Electric Power Systems Research 160 (2018) 89–98 Contents lists available at ScienceDirect Electric Power Systems Research j o ur na l ho mepage: www.elsevier.com/locate/epsr Management of fuel cell power and supercapacitor state-of-charge for electric vehicles A. Tahri a,* , H. El Fadil a , F.Z. Belhaj a , K. Gaouzi a , A. Rachid a , F. Giri b , F.Z. Chaoui c a ESIT Team, LGS Laboratory ENSA, Ibn Tofail University, 14000 Kénitra, Morocco b Laboratoire d’Automatique de Caen, Université de Caen, Bd Marechal Juin, B.P 8156, 14032, Caen, France c ENSET, Mohammed V University, Rabat, 10000, Morocco a r t i c l e i n f o Article history: Received 15 November 2016 Received in revised form 6 March 2017 Accepted 6 February 2018 Keywords: Fuel cell Supercapacitor Power converters Power management Nonlinear controller a b s t r a c t In this paper a power management system (PMS) is designed to achieve, for automotive applications, a control strategy aiming to split the load power between a fuel cell and a supercapacitor accounting for the fuel cell limited dynamics, its rated power and bounded supercapacitor voltage. The power sources are connected to a DC bus through boost and buck-boost converters. The converters are controlled to regulate the Dc bus voltage and the supercapacitor current must track a reference provided by the PMS unit. The fuel cell is the main source and the supercapacitor is the auxiliary one, which recovers power at a braking or a decelerating mode. The supercapacitor current is also controlled in order to keep the state-of-charge (SOC) within accepted bounds. Thus, the fuel cell charges the supercapacitor when the SOC is too low, and, the supercapacitor feeds the power-train, whenever it is overcharged. Meanwhile, the fuel cell dynamics is perfectly controlled during algorithm commutations. Theoretical analysis and results, for a practically validated high-fidelity simulation model, show that the proposed controller and the power management system meet all the objectives. © 2018 Elsevier B.V. All rights reserved. 1. Introduction Scientists agree on the greenhouse effects of fossil fuels and their depletion is inevitable, that have encouraged researchers and industry to seek clean and sustainable energy sources. Among the promising electric sources is fuel cell because it consumes hydro- gen and its byproduct is merely water and heat [1,2]. Even though, a fuel cell (FC) is a source that has relatively low power level. Further- more, it cannot neither provide power to fast changing loads nor recover braking energy. Therefore, an energy storage system (ESS) is necessary to ensure better performance in hybrid electric vehi- cles [3]. An ESS can be implemented by a battery or a supercapacitor (SC). In confronting these two storage devices, the supercapacitor charging time is advantageous because it can reach 1–10 s, com- pared with the new fast lithium-ion battery which can be charged at 70% in few minutes [4]. In addition, the supercapacitor can pro- vide with better performances peak powers, it have a long lifecycle * Corresponding author. E-mail addresses: abdelouahadtahri@um5s.net.ma (A. Tahri), hassan.elfadil@uit.ac.ma (H. El Fadil), Fatimazahra.belhaj@uit.ac.ma (F.Z. Belhaj), khawla.gaouzi@uit.ac.ma (K. Gaouzi), aziz.rachid@uit.ac.ma (A. Rachid), giri@greyc.ensicaen.fr (F. Giri), f.chaoui@um5s.net.ma (F.Z. Chaoui). and it’s virtually free of maintenance. Therefore, in this work, we consider a supercapacitor bank as an energy storage system. The use of this technology combining the two sources of energy has an undeniable asset for the following reasons: - The fuel cell will be employed to meet the average and permanent power demand of the vehicle, - The supercapacitor, meanwhile, will be used to meet the peak and transient power demand. It also allows energy recovery during braking and deceleration phases. - As the fuel cell is not used to support rapid load changes, it would avoid the problem of ‘fuel starvation’ which would cause per- manent damage to the proton exchange membrane of the cell [4]. This combination gives an efficient fuel cell hybrid power system because the fuel cell has relatively lower efficiency at low and high output power [5]. Moreover, this hybridization can downsizing the fuel cell then reducing the power system cost because the FC is the most expensive component [6]. In this work, we develop a new power management system based on a multi-loop nonlinear controller for a boost and buck- boost converters connected respectively, to a FC, as a main source, and to a SC as an auxiliary one. The whole control unit is designed https://doi.org/10.1016/j.epsr.2018.02.003 0378-7796/© 2018 Elsevier B.V. All rights reserved.