Soft switching characteristics of a novel and efficient DC / DC converter

LIU Guo-qiang， PANG Jin-yong， XIE Yu， WANG Zheng-shi， SU Xiu-rong
（College of Electrical Engineering， Zhejiang University， Hangzhou 310027，China）

Abstract：Aiming at solving the problems of magnetic bias that may exist，large current stress，poor soft switching performance and duty cycle loss of phase-shift full-bridge circuit，a novel circuit topology that combines Boost circuit，phase-shift full-bridge circuit and resonant circuit was proposed. The working principles of the circuit were described firstly，and then the key waveform diagram of the circuit was given. A detailed study focusing on the conditions to achieve soft switching on the basis of working status and mathematical models with fundamental component method was made，and the design method to realize the soft switching of the novel DC/DC converter was given. The existing problems were studied and solutions were proposed. A 1 000 W prototype was developed. The experimental results indicate that the converter has a good performance，and verifies the correctness of the analysis and calculation.
Key words： phase-shift full-bridge（PSFB）； DC/DC converter； series resonant；soft-switching characteristic； efficiency