An Integrated Energy Management Strategy With Parameter Match Method for Plug-In Hybrid Electric Vehicles

A battery-ultracapacitor hybrid energy storage system (HESS) is a reliable candidate to overcome the drawbacks of a single power source system for its complementary features of power and energy in plug-in hybrid electric vehicle application. In this paper, an integrated energy management strategy procedure, which consists of three layers, is presented to distribute the power of the battery packs and the ultracapacitor packs. First, an HESS parameter match method is developed under different driving cycles with optimization objectives of cost and weight. Second, three-level wavelet transform (WT) algorithm is employed to isolate the different frequency components of power demand. The low-frequency components with less transients and sharps in power demand are provided by extending the battery lifetime, while an ultracapacitor satisfies the high-frequency components for its nice features of high specific power. Finally, fuzzy logic control is used to manage power flows between various components for guaranteeing the HESS performance. The simulation results show that compared with WT-based-only energy management strategy, the proposed procedure can always control the battery currents within 2C rate and reduce the energy consumption of about 6.54%.