Design and Modeling of an Equalizer for Fuel Cell Energy Management Systems

• Published in: IEEE transactions on power electronics 2019-11, Vol.34 (11), p.10925-10935
• Main Authors: Bahrami, Milad, Martin, Jean-Philippe, Maranzana, Gael, Pierfederici, Serge, Weber, Mathieu, Meibody-Tabar, Farid, Zandi, Majid
• Format: Article
• Language: English
• Subjects: Capacitors; Computer simulation; Controllability; Conversion ratio; converter; Converters; Electric potential; Electric power; Electrolytic cells; Energy management; Energy management systems; Engineering Sciences; equalizer; Equalizers; Fuel cells; Inverters; polymer electrolyte membrane fuel cell (PEMFC); Proton exchange membrane fuel cells; Switches; Topology; Voltage; Voltage control
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2019.2899150

During the lifespan of a polymer electrolyte membrane fuel cell (PEMFC) system, some heterogeneities between the cells constituting the stack can appear. The voltage of one particular cell in a stack may decrease because of specific aging or local malfunctioning such as drying. As a result, more heat is generated in this cell leading to an increase in its temperature and, thus, an additional voltage loss. This snowball effect can result in the failure of the cell. Therefore, the lifetime of a PEMFC stack can be increased by applying energy management to its cells. Note that the output voltage of a cell is lower than a stack. Hence, a high conversion ratio converter is necessary to implement such energy management. An efficient way to increase the output voltage is to connect the output capacitors of the converters such as the boosts in series. Ensuring the converters' controllability is a key point to implement energy management. In this paper, an equalizer system is proposed to ensure the controllability of the boost converters. The balancing speed and the low number of switches are the main advantages of this system. The validity of the proposed system is verified through simulation and experiments.