Integrated Inertia Control Method for Off-Grid Hybrid Microgrid Based on Nonlinear Adaptive Droop Control

In the off-grid operation mode, AC/DC hybrid microgrids often face the problems of poor stability of system power balance and slow switching rate of interconnection converters. In order to solve the above problems, this paper proposes a comprehensive control strategy based on the smoothing exponential function for improved droop control and nonlinear adaptive control of wind turbine and energy storage. Firstly, the setting of output active and reactive power ratings is changed in the IC control, and the continuous exponential function is introduced to replace the traditional segmented droop control, so as to accelerate the power flow between sub-microgrids and ensure the power balance of the system. Secondly, the nonlinear adaptive droop control with PI feedback was introduced into the control of AC side fan-energy storage, which improved the dynamic response speed of the system. Finally, Matlab/Simulink simulation analysis is carried out to verify that the proposed control strategy not only accelerates the speed setting of the exchange power of the bidirectional AC-DC converter, but also effectively improves the steady-state performance of the AC/DC hybrid microgrid when the sub-microgrids do not communicate with each other.