Wavelet-transform Algorithm Application in Hybrid Power System Optimization of Electric Vehicles

In order to reduce the changing times of battery's output power loads and currents, a novel energy management strategy was developed for hybrid power system including a battery pack and an ultracapacitor (UC) pack. The strategy is utilizing wavelet-transform algorithm to allocate power components with different frequency contents among the on-board energy sources. The models of hybrid power system were developed and simulated in MATLAB/Simulink. Simulation results show that: Compared with the logic threshold strategy, the wavelet control method can avoid battery to receive chaotic high-frequency components more effectively. Meantime, the utilization of ultra-capacitor can be improved. Thus battery can be protected and the efficiency of electric vehicles can be increased. (paper)