Observer-Based Air Excess Ratio Control of a PEM Fuel Cell System via High-Order Sliding Mode

Abstract

This paper deals with a high-order sliding mode (HOSM) approach to the observer-based output feedback control of a proton exchange membrane (PEM) fuel cell (FC) system consisting of a compressor, a supply manifold, an FC stack, and a return manifold. The treatment is based on a lumped parameter nonlinear modeling of the PEM FC system under study. The suggested scheme assumes the availability for measurements of readily accessible quantities such as the compressor angular velocity, the load current, and the supply and return manifold pressures. The control task is formulated in terms of regulating the oxygen excess ratio (which is estimated by a nonlinear finite-time converging HOSM observer) to a suitable set-point value by using, as adjustable input variable, the compressor supply voltage. The proposed observer embeds an original synergic combination between second-and third-order sliding mode (SM) algorithms. The controller also uses a second-order SM algorithm complemented by a novel tuning procedure, supported by local linearization and frequency-domain arguments, which allows the designer to enforce a practical SM regime with some prespecified and user-defined characteristics. Thoroughly discussed simulations results certify the satisfactory performance of the proposed approach.Index Terms-Fuel cell (FC), observer-based output feedback, oxygen starvation, sliding mode (SM) control. 0278-0046

Modeling, Diagnosis, and Control of Fuel-Cell-Based Technologies and Their Integration in Smart Grids and Automotive Systems

“…Modelling & System Diagnosis [1], [2], [3], [4] Management & Control [5], [6], [7], [8], [9], [10], [11], [12] Monitoring & Observation [13], [14], [15], [16], [17] PEMFC-based Setups [1], [2], [3], [4], [8], [10], [12], [13], [14], [15] Other Configuration Setups [7], [9], [11] recent and relevant advances in control-oriented modeling and validation, system diagnosis and advanced control design of complex energy conversion systems based on fuel cells. Moreover, the Special Section is also focused on providing the researchers and engineers with the state-of-art research and guidelines in these important fields for the next years.…”

“…Innovative approaches in the field of control design based on sampled-data passivity [5], model predictive control (MPC) [6], interval-based sliding mode control (SMC) [7], ditterless extremum seeking [8], economic MPC [9] and high-order SMC [10] are reported and further discussed for different PEM fuel-cell-based systems as well as other configuration setups such as microgrids. Moreover, advanced topics on energy management also applied to hybrid systems are reported [11].…”

Control of the Air Supply Subsystem in a PEMFC with Balance of Plant Simulation

“…But a major concern in the system management is the air supply subsystem; herein the problems of oxygen excess ratio regulation, equalization of anode and cathode pressures and water management control are essentially addressed in PEMFC control studies using a variety of techniques, e.g., nonlinear model-based predictive control of gas pressures was applied to deal with different events of errors in PEMFC systems, along with several types of dynamic load changes [9,10]. It has been acknowledged that oxygen excess ratio control is one of the most important actions to enhance protection and performance of fuel cells; thus, well-suited control strategies with this target have been proved, three related works are the following: a sliding mode control achieved by adjusting the compressor supply voltage was assisted with a nonlinear observer predicting the oxygen excess ratio and improved with a novel tuning procedure [11]. In a second work, a feedforward fuzzy-PID control was proposed; the model used for designing the oxygen excess ratio controller included cathode and anode mass flow transients, membrane hydration dynamics, as well as the fuel cell BOP simulation [12], the controller was developed to adapt the PID parameters to achieve the regulation of the air flow rate using on-line fuzzy logic optimization loop.…”

Nonlinear observation in fuel cell systems: A comparison between disturbance estimation and High-Order Sliding-Mode techniques

“…Other works present the nonlinear observation of the inlet hydrogen and oxygen flows through the measurement of the input and output manifold pressures of the PEMFC [12,13]. Measuring the compressor rotational speed and the pressures in the cathode inlet and outlet manifolds, the oxygen excess ratio in the fuel cell is observed in [14] and its observed value is used in a feedback control loop.…”