Research On Independent Site-Type Regenerative Braking Energy Feedback Device Of Electrified Railway Train

In recent years,Chinese electrified railway with representative of the high-speed and heavy load develops rapidly,and high-speed EMU and high-power locomotive use cross-drive transmission system.Electrified railway train with AC drive can use the regenerative braking way to feed back the brake energy from the traction power supply network to the power system by controlling its converter,and energy saving is significant.As the power of the railway feeding back to the power system has negative sequence,harmonic and other power quality problems,the power sector take the way of charging which is called" reverse positive count"for this part of regenerative braking energy,and in fact,it did not improve the economic operation of the railway system.So,this paper intends to research a cross-AC converter technology to feed back the regenerative braking energy from the 25kV traction network to the 10kV railway power supply system,which can achieve the goal of economic use of regenerative braking energy by absorbing the energy by the railway system itself.Firstly,in this paper,existing regenerative braking energy recovery technologies are introduced,including the types of energy storage and feedback.By comparing their working principle,technical superiority and economy,this paper analysis every technology its own advantages and disadvantages,and two kinds of regenerative energy recovery devices(independent site type and cascade type)are studied to make the electric energy not feed back directly to the grid in order to solve the problem of" reverse positive count" for the type of energy feedback.The two methods are analyzed and compared in detail,and the advantages and disadvantages of these two methods are discussed.This paper focus on independent site type energy recovery device,and the device can send the regenerative power of the catenary to the railway 10kV power through line,which is responsible for the power supply of the station signal,communication,lighting and maintenance equipment along the railway.Then,in this paper,the structure and working principle of the main circuit of the independent site type energy recovery device are analyzed in detail.The detection system judges that the train is in the regenerative braking condition according to the power direction of the traction net.The device will make the brake energy step-down to 800V through the single-phase transformer,and then rectify it to 1500V DC,then,step-up it to 10kV three-phase AC after inverting it by three-phase inverter with LCL filter,finally,it is connected to 10kV power through line.At the end of the paper,in order to verify the feasibility of the main circuit design of the independent site type energy recovery device,the simulation model is built by using MATLAB/Simulink tool,and the function of each link of the main circuit is simulated and analyzed according to the calculation parameters.The simulation results show that the main circuit of the device and the control strategy can meet the requirements.On the basis of theoretical and simulation analysis,the prototype of the model is set up,and the test result verifies its application feasibility.