Development And Efficiency Optimization Of Wireless Charging System For Electric Moped

With the increase of the aging population in China,the travel safety of the elderly has become a hot issue.As a travel tool for the elderly,the safety of electric moped deserves more attention.Compared with wired Power transmission,Wireless Power Transfer(WPT)has a closed Power transmission mode,which reduces the risk of plug wear and electric shock during charging,and improves the safety of electric moped.However,the early wireless power transmission is not mature due to its efficiency and power limitation.With the improvement of process technology and the application of high speed processor,wireless power transmission technology is gradually applied to medical,military,transportation,electric power industries.Compared with wired power transmission,WPT has room for further improvements in power and efficiency.At present,the research focus of wireless power transmission is mainly focused on coupling mechanism,anti-offset ability,control algorithm to improve stability and other aspects,the ultimate purpose of which is to improve its efficiency and power.In this paper,based on LCC compensation topology and DD coupling mechanism,the efficiency of wireless power transmission system is optimized to improve the efficiency of wireless power transmission system without affecting the system power output.Firstly,the development and trend of wireless power transmission are described,and several basic compensation topologies are introduced.The transmission characteristics of bilateral LCC structure were analyzed,including the relationship between constant current transmission characteristics,coupling coefficient and system output power and efficiency,and the simulation model was established to verify the transmission characteristics.Secondly,on the basis of the theory,the efficiency optimization design of the ZVS,the coupling coefficient of the coupling mechanism and the rectifier circuit at the receiving end of the radio power transmission is carried out.In order to reduce the switching loss of the system and minimize the reactive power of the system,two schemes are designed to realize the ZVS of the inverter circuit,and the influence of the two schemes on the power and efficiency of wireless power transmission is analyzed.Based on the relationship between coupling coefficient and output power and efficiency,the circuit model of coupling mechanism is established to optimize the coupling coefficient between transmitter and receiver.In the rectifier current path at the receiving end,the diode is replaced by MOSFET switch tube to reduce the conduction loss of the rectifier tube.Finally,with the overall efficiency of wireless power transmission as the optimization goal,a set of wireless power transmission device with transmission distance of 12 cm is designed,and its rated transmission power is 300 W,which meets the charging power requirements of electric moped.The correctness of theoretical derivation is verified through experiments.