Research On Regenerative Braking Energy Feed-Back Control System Of Urban Rail

The development of rail transit is an important symbol of the modernization of the city and is also one of the effective ways to solve traffic congestion.It has been developed rapidly in recent years because of its large capacity,convenient and quick characteristics.How to effectively utilize the energy generated during braking,im-prove the utilization of energy and reduce the operation cost of the subway operation has become the key problem to be solved in the development of urban rail transit.Currently regenerative braking energy absorbing includes:resistance consump-tion type,energy storage type and feedback type inverter.Among them,because of its simple structure and mature and stable characteristics,the resistance-consumption type has been widely used at home and abroad.Energy storage types include:super capacitor energy storage,flywheel energy storage,battery storage,etc.The inverse feedback type includes:feedback to 0.4kV low-voltage feedback and feedback to 10/35kV medium-voltage feedback.In this paper,a hybrid absorption device com-posed of low voltage feedback and battery energy storage is mainly studied.By the effective coordination and pontrol,we can achieve the functions of recovering brak-ing energy,optimizing capacity configuration and energy scheduling.Firstly,the 24-pulse uncontrolled rectifier model of traction substation,the traction network model,and three phase asynchronous motor model are introduced,simulation is built.Secondly,the structural topology and control strategy of the hy-brid energy absorption device combining the battery energy storage type and the in-verter feedback type are given.A parallel connection is used to connect the energy storage device with the inverter feedback device on the DC traction network.The inverter side is a high-power voltage source inverter,and the energy storage side is a triplex DC/DC converter;Then the coordination control strategy is given to accom-plish the function of energy dispatch.The effective control strategy can reduce the impact of regenerative braking energy on the power grid,maintain the voltage sta-bility of the DC network,improve the system capacity utilization,etc.Finally,a simulation model of rail transit traction power supply system with absorptive devic-es is built to verify the realization of various functions and the effectiveness of coor-dinated control.The hardware in the loop real-time simulation platform based on APPSIM software further verifies the reliability of the control strategy proposed in this paper,the feasibility of the structure and the correctness of the algorithm.It will provide some reference and theoretical guidance for the next field experiment.