Research On Multi-module Electric Vehicle Charging Interface Based On Combination Switch

The environmental problems brought by the rapid development of the economy and the drying up of primary energy have become a difficult problem facing the world.Under the premise of meeting the basic requirements of the human travel,the electric vehicle can reduce the pollution to the environment and reduce the consumption of the primary energy.It has become the inevitable development direction of the future automobile industry.The popularization and use of electric vehicles must be based on the comprehensive construction of the electric vehicle charging station.The DC converter used in electric vehicle charging station is mainly based on single module,the corresponding voltage and power level is low,and the randomness of electric vehicle charging will inevitably make the charging station power idle.In this paper,a multi module DC converter system applied to electric vehicle charging is mainly studied in this paper.Firstly,taking the electric vehicle charging station as the research background,this paper analyzes the operating characteristics and the transformation principle of the DC converter applied to the charging station.The DC converter uses a double stage structure,the front end uses three level Buck converter to realize the voltage regulation function,and the back end adopts the LLC resonant converter to realize high frequency isolation.The operation frequency of the switch tube is increased by the carrier phase shift modulation(carrier phase shift modulation)strategy,and the voltage stress of the switch tube device is half the DC bus voltage.The back end LLC resonant converter can realize zero voltage switching(Zero-Voltage-Switch,ZVS)of converter switch device,and zero current off(Zero-Current-Switch,ZCS)of the two side rectifier diode,which can further reduce the loss of the converter and improve the transmission efficiency of the converter significantly.Secondly,the influence of the large scale access of electric vehicles on the transmission and distribution network and the load side is studied.In order to meet the charging requirements of the high voltage and high voltage of the electric vehicle,the multi module DC converter is composed of the IPOP cascade technology with the bipolar DC converter as the sub unit,and the charge and discharge control strategy of the single module DC converter is divided.The charge and discharge control strategy of IPOP multi module DC converter is designed,including constant current control,constant voltage control and master slave control.The corresponding simulation system diagram is built on the basis of IPOP two module DC converter.The corresponding steady-state and dynamic experiments are designed.The simulation results demonstrate the feasibility of the proposed control strategy.Finally,in order to provide the electric vehicle multi power grade charging interface and improve the transmission efficiency of electric vehicle charging station to solve the problem of power idle,this paper puts forward a IPOP type multi module DC converter system based on the combined switch,which is based on the national standard of electric vehicle charging.The system is based on the four-module IPOP DC converter.The switching scheme of the combined switch is designed to optimize the action of the combined switch,to realize the flexible switching of the multi power interface of the electric vehicle charging device and the function of the parallel charging of multiple electric vehicles.The PSIM software builds a multi module electric vehicle charging connection simulation test system based on the combined switch,based on the simulation waveform test.The rationality of parameter design of two-stage power conversion unit is verified,and the correctness of the multi module electric vehicle charging interface structure based on combined switch is verified.