Dynamic Semiempirical PEMFC Model for Prognostics and Fault Diagnosis

Abstract

This paper introduces a dynamic semiempirical model that predicts the degradation of a proton exchange membrane fuel cell (PEMFC) by introducing time-based terms in the model. The concentration voltage drop is calculated using a new statistical equation based on the load current and working time, whereas the ohmic and activation voltage drops are updated using time-based equations borrowed from the existing literature. Furthermore, the developed model calculates the membrane water content in the PEMFC, which indicates the membrane hydration state and indirectly diagnoses the flooding and drying faults. Moreover, the model parameters are optimized using a recently developed butterfly optimization algorithm. The model is simple and has a short runtime; therefore, it is suitable for monitoring. Voltage degradation under various loading currents was observed for long working hours. The obtained results indicate a significant degradation in PEMFC performance. Therefore, the proposed model is also useful for prognostics and fault diagnosis. INDEX TERMS Fault diagnostics, optimization, PEMFC, prognostics, statistical analysis Engineering for Smart & Sustainable Systems Research Department at Mohammadia School of Engineering (Rabat/Morocco). His scientific activities have mostly focused on fuel cells as a solution of storage of energy (more exactly, developing new methods for modeling and control of fuel cells).

Passivity-Based Control for Output Voltage Regulation in a Fuel Cell/Boost Converter System

“…A PEMFC EGS is integrated by several subsystems such as a PEMFC stack, a hydrogen supply system that regulates the hydrogen flow or pressure through a valve, an air supply system designed to increase the power density, a humidification system to prevent dehydration of the FC membrane, and a cooling system to reduce the temperature of the inlet air [ 11 ]. In this way, PEMFCs are ultimately electrochemical devices that convert chemical energy to electrical energy via an exothermic reaction that consumes hydrogen and oxygen [ 9 ]. The PEMFC is internally composed of an electrolyte, an anode (negative electrode), and a cathode (positive electrode).…”

“…Note that the output voltage generated by a single FC is low (less than 1.2 V), so, in order to supply the desired demand series, parallel arrangements are created to form stacks. Additionally, auxiliary systems (such as valves, pumps, and air compressors) are required in order to obtain a PEMFC energy generation system (EGS).Compared to green EGSs such as photovoltaic systems or wind turbines, PEMFC EGSs are a non-intermittent energy source that converts chemical energy to electrical energy, heat, and water via an exothermic reaction that consumes hydrogen and oxygen [ 9 ]. However, drawbacks such as its strongly nonlinear characteristics [ 10 ], slow dynamic response [ 11 ], lifetime reduction due to the fuel starvation phenomena (voltage drop due to a rapid load demand) [ 12 ], and unregulated output voltage make FCs require additional systems in order to increase their reliability and durability [ 13 , 14 ].…”

A review of fault diagnosis and fault-tolerant control of vehicular polymer electrolyte membrane fuel cell power system

“…(2) Experience-mechanism hybrid model In the experience-mechanism hybrid model (EMM), one is to express the undetermined parameters that are difficult to describe in the mechanism by empirical coefficients according to experimental data, or to modify them, the other is to express reactions that are hard to measure. Due to cells' small size, it is not easy to know the transfer process and local distribution of inner-reactants by test, the mechanism model is suitable for expressing inner-reactions [39]. It makes the model easier and save solving time within tests 'experience, and does not depend on experimental optimization, thus improving the universality of the model.…”