Research On Power Quality Hybrid Control And H∞ Control Of Traction Power Supply System Based On RPC

In recent years,high-speed and heavy-haul railways have developed extensively in China,and transportation efficiency has been greatly improved.At the same time,electric locomotive needs more and more traction power,and the impact and voltage fluctuation are also more serious.Because the traction power supply system itself is a three-phase asymmetric load,the electric locomotive is a mobile single-phase rectified impact load,which generates a large amount of harmonics and negative sequence,which are injected into the power system,resulting in a decline in the power system power quality.It brings great safety risks to the stable operation of the power system.Therefore,it is of great significance to improve the power quality of electrified railways by conducting research on the power quality of traction power supply systems.Aiming at the power quality problems of electrified railways,this paper conducts detailed research on traction power supply system modeling and simulation,traction power supply system harmonics and negative sequence detection methods,RPC-based traction power supply system power quality hybrid management,and H∞ control.Some engineering conclusions are drawn.The thesis mainly researched from the following aspects and achieved corresponding results:(1)The SS9-type electric locomotive,CRH2-type electric locomotive and the mixed running of two types of locomotive were simulated and modeled,and their respective harmonic characteristics were analyzed in detail.The negative sequence current generation mechanism of traction transformers with different wiring such as V / v,Scott,and YNd11 was analyzed,and the simulation analysis and comparison were performed.The simulation results show that the mixed running of the two locomotives shows new harmonic characteristics,and the harmonic content near 2500 Hz is relatively high.The wiring mode of the traction transformer has less influence on the system harmonics,but has a greater influence on the voltage and current imbalance.(2)Analyze three harmonic and negative sequence current detection principles including FBD detection method,PQ detection method and ip-iq detection method 、 establish corresponding simulation models for the three detection methods respectively and prove the effect of this method.Simulation results show that FBD detection method is superior to ip-iq detection method and PQ detection method in both harmonic detection and negative sequence current detection.(3)The working principle of RPC harmonic suppression and balanced negative sequence is analyzed in detail,the command expressions of RPC comprehensive control of harmonics and negative sequence current are derived,and the RPC comprehensive control scheme based on DC voltage PI control and current hysteresis control is analyzed.At the same time,a mixed power quality management model based on RPC was established,and the effect of comprehensive power quality management under the condition that only one-phase power supply arm has a locomotive load and two-phase power supply arms have a locomotive load is simulated.The simulation results show that RPC based on the DC voltage PI control and current hysteresis control scheme has a better effect on the hybrid control of the power quality of the traction power supply system.(4)Based on the parameter perturbation of the integrated management system,the H∞ robust control method of the RPC power quality integrated system is analyzed,and the simulation models of the H∞ controller based on the mixed sensitivity and the H∞ controller based on the LMI are established,and The RPC comprehensive management scheme under the control of PI was compared with simulation.Simulation results show that H∞ controller based on RPC system is more robust than PI controller.