基于全桥结构全数字控制单级隔离PFC变换器

提出了一种适合中功率应用场合的功率校正电路的解决方案.采用单级隔离型全桥结构并结合传统Boost型功率因数校正(Power Factor Correction,简称PFC)的输入电感和RCD箝位电路作为主电路,融合基于数字信号处理器(Digital Signal Processing,简称DSP)的全数字控制方案,对中大功率单级隔离型PFC进行了研究.在应用主电路工作原理和小信号动态模型的基础上,分析了该模型的数字控制设计方法.所采用的双环全数字控制方案同时具有良好的动态响应和稳态调节特性,可消除变压器的偏磁现象.最后基于提出的拓扑及控制方案制作了3kW,110kHz的样机.实验结果表明,该变换器的满载功率因数达0.995,效率超过92%.

Fully Digital Controlled Single-Stage Isolated PFC Converter based on Full Bridge Structure

This paper deals with a Power Factor Correction(PFC) converter which is appropriate to medium power level application.Isolated PFC converter is investigated by combining isolated full-bridge(FB) structure within input in-ductor of conventional Boost type PFC and RCD clamp snubber circuit with flexible and proficient digital control strategy.The digital control design consideration is analyzed based on the operation principle and small-signal dynamic modeling.Dual-closed-loop control strategy is adopted and the digital control strategy features fast dynamic response and excellent steady regulation charac-teristic.The problem of magnetic bias for the transformer which occurs in application of analogy control is successfully solved for excellent performance of digital controller.Finally,an experimental prototype is built to verify the performance of the converter.