Design Of The Charging And Discharging Controlling System For Battery Swap Station

Along with the wide application of electric cars, energy supply system forelectric cars is also developed rapidly. The State grid corporation of china hasproposed a novel energy supply model which is “replacing the battery mainly,charging auxiliary, centralized charging, uniform distribution”. This paper introducesa kind of battery swap station which has energy storage function. The main researchobject is intelligent charging and discharging system of battery swap station.Thesystem mainly include voltage-source PWM rectifier, vanadium redox battery energystorage device, bi-directional DC-DC converter and the control System.The focus ofstudy is the hardware design for the control System. The main research in this paperincludes the following respects:(1)The development of electric vehicle and battery swap station is simplyintroduced and battery charging modes and devices are briefly analyzed.(2)The basic principle of PWM converter is expounded. Three phase voltage typePWM rectifiers’ working principle and mathematical mode are analyzed. The controlmethod of voltage type PWM rectifiers is summarized. SVPWM control methodwhich is used in this paper is mainly described.The principle, working mode andcontrol method of DC-DC converter are discussed also.(3)The overall design plan of battery swap station with energy storage functionare proposed and the main functions are briefly introduced. The main circuit’s keyparamenters of the charging-discharging device are designed. The MATLABsimulation model of battery charger is established. The charger operatingcharacteristics of constant-voltage charging mode and constant-current dischargingmode are simulated. The simulation results verify the feasibility of the controlstrategy.(4) The hardware system of charging-discharging control system is designed. Thecore chip selection, power design, sampling circuit design, grid synchronizationcircuit design, isolated amplifying circuit design and protection circuit design aredepthly analyzed.Finally, the PCB hardware circuit for experimental facility isfinished. The sampling circuit board is debugged and the debugging results reachedthe design requirement.