一种新型临界模式控制的变频软开关全桥DC/DC变流器

A Novel Variable Frequency Soft Switching Full-bridge DC/DC Converter With Critical Continuous Mode Control

储能电感位于原边的全桥DC/DC变流器（full bridgeconverter with primary side energy storage inductor,FB-PESI）,采用传统的固定频率、移向控制（phase-shift,PS）方式时主要工作于断续导通模式（discontinuous conductionmode,DCM）,不适合应用于宽范围电压输入的场合。为克服PSFB-PESI变流器的这一缺点,提出一种新型的采用变频（variable frequency,VF）控制策略的FB-PESI DC/DC变流器（VFFB-PESI）。该VFFB-PESI变流器不仅保留了PSFB-PESI变流器宽范围软开关、高效率、高功率密度的优点,还可始终工作于临界导通模式（critical continuous operation mode,CrCM）,从而在宽输入电压范围内均可获得较高的变换效率。同时给出了针对该VFFB-PESI变流器的损耗分析方法和优化设计流程。通过制作的300 W、200~400 V输入、12 V输出样机实验,验证了理论分析的正确性。

The Full Bridge DC/DC converter with primary side energy storage inductor（FB-PESI） is not suitable for the applications with wide input voltage range because of its discontinuous conduction mode（DCM） with traditional constant switching frequency,phase-shift（PS） control strategy.This paper proposed a novel variable frequency（VF） PWM controlled FB-PESI DC/DC converter（VFFB-PESI）,which not only reserved the advantages of PSFB-PESI converter,such as,wide soft-switching range,high frequency and high power density,but also can always operate in the critical continuous operation mode（CrCM）,and obtain relatively high conversion efficiency over a wide input voltage range.The losses evaluation and optimal design procedure are also included.A 300 Watts prototype with 200~400 V input and 12 V output is built up.Experimental results verify the operating principle of the proposed converters.