Coordinated controller design and stability analysis of DC microgrid with constant power load

摘要

This paper presents a coordinated approach for the tuning of power electronic controllers and stability analysis considering constant power load in a DC microgird. The system consists of AC and DC loads, comprising of constant voltage and constant power characteristics. Constant power loads can be a potential source of instability for the system to which it is connected. Coordinated tuning of all the controllers is proposed to ensure enhanced dynamic stability of the system under the scenario considered. An eigenvalue based objective function is employed to find the optimal gains of all the controllers using swarm based intelligent optimization technique. Further, the stability of the system is verified using the impedance based stability criterion proposed by Middlebrook. The results are verified using time domain simulations under different system conditions. Time domain simulations are carried out in MATLAB/Simulink environment.