基于改进恒导通时间控制的临界连续导通模式Boost功率因数校正变换器

Improved Constant On-Time Control of Boundary Conduction Mode Boost Power Factor Correction Converter

为改善临界连续导通模式(BCM)Boost功率因数校正(PFC)变换器输入电流总谐波畸变率(THD),该文提出一种改进恒导通时间(COT)控制,分析改进COT控制对输入电流THD和变换器效率的影响;通过改进电流过零检测(ZCD)电路实现电感电流过零信号的提前检测,补偿信号传播延时的影响,缩短甚至消除反向谐振过程,改善输入电流THD的同时不增加控制的复杂度。最后,该文搭建一台160W BCM Boost PFC变换器实验样机,验证所提改进COT控制的可行性和有效性。

In order to obtain low input current total harmonic distortion(THD)of boundary conduction mode(BCM)Boost power factor correction(PFC)converter,an improved constant on-time(COT)control is proposed in this paper,and its influence on input current THD and efficiency is also analyzed.Furthermore,an improved zero-current-detection(ZCD)method is adopted to realize the early detection for ZCD signal.The influence of signal propagation delay is compensated,and the reverse resonance process is shortened or even eliminated,thereby improving the input current THD without increasing control complexity.Finally,an experimental prototype of a 160W BCM Boost PFC converter is established to verify the feasibility and effectiveness of improved COT control.