New energy urban rail vehicle hybrid energy storage control system

Abstract With the increasing demand for urban transportation and the gradual strengthening of environmental protection awareness, new energy urban rail transportation has gradually become the future trend of urban development. The hybrid energy storage system is one of the key technologies to achieve the goals of energy saving and emission reduction of new urban rail vehicles, improving operation efficiency and comfort. In the traction stage of urban rail vehicles, the energy storage unit composed of lithium batteries and supercapacitors is jointly supplied with the power grid. In the braking stage, the energy storage unit composed of lithium batteries and supercapacitors is a common way for urban rail vehicles to recover energy. This study validates the efficacy of employing fuzzy control methodology to enhance the performance of the energy storage system. The experimental results show that the fuzzy control method can better balance the load distribution between lithium batteries and supercapacitors, thus extending their service life and improving the overall system performance. Based on the SOC energy management strategy of supercapacitors, urban rail vehicle power is allocated to supercapacitors and lithium-ion batteries via a low-pass filter. System power is adjusted based on supercapacitor SOC, determining capacitor charging/discharging states and suppressing system output power.