Research On Phase - Shifted Full - Bridge ZVS Switching Power Supply With Power Factor Correction

In recent years, the switching power supply is gradually become the focus of research at home and abroad, with the continuous development of power electronic technology. The improvement of the performance is promoted by the new situation’s needs under the contemporary, and the study of switching power supply needs to be done more in-depth research for improving the performance. In this paper, to improve the switching power supply’s output stability and dynamic response speed, the phase-shifted full-bridge ZVS switching power supply with power factor had been carried on the research, mainly including the following aspects.Firstly, based on the overall design of switching power supply’s scheme, the functional structure was selected, according to the technical requirements, including the single-stage Boost PFC circuit and later-stage DC-DC conversion circuit. Aiming at the lagging arm hard to realize ZVS, the auxiliary resonant network is added. And its working principle is described in detail.Secondly, the cycle switch average model method and the state space average method are respectively used to analyze and establish the mathematical model for the PFC circuit and DC-DC circuit with the auxiliary network. The parameters of the components of the structure model are calculated and selected according to the performance’s requirements. Aiming at the problem of low power factor and large current ripple, the voltage and current double close-loop PI controller is designed. The self-tuning PID controller with system identification is designed to deal with the problem of the poor stability and poor anti-interference, to achieve control of the switching power supply.Finally, the PWM phase shift pulse model, PFC correction model and self-tuning PID control model are established by MATLAB software. Based on the simulation of the model, the simulation model of the whole system is established and simulated, its simulation results show that the PFC circuit by the double closed loop PI can’t only improved the power factor, but also provide a stable 400 V DC voltage to the later-stage circuit. And the later-stage DC-DC circuit has more stability output and faster response speed under the self-tuning PID control. In a word, the rationality of switching power supply’s design with power factor correction is verified by the simulation results.