ABSTRACT

Tight voltage regulation of the DC microgrid bus may lead to instability issue which leads to microgrid system collapse. Constant power load (CPL) is a serious problem that exists in cascaded power electronic converters which must have a robust controller to mitigate instability issue. The controller based on mathematical model is vulnerable to model mismatch which could lead to instability especially with highly nonlinear plant. Boost converter feeding CPL is a highly nonlinear non-minimum phase system which is difficult to control based on mathematical model. In this paper a supervisory stable Fuzzy Logic Controller (SFC) based on Lyapunov theory is designed to mitigate the instability issue that is caused by the negative incremental impedance which behaves as CPL of dc boost converter. The proposed SFC is able to stabilise the output voltage of the boost converter under nominal and uncertain conditions. The proposed controller is validated through simulation using Matlab/Simulink. To the best of the authors’ knowledge this method hasn’t been introduced before.

摘要

直流微电网母线的严格电压调节可能会导致不稳定问题，从而导致微电网系统崩溃。恒定功率负载 (CPL) 是级联电力电子转换器中存在的一个严重问题，它必须具有稳健的控制器来缓解不稳定性问题。基于数学模型的控制器容易受到模型失配的影响，这可能导致不稳定，特别是对于高度非线性的对象。升压变换器馈电 CPL 是一种高度非线性的非最小相位系统，难以基于数学模型进行控制。本文设计了一种基于 Lyapunov 理论的监督稳定模糊逻辑控制器 (SFC)，以缓解由负增量阻抗引起的不稳定性问题，该阻抗表现为直流升压转换器的 CPL。所提出的 SFC 能够在标称和不确定条件下稳定升压转换器的输出电压。所提出的控制器通过使用 Matlab/Simulink 的仿真进行验证。据作者所知，这种方法以前没有被介绍过。