Design On Bi-directional Converter Of6.5kW On Borard Charger And Inverter For Electric Vehicle

With the promotion of the concept of "Strengthening Police by science andtechnology ", the popularity of Mobile Police Platform in the provinces of the country’sgreatly improves the efficiency of the policemen to handle with emergencies, thuswhether Two-way power supply system in mobile police platform Stable work or notplays a crucial role in the whole public security system. In this paper, by using a twoisolation levels of topological structure design a high power factor, high efficiency ofon-Borad charger-inverter bidirectional converter, providing a stable and reliabletwo-way power supply system for mobile police platform in blade electric vehicles. Thismain research contents of this article are as follows:Propose two levels of topological structure of power to achieve bi-directional flowof the energy,the first stage adopt a Single-phase reversible bridge rectifier and the finalstages adopt an isolated Bi-directional dual half bridge converter. Through the modelsimplified, we can deduced that combination phase-shift plus duty cycle control can solvethe low efficiency problem of the former vice edge voltage mismatching in transformer.On the premise of realizing the basic skills of dual half bridge to design componentsparameters in main circuit.By introducing a switching function can solve the difficulty to modeling of dual halfbridge converter, established the state space average model the small signal model ofBi-directional dual half bridge converter. Based on small signal model to Deduce transferfunction of the control system，build the double closed loop control system. Through theplot of the current inner loop and voltage outer loop, controller has been designed andoptimized. Through the simulation has proved the validity of the selected control schemeand the designed control system has good dynamic and steady performance.When charging, through the analysis of Single-phase reversible bridge rectifier withone cycle control, deduced the target control equation of falling and rising edges,established the corresponding control principle diagram. Based on the conditions of thesystem stability, a calculation formula of the input inductor is derived. Finally, one cyclecontrol was adopted to realize the simulation of the power factor correction. Wheninverting, single polarity spwm control has been adopted to provide pure sine signal. Analysis the single polarity spwm control principle in single-phase bridge inverter.Through simulation to verify the feasibility of the single polarity spwm control in thesingle-phase reversible bridge inverter.Completed the construction of test platform. By testing different working modes ofthe converter, illuminated the superiority of the phase-shift plus duty cycle control overthe phase-shift control intuitively. Tested the ability to resist disturbance and efficiencycurve of converter in charger and inverter mode. The ripple of constant voltage andconstant current in charging mode were tested and analyzed.