arXiv subjects

Mostafaali Ayubirad

Publications and source records attributed to Mostafaali Ayubirad.

4 recordsLinked to original sources

arXiv2025

Comprehensive Dynamic Modeling and Constraint-Aware Air Supply Control for Localized Water Management in Automotive Polymer Electrolyte Membrane Fuel Cells

In this paper, a predictive constraint-aware control scheme is formulated within the Command Governor (CG) framework for localized hydration management of a proton exchange membrane (PEM) fuel cell system. First, a comprehensive nonlinear dynamic model of the fuel cell system is presented which includes a pseudo 2-dimensional (P2D) model of the stack, reactant supply and cooling subsystems. The model captures the couplings among the various subsystems and serves as the basis for designing output feedback controllers to track the optimal set-points of the air supply and cooling systems for power optimization. The closed-loop nonlinear model is then used to analyze the dynamic behavior of membrane hydration near the anode inlet, the driest region of the membrane in a counter-flow configuration, under various operating conditions. A reduced-order linearized model is then derived to approximate hydration behavior with sufficient fidelity for constraint enforcement. This model is used within the CG framework to adjust the air supply set-points when necessary to prevent membrane dry-out. The effectiveness of the proposed approach in maintaining local membrane hydration while closely tracking the requested net power is demonstrated through realistic drive-cycle simulations.

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arXiv2025

A Neural Network-based Multi-timestep Command Governor for Nonlinear Systems with Constraints

The multi-timestep command governor (MCG) is an add-on algorithm that enforces constraints by modifying, at each timestep, the reference command to a pre-stabilized control system. The MCG can be interpreted as a Model-Predictive Control scheme operating on the reference command. The implementation of MCG on nonlinear systems carries a heavy computational burden as it requires solving a nonlinear program with multiple decision variables at each timestep. This paper proposes a less computationally demanding alternative, based on approximating the MCG control law using a neural network (NN) trained on offline data. However, since the NN output may not always be constraint-admissible due to training errors, its output is adjusted using a sensitivity-based method. We thus refer to the resulting control strategy as the neural network-based MCG (NN-MCG). As validation, the proposed controller is applied as a load governor for constraint management in an automotive fuel cell system. It is shown that the proposed strategy is significantly more computationally efficient than the traditional MCG, while achieving nearly identical performance if the NN is well-trained.

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arXiv2025

A Machine Learning-Based Reference Governor for Nonlinear Systems With Application to Automotive Fuel Cells

The prediction-based nonlinear reference governor (PRG) is an add-on algorithm to enforce constraints on pre-stabilized nonlinear systems by modifying, whenever necessary, the reference signal. The implementation of PRG carries a heavy computational burden, as it may require multiple numerical simulations of the plant model at each sample time. To this end, this paper proposes an alternative approach based on machine learning, where we first use a regression neural network (NN) to approximate the input-output map of the PRG from a set of training data. During the real-time operation, at each sample time, we use the trained NN to compute a nominal reference command, which may not be constraint admissible due to training errors and limited data. We adopt a novel sensitivity-based approach to minimally adjust the nominal reference while ensuring constraint enforcement. We thus refer to the resulting control strategy as the modified neural network reference governor (MNN-RG), which is significantly more computationally efficient than the PRG. The computational and theoretical properties of MNN-RG are presented. Finally, the effectiveness and limitations of the proposed method are studied by applying it as a load governor for constraint management in automotive fuel cell systems through simulation-based case studies.

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arXiv2025

Modeling and Constraint-Aware Control of Pressure Dynamics in Water Electrolysis Systems

This paper addresses the challenge of pressure constraint violations in water electrolysis systems operating under dynamic power conditions, a problem common to both Proton Exchange Membrane and alkaline technologies. To investigate this issue, a control-oriented model of an alkaline electrolyzer is developed, capturing key pressure and flow dynamics. To manage rapid power fluctuations that may cause pressure to exceed manufacturer-defined operational boundaries, a model-based constraint-aware power governor based on the Reference Governor (RG) framework is proposed. Simulation results show that the strategy effectively maintains pressure within the specified operating range, outperforming conventional filtering methods while enhancing hydrogen production and reducing auxiliary energy consumption.

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