Optimal design of an advanced fuel cell hybrid electric vehicle.

Abstract

The optimal sizing of the fuel cell, battery, motor and hydrogen tank of a fuel cell hybrid electric vehicle (FCHEV) is achieved using a search tool based on Ordinal Optimization (OO). It incorporates a FCHEV optimal simulation tool that uses an approximate version of dynamic programming known as Single Stage Dynamic Programming (SSDP). The SSDP method is further enhanced as a Two-Step SSDP to reduce the operation simulation time to about one-fourth. In this work the effect of using light material on the power demand as well as on the hydrogen consumption will be studied and evaluated. For this purpose two separate FCHEV designs are proposed and evaluated. The first FCHEV will be a baseline model inspired from a Toyota Venza (2009) where the body of the FCHEV is mainly composed of steel-iron. The other will be an advanced model which is based on a light body vehicle inspired from a Lotus Engineering design. The suggested design will be further refined by accounting for the power losses in the electric power train. These losses will include stator and rotor copper losses in the induction motor as well as the switching and conduction losses in the inverter of the FCHEV. In the last part of the thesis an environmental cost will be calculated for the two FCHEV designs. This cost will take into consideration the electricity generation mix used to charge the battery, and the method used to produce the hydrogen used as the fuel for PEM fuel cell. This environmental cost will be calculated if the same design is used in different regions in the world. Therefore, this thesis will not only provide an advanced FCHEV design tool, but also a technical report that can be placed in the hands of government officials and decision makers willing to integrate FCHEV into their transportation sector. In this work we will test and simulate our FCHEV on a combination of two driving cycles consisting of the HWFET and the UDDS. In addition, proprietary acceleration and gradeability cycles are to select sizes for the motor and inverter.