid system for a 60 V light vehicle. A detailed design procedure for the passive hybrid test platform is presented with each component modelled and experimentally verified. The voltage error of the fuel cell and the supercapacitor model in the steady state is within 2% and 3%, respectively. Experimental results also validate the function of the passive configuration under conditions of a step load and a drive cycle. The simulation model of the passive hybrid system matches the measurements when a step load current is applied. The supercapacitor provides the transient current due to its smaller resistance while the fuel cell handles the steady state current, which makes it possible to downsize the fuel cell stack. For the drive cycle examined in this paper, the fuel cell stack can be downsized to one third of the load peak power

Optimized energy management strategies and sizing of hybrid storage systems for transport applications

205 p. El contenido del capítulo 4, sección 4.3 está sujeto a confidencialidad.Esta tesis doctoral aborda la temática acerca del óptimo dimensionamiento y operación de sistemashíbridos de almacenamiento de energía (HESS), combinando baterías y supercapacitores, con el objetivode ser integrados en vehículos para movilidad pública en entornos urbanos. Por una parte, se propone unainnovadora estrategia energética, basada en lógica difusa, para gestionar la división de la demanda depotencia entre las fuentes de energía disponibles a bordo del vehículo. La estrategia adaptativa que sepropone evalúa la información energética actual y futura (estimada) para adaptar, de una formaoptimizada y eficiente, la operación del sistema con el objetivo de mejorar el aprovechamiento de laenergía almacenada en los recursos a bordo del vehículo.Por otro lado, se ha propuesto una metodología para la co-optimización de la estrategia de gestión ydimensionamiento del HESS. Esta metodología de optimización evalúa tanto técnica comoeconómicamente las posibles soluciones mediante un problema multi-objetivo basado en algoritmosgenéticos. Para determinar el costo de reemplazo del HESS han sido aplicados modelo de envejecimientoy estimación de vida y se ha considerado la vida útil del vehículo.Con el objetivo de validar la propuesta de esta tesis doctoral, dos casos de estudio relevantes en latransportación pública han sido seleccionados: Tranvía Eléctrico Híbrido y Autobús Eléctrico Híbrido

An adaptive power split strategy with a load disturbance compensator for fuel cell/supercapacitor powertrains

Electric vehicles powered by fuel cell and supercapacitor hybrid power sources are of great interest. However, the power allocation between each power source is challenging and the DC bus voltage fluctuation is relatively significant in cascaded PI control schemes. This paper develops a power control strategy with an adjustable cut-off frequency, using an artificial potential field, to adaptively split the load current between the fuel cell and the supercapacitor under various load conditions. The adaptive cut-off frequency is calculated by cutting the load frequency spectrum with an allocation ratio that changes with the supercapacitor state of charge. Therefore, the relatively lower frequency portion of the load current is provided by the fuel cell and the supercapacitor handles the higher frequency portion. To enhance the control performance of the DC bus voltage regulation against the load disturbance, a load disturbance compensator is introduced to suppress the DC bus voltage fluctuation when the load variation occurs, which is implemented by a feed-forward controller that can compensate the load current variation in advance. The effectiveness of the proposed strategy is validated by extensive experiments

Insights for Industry 4.0 Applications into a Hydrogen Advanced Mobility

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Energy management strategies for fuel cell vehicles: A comprehensive review of the latest progress in modeling, strategies, and future prospects

Fuel cell vehicles (FCVs) are considered a promising solution for reducing emissions caused by the transportation sector. An energy management strategy (EMS) is undeniably essential in increasing hydrogen economy, component lifetime, and driving range. While the existing EMSs provide a range of performance levels, they suffer from significant shortcomings in robustness, durability, and adaptability, which prohibit the FCV from reaching its full potential in the vehicle industry. After introducing the fundamental EMS problem, this review article provides a detailed description of the FCV powertrain system modeling, including typical modeling, degradation modeling, and thermal modeling, for designing an EMS. Subsequently, an in-depth analysis of various EMS evolutions, including rule-based and optimization-based, is carried out, along with a thorough review of the recent advances. Unlike similar studies, this paper mainly highlights the significance of the latest contributions, such as advanced control theories, optimization algorithms, artificial intelligence (AI), and multi-stack fuel cell systems (MFCSs). Afterward, the verification methods of EMSs are classified and summarized. Ultimately, this work illuminates future research directions and prospects from multi-disciplinary standpoints for the first time. The overarching goal of this work is to stimulate more innovative thoughts and solutions for improving the operational performance, efficiency, and safety of FCV powertrains

Optimized energy management strategies and sizing of hybrid storage systems for transport applications

205 p. El contenido del capítulo 4, sección 4.3 está sujeto a confidencialidad.Esta tesis doctoral aborda la temática acerca del óptimo dimensionamiento y operación de sistemashíbridos de almacenamiento de energía (HESS), combinando baterías y supercapacitores, con el objetivode ser integrados en vehículos para movilidad pública en entornos urbanos. Por una parte, se propone unainnovadora estrategia energética, basada en lógica difusa, para gestionar la división de la demanda depotencia entre las fuentes de energía disponibles a bordo del vehículo. La estrategia adaptativa que sepropone evalúa la información energética actual y futura (estimada) para adaptar, de una formaoptimizada y eficiente, la operación del sistema con el objetivo de mejorar el aprovechamiento de laenergía almacenada en los recursos a bordo del vehículo.Por otro lado, se ha propuesto una metodología para la co-optimización de la estrategia de gestión ydimensionamiento del HESS. Esta metodología de optimización evalúa tanto técnica comoeconómicamente las posibles soluciones mediante un problema multi-objetivo basado en algoritmosgenéticos. Para determinar el costo de reemplazo del HESS han sido aplicados modelo de envejecimientoy estimación de vida y se ha considerado la vida útil del vehículo.Con el objetivo de validar la propuesta de esta tesis doctoral, dos casos de estudio relevantes en latransportación pública han sido seleccionados: Tranvía Eléctrico Híbrido y Autobús Eléctrico Híbrido

Hybrid power management for fuel cell-supercapacitor powered hybrid electric vehicle

Fuel cell (FC) with a combination of supercapacitor (SC) based hybrid electric vehicles have been regarded as a potential solution in the future transportation system. This is due to their zero-emission, enhancement of transient power demand, ability to absorb the energy from the regenerative braking, high efficiency, and long mileage. Nevertheless, the nonlinear output characteristics of the FC system are a feeble point owing to internal constraints such as membrane water content and cell temperature. Hence it is essential to extricate as much power as possible from the stack to avert excessive fuel usage and low system efficiency. Conversely, despite the advantages of the SC as an auxiliary energy storage system, the series connection of SC cells causes a cell imbalance problem due to uneven cell characteristics that occur during the manufacturing process and its ambient conditions. This discrepancy of cell voltages in a supercapacitor module leads to reduce the stack’s efficiency and its lifetime. Furthermore, the above limitations of the power sources and initial state of SC’s charge affect the power management’s distribution of power among the multiple sources. Therefore, the aim of this thesis is to propose a hybrid power management for fuel cell-supercapacitor powered hybrid electric vehicles to solve the three identified problems. Firstly, this thesis focuses on a maximum power point tracking (MPPT) controller with a modified 4-leg interleaved boost converter (M-FLIBC) topology for the FC system. The effectiveness of the proposed IBC with a controller for the FC is compared with the two additional controllers couples with the conventional FLIBC topology. Next, a global modular balancer for voltage balancing of multiple supercapacitor cells is connected in series for an HEV system. The global modular balancing architecture is proposed based on forward conversion, which integrates cell balancing, module balancing, and operating for different frequencies. Thus, greatly reducing the volume and implementation complexity. Finally, the thesis evaluates hybrid power management (HPM) for effective power sources distribution, in order to reduce hydrogen consumption and enhance the vehicle's fuel economy. In this case, an equivalent circuit model of SC is developed for the energy storage system. The combination of an extended Kalman filter (EKF) and traditional coulomb counting (CC) method is used to estimate the SC state of charge in improving the effectiveness of the HPM. To evaluate the fuel economy under realistic driving conditions, the combined environmental protection agency (EPA) test cycles for a city and highway are considered. The outcome of performance comparison of the different controllers based on MPPT technique in terms of voltage, current, power, settling time, and efficiency of the FC indicates that the radial basis function network (RBFN) based MPPT controller with the M-FLIBC outperforms the PID and Fuzzy based controllers. With respect to controlling of SC in HEV environment, the proposed topology of SC presents effective voltage balancing with a lower component count, able to operate at different frequencies, i.e., 10 to 70 kHz, as well opens to unlimited stackable modular numbers of SC cells for the HEV performance analysis. Ultimately, with all the proposed control topologies and combined EKF-CC based power management for the FC-SC in Series HEV, the vehicle's fuel economy is increased to 93.38 km/kg as compared to traditional CC based power management of 86.53 km/kg, besides it improves the vehicle’s acceleration within 0-100 km/h in 9.0 seconds respectively. Finally, the research shows that the hybrid power management of FC and SC powered HEV leads to improved performance of the vehicle in terms of the key measures. Suggestions for future research are also highlighted

Toward Holistic Energy Management Strategies for Fuel Cell Hybrid Electric Vehicles in Heavy-Duty Applications

The increasing need to slow down climate change for environmental protection demands further advancements toward regenerative energy and sustainable mobility. While individual mobility applications are assumed to be satisfied with improving battery electric vehicles (BEVs), the growing sector of freight transport and heavy-duty applications requires alternative solutions to meet the requirements of long ranges and high payloads. Fuel cell hybrid electric vehicles (FCHEVs) emerge as a capable technology for high-energy applications. This technology comprises a fuel cell system (FCS) for energy supply combined with buffering energy storages, such as batteries or ultracapacitors. In this article, recent successful developments regarding FCHEVs in various heavy-duty applications are presented. Subsequently, an overview of the FCHEV drivetrain, its main components, and different topologies with an emphasis on heavy-duty trucks is given. In order to enable system layout optimization and energy management strategy (EMS) design, functionality and modeling approaches for the FCS, battery, ultracapacitor, and further relevant subsystems are briefly described. Afterward, common methodologies for EMS are structured, presenting a new taxonomy for dynamic optimization-based EMS from a control engineering perspective. Finally, the findings lead to a guideline toward holistic EMS, encouraging the co-optimization of system design, and EMS development for FCHEVs. For the EMS, we propose a layered model predictive control (MPC) approach, which takes velocity planning, the mitigation of degradation effects, and the auxiliaries into account simultaneously