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Nowadays, the major problems of air pollution, in big countries, are caused mainly by means of transport. In addition, the energy storage systems, usually batteries are well aware of customer needs and have responded by offering packing that best suit to electric-vehicles. A consequence, abandoned batteries become the terrible poison sources of the environment. The use of batteries still restricted because of its charging problems (Barcellona, Brenna, Foiadelli, Longo, & Piegari, 2015). In fact, Hybrid Power System (HPS) is considered as an appreciating research issue that ensures the demand of electricity and thanks to its benefits (like low-noise, low exhaust emissions, modular production and fuel flexibility and high efficiency) (Pera, Candusso, Hissel, & Kauffmann, 2007), (Han, Lee, & Chang, 2002), (Granovskii, Dincer, & Rosen, 2006).
Among the different FC technologies, the Proton Exchange Membrane Fuel Cell (PEMFCs) could be a promising candidate for several applications due to their low operating temperatures and high power density (Pei, Chang, & Tang, 2008), (Gencoglu & Ural, 2009). One major obstacle toward the adoption of PEMFC as the power source. As a result, the PEMFC could not be able to match the supply/demand of load rapidly changing due to its slow dynamic response (Corbo, Migliardini, & Veneri, 2008), (Uzunoglu& Alam, 2006). To cater to the load profiles having fast dynamics, most of the system adopts hybridization of PEMFC with bridge power like the Ultracapacitor (UCap). This latter was evidently the best solution to resolve the limits adoption to PEMFCs. As a result, this system was used to assist the PEMFC, to recover the power from regenerative braking and to fulfill the peak power supply/demand.
In the literature, there are some approaches related to HPS. Each of these approaches has its own merits and demerits. For example, the authors of (Vega-Leal, Palomo, Barragán, García, & Brey, 2007) propose a nonlinear system using PEMFC component and linearize it for the linear control approach. The simplest model is where Ucap is directly tied to PEMFC. The authors of (Hou, Yang, & Wan, 2010) propose a model which is a semi-empirical dynamic model for stack voltage based on experimental investigations. Many studies have used and expanded on this model to apply supervisory control and to verify system performance. Whereas, the authors of (Gencoglu & Ural, 2009) emphasize a merit by connecting Ucap in parallel to improve the performance of the system with reduced Hydrogen-Consumption. The authors of (Wu & Gao, 2006) use the same configuration in hybrid vehicle and they discuss the obtaining of the minimum cost, according to the Impact-of-Driving-Cycle and Hydrogen-Consumption. The authors of (Aouzellag, Abdellaoui, Iffouzar, & Ghedamsi, 2015) develop a power management system to manage and to minimize the fuel cell power demand transitions and enhance its lifetime. At the same context, the authors of (Amari, Jamel, & Faouzi, 2015) propose an innovative control strategy of a single converter for PEMFC/UCap hybrid system. The proposed system increases the utilization ratio of the Ucap/ DC/DC boost converter. The authors of (Zhu, Li, Shen, & Xu, 2010) and (Jia, Wang, Cham, Wang, & Han, 2010) use an Energy Management System (EMS) for a 5 kW PEMFC distributed power system. Finally, the authors of (Ashok, Shtessel, & Smith, 2013) propose a Sliding-Mode-Control to control the output current of the system.
This paper extends these ideas by modeling an HPS system that can be used for system evaluation. It can provide, also, a sustainable electricity using an efficient PMU. To resolve the problems related to the slow dynamic of the PEMFC and the energy storage device during the peak demand periods, our work proposed and discussed a Multi-Input Single-Output (MISO) State Space model.