| With the development of power electronics technology and switching power supply,the miniaturization,low weight,high power density,high efficiency and high reliability of power modules have gradually become the research focus and development trend.However,with the increase in the integration of power modules and the increase in power density and efficiency requirements,module power supplies still have many problems to be improved.The main technical difficulties faced at home and abroad are the same,which is increasing switching frequency is contradictory to high efficiency and high reliability.This paper introduces the characteristics and development status of module power supply.By comparing the development status at home and abroad,the main research contents of this paper are determined.Then according to the requirements of the system indicators,the Buck-LLC cascade structure using digital-analog hybrid control is finally adopted after analyzing and comparing various topological structures and control methods.Besides,the traditional circuit topology has been improved and a novel Buck-LLC cascade structure is presented in consideration of the size of the power module and the purpose of simplifying control and improving system stability.The principle of each circuit module is analyzed in detail and the parameter design and loss calculation are carried out.The small signal model was built according to the characteristics and parameters of each stage circuit,furthermore,the compensation network of system was designed according to the transfer function.The principle and parameters of system were verified by saber software,and the feasibility,effectiveness and stability of the system were verified by prototype experiments.The power density,efficiency and reliability of the system presented in this paper are improved by improving circuit topology,optimizing circuit structure and PCB layout,adopting new power devices and planar magnetic elements,and system modeling. |
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