Research On Anti-offset Structure For Sectional Track-Based Dynamic Wireless Charging System Of Electric Vehicle

Today,with the shortage of traditional fossil energy and increasing environmental pollution,the development of environmentally-friendly transportation has become a hot research topic.In this era,electric vehicles have become an important means to solve environmental and transportation problems due to their low energy consumption and low pollution.The traditional plug-in charging and static charging not only requires the installation of a large-capacity car battery,but also has a long charging time and a short cruising range.In order to solve these problems,a segmented dynamic wireless charging technology based on magnetically coupled resonance is proposed,which not only has a low requirement on the vehicle battery capacity,but also does not need to stop for charging.However,due to the fluctuation of the coupling coefficient during the driving of the car,the output current and the transmission power will fluctuate.In order to solve the above problems,this paper proposes a multi-transmission singlereceive structure.When the length of the receiving coil is equal to the length of the transmitting coil plus the separation distance of the transmitting coil,the sum of the coupling coefficients for any transmitting coil proportionality coefficient remains basically constant.At the same time,in order to select the number of transmitting coils,the efficiency of multiple transmitting structures and the fluctuation rate of the sum of coupling coefficients are compared in this paper,and finally the three transmitting single receiving structure is selected.Secondly,the compensation topology chooses the LCL-LCL type.The output current of this compensation topology has no relationship with the load resistance.With the anti-offset structure,the output current is ultimately independent of the load resistance and offset,and the output current is constant.Three different sizes of transmitting coils were selected in the experiment,and the fluctuation rate of the sum of the coupling coefficients in one period was 1.37%,1.09%,2.54%,which was basically consistent with the results of Max Well simulations of 0.865%,0.946%,and 1.194%.Therefore,the sum of the coupling coefficients remains basically constant.At the same time,the output current fluctuation rate measured by the experiment is 1.47%,1.21%,2.32%,and the output current also remains basically constant.Secondly,in order to verify the ability of the LCL-LCL compensation topology to keep the current constant,keep the sum of the coupling coefficients unchanged,and change the load resistance to make it rise from zeroto 100 ohms.At this time,the output current drops by 5.05% and remains basically constant.In summary,with the change of the load resistance and offset,the output current of the secondary side is basically kept constant,so as to realize the constant current charging of the load.The experimental results verify the correctness of theoretical analysis and simulation.