Auto-Tuning Control of PEM Water Electrolyzer with Self-Assessment and Gain Scheduling

2020 ◽  
Author(s):  
Alicia Keow ◽  
Zheng Chen
Keyword(s):  
Metal Hydride ◽  
Transient Behavior ◽  
Gain Scheduling ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Self Assessment ◽  
Set Point ◽  
Model Free ◽  
Pem Electrolyzer ◽  
Auto Tuning

Abstract Proton exchange membrane (PEM) electrolyzer with the ability to produce gases at the pressure suitable for direct storage into metal hydride cylinders allows bypassing of compressors and other auxiliary components. For direct storage into metal hydride containers, hydrogen gas's pressure and flow rate must be well controlled. However, the PEM electrolyzer's time-variant and nonlinear dynamics call for an adaptive control to maintain its output performance. Therefore, in this paper, a model-free relay-feedback auto-tuning approach is proposed to tune a proportional-integral (PI) controller online. The controller determines the voltage supply to the electrolyzer to track a certain current set-point, which corresponds to a constant hydrogen production rate. A gain scheduling approach is developed to pick up the right controller gain at different set-points, minimizing the tuning frequency. A self-assessment algorithm is developed to determine the situations where the auto-tuner should activate to update the PI parameters, thus allowing the control system to be tuned autonomously. The auto-tuning PI control is successfully tested with a PEM electrolyzer setup. Experiment results showed that auto-tuner with gain scheduling could tune the controller parameters producing a desired transient behavior and is adaptive to the variations in set-point and operating conditions.

Auto-Tuning Control of PEM Water Electrolyzer

2019 ◽  
Author(s):  
Alicia Keow ◽  
Zheng Chen
Keyword(s):  
Hydrogen Production ◽  
Production Rate ◽  
Metal Hydride ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Hydrogen Production Rate ◽  
Relay Feedback ◽  
Model Free ◽  
Pem Electrolyzer ◽  
Auto Tuning

Abstract Proton exchange membrane (PEM) electrolyzers with the ability to produce gases at a pressure suitable for direct metal hydride storage are desirable because they do not require the use of compressors and other auxiliary components. Direct storage into metal hydride cylinders is made feasible when the pressure and flow rate of hydrogen is controlled. The nonlinear dynamics of the PEM electrolyzer change with temperature and pressure, both of which change with the hydrogen production rate, and are thus difficult to estimate. Therefore, a model-free, relay-feedback, auto-tuning approach is used to tune a proportional integral (PI) controller. This allows for the determination of the voltage supply to the electrolyzer by tracking the current set-point and correlating it to the hydrogen production rate. A gain scheduling approach is used to record the tuned controller’s parameters at different set-points, minimizing the frequency of tuning the device. A self-assessment test is used to determine situations where the auto-tuner should activate to update the PI parameters, thus, allowing for the system to operate without supervision. The auto-tuning PI control is successfully tested with a PEM electrolyzer setup. Experimental results showed that an auto-tuner can tune the controller parameters and produce favorable transient behaviors, allowing for a degree of adaptability for variations in system set-points.

scholarly journals Faraday’s Efficiency Modeling of a Proton Exchange Membrane Electrolyzer Based on Experimental Data

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4792 ◽  
Author(s):  
Burin Yodwong ◽  
Damien Guilbert ◽  
Matheepot Phattanasak ◽  
Wattana Kaewmanee ◽  
Melika Hinaje ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrogen Pressure ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Gas Pressure ◽  
Operating Conditions ◽  
Mechanical Resistance ◽  
Pem Electrolyzer ◽  
Hydrogen Crossover ◽  
Exchange Membrane

In electrolyzers, Faraday’s efficiency is a relevant parameter to assess the amount of hydrogen generated according to the input energy and energy efficiency. Faraday’s efficiency expresses the faradaic losses due to the gas crossover current. The thickness of the membrane and operating conditions (i.e., temperature, gas pressure) may affect the Faraday’s efficiency. The developed models in the literature are mainly focused on alkaline electrolyzers and based on the current and temperature change. However, the modeling of the effect of gas pressure on Faraday’s efficiency remains a major concern. In proton exchange membrane (PEM) electrolyzers, the thickness of the used membranes is very thin, enabling decreasing ohmic losses and the membrane to operate at high pressure because of its high mechanical resistance. Nowadays, high-pressure hydrogen production is mandatory to make its storage easier and to avoid the use of an external compressor. However, when increasing the hydrogen pressure, the hydrogen crossover currents rise, particularly at low current densities. Therefore, faradaic losses due to the hydrogen crossover increase. In this article, experiments are performed on a commercial PEM electrolyzer to investigate Faraday’s efficiency based on the current and hydrogen pressure change. The obtained results have allowed modeling the effects of Faraday’s efficiency by a simple empirical model valid for the studied PEM electrolyzer stack. The comparison between the experiments and the model shows very good accuracy in replicating Faraday’s efficiency.

scholarly journals Dynamic Emulation of a PEM Electrolyzer by Time Constant Based Exponential Model

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 750 ◽  
Author(s):  
Damien Guilbert ◽  
Gianpaolo Vitale
Keyword(s):  
Dynamic Behavior ◽  
Proton Exchange Membrane ◽  
Exponential Model ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Model Parameters ◽  
Dynamic Operating ◽  
Pem Electrolyzer ◽  
Current Interval

The main objective of this paper is to develop a dynamic emulator of a proton exchange membrane (PEM) electrolyzer (EL) through an equivalent electrical model. Experimental investigations have highlighted the capacitive effect of EL when subjecting to dynamic current profiles, which so far has not been reported in the literature. Thanks to a thorough experimental study, the electrical domain of a PEM EL composed of 3 cells has been modeled under dynamic operating conditions. The dynamic emulator is based on an equivalent electrical scheme that takes into consideration the dynamic behavior of the EL in cases of sudden variation in the supply current. The model parameters were identified for a suitable current interval to consider them as constant and then tested with experimental data. The obtained results through the developed dynamic emulator have demonstrated its ability to accurately replicate the dynamic behavior of a PEM EL.

Partial Impedance Spectroscopy Tests of a 6 kW Proton Exchange Membrane Water Electrolyzer Stack

2010 ◽  
Author(s):  
Taehee Han ◽  
Hossein Salehfar ◽  
Nilesh V. Dale ◽  
Mike D. Mann ◽  
Jivan N. Thakare
Keyword(s):  
High Frequency ◽  
Proton Exchange Membrane ◽  
Low Frequency ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Frequency Range ◽  
Impedance Characteristics ◽  
Pem Electrolyzer ◽  
Exchange Membrane ◽  
Partial Current

Impedance characteristics of a 6 kW proton exchange membrane (PEM) electrolyzer stack are presented under various operating conditions. An electrolyzer stack was operated under room temperature and partial current range (0 to 80 A). The whole stack impedance spectrums were measured by three different power supply configurations. The total sweeping frequency range (0.5 Hz to 20 kHz) is divided into low frequency (0.5 to 20 Hz), middle frequency (20 Hz to 1 kHz), and high frequency (1 to 20 kHz). Each frequency range required a different measurement setup to measure the whole stack impedance data. In this study, the partial impedance spectrums at low and high frequency ranges are successfully measured and analyzed. The measured data is verified with Kramers-Kronig relations. Measurement issues at the middle frequency region are discussed.

scholarly journals Two-Dimensional Dynamic Simulation of Hydrogen Storage in Metal Hydride Tanks

2006 ◽  
Author(s):  
Tim M. Brown ◽  
Jacob Brouwer ◽  
G. Scott Samuelsen ◽  
Franklin H. Holcomb ◽  
Joel King
Keyword(s):  
Hydrogen Storage ◽  
Metal Hydride ◽  
Proton Exchange Membrane ◽  
Dynamic Performance ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Polar Coordinates ◽  
Two Dimensional ◽  
Flow Mechanisms ◽  
Cylindrical Polar Coordinates

As proton exchange membrane fuel cell technology advances, the need for hydrogen storage intensifies. Metal hydride alloys offer one potential solution. However, for metal hydride tanks to become a viable hydrogen storage option, the dynamic performance of different tank geometries and configurations must be evaluated. In an effort to relate tank performance to geometry and operating conditions, a dynamic, two-dimensional, multi-nodal metal hydride tank model has been created in Matlab-Simulink®. Following the original work of Mayer, Groll, and Supper and the more recent paper from Aldas, Mat, and Kaplan, this model employs first principle heat transfer and fluid flow mechanisms together with empirically derived reaction kinetics. Energy and mass balances are solved in cylindrical polar coordinates for a cylindrically shaped tank. The model tank temperature, heat release, and storage volume have been correlated to an actual metal hydride tank for static and transient adsorption and desorption processes. The dynamic model is found to accurately predict observed hardware performance characteristics portending a capability to well simulate the dynamic performance of more complex tank geometries and configurations. As an example, a cylindrical tank filled via an internal concentric axial tube is considered.

Modeling and Analysis of Transient Behavior of Polymer Electrolyte Membrane Fuel Cell Hybrid Vehicles

2006 ◽  
Vol 4 (3) ◽  
pp. 261-271 ◽  
Author(s):  
Ivan Arsie ◽  
Alfonso Di Domenico ◽  
Cesare Pianese ◽  
Marco Sorrentino
Keyword(s):  
Control System ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Dynamic Performance ◽  
Transient Behavior ◽  
Cell System ◽  
Proton Exchange ◽  
Operating Conditions ◽  
State Variables ◽  
Accurate Analysis

The paper focuses on the simulation of a hybrid vehicle with proton exchange membrane fuel cell as the main energy conversion system. A modeling structure has been developed to perform accurate analysis for powertrain and control system design. The models simulate the dynamics of the main powertrain elements and fuel cell system to give a sufficient description of the complex interaction between each component under real operating conditions. A control system based on a multilevel scheme has also been introduced and the complexity of control issues for hybrid powertrains have been discussed. This study has been performed to analyze the energy flows among powertrain components. The results highlight that optimizing these systems is not a trivial task and the use of precise models can improve the powertrain development process. Furthermore, the behavior of system state variables and the influence of control actions on fuel cell operation have also been analyzed. In particular, the effect of introducing a rate limiter on the stack power has been investigated, evidencing that a 2kW∕s rate limiter increased the system efficiency by 10% while reducing the dynamic performance of the powertrain in terms of speed error.

scholarly journals Sensors Integrated Control of PEMFC Gas Supply System Based on Large-Scale Deep Reinforcement Learning

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 349
Author(s):  
Jiawen Li ◽  
Tao Yu
Keyword(s):  
Reinforcement Learning ◽  
Large Scale ◽  
Integrated Control ◽  
Supply System ◽  
Proton Exchange ◽  
Coordination Problem ◽  
Hydrogen Flow ◽  
Model Free ◽  
Integrated Controller ◽  
Gas Supply

In the proton exchange membrane fuel cell (PEMFC) system, the flow of air and hydrogen is the main factor influencing the output characteristics of PEMFC, and there is a coordination problem between their flow controls. Thus, the integrated controller of the PEMFC gas supply system based on distributed deep reinforcement learning (DDRL) is proposed to solve this problem, it combines the original airflow controller and hydrogen flow controller into one. Besides, edge-cloud collaborative multiple tricks distributed deep deterministic policy gradient (ECMTD-DDPG) algorithm is presented. In this algorithm, an edge exploration policy is adopted, suggesting that the edge explores including DDPG, soft actor-critic (SAC), and conventional control algorithm are employed to realize distributed exploration in the environment, and a classified experience replay mechanism is introduced to improve exploration efficiency. Moreover, various tricks are combined with the cloud centralized training policy to address the overestimation of Q-value in DDPG. Ultimately, a model-free integrated controller of the PEMFC gas supply system with better global searching ability and training efficiency is obtained. The simulation verifies that the controller enables the flows of air and hydrogen to respond more rapidly to the changing load.

scholarly journals Modelling of Humidity Dynamics for Open-Cathode Proton Exchange Membrane Fuel Cell

2021 ◽  
Vol 12 (3) ◽  
pp. 106
Author(s):  
Fengxiang Chen ◽  
Liming Zhang ◽  
Jieran Jiao
Keyword(s):  
Fuel Cell ◽  
Mass Flow ◽  
Proton Exchange Membrane ◽  
Flow Model ◽  
Transport Theory ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Output Performance ◽  
Exchange Membrane

The durability and output performance of a fuel cell is highly influenced by the internal humidity, while in most developed models of open-cathode proton exchange membrane fuel cells (OC-PEMFC) the internal water content is viewed as a fixed value. Based on mass and energy conservation law, mass transport theory and electrochemistry principles, the model of humidity dynamics for OC-PEMFC is established in Simulink® environment, including the electrochemical model, mass flow model and thermal model. In the mass flow model, the water retention property and oxygen transfer characteristics of the gas diffusion layer is modelled. The simulation indicates that the internal humidity of OC-PEMFC varies with stack temperature and operating conditions, which has a significant influence on stack efficiency and output performance. In order to maintain a good internal humidity state during operation, this model can be used to determine the optimal stack temperature and for the design of a proper control strategy.

Transient Response of Polymer Electrolyte Membrane Fuel Cell to Variations in Operating Parameters

2013 ◽  
Author(s):  
A. Verma ◽  
R. Pitchumani
Keyword(s):  
Fuel Cell ◽  
Transient Response ◽  
Single Channel ◽  
Rapid Change ◽  
Transient Behavior ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Operating Parameters ◽  
Complex Species ◽  
Cyclic Changes

Due to rapid change in loads during automotive applications, study of dynamic behavior of proton exchange membrane (PEM) fuel cells is of paramount importance for their successful deployment in mobile applications. Toward understanding the effects of changes in operating parameters on the transient behavior, this paper presents numerical simulations for a single channel PEM fuel cell undergoing cyclic changes in operating parameters. The objective is to elucidate the complex interaction between power response and complex species (water, hydrogen and oxygen) transport dynamics for applied cyclic changes. This study focuses on studying the transient response of fuel cell for specified changes in operating parameters — voltage, pressure and stoichiometry at the cathode and the anode. Numerical studies are carried out on single-channel PEMFC’s to illustrate the response of power as the operating parameters are subjected to specified changes. The operating parameters are further optimized using a one dimensional physics based model with an objective to match the power requirements of a drive cycle over a defined period of time.

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