基于脉宽调制的电流断续型谐振变换器

Discontinuous Current Mode Resonant Converter with Pulse Width Modulation Control

该文提出一种基于脉宽调制的电流断续型谐振变换器,并对其进行深入研究。该变换器采用定频脉冲宽度调制控制,其在一次侧桥臂增加了辅助电感和辅助电容,通过调节一次侧桥臂驱动信号的占空比可以改变桥臂中点之间的电压幅值,继而可以调节变换器的电压增益。通过合理的参数设计,变换器的谐振电流工作在断续模式,因此不存在无功电流。同时,该变换器的所有开关管皆可实现软开关,减小了开关损耗。该文首先对变换器的工作原理及开关模态进行分析;然后结合变换器的工作特性,推导变换器的电压转换增益、软开关条件以及断续工作的条件,并且提出一种参数设计方法;最后研制了一台1000W的样机来验证变换器的可行性与理论分析的正确性。

This paper proposes a discontinuous current mode resonant converter with pulse width modulation(PWM)control.The fixed-frequency PWM control is employed,and an auxiliary inductor and an auxiliary capacitor are added to the primary side switch network.By adjusting the duty cycle of the drive signal of the primary side switch,the voltage amplitude between the midpoints of the bridge arm can be changed,and then the voltage gain of the converter can be adjusted.The resonant current works in discontinuous mode through a suitable parameter design for the converter,so there is no reactive current.Meanwhile,all switches can realize soft-switching,which reduces the switching loss.This paper first analyzes the working principle and operating modes of the converter.Then,the characteristics of the converter,including the voltage gain,soft-switching conditions,and discontinuous current mode conditions,are deduced,and a parameter design method is proposed.Finally,a 1000W prototype is built to verify the feasibility of the converter and the correctness of the theoretical analysis.