A novel flexible power support control with voltage fluctuation suppression for islanded hybrid AC/DC microgrid involving distributed energy storage units

Abstract

In this paper, a novel flexible power support control with voltage fluctuation suppression is proposed for islanded hybrid AC/DC microgrid involving distributed energy storage units. The virtual inertia and the interactive relationship between DC bus voltage and AC frequency are introduced into energy storage units (ESs) both in AC and DC subgrids. Therefore, mutual power support from opposite subgrid can be realized and the system inertia can be enhanced while the AC frequency and DC bus voltage are managed. Then, the active power reference of bidirectional interlinking converter (BIC) is modified with the proposed control strategy to achieve proportional power sharing in the whole islanded hybrid AC/DC microgrid. In addition, a controller based on linear active disturbance rejection control (LADRC) is designed according to the BIC model to suppress AC bus voltage fluctuation by using the estimates of disturbances obtained from linear extended state observer (LESO). Finally, stability of the system is analyzed and the results of an RT-LAB-based real-time simulation platform verify the correctness and effectiveness of the proposed control strategy.