Isolated microgrid (IMG) power systems face the significant challenge of achieving fast power sharing and stable performance. This paper presents an innovative solution to this challenge through the introduction of a new droop control technique. The conventional droop controller technique used in inverter-based IMG systems is unable to provide satisfactory performance easily, as selecting a high droop controller gain to achieve fast power sharing can reduce the system’s stability. This paper addresses this dilemma by proposing a modified droop control for inverter-based IMGs that effectively dampens low-frequency oscillations, even at higher droop gain values that would typically lead to instability. The design is described step-by-step, and the proposed controller’s effectiveness is validated through time domain simulation analysis. The results demonstrate the significant improvement in stability and fast power sharing achieved with the proposed controller. This innovative technique presents a promising solution for achieving fast power sharing and stable performance in IMG power systems.

Recently, Modular Multilevel Converter (MMC) has become one of the most popular converters in medium / high power applications. In this paper, a new technique is presented to decrease the computational time of the MMC by using switching state grouping for the predictive controller. The proposed technique has the ability to control the output current, minimize the circulating currents, and balance all capacitor voltages, simultaneously. For a predefined number of MMC submodules (SMs), the number of the available switching states is known. The proposed technique uses two stages of predictive modules. In the first stage, the switching states of the MMC are divided equally into a number of groups, controlled simultaneously by same number of predictive modules. The optimal number of the switching state groups in the first stage is obtained. In the second stage, only one predictive module is used to obtain the optimal switching state of the MMC without any other complexities or additional sorting controllers. The effectiveness of the proposed control technique has been verified by using MATLAB/SIMULINK software considering steady state and dynamic analysis. The results of the proposed technique are compared with the conventional one in terms of computation time, verifying a better performance of the proposed method.

Supplying electric energy in remote areas presents a significant challenge due to their relatively far distance from the main grid, low population density, high infrastructure costs, and limited resource. One promising solution to this challenge is the isolated hybrid microgrids (MGs) which can deliver reliable electricity and support economic development. The current work introduces an optimal design of isolated hybrid MGs for remote areas, whereas, a small Nubian village in Aswan, Egypt (a desert climate region) is taken as a case study. The study mainly relies on techno-economic and environmental analyses for different microgrid configurations. The analysis has been carried out utilizing Hybrid Optimization Model for Electric Renewable (HOMER Pro software) to find the least-cost design among hundreds of alternatives based on the weather conditions in this area. Recently, incorporating the renewable energy sources (RES) into local power networks is among the most prominent research areas. Although many typical components can be used to develop the required microgrid system, there are also many limitations on these components, such as resources availability and costs. Several photovoltaic (PV) /wind/diesel/storage Hybrid Energy Systems (HES) have been studied in this paper. Additionally, the effectiveness of a mechanical PV tracking system and impact of battery technologies, such as lead-acid and lithium-ion on the overall costs of the energy system has been discussed. The proposed analysis shows that the PV-wind-lithium-ion battery energy system with vertical-axis PV tracking system is the most economical option, which attains a Net Present Cost (NPC) of $853,634.53 and a cost of energy (COE) of $0.255 and produces acceptable environmental gas emissions of 64018.15 kg/yr. Besides, a 7 years payback of the proposed microgrid system (25-years-lifetime) has been attained.

Sierra Leone is suffering from a persistent electricity gap that has crippled its economic growth and prevented it from attaining several health and education development goals. This persistent electricity gap has generated significant interest in tackling the country’s long-lasting energy deficiency. Providing electricity in a reliable, sustainable, and cost-effective manner in Sierra Leone requires adopting robust integrated energy planning and appropriate technologies. Despite various interventions by the government, a balance between electricity demand and supply has yet to be achieved. Using the Long-range Energy Alternatives Planning System (LEAP), this work assesses Sierra Leone’s energy supply and demand for 2019–2040. We developed three case scenarios (Base, Middle, and High) based on forecasted demand, resource potential, techno-economic parameters, and CO₂ emissions. The Base case considers the electricity sector as business as usual, the Middle case examines the electricity sector reform roadmap and the prospect of integrating renewable energy into the power system, and the High case examines the sustainable development of the power generation system considering the electricity sector roadmap. As part of this study, we analyze potential alternatives to conventional electricity generation systems aimed at providing electricity in a sustainable, reliable, and affordable manner, including the use of renewable energy sources and technologies with less CO₂ emissions. Model results estimate an increase in electricity demand of 1812.5 GWh, 1936 GWh, and 2635.8 GWh for Base, Middle, and High cases respectively. Also, there is a reduction in production, fuel cost, and CO₂ emission in the High case to the Base case by 67.15%, 35.79%, and 51.8%, respectively. This paper concludes with recommendations devised from the study results for the power system of Sierra Leone.

This paper presents a new phase-shift modulation for isolated dual active bridge (DAB) direct current–direct current (DC–DC) converter. The proposed technique aims to minimize the maximum current stress of the converter, which could directly increase the efficiency and reduce the device losses. This modulation technique controls the converter power through only two phase-shift angles or two degrees of freedom; one phase shift is used between the legs of its first bridge and the other one between the legs of the second bridge. Although the traditional single-phase shift (SPS) technique has only one degree of freedom, it suffers from many drawbacks in terms of high current stress and reverse circulating power flow, which decrease the converter efficiency. On the other hand, increasing the number of phase-shift angles can enhance the system performance but also increase the control complexity. Thus, a comparative analysis between the proposed modulation technique and the traditional SPS was conducted; the new method showed better performance in terms of current stress reduction, along with implementation simplicity.