Research On The Current-fed Push-pull Full-bridge Converter

This paper first introduces broadly application background and development overview of Bi-directional DC-DC Converters. Topologies of Bi-directional DC-DC Converters based on basic DC-DC Converters are given. Aiming at the applications of high power situation, a Current-fed Push-pull Full-bridge Bi-directional DC-DC Converter is researched in this paper.The basic principle is verified by simulation. In two operation modes, switch and body diode used as a rectifier have different influence on voltage spike when switch in the Push-pull circuit is turned off. Contrastive analysis and simulation with Saber are given. In boost mode, compared with the way switch used as a rectifier, body diode used as a rectifier can reduce voltage spike. But in buck mode, they have no difference. In order to avoid the bias-magnetic of the transformer, blocking capacitor is usually used in practical application. The feasibility of blocking capacitor used in two power flows is verified by simulation results.The analysis and design of an active clamped current-fed push-pull full-bridge bi-directional DC-DC converter is presented in this paper. By using an active clamp circuit, it can effectively eliminate voltage spike and obtain zero-voltage switching of auxiliary switch. The principle of operation in CCM is given in detail. Simulation results are given. The relationship of the input and output voltage is derived. The condition of realizing ZVS is given. The relationship of the condition of realizing ZVS and circuit parameters is analyzed. The design of main devices are given. Experimental results are given.