Power distribution strategy based on fuzzy controller and Savitzky-Golay selective filtering in hybrid energy storage system

Lithiumion batteries, as the power of electric vehicles, are facing challenges due to their intrinsic defects. The hybrid energy storage system with the combination of high power supercapacitor and lithium-ion battery are better promising solution. The peak current output by the lithium battery would be reduced greatly, which would result in great heat reduce and further enhancement of life cycle and safety of the lithium-ion battery. In considering their different charge and discharge behaviors, a high efficient control strategy is necessary for better performances. Here, an intelligent energy control strategy that combines fuzzy controller and Savitzky-Golay selective filtering is studied for HESS controlling. The fuzzy controller has good robustness and is suitable for nonlinear control, while the Savitzky-Golay filter can effectively smooth the waveform, and by selecting the output of both can effectively improve cell performance index. The simulation results show that compared with ESS under the tested cycle conditions, the proposed control strategy reduces the maximum current of the battery by 8.5% and the maximum temperature is reduced by 7.98%; when compared with a single fuzzy controller used by HESS, the proposed strategy can reduce the maximum battery current and maximum temperature by 7.02% and 1.50%, respectively.