| At present,electronic products are rapidly updated,and more and more external power lines not only occupy space,but also have various hidden dangers,and are less adaptable to outdoor weather changes.And wireless charging technology can solve these problems very well.However,the application of a large number of switching power supply leads to current waveform distortion,power factor and power supply efficiency reduction.In the process of wireless charging,the main reasons that hinder the popularization of wireless charging technology are the strict alignment of transmitting and receiving coils,poor anti-offset performance and too small charging area.In this thesis,through the research of PFC power factor correction module and transmitting coil module,which are the key parts of wireless charging and transmitting system,the loss of the system is reduced,the transmission power of the system is improved,the anti-offset performance is improved,and the area of charging area is enlarged.The main contents of this paper are as follows:1.The static and switching characteristics of SiC SBD are studied in depth,and the advantages of SiC devices are summarized by comparing with Si diodes.The advantages of SiC devices are summarized.The system efficiency and output power of two compensation structures of resonant network are deduced.The influence trend of load resistance on system power and efficiency is simulated and analyzed by using MATLAB software.According to the applicable object of wireless charging system designed in this thesis,the S-S compensation structure is selected.2.According to the design requirements,the design scheme of active power factor correction circuit based on IR1150 is determined.According to the calculation of key parameters,the selection of components and the replacement of Si FRD with SiC SBD are completed.The prototype of PFC circuit module is made and various test experiments are carried out.The ACDC test results show that the input current can follow the change of input voltage and show sinusoidal waveform.The experimental results show that the PFC module using SiC device can effectively suppress the current harmonic peak,and greatly reduce the system loss and improve the output power.3.Design of enlarging the area of charging area by parallel connection of multiple primary coils is taken.Firstly,the magnetic field intensity on the surface axis of square current-carrying coil and at some point in space is calculated.When the turns of concentrated winding are given,the mutual inductance of primary coil is used as optimization tool,and the turns of spiral coil are determined by iteration search in MATLAB.According to the principle of electromagnetics,the current density which makes the axial magnetic induction intensity uniformly distributed on the surface of the primary transmitting coil is reasoned and verified.The current density distribution is discretized and the edge length of the helical winding coil is determined.A new coil structure is proposed.Through the modeling and Simulation of square spiral coil,a new design scheme of wireless charging platform is proposed and modeled.4.According to te charging requirements of small and medium power electronic equipment in this thesis,a 150W wireless charging and transmitting system platform is built.The mutual inductance coefficient and receiving power of the receiving coil are tested.The test results show that the receiving power is not changed due to the change of the receiving device position,and the receiving power is high in a wide load range,and the wireless charging platform has good scalability.The feasibility of the whole design scheme is proved. |
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