Study On The Text And Simulation Of New Scheme Of Regenerative Energy Utilization In Subway

With the development of national economy and the acceleration of urbanization,urban rail transit industry is in a period of rapid development.In order to respond to the call for energy-saving emission reduction and sustainable development,and solve the problem of energy waste caused by frequent braking of trains,the regenerative energy utilization technologies of subway have become the research focus of experts and scholars in recent years.Among the three types of subway regenerative energy utilization methods,inversion feedback method has great advantages in terms of energy-saving effect,technology maturity,and economic efficiency.Therefore,in this paper the inversion feedback method of subway regenerative energy utilization will be studied.Firstly,the research background and significance of the utilization of regenerative energy in subway is introduced.The application status,advantages and disadvantages of the existing three regenerative energy absorption devices are summarized and compared,and the inversion feedback method is selected as the research object.Secondly,the principle and characteristics of the rectifier which is the core unit of traction power supply system are analyzed.The significant effects on reducing harmonic pollution of the power grid and improving the quality of power supply of 24-pulse rectifier unit are showed in the MATLAB/Simulink simulation.According to the differences of grid-connected voltage grades of inversion feedback method,the characteristics of medium and low voltage inversion feedback schemes and their applicable external power supply methods are analyzed.Then,an inversion feedback device is designed.The LCL filtering three-phase bridge inverter structure is adopted in main circuit,and the voltage current double closed-loop control strategy based on feed forward decoupling is adopted in control system.The inversion feedback device model is built on the MATLAB/Simulink simulation platform.The voltage outer loop control having a good voltage stabilizing effect on the DC side voltage,and the current inner loop control making the current harmonic content and power factor of the AC side accord with the national standards is verified in the simulation results.Finally,the misjudgment of the voltage-type judging method of inversion feedback device under the condition of voltage fluctuation on the AC side is analyzed.In order to avoid the misoperation of the inversion feedback device,the principle of the current-type regenerative energy feedback identification method is introduced.The regenerative energy utilization test system structure including a rectifier and two converters is designed and through MATLAB/Simulink simulation,the feasibility of simulating the regenerative braking and inversion feedback process of two converters running in parallel is verified.The experimental physical platform is constructed.Testing the performance of inversion feedback device with the actual train load process is proposed in order to replace the field trial operation.The current-type control scheme is designed and the test results show that the test system structure can reliably simulate the typical working conditions of the train,and effectively feedback the regenerative energy under the current-type control method.