Energy economy optimization and comprehensive performance improvement for PEMFC/LIB hybrid system based on hierarchical optimization

Abstract

In order to improve the motion range of mobile welding robot, energy management strategy of fuel cell hybrid power system were studied, which involves energy economy optimization and comprehensive performance improvement. The energy management strategy adopts hierarchical optimization control. Inner layer realizes power distribution and energy optimization, using the maximum power point tracking control (MPPT) based on hybrid algorithm and an improved equivalent consumption minimization strategy (ECMS) to optimize the output power distribution. MPPT allows fuel cell to output maximum power stably and maximize the fuel cell utilization. The improved ECMS optimizes the equivalence factor by fuzzy logic control to increase the calculation accuracy. This strategy improves the economy of system energy consumption. The outer layer uses state machine control to switch the control strategy according to the operating state of the system. When the SOC of the battery is lower than the set threshold, MPPT control is used. And when the SOC is higher than the set threshold, ECMS is used. Experimental results show that the rationality of PEMFC output power and battery charge-discharge has been improved, and the economy of hybrid power system has also been improved.