Optimal Design Of Planar Printed Circuit Board Transformer

As the key component of the switching power supply,the transformer directly affects the size of the whole device of the switching power supply.With the development of the switching power supply towards the trend of "short,small,light and thin",the transformer has begun to develop from vertical transformer to planar transformer.Compared with traditional winding transformers,planar transformers use low-height and flat-shaped magnetic cores.The windings are mostly made of printed boards or copper foils.The core skeleton is omitted,making the planar transformers small in size,good in heat dissipation and leakage.The advantages of low sense,good repeatability and high accuracy in production,have been widely used in high power density and high frequency switching power supplies.This article mainly focuses on the research and design of the planar printed circuit board transformer in the flyback power supply.First,starting from the characteristics of the planar transformer,the equivalent circuit of the planar transformer is established,and the transformer winding loss,core loss,leakage inductance and distributed capacitance are analyzed.Based on the Maxwell equations,the calculation formula of winding loss is derived,and it is proved that under the one-dimensional model,the loss caused by the rectangular copper conductor skin effect and the loss caused by the proximity effect are orthogonal.Aiming at the problem that the area product method and geometric parameter method do not consider the high frequency effect of the windings in the design of the transformer,and the winding design and the selection of the magnetic core cannot be optimized,the PExprt software is used to design the flat printed board transformer.Then,from the perspective of reducing winding losses,the theoretical analysis of winding staggered arrangement and winding parallel technology is carried out,and the corresponding model is built through finite element simulation software to verify the feasibility of winding staggered arrangement and winding parallel in optimizing transformer design Sex.Aiming at the situation of multi-turn windings in the same layer of printed board windings,finite element software is used to conduct in-depth research on the winding loss and the relationship between the spacing between the winding layers and the winding width.Finally,based on the study of the winding optimization,three design schemes for planar printed circuit board transformers were proposed,and the relevant parameters of the transformer were simulated and analyzed by ANSYS software.In view of the inductance magnetic field characteristics of the flyback planar printed circuit board transformer,the position distribution of the transformer windings was further optimized.The simulation model was used to make the corresponding object,and the accuracy of the design was verified by measuring the inductance value of the transformer and comparing with the simulation.The actual transformer was used in the flyback power supply,and the feasibility of the optimized scheme was verified through efficiency comparison.