摘要
详细研究了移相控制全桥零电压开关脉宽调制变换器(FB-ZVS-PW M )的换流过程。分析得出,若考虑开关管关断过程中的电流下降特性,则当开关管关断时,在无损吸收回路的作用下,电路关断换流过程会出现两个不同的换流阶段,并在此基础上推导出这两个不同阶段的换流方程。针对其滞后桥臂负载电感偏小给零电压导通造成的困难,文中放弃了负载电流为恒流源的假设,推导出描述其换流过程的方程。基于这些方程,研究了实现软开关的条件,并从关断损耗和占空比丢失的角度探讨了吸收电容与电路最高工作频率的关系,给出了工程设计公式。仿真和实验结果验证了该方程的正确性。
The switching process of FB ZVS DC/DC converter based on phase-shift PWM control is detailed in this paper.If the current falling characteristic of power switch is considered,two transition processes come forth when the power switch is turned off.Based on the two processes,some equations are deduced.As known,the load inductance is very small when the lag legs are turning off,which causes a difficulty in ZVS.In order to describe the process,that asumption of the load current is current source being aborted,and some equations are deduced in detail.Based on the equations,the condition of ZVS is analyzed,and the engineering design method of highest working frequency is discussed,which is based on dissipation of turning off and duty cycle lose.The simulation and experiment results validate the equations.
出处
《电力电子技术》
CSCD
北大核心
2005年第2期108-110,共3页
Power Electronics
