| In order to solve the global energy crisis and reduce environmental pollution,electric vehicles have been widely promoted around the world.In the development of electric vehicles,it has always been limited by the battery capacity and charging facilities.The traditional charging methods have some disadvantages such as fixed charging location and slow charging speed.Therefore,the cruising range of the electric vehicle is usually limited.However,electric cars are vulnerable to charging equipment and charging speeds,making it impossible to travel long distances.The dynamic wireless charging technology of electric vehicles is not only safe and reliable,but also can solve the problem of the cruising range of electric vehicles.In this paper,a dynamic wireless charging system for electric vehicles based on the principle of magnetic coupling have been designed,the control strategy of the secondary parallel DC/DC converter and the soft-switching characteristics of the primary inverter are studied.Its main research content is as follows:The overall structure of the dynamic wireless charging system is introduced,The simulation analysis of the coupling coil relationship between the primary and secondary sides is performed with ANSYS Maxwell simulation software,and the dynamic parameter changes are obtained.The working principle of the primary-side inverter,bilateral LCC resonant circuit,secondary-side rectifier circuit and secondary-side interleaved DC/DC converter in the system are analyzed in detail,and the parameters of each part are designed.The working mode of the soft-switching of the primary inverter is analyzed,and the various operating modes of the soft-switching are analyzed in detail based on the output voltage and current waveform of the inverter in the system.Through the analysis,the conditions of the soft-switching of the primary inverter in the dynamic process are obtained by analyzing.In addition,the loss model of each section of the system is established and analyzed.The mathematical model of the interleaved parallel DC/DC converters of the secondary side of the system is established and analyzed and the open-loop Bode diagram of system is drawn.A double closed-loop PI control strategy for the current outer loop voltage and inner loop is designed,The PI controller is designed to compensate the system to ensure the control performance of the closed-loop system according to Bird diagram.In addition,the current sharing control strategy is designed to achieve the current sharing control of the interleaved DC/DC converters.The dynamic wireless charging system is simulated and analyzed by PLECS.The waveforms of output voltage and current of inverter on the primary side and the main waveforms of the DC/DC converters of interleaved DC/DC converter on the secondary side and the current of the DC/DC converter are analyzed.Finally,the experimental waveforms are observed on the experimental platform by testing,the soft-switching characteristics of the primary inverter in the dynamic wireless charging system is verified.It is also verified that the output power and transmission efficiency of the system are significantly improved under the double closed-loop PI control strategy. |
PDF Full Text Request