A LADRC-based Control Strategy with Performance Guarantee for On-board SC ESS of Urban Rail Traction

A LADRC-based control strategy with performance guarantee for on-board supercapacitor (SC) energy storage systems (ESS) of urban rail traction is proposed in this paper. An outer loop control structure utilizing linear active disturbance rejection control (LADRC) is employed to improve bus voltage tracking performance and alleviate the impact of system disturbances and minor faults that may cause performance degradation. A fuzzy logic-based state of charge (SOC) restriction unit is implemented to prevent overcharging and over-discharging of the SC. Moreover, a hysteresis-comparison-based selecting signal generator is used for switching between charge and discharge modes. Simulation results show that the proposed strategy outperforms the traditional double closed-loop PI control in terms of control performance and provides better guaranteed performance.