Research On The Technology Of Wireless Charging System For Electric Vehicle

In recent years,with the actual demand of wireless charging for mobile electric vehicles such as electric vehicles,industrial and mining vehicles and electric vehicles,people have paid great attention to the research of wireless charging technology.The wireless charging technology of electric vehicles realizes the complete electrical isolation between power supply and electrical equipment,which has many advantages such as safety,reliability and flexibility,and also avoids a series of problems caused by charging line mismatch,plug aging and wear,so it has practical application significance.Magnetic-coupled wireless charging technology is considered as an effective solution to solve wireless charging problems due to its good medium-distance transmission characteristics.The magnetic coupling wireless charging system consists of two parts,the sending end located on the ground and the receiving end located in the car.When the two-part circuit is coupled at a specific frequency,the electrical energy can be transmitted through space.However,due to the problem of parking technology,the receiving end of electric vehicles cannot be fully aligned with the transmitter end,resulting in a displacement difference.Therefore,the transmission power of wireless charging technology of electric vehicles is not high.From the structure of the magnetic coupling coil and the compensation circuit,the transmission power of the charging system are improved.Firstly,according to the problem of large leakage in the system,we further analyze the model of double LCL,double LCC and double LCCL composite compensation circuit,analyze the transmission characteristics,select the most appropriate double LCL compound compensation circuit,and find the value size and working frequency of the components of the circuit.Secondly,for the problem of poor anti-offset of magnetic coupling charging mode,after comparing the transmission power under the same area of the circular and square coupling coil,the selected double D coil is studied by finite element simulation software,mainly including:(1)the model establishment of double D-type coil;(2)the analysis of self-sensing characteristics,mutual sensing characteristics and anti-offset characteristics of the coil;(3)the numerical structure analysis of the coil.The structure of double D coupled coils was optimized by Comsol finite element simulation software to meet the design requirements of this experiment.Finally,the design of double LCL composite double D magnetic coupling wireless charging system,using Multisim simulation software to set up a working frequency of 85 k Hz,transmission power of 6.6KW wireless charging system,the charging system in100 mm charging distance coupling coefficient can reach 37.1,can reach 82.93%transmission efficiency,in the transverse deviation is 20 mm,is still 60% transmission efficiency.And a scaled down physical model was built in the laboratory,and mutual verification between the physical model and simulation results was completed.