| In recent years,the development speed of urban rail transit construction in China has been accelerated gradually,and the renewable braking energy utilization technology has been used widely.It is of great significance to the sustainable development of the concept of improving the efficiency of train regeneration braking,saving energy and reducing emission reduction,and reducing the operating cost.The train braking energy feedback system not only has the function of energy feedback,but also can restrain the pressure rise of traction network,improve the quality of power supply,and take into account the function of reactive power compensation.How to make effective use of regenerated braking energy and reduce the return on investment cycle has become a hot research topic in the field of urban rail transit.The paper begins,to the background and significance of the research explains the development and application status of the braking energy feedback system of urban rail trains at home and abroad briefly,and compares and analyzes the advantages and disadvantages of resistance energy consumption,capacitance energy storage type,flywheel energy storage type and inverter feedback device.Through the comparison and the analysis,the advantages of medium voltage inverter energy feedback device are obvious,but the technology is still in the development stage.This paper has important research value for the application research of medium voltage inverter energy feedback device.The composition of urban rail transit power supply system is analyzed in detail,and the medium voltage ring network system and DC traction system in the composition of urban rail transit power supply system are analyzed in detail,and the characteristics of rectifier unit are simulated and analyzed.The train traction braking system of urban rail transit is analyzed,the basic train resistance,train braking mode and train traction condition are analyzed quantitatively,and the ratio of train feedback to traction electricity is about 34.3% calculated by theoretical analysis.Taking the medium voltage energy feed braking energy feedback device used in a urban rail transit in southern China as the research object,the mathematical model of the control principle is studied and analyzed,and the matlab simulation is established.Through the analysis of the simulation model,it is reasonable to set the DC1700 V energy feedback threshold,which can reduce the starting times of the device and obtain a higher braking energy feedback ratio.The primary structure and technical parameters of the medium voltage energy feed braking energy feedback device in use are studied,and it is put forward that the frame protection function design of the energy feed device in use can be improved,which can reduce the influence range of the frame fault of the energy feed device effectively while protecting the equipment and personal safety.Finally,analyzing the energy saving of braking energy feedback device which has been put into use on a city line in South China,the test results are in good agreement with the previous theoretical analysis from three aspects of test verification including starting threshold,energy saving influence factor and energy saving effect of braking energy feedback device.After putting in the energy feed device,it is estimated that the electricity bill can be saved by 1.26 million yuan per year,and the cost recovery period is about 7 years.The energy saving effect is obvious and the economic benefit is remarkable.At the end of the paper,the above research is summarized,which is helpful for manufacturers to perfect the function of energy feedback device,improve the energy saving effect,and also provide theoretical and data support for the design of energy feed device of urban rail transit power supply system. |
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