Design And Research Of Electric Vehicle Operation /Braking Energy Recovery And Photovoltaic Storage Charging Station

Electric vehicles use cleaner electric energy to provide power during operation,do not generate exhaust and have low noise during driving,which has gradually become one of the focus of energy development in China.Although the development of electric vehicles has made some progress,there are currently two problems that need to be resolved: 1)insufficient driving range of electric vehicles;2)The imperfect construction of charging infrastructure and large-scale connection of electric vehicles to the power grid will adversely affect the power grid.Braking energy recovery technology is great significant to improve the driving range of electric vehicles,the braking process of an electric vehicle will generate braking energy,and this energy can be recovered and reused by using an energy storage device,and the driving range will be greatly improved.And distributed photovoltaic micro-grid is an effective way to solve the problems caused by the construction of charging infrastructure and the connection of electric vehicles to the power grid.This article focuses on these two issues,and the main research contents are as follows:This paper selects the widely used electric bus as the research target,and proposes an energy storage system combining two different types of supercapacitors,which is applied to the operation and braking energy recovery of electric buses.An experimental platform for vehicle operation and braking energy recovery is set up to focus on key parameters such as the output voltage and energy consumption of supercapacitors under different load operations;For the different braking conditions of electric buses,the effects of different braking times on the recovered braking energy power and recovered energy of the supercapacitors were studied.Finally,the power characteristics of supercapacitor electric buses under continuous operating conditions are concerned.Experimental results show that as the load rate increases,the energy consumption and utilization efficiency of electric buses gradually increase;the initial braking power of electric buses is inversely proportional to the braking time,and the energy recovery efficiency is directly proportional to the braking time.In this paper,an optical storage micro-grid composed of distributed photovoltaic power generation and lithium iron phosphate battery energy storage system is designed and used in the construction of electric vehicle charging stations.Using distributed photovoltaic power generation technology as the main power source,it works with the power grid to provide electric energy for electric vehicles.The matching lithium iron phosphate battery energy storage system can smooth the fluctuation of photovoltaic power generation and reduce the effect of peak-to-valley gap.The charging station consists of 100 kW photovoltaic power generation?250 kW / 500 kWh lithium iron phosphate energy storage batteries?supercapacitor energy storage system?power converter system(PCS)and DC charging piles.The grid-connected test results show that the integrated light-storage-charge integrated electric vehicle charging station designed in this paper can well solve the charging problem of electric vehicles,and perform peak-cutting and valley-filling through the energy storage system.