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This paper proposes a cooperative strategy for the flexible integration of stand-alone AC microgrids using an intermediate multiterminal DC link based on voltage source converters. The strategy manages cooperative power exchange between microgrids through a knowledge-based fuzzy inference system that relies on the current operating conditions of the microgrids. By determining the amount of power to be exchanged between microgrids to improve global reliability, the cooperative strategy achieves an overall reduction in load loss and an increase in the use of available renewable energy. Additionally, the multiterminal DC link provides complete isolation between microgrids, allowing for independent AC bus voltage regulation and management. The effectiveness and expandability of the proposed cooperative energy exchange strategy for enhancing the overall operation of multiple integrated microgrids have been fully verified by simulation and experimental validation. • Multy-Microgrid Power Exchange through a VSC-based multiterminal conversion stage with a common dc bus. • Knowledge-based cooperative Strategy deployed by means of fuzzy inference systems. • The proposed cooperative strategy is easy to expand to more than two Microgrids, requirements are also discussed. • Simulation and experimental validation of the proposed coordination strategy. [ABSTRACT FROM AUTHOR]

String inverter photovoltaic (PV) systems with bypass diodes require improved global maximum power point tracking (GMPPT) algorithms to effectively reach the absolute maximum power operating point. Several GMPPT algorithms have been proposed to deal with this problem, but most of them require scanning wide voltage ranges of the PV array from nearly zero voltage to open-circuit voltage that increases the scanning time and, in turn, causes energy loss. This paper presents a novel GMPPT method which significantly restricts the voltage window search range and tracks the global power peak rapidly in all shading conditions. Simulation tests and experimental comparisons with another GMPPT algorithm are presented to highlight the features of the presented approach. [ABSTRACT FROM PUBLISHER]

A complete design of a Takagi-Sugeno-Kang (TSK) fuzzy controller for a PWM boost DC-DC switching regulator operating at different steady-state voltages is presented. This controller performs a supervisory role through its region characteristic. On the one hand, the controller assigns different linear control laws according to the steady-state voltage value and limits their application to small-signal perturbations. On the other hand, the controller ensures a proper start-up to reach the desired steady-state voltage by means of properly saturating the PWM according to sliding-mode control principles. As a result, both an equalized small- signal behavior and a controlled start-up are achieved for different steady-state voltages, thus extending the features of the regulator. Simulation and experimental results carried out on a current-controlled boost regulator operating at two different steady-state. [ABSTRACT FROM AUTHOR]

The article discusses papers published within the issue, including one on an advanced technique for maximum power point tracking of wind turbines and another on the concept of smart panel device.

Nowadays, the increase in electric power coverage worldwide is a priority scope of the study, where Microgrids (MG) emerge as feasible solutions to supply electricity. The use of MG to provide energy to isolated communities, especially its use as Isolated Multi-Microgrid (IMMG) systems, has become an object of study worldwide. Different control techniques have been developed to improve and optimize the energy management system (EMS) associated with an isolated MG and new alternatives for energy exchange between IMMGs. However, the geographical location of a possible implementation of an MG directly affects the optimal dimensioning, the operating cost, and the environmental impact, among others. In this context, this work proposes a novel design of an EMS based on a fuzzy logic controller focusing on power exchange between IMMG systems. The proposed EMS aims to minimize the consumption of fossil fuels, reduce the total energy wasted by the power generation units, and keep the state-of-charge of the energy storage system (ESS) at safe levels to extend its useful life. Moreover, an ESS state of health analysis is presented to determine its degradation over time when applying the proposed EMS. In addition, the proposed EMS considers the uncertainties in the disconnection of any MG, ensuring the independent operation of each one. Simulation results are performed for a case study of an isolated community in the Amazon region of Ecuador. For this purpose, a group of microgrids is considered in three different scenarios. In the first scenario, there is no power exchange between the microgrids. In the second scenario, the microgrids exchange power using a simple EMS based on a set of analytical rules, and in the third scenario, the microgrids exchange power using the proposed EMS. The results show an improvement in the overall performance of the third scenario compared to the first two, both in reducing the energy wasted by the PV system and in the cost of fossil fuel. Finally, the experimental validation, using Typhoon Hardware-in-the-loop HIL-402 devices in real-time operation, highlights the proposed EMS's effectiveness and feasibility for IMMG systems. • A complete Fuzzy-based energy management system focusing on power exchange in multiple interconnected isolated microgrids. • A suitable solution for improving electricity access in rural communities. • An interconnected microgrid system that reduces the wasted power of generation units and extends the ESS's lifetime. • An experimental validation of IMMG using two Hardware-in-the-Loop Typhoon HIL-402 devices. [ABSTRACT FROM AUTHOR]

• Analyzes the development of power generation systems in the Galapagos Islands. • Describes the island's energy matrix and RES-based power generation proposals. • Presents a state-of-the-art analysis carried out to introduce RES in the Islands. • Analyzes the regulations and policies governing RES installation on the islands. The sources of electricity generation in the Galapagos Islands have been diversified due to the high risk represented by the use and transportation of fossil fuels and the application of the Zero Fossil Fuels initiative. This has increased the implementation of projects using different renewable energy sources. Despite being a World Heritage Centre, very little research has been carried out that presents the current situation of the electrical system in the Galapagos Islands. Therefore, this study reviews the current electricity sector situation in the Galapagos Islands. The characteristics of generation, distribution, and demand in the Galapagos Islands are presented. Also, the research studies and the regulations to be met for designing and implementing electric power generation projects based on renewable energy sources are detailed. In addition, this study presents the changes in the energy matrix of the Galapagos Islands in recent years, where the generation capacity and investment in hybrid systems (photovoltaic, wind, biomass, and vegetable oil - Jatropha) have been diversified and increased, encouraging research into new sources such as geothermal, biomass, waves, tides and green H2. Finally, the central policies and regulations that govern the installation of renewable generation systems in the Galapagos Islands are analyzed. [ABSTRACT FROM AUTHOR]

This paper presents the design of an energy management strategy based on a low complexity Fuzzy Logic Control (FLC) for grid power profile smoothing of a residential grid-connected microgrid including Renewable Energy Sources (RES) and battery Energy Storage System (ESS). The proposed energy management strategy uses generation and demand forecasting to anticipate the future behavior of the microgrid. Accordingly to the microgrid power forecast error and the Battery State-of-Charge (SOC) the proposed strategy performs the suitable control of the grid power. A simulation comparison with previous energy management strategies highlights the advantages of the proposed work minimizing fluctuations and power peaks in the power profile exchanged with the grid while keeping the energy stored in the battery between secure limits. Finally, the experimental validation in a real residential microgrid implemented at Public University of Navarre (UPNa, Spain) demonstrates the proper operation of the proposed strategy achieving a smooth grid power profile and a battery SOC center close to the 75% of the rated battery capacity. [ABSTRACT FROM AUTHOR]

• A model predictive control-based energy management for an electro-thermal microgrid. • The strategy minimizes operating costs and pollution avoiding battery degradation. • Analyze the state of health of the battery system to reduce degradation. • A comparison with a Unit Commitment approach under different generation scenarios. Access to electricity is a fundamental key to developing countries' growth. Microgrids (MG) have become potential solutions to provide energy to isolated rural areas in a safe and environmentally friendly way. Therefore, proposals for alternative solutions to bridge the electrification gap in the Ecuadorian Amazon – which has the most significant percentage of its population without access to electricity – are of significant interest. Consequently, this paper presents the design of an Energy Management System (EMS) based on Model Predictive Control (MPC) for an isolated electro-thermal microgrid comprising a photovoltaic generator, a diesel generator, a lithium-ion battery Energy Storage System (ESS), electrical loads, and a domestic hot water system. The EMS aims to supply energy reliably and safely, minimize the MG's operation costs, and extend the ESS's useful life while satisfying the end users' comfort. This study includes an estimated degradation model for the ESS's State of Health (SOH), an essential parameter contributing to reducing the microgrid's operating costs in the long term. Simulation results using one-year data present the influence of the prediction horizon on the MG's scheduling. In addition, the benefits of the proposed EMS are highlighted by comparing it with the results achieved by a Unit Commitment approach, where it is demonstrated that the proposed EMS presents a reduction in MG operating costs and greenhouse gas emissions while maximizing the utilization of renewable energy and extending the lifespan of the ESS. Finally, an experimental validation, using a Typhoon Hardware-in-the-loop HIL-402 device in real-time operation, stands out the effectiveness and feasibility of the proposed MPC-based EMS. [ABSTRACT FROM AUTHOR]

This paper presents an energy-balance control strategy for a cascaded single-phase grid-connected H-bridge multilevel inverter linking n independent photovoltaic (PV) arrays to the grid. The control scheme is based on an energy-sampled data model of the PV system and enables the design of a voltage loop linear discrete controller for each array, ensuring the stability of the system for the whole range of PV array operating conditions. The control design is adapted to phase-shifted and level-shifted carrier pulsewidth modulations to share the control action among the cascade-connected bridges in order to concurrently synthesize a multilevel waveform and to keep each of the PV arrays at its maximum power operating point. Experimental results carried out on a seven-level inverter are included to validate the proposed approach. [ABSTRACT FROM PUBLISHER]

Examines a fixed-frequency quasi-sliding control algorithm based on switching surface zero averaged dynamics (ZAD). Features of the sliding mode controlled buck inverter; Use of an analog signal conditioner; Overview of a field programmable gate array-based ZAD control loop implementation.