Energy management for Hybrid Electric Vehicles using load power fluctuation compensation - ultracapacitors and lithium-battery

This paper presents ultracapacitors (U) and lithium-battery connection with an energy management strategy based on the frequency distribution approach. The module of ultracapacitors is linked to DC-bus through the buck-boost converter, and that of the lithium-battery is connected to DC-bus without a converter. DC/AC converter (inverter) and electrical machine (EM) are used to emulate the Hybrid Electric Vehicle (HEV) behavior. The contribution of this paper is focused on demand energy in HEV sharing between ultracapacitors module and battery pack according to the dynamic responses of these sources. The performances of the proposed method are evaluated through some simulations and experimental tests using a dynamic drive cycle.