Research And Design Of On-board Forward Bidirectional AC/DC Converter For V2G

As an important breakthrough to solve environmental pollution and resource shortages,new energy electric vehicles have received strong support from the state.The energy storage battery of the electric vehicle can be used as the load end of the power grid or feedback energy to the grid;based on this,V2G(Vehicle-to-Grid)realizes the interaction between the electric vehicle and the smart grid energy information,reduces the grid operation cost,and improves the grid.The advantages of comprehensive operational efficiency have become a hot topic in current research.The bidirectional vehicle charger is a key component of the V2 G technology of electric vehicles.In this context,the research on the front-end bidirectional AC/DC converter of V2 G vehicle charger is carried out.Firstly,this thesis introduces the basic concept and application background of V2 G,analyzes and summarizes the development status of V2 G technology and vehicle charger.It also introduces the bidirectional topology of vehicle charger in V2 G system.According to the requirements and characteristics of the charger,the single-phase voltage type full-bridge topology is selected as the research object of the pre-stage bidirectional AC/DC.The working principle,operation mode and performance characteristics are analyzed,and the mathematical model of the converter is derived.Secondly,on the basis of the above analysis,the control strategy of the V2 G charger is mainly studied.In the rectification mode,for the defect of large current(THD)and slow dynamic response in traditional average current control,it is proposed to use the duty cycle prediction improved average current control to effectively suppress the zero-crossing distortion and greatly reduce the THD of the input current.At the same time,it also enhances the dynamic performance of the system.The strategy of current instantaneous control and current mode control in the inverter mode optimizes the control loop and improves the stability and reliability of the system.On this basis,the influence of the change of controller parameters on the loop is analyzed in detail.According to the steady-state and dynamic performance characteristics of the converter,the compensator of the control loop is designed and verified by simulation.Finally,based on the theoretical analysis,the experimental research on the vehicle front-stage bidirectional AC/DC converter is carried out.The hardware parameters and device selection of the main power loop and the control loop are designed,and the device loss of the main power loop is analyzed and calculated.Then,based on the theoretical research of the control strategy,the design of the overall software system of the converter and the corresponding codes of each part are completed.Written.The hardware and software systems were debugged on the prototype platform.The relevant experimental results verified the correctness and effectiveness of the theoretical analysis.