Equipment Development Of Modular High Frequency Power Supply

Since entering the electric society,various kinds of new technologies and inventions have been applied.The application of electric energy has greatly changed people's production and lifestyle,and has produced far-reaching impact especially in the areas of economy,culture,military,and technology.Power supply technology,as an important part of power applications,has played a crucial role in modern communications,electronic instruments,computers,industrial automation,and certain high-technology industries.Today's mainstream power technology is switching power supply technology.With the continuous innovation and development of power electronics technology,switching power supply technology is also constantly improving and progressing.Currently,switching power supply technology is developing in the direction of miniaturization,lightweighting,modularization and digitalization.It has been almost applied in all power,electronics and telecommunication industries,and is a key of the rapid development of these industries.Based on phase-shifted full-bridge converter,a modular high-frequency power supply is designed,where the topology,small-signal model,current sharing control and parameter selection are studied.The main work of this article is as follows:(1)A variety of topologies of switching power supply and their advantages & disadvantages of the power supplies are analyzed.The basic topologies of the switching power supply are studied,which can provide a basis for the design of the modular high-frequency switching power supply.In the paper,the advantages and disadvantages of common current sharing control strategies for multi-module switching power supply system is analyzed,which can provide a basis for the design of current-sharing control strategy of multi-module switching power supply system.(2)The modulation strategy of the high-frequency switching power supply is analyzed.Twelve duty cycles of the modular switching power supply are studied in detail.The voltage and current states of each power switches in each cycle are plotted.Additionally,the working characteristics and common problems under the operation are also analyzed.A mathematical model of a modular high frequency switching power supply based on the state average equation is established.(3)The output-current imbalance phenomenon of multi-module parallel system is analyzed and the necessity of the current sharing control is analyzed.The current-sharing control strategy based on external characteristic is analyzed in detail,and an improved external-characteristic drooping method is also proposed.The principle and implementation method are described,and the stability of the control system is analyzed.(4)An experimental equipment of modular switching power supply is built.The overall structure,main circuit design and control system design are performed.The three-phase rectifier bridge,inverter bridge and high-frequency rectifier bridge are selected respectively.And then,the high-frequency transformer and output filter circuit are designed.The control system based on UCC3895 phase-shifted full-bridge control chip is designed,including the selection of its peripheral devices,the design of sampling protection circuit and compensation loop.