DC microgrids (MGs) have gained significant attention for its remarkable advantages of integrating renewable energy sources (RESs) and electronic loads. In order to improve the operational performance of the DC MG in both steady and transient states, a fully distributed fixed-time based secondary controller is proposed to remove the DC voltage deviation and provide proportional current sharing simultaneously. The secondary control of each DG consists of a fixed-time consensus-based current and voltage regulators that use relative information from the neighboring DGs through a sparse communication network. In contrast to the existing controllers, the proposed controller is distinguished with its accelerated convergence time which does not rely on the initial values. Besides, the stability of the proposed method is verified through the Lyapunov function. A simulation model is built in PLECS to prove the effectiveness of the proposed control strategy. Some scenarios are introduced to validate the link-failure resiliency, plug and play capability, the scalability, and the feasibility under various time delays. Meanwhile, a DC MG experimental prototype is built to verify the controller performance.

This paper addresses a fully distributed hierarchical coordination controller, which minimizes the global total generation cost (TGC) for a cluster of DC microgrids (MGs) through handling the optimal power-sharing between MGs. It consists of local and global tertiary controllers, in which a two-layer communication network is modeled to share information with a reduced complexity as one or some distributed generators (DGs) of each MG are pinned from the local network to broadcast the information between MGs at the global network. Under this control structure, the global tertiary controllers, based on dynamic consensus technique, generate the global optimum incremental cost (IC) reference to attain the entire cluster's economic operation. Moreover, using pinning-based leader-follower consensus algorithm, the local tertiary controllers assign MG average voltage reference at which the ICs of all DGs are matched at the global reference to ensure optimal operation of the cluster with considering DGs generation boundaries. Finally, the nominal voltage set points of each DG can be determined by the secondary controller to guarantee the generation-demand power balance. The feasibility of the proposed controller is demonstrated by simulation and experiment under various test scenarios.

Load Frequency Control (LFC) plays a crucial role in controlling power exchanges within multi-area networks, ensuring grid stability in modern power systems. This study proposes a fractional calculus-based TFOID (Tilt fractional order integral and derivative) control for frequency regulation loops. The effectiveness of the proposed controller against existing control techniques such as Proportional Integral Derivative with Filter (PIDF) and Fractional-Order Proportional–Integral–Derivative (FOPID) has been assessed. The imperialist competitive algorithm (ICA) has been utilized to find the optimal parameters of the controller. Five different case studies investigate LFC strategies in various scenarios within modern power systems. Firstly, it explores LFC under the high penetration of hybrid RESs in multi-area networks, examining the challenges and solutions associated with integrating a substantial amount of RESs. Secondly, the study delves into LFC in the context of power deregulation, navigating the complexities of competitive power markets where consumers have the freedom to choose their electricity suppliers. Thirdly, it investigates LFC models coupled with DC links, exploring the integration of direct current links to enhance frequency control strategies. Fourthly, the case study addresses LFC models tailored for single-area grids to the specific power requirements and challenges of regional power systems. Lastly, it examines LFC models in multi-micro grid scenarios, acknowledging the dynamic landscape of interconnected microgrids and their implications for frequency control. Statically data in terms of settling time, overshoot, undershoot, and fitness function validated the superiority of the proposed hybrid controller. The proposed controller reduces undershoot, overshoot, and settling time by approximately 90.91%, 66.78%, 49.40% and 78.89%, 50.49%,36.83% compared to the PIDF and FOPID controller in multi-load perturbation. Other simulated results in terms of Δ F₁ , Δ F₂ , and Δ P_tie also validated the excellence of the considered controller.

This paper presents a fully distributed finite-time control strategy to optimize the load power dispatch of islanded DC microgrids (MGs) in a finite-time manner. In which, based on the finite-time consensus protocol, a power optimizer is developed to realize MG’s optimal operation by matching the incremental costs (ICs) of all the distributed generators (DGs) within a finite settling time. Moreover, the finite-time voltage regulator restores the average voltage across the MG to preserve the power balance among generation and demand. The developed controller achieves an improved performance with an accelerated convergence rate, which is important for MGs with a high penetration level of renewable distributed generators (RDGs), over the conventional distributed secondary controllers. The convergence of the proposed controller is confirmed by a thorough analysis. The performance of the developed controller is validated through simulation and experimental results under different case studies.

The integration of adjacent dc microgrids (MGs) results in the formation of a dc MG cluster which can increase the system power supply capacity. This article proposes a control strategy for dc MG clusters which combines communication-free control and distributed fixed-time control to simultaneously achieve current sharing and voltage regulation with excellent transient characteristics. Firstly, a communication-free control, which presents greater flexibility than the distributed control, is used in the dc MG layer. Subsequently, the distributed fixed-time control is used in the dc MG cluster layer to balance the output current of each MG. The optimal control parameters are obtained by using the zero-pole distribution diagram and establishing a small-signal model of the dc MGs; the stability of the proposed control strategy is also verified. Different scenarios are considered to validate the plug-and-play capability and controller performance by using a dc MG experimental prototype. Real-time hardware-in-the-loop verification containing three MGs is conducted using two RT-boxes to prove the scalability of the proposed cluster control.