Power Sharing Based Algorithm for Sizing Components in Fuel Cell Hybrid Electric Vehicles

This paper presents an algorithm for sizing components in fuel cell hybrid electric vehicles through separation of load power demand into high, low, and intermediate frequency components. The approach considers a combination of hybridization with fuel cell units, battery packs and super capacitors. A unique and exhaustive search is performed through iterative loops based on response times of energy sources, battery pack power limits, and DC-DC converter voltage conversion ratios. The approach also considers non-idealities such as battery hysteresis and battery and super capacitor resistive losses. Simulation and design results are presented for a high performance vehicle based on an aggressive drive cycle. The results show an approximately 41 % improvement in weight using a fuel cell and super capacitor hybrid combination and a 26 % improvement using fuel cell, battery and super capacitor hybrid combination over battery only or other hybrid combinations.