The Research On AC And DC Integrated Charge-Drive On-Board Converter For Electric Vehicles

Electric vehicle drives and chargers are an essential part of electric vehicles.The integrated on-board converter uses the switching devices of the electric vehicle motor inverter and power electronic devices such as motor inductors to enable the electric vehicle to charge the electric vehicle when it is stopped,and uses a set of power electronic topological circuits to simultaneously realize driving and battery charging.Charging function.A new type of vehicle-mounted converter proposed in this topic,which can realize the functions of driving,AC or DC charging and AC or DC grid connection through the mode selection switch.First,the thesis analyzes the domestic and foreign research status of integrated OnBoard converters,summarizes the advantages of various On-Board converters,and briefly analyzes the existing problems.Secondly,based on the current research status,An improved integrated On-Board charger(OBC)proposed in this paper,converter based on the original inverter circuit of electric vehicles,which can realize driving,DC or AC charging,and DC or AC grid connection function.The thesis introduces the overall structure of the integrated OBC system,and then introduces the topological circuits of the OBC in driving mode,DC working mode and AC working mode according to the working mode.Afterwards,the DC working mode of the integrated OBC is analyzed in detail.This paper first analyzes the principle of the DC working mode,and on this basis,introduces the current flow diagram of each working state,designs the control strategy of the carrier phase shift,and calculates the boost ratio between the input and the output.Then according to the conduction diagram,the state equation of the system in the DC working mode is listed,and the transfer function of the system is calculated to verify the stability of the system.Then,this paper analyzes the AC working mode of the integrated OBC.Based on the conduction state diagrams of AC charging mode and AC grid-connected mode,this paper obtains the state equations of AC charging mode and AC grid-connected mode.According to the state equation,the transformation ratio of the converter system in the charging mode and the grid-connected mode is calculated,and the corresponding control strategies are given for the charging mode and the grid-connected mode.Finally,the influence of the duty cycle on the current ripple is analyzed.Finally,this paper simulates and verifies the proposed integrated on-board converter through the MATLAB/Simulink platform,and uses the hardware-in-the-loop platform to verify the converter experimentally.The rationality of the integrated vehicle converter topology and control strategy proposed in this paper is verified by experiments.