Development and management of a fuel cell/battery/ultra-capacitor hybrid system through a multi-phase multi-input converter

Increasing environmental concerns, unstable oil prices, and advancements in the technology of batteries have accelerated studies on electrical vehicles (EVs). Moreover, environmentally friendly and cost-effective energy production makes a great contribution to EV research. Unfortunately, recent batteries fail to meet the dynamic profiles of EVs owing to their low power density. Moreover, their limited energy densities result in a low range on a full charge. Long charging times of batteries are another issue with batteries. To overcome the aforementioned problems, the utilization of hybrid power systems (HPSs) in EVs has been offered in the literature. For example, the battery/ultra-capacitor (UC) HPSs allow building systems with high power/energy density and longer battery life. Moreover, through a fuel cell (FC) system, the travel range can be extended in an environmentally friendly and economic way. HPSs classes are mainly: passive and active. The passive HPSs have no power electronics converter; thus, these systems are simple, economic, and efficient; however, they cannot control source energies fully. Conversely, in the active HPSs, the power electronics structures, which can be classified as single-input converters (SICs) and multi-input converters (MICs), are used to process the power. Separate SICs for each input are used in the multiple converter approach in which high cost, complex design, and control difficulties are expected. Alternatively, HPSs having MPCs offers many advantages; such as compact design, low component count, and high energy density. Additionally, MICs can be designed as having single-phase or multi-phase. The parallel legs that ideally split the power equally in multi-phase MICs (MPMICs) help to build efficient HPSs having many advantages in terms of filter requirements, inductor sizes, electromagnetic interference, and thermal management in spite of the increased complexity and cost. This thesis aims to develop a FC/battery/UC HPS by a single dc-dc converter which is a MPMIC. The source energies in this HPS are controlled by a fuzzy logic-based energy management strategy (EMS) to assure a sustainable operation. In this thesis, the proposed HPS along with the developed EMS is first analyzed, then it is tested via a simulation study.