Abstract: DC operation power source is commonly supplied by lead-acid batteries. This method is characterized by slow response speed to high-frequency equipment and environmental contamination. To deal with this problem, the paper proposes a novel hybrid DC power supply system, which consists of lithium batteries and super conductors. A novel energy management strategy, which uses the SOC feedback of the superconductor to limit the power output of the lithium battery, is also presented. The proposed energy management strategy, which is achieved by particle swarm optimization (initially proposed by Nelder Mead), can effectively reduce the instantaneous power output of the lithium battery, thus extending the life span of the equipment. The validity of the proposed approach is demonstrated and verified by Matlab/Simulink and field experiment. Experimental results suggest that the response speed is fast when the proposed strategy is adopted, thus indicating good reliability and engineering value.

Key words: DC power supply, lithium battery, super-capacitor, energy storage system, particle swarm optimization-nelder mead (PSO-NM), power limit