An Efficient and Robust Current Control for Polymer Electrolyte Membrane Fuel Cell Power System

Mohammed Yousri Silaa,Mohamed Derbeli,Oscar Barambones,Ali Cheknane,José María Gonzalez De Durana,Cristian Napole

doi:10.3390/su13042360

Mohammed Yousri Silaa, Mohamed Derbeli + Show 4 more

Open Access

https://doi.org/10.3390/su13042360

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Abstract

Taking into account the restricted ability of polymer electrolyte membrane fuel cell (PEMFC) to generate energy, it is compulsory to present techniques, in which an efficient operating power can be achieved. In many applications, the PEMFC is usually coupled with a high step-up DC-DC power converter which not only provides efficient power conversion, but also offers highly regulated output voltage. Due to the no-linearity of the PEMFC power systems, the application of conventional linear controllers such as proportional-integral (PI) did not succeed to drive the system to operate precisely in an adequate power point. Therefore, this paper proposes a robust non-linear integral fast terminal sliding mode control (IFTSMC) aiming to improve the power quality generated by the PEMFC; besides, a digital filter is designed and implemented to smooth the signals from the chattering effect of the IFTSMC. The stability proof of the IFTSMC is demonstrated via Lyapunov analysis. The proposed control scheme is designed for an experimental closed-loop system which consisted of a Heliocentric hy-Expert™ FC-50W, MicroLabBox dSPACE DS1202, step-up DC-DC power converter and programmable DC power supplies. Comparative results with the PI controller indicate that a reduction of 96% in the response time could be achieved using the suggested algorithm; where, up to more than 91% of the chattering phenomenon could be eliminated via the application of the digital filter.

Highlights

It is noticed that the performance of the FC-50W is enhanced by the increase of temperature from 20 °C to 46 °C which could be interpreted by the rise of the membrane conductivity, and by the improvement in the exchange of the current density which will results in diminishing the activation losses
Notwithstanding these improvements, at higher temperatures such as T > 46 °C, the conductivity of the membrane starts to drop due to the lack of the relative humidity; which will result in a reduction in the performance of the polymer electrolyte membrane fuel cell (PEMFC)
It should be noted that the performance study of the FC-50W was limited due to the constraints in the oxygen and hydrogen partial pressures; these were narrowed since the rates are automatically controlled by an integrated control

Summary

Introduction

Polymer electrolyte membrane fuel cells (PEMFCs) are among the most efficient electrical generators due to several properties like high energy density, performance and high robustness [3], which leads to multiple applications such as portable power generation, cars, aircrafts and space shuttles [4,5,6,7,8,9,10]. In such application, DC-DC high step-up power converters are usually desired for boosting the PEMFC low voltage, and to provide regulated output voltage for end use.

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