Research On Energy Storage And Power Supply Technology Of Modern Trams Based On Super Capacitor

The modern streetcar based on supercapacitor refers to an electric energy driven rail locomotive whose core energy storage unit is a supercapacitor and is an advanced electric energy driven transport vehicle which is optimized and upgraded on the basis of the traditional streetcar.Compared with the traditional streetcar,the supercapacitive streetcar uses pure electric energy,and the operation process is clean,environment-friendly and pollution-free;it does not need to power line for charging along the way,and only needs to set the charging station at the starting station or the intermediate site as a direct interface for energy conversion between the train storage medium and the power grid.After the train pit stops,only the power absorbed from the grid by the passengers on and off the station can be used to meet the requirements of the train operation need.The overall performance is more environmentally friendly,beautiful,efficient and practical.Therefore,in recent years it has been widely used in major cities at home and abroad and infrastructure construction.Generally,multi-pulse rectification technology is used in orbit and metro complete rectification technology.This technology is mature,reliable and low cost.However,considering the impact of supercapacitor charging on the instantaneous impact power of the power grid and the uncontrolled rectification current and voltage harmonics,the impact of power factor could not be ignored.It is the core of this device to connect the current-sharing technology of large capacity power circuit in parallel,high-power PWM vector control technology and DC output filter control.In this thesis the power supply technology of streetcar based on supercapacitor as energy storage device is researched,it mainly analyzes the high power complete rectifying and charging device whose main loop uses double pulse width modulation(PWM)to control the AC/DC DC/DC voltage type frequency converter.The mathematic model of the grid side converter,the control strategy of the grid side converter,the mathematical model of the DC side charging device and the control strategy of the DC side converter are analyzed in detail.According to the load characteristics,that is the self-charging rule of the supercapacitor,the control strategy of charging mode in constant current and constant pressure under different operating conditions is studied;it also explains how to effectively reduce grid-induced harmonic distortion and voltage sag caused by grid-connected charging;to establish the system model through MATLAB simulation to verify the above theoretical analysis,The hardware and software design of the experimental system and the experimental platform of the prototype are completed.The control strategy of the grid side and the DC side of the energy storage charging control system is verified.Finally,the conclusion is drawnThe research work done in this paper provides some theoretical references for the engineering design of the energy storage and power supply system of modern streetcar and lays the foundation for engineering application.