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Design of a Real-Time Predictive Neural Controller and Monitor for Fuel Cells Model based on Internet of Things

By researcher Fatima Abdel Sattar and supervisor Dr. Professor Ahmed Sabah

Hydrogen Fuel Cells (FCs) are a type of renewable energy source that is gaining global interest as a sustainable energy choice for clean energy sources. A big challenge is to achieve optimum FC efficiency in the presence of multiple factors that impact the cell’s performance, such as pressure, temperature, humidity, and supplied current, which results in a nonlinear dynamic behavior in the system’s generation. Thus, control and monitoring of a FC are essential to improving global efficiency, hydrogen and air utilization, and achieving consistent and accurate power response, which contributes to optimizing its efficiency, safety, cost, and durability. In this work, a new development of a predictive voltage neural controller and remote monitoring for the nonlinear proton exchange membrane fuel cell (PEMFC) system is implemented in real-time. The major purpose of this work is to precisely and rapidly determine the appropriate hydrogen partial pressure (PH2) control action with a minimum number of step-ahead predictions (one step). This optimal control action improves the fuel cell’s nonlinear performance under varying load currents, preventing damage to the fuel cell membrane and thereby prolonging the fuel cell’s lifetime. Moreover, another purpose is to enables the remote monitoring of the nonlinear PEMFC system response based on the Internet of Things (IoT). The proposed predictive voltage controller consists of three sub-controllers. The first one is the numerical feed-forward controller (NFFC), which is used to decide the steady-state PH2 control action depending on the desired voltage. The second sub-controller is a feedback neural controller that uses a multi-layer perceptron (MLP) neural network structure and a back-propagation learning algorithm to generate the hydrogen partial pressure feedback control action to track the desired output voltage of the fuel cell during transient conditions. The third sub-controller is the predictive control law equation, which is based on the modified Elman recurrent neural network (MERNN) as an identifier for the PEMFC model and the multi-objective performance index (Mean Square Error). From the simulation results using the MATLAB program, the proposed controller has the capability to generate a precisely and quickly timed response to the PH2 control action without any saturation state in order to minimize the tracking voltage error and eliminate oscillation in the output voltage of the FC. The suggested predictive control strategy’s numerical simulation results are then verified by comparing them with those of other types of controllers in terms of the minimum number of steps ahead prediction (reducing from 10 to 1 step), enhancement of the tracking voltage error by 81.8% compared with a predictive neural controller, and improvement of the tracking voltage error by 87.5% compared with an inverse neural controller. Moreover, the oscillation effect in the output voltage is completely eliminated, resulting in a response without any overshoot. The Laboratory Virtual Instrument Engineering Workbench (LabVIEW) package is used to demonstrate the real-time performance of the proposed predictive voltage neural controller applied to the 150-watt PROTIUM PEMFC, which will be used to generate the appropriate amount of PH2 control action that will enter the fuel cell for stabilizing the desired output voltage. The IoT based on the Message Queuing Telemetry Transport (MQTT) protocol and a Raspberry Pi 4 acting as a local server are the building blocks upon which the monitoring component of the proposed system is implemented in order to monitor the desired output voltage, the fuel cell output voltage, and PH2. The Raspberry Pi collects the necessary fuel cell data and sends it to the Node-RED dashboard for monitoring. According to the simulation and the experimental results obtained using the proposed predictive neural controller on PROTIUM PEMFC, the proposed controller can generate an accurate, prompt, and timely reaction to the PH2 control action to reduce the tracking voltage error and to get rid of fuel cell output voltage oscillation. The proposed experimental work was compared to the simulation findings to confirm its effectiveness in terms of effectively tracking the desired output voltage, providing a fast response, and achieving the optimal partial pressure of hydrogen. However, in the simulation findings, a voltage error of 0.01 volts was observed without any oscillation. On the other hand, the experimental results indicate a slightly higher voltage error of approximately 0.1 volts, accompanied by oscillations of around ± 0.1 volts.