Research On The Interleaved Flyback Converter With Magnetic Integration

As information technology continues to develop, the power supply needsto provide more current, reducing size and cost at the same time.Therefore, theconverters are developing toward low-voltage and high current. In order to meetthe requirement of high current, interleaved technology of the converter hasbeen widely used. It can reduce output ripple, distribute heat loss, double theoperating frequency of the converter.However, the ripple of each branch is stilllarge, preventing the further efficiency improvement.The interleaved converterwith magnetic integration reduces the number of magnetic components, the sizeof magnetic components, and decreases the losses,improving the efficiency ofthe converter, and increasing the converter power density at the same time. Theinterleaved converter,for the non-isolated occasions, has been widely applied:Interleaved PFC (Boost Converter), VRM-Voltage Regulator Module(Interleaved Buck Converter) came into being; in the isolated occasions,interleaved flyback converter has been concerned because of simplification andthe fewer components.This paper introduces the interleaved Flyback converter with magneticintegration,then the steady-state performance has been analysed.Based on theanalysis of the magnetic integration,it derivates the equivalent circuit of theconverter by building the dual relationship between magnetic circuit andelectric circuit,and analyses the equivalent circuit (using Lxto express thecoupling effect) with small signal model，then the transfer functions of theconverter and the closed-loop transfer functions can be gained.The analysis ofthe converter transfer function can be used to characterize an equivalentinductance to express the integrated magnetics, and it does not change thecharacteristics of the Flyback converter.The influence of the transfer functionby the coupling effect has been described.The discontinuous current modemechanism of the interleaved Flyback converter with magnetic integration hasbeen analysed,and the relationship of input–output has been derived.The composition of magnetic integration, and the analysis of AC and DC flux, thecore losses and the coil losses has been described.Based on the analysis above,itcan be expanded to the multi-interleaved Flyback converter with magneticintegration.The simulation and prototype experiment of interleaved Flybackconverter with magnetic integration verify the validity of the analysis,providing further understanding and the effective analysis.