Independence in energy generation, attention to environmental issues, limited fossil fuel sources, and easy access to renewable energy sources have led governments, industry, and engineering to use renewable energy sources for decades. Meanwhile, microgrids for residential, commercial, industrial, and military purposes are widely used using these resources. However, the use of these sources in microgrids is associated with the challenges of uncertainty and lack of inertia. Therefore, by using energy storage systems in DC microgrids, the mentioned challenges can be overcome by emulating inertia. The purpose of this paper is to present a virtual compounded DC machine (VCDCM). The governing equations of the compounded DC machine have been accurately studied and the desired characteristics of this machine have been used to emulate inertia through the control of the buck‐boost converter connected to the energy storage systems in the concept of VCDCM. Proposed scheme; in an islanded microgrid with maximum components and standards required; Simulated in the Simulink/MATLAB environment. The results obtained under different scenarios confirm the ability of the proposed scheme to stabilize the DC bus voltage. The magnitude of DC bus voltage deviation from the reference value when an error occurs has resulted in a significant reduction compared to conventional schemes.

This paper presents the principles of operation, electromagnetic behavior analysis and a search technique based on finite element analysis in order to determine the optimum control parameters of improved flux path Homopolar brush less DC motor (IFP-HBLDC). In the proposed IFP-HBLDC structure, permanent magnet is replaced by a DC excited assisted field coil to control and regulate the flux. In this paper, for different values of speed, maximum torque is determined by calculating the optimal turn-on and turn-off angles and the optimal field current which provides more flexible control over wide ranges of speed. To such aim, the behavior of the commutation angles is analyzed first by a numerical technique using the 3-D electromagnetic field analysis, which the analysis of the collected data has shown that the commutation angles providing the maximum electromagnetic torque. The technique was successfully used offline to determine the optimum firing angles for achieving highest drive efficiency to maximize the electromagnetic torque in a prototype 1.5-kW three-phase IFP-HBLDC motor drive intended for variable speed application. The performance prediction and test results are found in good correlation.

The primary goal of grid‐connected microgrids is to control the active and reactive power, which is reachable by the inner current control loop in the control structure of power converters. However, when facing unbalanced conditions, the inner current control loop implemented in the dq frame does not function properly. In such conditions, the popular current control loop malfunctions since there is an oscillatory coupling between harmonic components. Therefore, in this study, a new harmonic detector based on decoupled double synchronous reference frame within the current control loop is proposed in which the oscillatory coupling between harmonic components is eliminated, and the overall performance of the power converter control system is significantly improved. The performance of the precisely developed mathematical models is verified by Matlab simulations, and the simulation results confirm the accuracy and proper operation of the proposed strategy.