Fuzzy piecewise coordinated control and stability analysis of the photovoltaic‐storage direct current microgrid

Abstract

In order to ensure the safe and reliable operation of photovoltaic-storage DC microgrid in islanded mode, this paper proposes a piecewise coordinated control strategy based on fuzzy logic to independently judge the working mode of microgrid. Firstly, according to the operation characteristics of microgrid, the device-level control of each unit (photovoltaic, energy storage and load) is designed successively. Then, according to the requirement of supply and demand balance of microgrid, fuzzy logic is introduced to realize the independent division of threshold nodes on the basis of piecewise control, so as to ensure the fast switching of working mode and stable operation of the system in various complex environments, that is system-level control. And the method of impedance analysis is used to analyze the stability of microgrid under different working modes. Finally, the effectiveness and feasibility of the proposed coordination control strategy are verified by MATLAB/Simulink simulation results.