Research On ZVS DC-DC Converter Using Non-Dissipative Snubber Circuit

With the advancement of technology and the development of the electricity industry, switching supply has been widely used for industry, transportation, electricity, communication, household appliances etc. And it has been a very active hot technology. But the conventional converter operates in hard switching, low switching frequency and low efficiency. These reasons severely constrain the switching supply towards miniaturization, modular direction. So the soft-switching PWM (pulse width modulation) technology is proposed. And it makes converter that operates in high efficiency and high frequency as possible. Based on this background, this paper studies the ZVS (zero-voltage switching) PWM DC-DC converter.This paper briefly introduces development process of the soft switching technology and analyzes operating process and disadvantages of the conventional phase-shifted full bridge ZVS PWM DC-DC converter, such as the narrow ZVS range, the severe loss of the duty, the severe secondary side rectifier voltage rings and low conversion efficiency etc. According to above disadvantages, this paper proposes a novel ZVS PWM DC-DC converter using non-dissipative snubber circuit and analyzes its operating principle and soft switching achievement condition in detail. Based on equivalent switching circuit model and combined with phase-shifted control mode and characteristics of soft-switching resonant circuit, the model of improved converter is established. The nonlinear dynamics behavior of the improved converter can be demonstrated by using this model.Based on the analyzing of the theory, simulation of the improved converter is researched, and the main circuit, the protection circuit and parameters of components are designed. The control circuit is composed of the PCB grounded on TMS320F2812 DSP and its evaluation module. It mainly generates trigger signals and protection signals to implement partial functions of the converter. This paper designs the software of the system, achieves the double closed-loop control of the system and improves the static and dynamic performance of the converter.To validate the performance of the improved full-bridge ZVS PWM DC-DC...