Research And Design Of Wireless Charging System For Electric Vehicles

Compared with contact charging,the wireless charging method has the characteristics of convenience,flexibility,security,etc.It has gradually become the development trend of electric vehicle charging system.The research on wireless charging related technologies for electric vehicles can further promote the development of electric vehicles.Based on the principle of magnetic coupling resonance,this paper conducts in-depth principle analysis,modeling and verification of wireless charging system,and verifies that the system has high transmission efficiency.This paper first analyzes the principle of wireless energy transmission system based on magnetic coupling resonance,analyzes the resonant circuit in series and in parallel,deduces the model of magnetic resonance equivalent circuit,and compensates the primary and secondary sides of the coupled transformer.The circuit is analyzed and the compensation circuit of the S-S topology is finally selected by modeling and simulating four types of compensation circuits.Secondly,by comparing the coils of the three structures,the two coil structures suitable for this design are selected.The magnetic induction of MATLAB was simulated for different shapes of coils,and the spiral of the three-dimensional spiral structure was selected.For the influence of the coil on the transmission efficiency when the space position changes,the formula of the coupling coefficient of the coil in different spatial positions is deduced first,then the variation curve of the coupling coefficient with the position is simulated by MATLAB,and the Maxwell electromagnetic simulation software is verified.It provides a reasonable basis for the coil design.Then,the principle analysis and simulation verification of the primary-side inverter circuit and the secondary-side rectifier and DC conversion circuit are performed,and the parameter design is completed.The phase-locked loop is adopted in the case of the influence of the frequency shift on the transmission power.Frequency tracking technology to complete the frequency of tracking,and simulation verification.Finally,a simulated wireless transmission experiment platform was set up to complete the design of the software and hardware of the control system based on STM32 as the main control chip,and the experimental results were analyzed.Through the multiple sets of data of the experimental platform,the influence of the resonant frequency,coil position and coil distance on the transmission efficiency of the wireless charging system is verified.The wireless charging system based on magnetic coupling resonance has higher fault tolerance to the coil and has a certain degree of certainty.Its practical value provides a viable reference for the construction of a wireless charging platform for electric vehicles.