| The traditional high-frequency switching power supply is based on the uncontrollable rectification of t he diode,which has the disadvantages of low power factor and large harmonic pollution on the grid side.In this paper,a low-voltage and high-current high-frequency switching power supply is studied in this paper.Rectification and DC/DC(Direct Current)conversion of phase-shifted full-bridge soft-switch based on proportional-integral control.Compared with the traditional high-frequency switching power supply,the high-frequency high-frequency switching power supply studied in this paper can realize the r ectification with power factor of 1,and improve the power factor of the device,and greatly reduce the current harmonic content of the grid side.This paper mainly studies the following aspects:(1)The working principle and topology of high-frequency switching power supply are analyzed,the topology and structure of three-phase rectifier circuit and the topology and structure of DC/DC converter are also analyzed.The topology of the low-voltage high-current high-frequency switching power supply used in th is paper is proposed,and the working principle of the PWM rectifier and the working principle of the DC/DC converter are analyzed.(2)The control strategy of low-voltage high-current high frequency switching power supply and the basic principle of model predictive control are introduced,the prediction current control strategy of the front-stage PWM rectifier model is analyzed in detail,including the PWM rectifier model,the establishment of cost function and the predictive current control of PWM Rectifi er and its program realization.(3)A detailed analysis of the working principle of the phase shift full-bridge soft switch DC/DC converter,as well as the proportional integral control strategy and its program realization,the principle of synchronous rec tifier technology and its program implementation method.Through the simulation of Matlab/simulink software,it is shown that the control strategy proposed in this paper can realize the power factor 1 operation,and can greatly reduce the current harmonic of the network side,and verify the effectiveness of the control strategy proposed in this paper.(4)The development of low-voltage high-current high-frequency switching power supply device is introduced,including the main circuit hardware design,control system hardware design and control system software design.The experiment shows that the low-voltage high-current high-frequency switching power supply has the advantages of high power factor,low current harmonics,no pollution to the power grid,and verifies the effectiveness of the control policy proposed in this article. |
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