Low-frequency oscillation suppression method for EMU-traction network coupling systems based on shunting model PI control
Low-frequency voltage oscillations in high-speed railway EMU-traction network coupling systems frequently occur when multiple EMUs start simultaneously under light-load conditions.These oscillations can easily lead to traction blockades,significantly jeopardizing the safe operation of high-speed railways.Addressing this low-frequency oscillation issue,this study focuses on the CRH3 EMU to investigate the mechanism and suppression methods of low-frequency oscillations.First,an imped-ance model of the EMU-traction network coupling system is developed,and the generation mecha-nism of low-frequency oscillation is analyzed using impedance ratio Bode diagram.Second,a shunting model PI controller is designed,and its performance is compared through simulations with that of tra-ditional PI controllers,Active Disturbance Rejection Control(ADRC)and Self-Adaptive Auto Distur-bance Rejection PI(SAADR-PI)controller.Then,a transient direct current control strategy based on the shunting model PI control is proposed,and simulations are conducted to evaluate its suppression effectiveness on low-frequency oscillations.Finally,a comparative experiment between the shunting model PI control strategy and the traditional PI control strategy is carried out on a low-power experi-mental platform.The results show that the DC-side voltage overshoot of the four-quadrant converter in the EMU equipped with the shunting model PI controller is 17.13%,with a regulation time of 0.104 s and a voltage fluctuation of±54 V,indicating enhanced dynamic performance of the four-quadrant converter.When six EMUs using the shunting model PI control strategy start simultaneously under light-load conditions,the system stabilizes in approximately 0.4 s,with a DC-side voltage regu-lation time of 0.27 s,an overshoot of 7.12%,and a stabilized voltage fluctuation of±32 V.These findings confirm that the shunting model PI control strategy effectively suppresses low-frequency oscil-lations,providing valuable insights for further research on the suppression of such oscillations in high-speed railway EMU-traction network coupling systems.
high-speed railwayEMU-traction network coupling systemlow-frequency oscillationshunting model PI controllerfour-quadrant converter
万方数据
维普
