At the present status of electric vehicle (EV) technologies, none of the av
ailable energy sources can solely fulfill all the demands of EVs to enable
them to compete with gasoline powered vehicles. In this paper, an energy ma
nagement system, adopting the so-called hybridization of energy sources, is
proposed to coordinate multiple energy sources for EVs. Hence, the unique
advantages of various EV energy sources dan be fully utilized, leading to o
ptimized fuel economy while fulfilling the expected driving range and maint
aining other EV performances. The proposed optimization is performed by tun
ing two ratios, namely the mass ratio and the hybridization ratio. (C) 2001
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