电压型纹波准定频控制SIDO变换器稳定性分析

Stability Analysis of Voltage-ripple Quasi-fixed-frequency Control for SIDO Converter

电压型纹波变频控制技术因其轻载效率高、瞬态响应速度快,在开关变换器中得到广泛应用,但其稳定性受输出电容等效串联电阻(ESR)影响,同时开关频率宽范围变化使得滤波器的设计变得困难。此处提出一种适用于单电感双输出(SIDO)开关变换器的电压型纹波准定频控制技术,不同于现有的电压型纹波变频控制单输出开关变换器,此处所提控制技术不仅可以有效解决输出电容ESR导致的稳定性问题,而且变换器开关频率变化范围小。此处首先阐述电压型纹波准定频控制的工作原理;然后利用分岔图分析输出电容ESR和负载电阻变化时变换器的工作状态;最后搭建仿真和实验平台,验证理论分析的正确性。

Voltage-ripple variable-frequency control technology is widely used in switching converters due to its high light-load efficiency and fast transient response speed.However,its stability is affected by the equivalent series resis-tance(ESR)of the output capacitor,and the switching frequency varies in a wide range causes the filter design dif-cult.A voltage-ripple quasi-fixed-frequency control technology is proposed for single-inductor dual-output(SIDO)swi-tching converters.Unlike the existing voltage-ripple variable-frequency control single output switching converters,the proposed control technology not only effectively solves the stability problem caused by output capacitor ESR,but also has a small range of converter switching frequency changes.Firstly,the working principle of voltage-ripple quasi-fixed-frequency control is explained.Then,the bifurcation diagram is used to analyze the working state of the converter wh-en the output capacitor ESR and load resistance change.Finally,a simulation and experimental platform is built to ve-rify the correctness of the theoretical analysis.