Research On The Control Strategy Of The Bidirectional Power Converter Of Electric Vehicle Charging Pile Based On V2G Technology

Electric vehicle charging pile is the key equipment to implement the V2G technology,its performance directly affects the development of electric vehicles.Moreover,bidirectional power converter,which is considered as a carrier of energy exchange between smart grid and electric vehicle,is an important research topic of charging pile.The thesis mainly studies the bidirectional power converter of electric vehicle charging pile based on V2G technology,and it includes:Firstly,the VSI bidirectional AC/DC converter structure and isolated full-bridge DC/DC converter structure are chosen to be the two-stage main circuit topology of electric vehicle charging pile after analyzing and comparing the commonly used electric vehicle charging pile circuit topologies.Afterwards,the SPM(Six-Pulse Modulation)and SOLM(Synchronous One Leg Modulation)control methods are designed based on the analysis of the traditional full-bridge phase-shift control methods and SPWM control methods,and the thesis analyzes the principles of the SPM and SOLM control methods in detail.Furthermore,the electric vehicle charging pile is simulated based on SPM and SOLM control methods under the Simulink environment.And the thesis calculates and compares the switching loss of circuit controlled by SPWM methods with SOLM methods theoretically,the results of calculation indicate that,the power switching loss of SOLM control method is 0.5 times as much as that of the SPWM mode under different loads.Meanwhile,SOLM control method has the lowest switching loss,only 0.134 times as much as that of the SPWM control method under the pure resistive load,which effectively improves the system efficiency.Finally,an experimental prototype of charging pile with power of 500W is designed,which includes the hardware circuit module and the software programming.More specifically,the main circuit structure of the hardware is composed of VSI bidirectional AC/DC converter and isolated full-bridge DC/DC converter,the voltage and current signals in the circuit are detected by the Hall voltage sensor VSM025A and Hall current sensor CSM005A,the MOSFETIRF860 is chosen to be main circuit field-effect tube.Moreover,the design of software includes software main routine,interrupt routine,initializer and self-check,signal sampling,and SPM and SOLM control algorithm.Eventually,the experimental results indicate that,the switching losses of power switching devices in EV charging piles are effectively reduced,and the efficiency of EV charging piles bidirectional power converters is effectively improved under the control of the improved SPM and SOLM strategy.