Symlets Wavelet Transform based Power Management of Hybrid Energy Storage System

Focused on the power demands of electric vehicles(EV) involving chaotic and high frequency transient component, the EV can hardly handle these power demand components due to the limitations of characteristics of the single Lithium-ion power battery. A symlets wavelet transform strategy is proposed for the power management of hybrid electric vehicles (HEV) with hybrid energy storage systems(HESS) including a Lithium-ion power battery and an ultracapacitor(UC). Firstly, the control system mechanism of multiport bidirectional DC/DC converter were presented briefly. Then the algorithm of symlets and the symlets wavelet transform based power management for HESS were analyzed. The proposed symlets wavelet transform strategy can distinguish the high-frequency components and low-frequency components in the power requirements of HEV, and allocate power to sources with different frequency characteristics to achieve the best power management control algorithm. Finally, a scaled-down experiments were performed under Highway Fuel Economy Test driving cycle(HWFET). The experimental results validated the effectiveness of symlets wavelet transform strategy management algorithm.