A novel control approach to improve the stability of hybrid AC/DC microgrids

Abstract

Overall, voltage and frequency(V/F) stability are essential in microgrids (MGs) to ensure reliable and high-quality power supply for critical loads and to support the integration of renewable energy sources (RESs) while maintaining the stability of the power system. Therefore, V/F stability is particularly important for causes such as load balancing, quality of power supply, renewable energy integration, and grid stability. This study aims to introduce an interactive control system for hybrid MGs (HMGs) based on distributed energy resources (DERs). Here, the defined control strategy objective is to ensure the four system parameters’ stability, including voltage/frequency (V/F) and active/reactive (P/Q) power for the units. In this study, the research innovation consists of two layers. The first layer aims to adjust the unit V/F, using an internal voltage and current controller loop combined in the power droop controller (PDC). The second layer is concerned with the steady-state error minimization, created in the first layer due to the droop controller performance. Therefore, the secondary distributed V/F control strategies are designed based on finite-time consensus theory (FTCT) owing to its resistance and stability against various load perturbations and system disturbances, which makes flexible convergence time possible according to different user preferences and operating conditions. The simulation results prove the efficiency of the proposed method strategy. Furthermore, the values of improving the amplitude of oscillations and fluctuations for V/F components vary from 0.02pu-0.2pu and 0.178pu-0.216pu, respectively.