Combinatorial approach for sizing and optimal energy management of HEV including durability constraints

This paper presents a combinatorial approach used to solve an optimization problem including component sizing and energy management control applied to an offroad hybrid electric vehicle with durability constraints. The problem under consideration is the optimization of the hybrid power supply system of an electric mini-excavator. It is composed of a fuel cell system and one energy storage system, i.e includes a lithium battery or a supercapacitors pack. The goal is to minimize the global cost of the machine during its entire working lifetime. In order to fulfill the requirements, an ageing model is included in the original problem to simulate the degradation of the battery and the fuel cell. The paper is focused on the reformulation of the nonlinear original problem into combinatorial subproblems. Then a branch and bound algorithm is applied to solve all sub-problems. Some results are presented to compare the different energy storages configurations.