Research And Design Of Magnetic Integrated DC-DC Converter Based On GaN Device

With the official commercialization of 5G,5G communications have attracted more and more attention,and the global 5G market will continue to expand.The application of 5G increases the power consumption and puts forward higher requirements for power supply.The communication power supply is the heart of the5 G communication system.A reliable and stable communication power supply system is the key guarantee for the reliable and safe operation of the communication system.Therefore,5G communication power is increasingly becoming the focus of attention of the market and researchers.The purpose of this article is to design a converter with high efficiency and high power density.On the one hand,the application of Ga N devices and high-efficiency converter topology is used to improve efficiency,and on the other hand,Ga N devices and magnetic integration technology are used to increase power density.The main research content of this paper is as follows: First,the characteristics and working principle of the single enhancement mode gallium nitride power transistor are studied,and the structure is compared with silicon,silicon carbide,and cascade gallium nitride power transistors.The double-pulse experiment verifies that compared with silicon power transistors,single enhancement mode Ga N power transistors have the advantages of faster switching speed and lower switching loss.Aiming at 48 VDC and 24 VDC in the communication power supply,this paper proposes a cascaded topology.The front stage is a full bridge LLC resonant converter and the latter stage is a double-frequency Buck converter.For the 48 VDC in the communication power supply,this paper uses a full bridge LLC resonant converter to convert the high-voltage DC bus voltage to 48 VDC.Under the phase-shift control,the converter is always in a highly efficient resonance state,which improves the efficiency of the converter.At the same time,different magnetic integration methods of inductors and transformers are compared,and the leakage inductance substitution method is selected to integrate the inductors and transformers in a magnetic core,which improves the power density of the converter.For the 24 VDC in the communication power supply,this article uses a double-frequency Buck converter to convert the DC bus voltage 48 VDC output by the front-stage full bridge LLC resonant converter into 24 VDC,so that the converter is in a state where the low-frequency network shunts the high-frequency network current under the average current control.,Reduce switching loss,improve efficiency.For the magnetic integration of two inductors operating at different frequencies in a double-frequency Buck converter,compared with the existing magnetic integration method of inductors and inductors,a new type of magnetic integration method of inductors and inductors is proposed.The new magnetic integration method can integrate inductances running at different frequencies into a magnetic core.Compared with discrete magnetic parts,this method reduces the weight and volume of the magnetic parts,increases the power density of the converter,and reduces the cost.Compared with the existing magnetic integration scheme,this method can further increase the power density of the converter,reduce the magnetic saturation of the integrated magnetic parts,thereby reducing the core loss,and at the same time can improve the dynamic response of the low frequency network and reduce the switching loss.Finally,on the basis of the previous research,based on a single enhanced Ga N power transistor,a cascaded experimental prototype of a full bridge LLC resonant converter with a rated power of 400 W and a double-frequency Buck converter with a rated power of 150 W was built.The front-stage converter supplies power to the48 VDC load and double-frequency Buck converter,and the latter-stage converter supplies power to the 24 VDC load.The efficiency of the full bridge LLC resonant converter is as high as 96%,achieving soft switching and stable 48 VDC output.The efficiency of the double-frequency Buck converter is as high as 97%,achieving a highly efficient and stable 24 VDC output.The validity and correctness of the converter and magnetic integrated design are verified.