Study On Regenerative Braking Traction Simulation And Energy Saving Scheme Based On Inverter In Urban Rail Transit

In recent years, with the great development of the city size and population, the demandto transportation is increasing day by day. As the representative capacity of the largemodern traffic tools, the urban rail transit has been adopted in a number of large andmedium-sized cities in our country. How to upgrade the construction level, improve theenergy utilization and decrease the operating costs to meet the demand of low-carboneconomy and energy saving become the core purposes of the research to the urban railtransit.The traction simulation calculation is a key link in the construction of the urban railtransit, which is the basis of the analysis and design to the operation condition. The brakingtechnology is one of the key technologies in the operation of the urban rail train, which hasthe direct bearing on the safety, accuracy and comfortably of the pull in of the train. Theregenerative braking should be given preference to for the present. However, theregenerative braking would lead a voltage rise to the traction network when theregenerative energy is not absorbed by other trains timely, which should be solved by somemeans. Revolving around these purposes, this paper launches into the regenerative brakingurban rail transit traction simulation calculation and the inverter based regenerative brakingenergy absorbing and utilization scheme.Firstly, the theory of the traction calculation is analyzed, and the expected function, thedesign idea and the program flows are given in detail. The program of “one train-twostations”,“one train-multi stations” and “multi trains-multi stations” are given, which couldgive a series of outputs including the speed, the distance and the acceleration speed of thetrain, the current and the power that absorbed by the train, the time and the run chart, etc.The results of the traction calculation program is analyzed and compared with the existingtraction calculation report. The two are alike to some extent, which proves that the programcould show the operational process and its parameters variation in a way and could supplytheoretical basis and data to the analysis of the regenerative braking.Then, the regenerative braking technologies of resistance-type, storage-type andinverter feedback-type are analyzed and compared. The inverter based regenerative brakingenergy feedback technology based on high-voltage and large power converter hasadvantages in energy utilization rate, working life and economical efficiency. Two schemes of medium voltage side inverter feedback mode and low voltage side inverter feedbackmode are proposed according to the two power supply systems of the centralized powersupply system and the decentralized power supply system used in the urban rail transit.Different modes should be applied in different power supply systems.At last, a simulation model of the urban rail transit using inverter based regenerativebraking energy feedback mode is built in MATLAB/Simulink. The simulation resultsconfirm that the inverter based regenerative braking energy feedback scheme couldeffectively restrain the voltage rise in the traction network. Besides, it could realize thefunctions of energy conservation and reactive compensation as well.