| The researching in switching power supply includes many technology areas such as power electronics, auto control and so on. Soft-switching is a hot point in power transfer technology. It can be seen in the future, power electronics converter will get higher efficiency and power density.These years more and more emphasize have been focused soft-switching control in phase-shifted ZVS PWM full-bridge DC/DC converter and more research need to be made.The principles of phase-shifted ZVS PWM full-bridge converter are described and analyzed. The small-signal model in main circuit are built by using average circuit model. The relationship of each small signal and efficiency duty cycle are described completely. Magnitude-frequency characteristics and Phase-frequency characteristics of each main transfer function are got.The advantages and disadvantages of current-mode control technique is analyzed and studied intently. According to these, the small signal model of phase-shifted full-bridge converter in continuous current is built. By using Matlab tools, the simulations of response of output voltage due to the step load are given.The principles and the characteristics of digital control method in phase-shift full-bridge converter are discussed. The small-signal model are built. Under the integral control mode, the same simulation results are got with the difference integral and differential coefficient when the step load happens. The conclusions are got that digital control can get the same static state and dynamic state as the analogy control.Average circuit model is the main modeling method and three-terminal small-signal modeling method is also used in this paper. PSPICE and MATLAB are used to analyzed the principles with computer and the simulation results are in positive with the theory.
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