Study On Efficiency Optimization Strategy Of Dynamic Wireless Charging System For Electric Vehicles

With the extensive application of electric vehicles,people have higher requirements for their endurance,high efficiency and safety of charging equipment.Under this background,electric vehicle dynamic wireless charging has been vigorously developed because of its safe,reliable and sustainable power supply characteristics.In this paper,the dynamic wireless charging system based on magnetic coupling principle is studied deeply,including its working principle analysis,system design and system efficiency optimization.The main research contents are as follows:Firstly,this paper introduces the structure of dynamic wireless charging system,and analyzes its working principle.The parameter of the double rectangular coil is designed and the magnetic field simulation is carried out in ANSYS Maxwell.The working principle of resonant circuit based on LCC compensation network is analyzed.In order to improve reliability and efficiency of the system,LCC circuit parameters must be designed to ensure that the inverter MOSFET zero voltage switching(ZVS)is achieved.The working principle of the transmitter circuit and the receiver circuit are analyzed and their parameters are designed to ensure the reliable operation of the system.The loss of each module in the dynamic wireless charging system is analyzed,including the loss of the resonant circuit,the loss of the DC / DC circuit,the loss of the rectifier circuit,the loss of the inverter circuit.And the loss model of each module is established.Then the system efficiency curve is calculated by MATLAB,which lays the foundation for the design of the efficiency optimization strategy.For designing the double closed-loop PI control algorithm,the average state equation modeling and small signal modeling of DC / DC circuit are established and the bode diagram is analyzed.By analyzing the characteristics of the system,the efficiency control strategy based on the coupling factor change tracking is developed,and the optimal control strategy is proved to improve the system power and efficiency obviously by theoretical analyzing in MATLAB.Finally,the system simulation is carried out in the PLECS,and the experimental test is carried out on the experimental prototype,including the inverter output test,the dynamic experiment test and the system efficiency test.The test results show that the ZVS of inverter MOSFET is achieved,the system power and efficiency are improved after using the efficiency optimization control.So it proves that the system has a high reliability and it completes the goal of efficiency optimization.