Research On Parameter Design And Impedance Matching Of High Frequency Transformer

High-frequency transformers have been widely used in recent years with the rapid development of power electronics technology.The planar transformer has the advantages of high operating frequency and flat low height.It is widely used in high current circuits.As an indispensable component of power converters,the application of planar transformers is more and more common and the size is getting smaller.As the frequency increases,the volume of magnetic components such as transformers decreases,and the energy density increases,but the effect of high-frequency effects on the normal operation of the transformer is also more obvious and the influence of the transformer parameters on the circuit cannot be ignored.Among them,the leakage inductance directly affects the overall electromagnetic interference performance,switching peaks,voltage stress and heating problems of the switch.Losses,especially winding losses,are critical to the efficiency of the entire circuit.Based on the principle of planar transformer and its structure and electrical characteristics,this paper studies the effects of different winding arrangement schemes on the leakage inductance and AC resistance of planar transformers by analyzing the distribution of spatial magnetomotive force and the distribution of current density in conductors.It is verified that the windings are completely staggered to reduce leakage inductance and AC resistance.Based on the complete staggered arrangement of the planar transformer windings,the influence of the coil current distribution in the winding layer on the leakage inductance and AC resistance of the planar transformer is studied.Based on the variational analysis,changing and designing the width of the winding coil can affect the coil current distribution.In turn,the leakage inductance and the AC resistance are reduced,and an optimized solution is obtained.Then through the finite element simulation,the feasibility of the optimization scheme is verified and the corresponding samples are made according to the simulation model.The comparison between the experimental results and the 3D simulation results further confirms that the winding coil width design according to the optimization scheme can reduce the leakage inductance and AC resistance of the planar transformer.For the impedance matching part,this paper proves through experiments that the influence of different winding arrangements on transformer impedance and impedance angle can change the applicable operating frequency range of the transformer.Based on the principle of impedance matching,the importance of high-frequency transformer for impedance matching is proposed.The equivalent circuit diagram of high-frequency transformer is established and analyzed by impedance analyzer.The analysis shows that different winding arrangements impact transformer impedance and working frequency range.