基于变速趋近律的Buck型变换器抗扰动控制

Disturbance rejection control of Buck converters based on variable rate reaching law

针对带有输入电压波动、输出负载突变以及电感电容参数摄动等匹配和非匹配扰动的Buck型变换器系统,提出一种基于变速趋近律和扰动观测器的抗扰动控制方法.设计反余切型辅助函数构造变速趋近律,通过改变系统状态的收敛速度,保证系统具有较快的瞬态响应速度和较小的控制器抖振.通过对系统模型进行低通滤波,设计一种新型扰动观测器估计系统匹配和非匹配扰动.该观测器只包含一个设计参数,且无需对系统状态量求导,可以避免因求导带来的系统噪声放大问题.最后,基于李雅普诺夫稳定性理论给出观测误差和输出电压误差的收敛性分析,并通过仿真和实验对比验证所提方法的有效性.

A disturbance rejection control scheme based on variable rate reaching law is proposed for Buck converters with matched and mismatched disturbances including input voltage variations, output load mutations, inductance and capacitance perturbations. The variable rate reaching law is constructed by designing an arc cotangent function, such that the convergence rate of the system states is changed to guarantee the fast transient response speed and reduce the controller chattering. By low-pass filtering the system model, a novel disturbance observer is designed to estimate the matched and mismatched disturbances. The developed disturbance observer includes only one design parameter, and the differentiation of the system states is not needed in the disturbance observer, such that the noise amplification problem resulted from the differentiation can be avoided. Finally, the convergence analysis of the observation error and output voltage error is provided based on Lyapunov stability synthesis. Comparative simulations and experiments validate the effectiveness of the proposed scheme.