Research on Wayside Energy Storage Control Strategy for Urban Rail Transit Based on Double Fuzzy Droop Control

Urban rail transit energy storage technology can improve the energy utilization rate of trains by absorbing regenerative braking energy on a large scale. Additionally, it can promote the consumption of nearby renewable energy sources, expand the multiple energy supply of rail transit, and form a highly efficient and coordinated energy management system encompassing “source, network, storage and vehicle”. Trains absorb or release electric energy from the 1 500 V traction network of urban rail transit during operation, leading to drastic traction network pressure fluctuations that can exceed the safety threshold range and affect travel safety. Therefore, a double fuzzy droop control (DFDC) strategy is proposed in this paper to solve the traction network pressure fluctuation problem. First, the train power is decomposed into high- and low-frequency power using a filtering method. Fuzzy rules are combined with the urban rail traction network voltage and decomposed power, to fuzzify the voltage compensation factor and droop coefficient, to obtain a complete energy storage control strategy. Second, light storage management is coordinated, combining it with the energy management strategy. Train operations under different working conditions are compared with traditional control and the proposed strategy, using Matlab/Simulink to verify the rationality and feasibility of the proposed strategy. The simulation results show that the proposed approach can improve the utilization rate of photovoltaics (PV) and storage, effectively reducing the voltage fluctuation of the traction network bus.