A wavelet transform based power allocation strategy for lithium battery and ultra capacitor hybrid vehicular power system

Hybridization of battery with other energy storage devices, such as Ultra-Capacitors (UC) are often equipped in vehicular applications, therefore a well-designed Energy Management Strategy (EMS) is necessary for it can be effective for power sharing between the lithium battery and UC. This paper puts forward a wavelet transform based power allocation strategy for the EMS of Hybrid Electrical Vehicles (HEV). The original power demand signal is decomposed by wavelet transform into high frequency and low frequency components, and then the decomposed power demands are allotted to the lithium battery and UC respectively according to their output characteristics. The developed strategy is validated by a typical HEV model in ADVISOR, the experiment result shows that the wavelet transform based power allocation strategy can dramatically improve the efficiency of the overall system, which helps minimizing the waste of energy and enhancing the transient performance of HEV.