电压模式控制Buck与源变换器级联的稳定性分析

Stability Analysis of Cascading Source Converters with VMC Buck Converters

不同的变换器之间构建一个级联系统,相互作用是其核心问题.在电压模式控制下Buck与其他变换器级联可能产生性能退化和不稳定.本文利用Buck变换器的小信号模型,设计了使变换器具有良好动态性能的PI控制器.提出了阻抗比判据通过图形化判定,以Nyquist稳定判据来评估此级联系统的稳定性,并构建了闭环级联变换器的仿真模型,提供了一个在电压模式控制下Buck变换器在级联应用的解决方案,以保持级联系统的稳定性和良好的动态性能.

The interaction between different converters is the core issue of building a cascade system.Buck converter under voltage mode control cascading with others may cause performance degradation and instability.In this paper,by using the small signal model of Buck converter,the converter is designed with the PI controller leading to a good dynamic performance.The graphical impedance criterion combined with Nyquist stability criterion is put forward to evaluate the stability of the cascade system,and simulation model of a closed-loop cascade converter built,application solution is provided for a Buck converter when being cascaded under voltage mode control,as well as keep stability and good dynamic performance of the cascade system.