Study On GaN High Efficiency High Power Totem Pole PFC Converter

High efficiency is not only an important trend of communication power,but also meets the economic requirements of low-carbon environmental protection and sustainable development.In this thesis,the advantages and disadvantages of the methods of improving the efficiency of power factor correction(PFC)in the existing communication power supplies are analyzed.Considering the characteristics of PFC topologies and the advantages of GaN switches,Ga N Totem Pole PFC is designed and studied.A new soft-switching scheme is proposed in this thesis,and the experiment and verification are carried out.In this thesis,the reason why the Ga N switch can play a new role in the tote m pole PFC circuit is analyzed in detail.Through the comparative analysis of tote m pole circuit and traditional bridge circuit,the reasons why Totem Pole PFC has higher efficiency are expounded.Furthermore,the feasibility of the new soft-switching scheme can improve efficiency is verified by Saber simulation.The feedback loop parameters of the PFC converter are designed and verified by the Bode diagram.The full-ripple current feedback model of totem pole PFC in average current control mode is established.The transfer function is established by the current feedback model.Open-loop transfer function is established by simplifying the control block diagram.Finally,the performance of the PFC converter is analyzed with Bode diagram of open-loop transfer function.According to PFC module performance parameters,select the core material,core type,winding diameter.The inductance parameters such as the number of winding turns are designed.The copper loss and iron loss of the inductor are calculated and analyzed.Select the type of TPH3205 WS gallium nitride switch.The working principle,conduction mode and parasitic parameters are analyzed in detail.Switch loss is calculated in theoretically.The driving requirements of gallium nitride devices are introduced.By analyzing the bootstrap drive circuit,the transformer driver circuit and the digital chip driver circuit,a simple and reliable sampling circuit and driver circuit are designed.Finally,the PCB board is designed.A PFC prototype is set up.The fastness o f the sampling circuit and the reliability of the driving circuit are tested.The experimental results show that this PFC prototype can operate stably in CCM mode and has a high power factor(PF)value.Compared with the efficiency of the Si MOS module,the higher efficiency of the GaN Totem Pole PFC is also verified.