Disturbance Observer-Based Frequency Regulation for Shipboard Microgrid With Communication Delay

Load frequency control of power systems is inherently a disturbance rejection issue. This paper proposes a disturbance observer-based frequency regulation approach for a shipboard microgrid system with communication delay. The proposed control method consists of the design of both disturbance observer and load frequency controller. The design of disturbance observer involves the acquisition of nominal model and the tuning of Q-filter. The nominal model is obtained via the complex curve fitting technique. Whereas the load frequency controller is designed by the frequency response model matching approach. The maximum sensitivity index is utilized as a robustness specification to tune both Q-filter and load frequency controller. The advantage of the proposed method is that inverse response process dynamics are considered into disturbance observer design to obtain better modeling accuracy and frequency regulation performance. Simulation examples including comparison with classical methods are presented to demonstrate the effectiveness of the proposed method.