Research And Design Of Wireless Charging Array Coil System Based On Magnetically Coupled Resonance

With the utility of UAVs in catastrophe rescue,environmental monitoring,energy inspection and other fields,magnetically coupled resonant wireless power transmission as a promising way of energy transmission has attracted greater attention.However,the precision of fixed point landing of UAVs is not high at present,and the efficiency of wireless charging technology will decrease sharply when the coil is not aligned.Therefore,this paper targets to develop the electricity transmission region of magnetically coupled resonant wireless charging underneath the premise of making sure high transmission efficiency,and research the circuit topology and electricity coil.The precise research contents are as follows:a)Resonance compensation topology is studied.Based on S-S-S and LCC-LCC topologies,this paper obtains a new LCC-S-LCC topology by replacing the S on both sides of the S-S-S topology with LCC.Then,by analyzing the equivalent circuits of S-S-S and LCCS-LCC,the paper proves the advantages of LCC-S-LCC topology in output power and transmission efficiency under the condition of the same coupling coefficient.Finally,the paper analyzes the constant current and transmission efficiency of LCC-S-LCC topology from the perspective of theory and simulation,and proves that LCC-S-LCC topology not only retains the advantages of LCC-LCC resonant compensation topology,but also improves the anti offset characteristics of the system.b)The design array coil unit is designed.In order to design an excellent array coil,we must first design an excellent array coil unit.The design of the unit should be based on the important index parameters of the coil: quality factor,equivalent AC resistance,self inductance,coupling coefficient and magnetic field distribution to study the wire diameter,shape,number of turns,turn spacing and size of the coil.At the same time,Ansys Maxwell is used to design the best coil.c)The transmission coil structure is designed.In this paper,a 2×2 overlapping array structure is designed by means of spatial dislocation overlapping arrangement.And overlap region is decided with the aid of analysing the magnetic subject distribution above the array coil and the coupling coefficient between the array elements.The connection mode of each array unit is improved from the traditional independent placement to serial connection.So the original four resonant capacitance is simplified to one resonant capacitance.It not only makes the coil design becomes more convenient,but also can improve the whole system by frequency division phenomenon caused by the decline in efficiency.Thus,the array coil system has better anti offset characteristics.d)The experimental platform was constructed.In this paper,Gallium Nitride Field-effect Transistor is used to build a full bridge circuit,and schottky diode is used to build a full wave uncontrolled rectifier bridge.And the system transmission efficiency and efficiency uniformity above the array coil are verified using electronic load simulation cells.The measured consequences exhibit that when the charging current is10 A and the charging power is 240 W in the region above the overlapping array,the transmission effectivity of the device stays between 73.5% and 78%,which is greater than 60% of the usual 2×2 planar array coil structure.