The penetration of renewable energies in the context of distributed generation represents challenges such as maintaining the reliability and stability of the system and considering the random behavior proper of generation and consumption. In this context, microgrids make it possible to manage effectively the generation and consumption of this energy, incorporating, electronic power converters, energy storage systems, and hierarchical control schemes. This paper presents the modeling, design, and application of controllers for a photovoltaic inverter operating in island mode. For this application, the photovoltaic inverter regulates the inverter output voltage via two control configurations implemented to follow the voltage reference imposed by the scheme droop. The first control scheme is configured with a two-degrees-of-freedom controller plus a repetitive controller. In this configuration, the repetitive controller is implemented in the direct loop. The second scheme is configured with an integral proportional controller—proportional controller plus a resonant controller. This configuration is formed by an integral proportional control in the direct loop plus a resonant controller and a proportional controller in the feedback loop. Both control configurations are implemented to improve the inverter disturbance rejection capability when it feeds both linear and non-linear local loads. In addition, these configurations allow the parallel connection of inverters with good performance, using a droop scheme that allows the parallel connection of converters. The tests are carried out by means of simulations using PSIMTM, which shows that, with the implemented controllers, the total harmonic distortion of the inverter output is below 5%, as recommended by the IEEE 519-1992 standard.

Laboratories across educational levels have traditionally required in-person attendance, limiting practical activities to specific times and physical spaces. This paper presents a technological architecture based on a system-on-chip (SoC) and a connectivist model, grounded in Connectivism Learning Theory, for implementing a remote laboratory in digital logic design using FPGA devices. The architecture leverages an Internet-of-Things (IoT) environment to provide applications and servers that enable remote access, programming, manipulation, and visualization of FPGA-based development boards located in the institution’s laboratory, from anywhere and at any time. The connectivist model allows learners to interact with multiple nodes for attending synchronous classes, performing laboratory exercises, managing the remote laboratory, and accessing educational resources asynchronously. This approach aims to enhance learning, knowledge transfer, and skills development. A four-year evaluation was conducted, including one experimental group using an e-learning approach and three in-person control groups from a Digital Logic Design course. The experimental group achieved an average performance score of 9.777, surpassing the control groups, suggesting improved academic outcomes with the proposed system. Additionally, a Technology Acceptance Model-based survey showed very high acceptance among learners. This paper presents a novel connectivist model, which we call the Massive Open Online Laboratory.

In the last three decades, the development of new electricity-generation strategies based on renewable energy has been promoted, which has made it possible to offset the increase in electricity consumption, reduce production costs, and positively impact climate change. These new-generation strategies are based on distributed generation (DG) at different points of the electrical power system, which has economic, social, and environmental impacts by reducing greenhouse gas emissions. The new concept of an electric microgrid, which is an integrated energy generation and management system with autonomous capacity, allows efficient production and consumption, with alternating current (AC) and direct current (DC) microgrids being available. This work presents a topology of direct current microgrids for island mode operation, which aims to supply electricity to variable and constant power loads (CPLs), as well as for the autonomous charging and discharging of batteries. To achieve this objective, a microgrid model is developed, current and voltage control loop controllers are designed, and their performance in different types of operation is analyzed. As a contribution to this work, the parasitic elements in the microgrid model are considered, and the design of the controller in the voltage loop is presented for the power supply to the local linear and non-linear loads, in addition to managing the energy coming from CPLs and controls the charge and discharge of the battery. To validate the performance of the controllers, three microgrid operation tests are carried out, which are presented in the Simulations section. In these tests, it is observed that with the PI controller in the voltage loop, the DC_Link signal presents transients with an amplitude of 5 V below and above the 200 V reference, which shows the poor performance of the controller. However, in all three tests with the modified PI-P controller, the DC_Link voltage remains constant at 200 V, with a negligible transient amplitude of almost 0 V, showing better performance.

This paper reports a remote laboratory architecture for Education 4.0 applied to Digital Logic Design courses using FPGA devices. The development of the proposed architecture is based on embedded systems, in which the V-model methodology and an Internet of Things (IoT) technological environment are applied. Nine laboratory exercises were designed for the proposed remote laboratory. To evaluate learners’ acceptance of the remote laboratory, the Technology Acceptance Model was used. An evaluation instrument comprising six variables and 21 pre-coded items on a Likert scale was designed and administered to 28 learners via a survey. The Cronbach’s alpha coefficients calculated for the six variables ranged from 0.72 to 0.91, suggesting adequate reliability of the evaluation instrument. The Wilcoxon signed-rank test was applied, yielding a p-value below the significance threshold of 0.001, which indicates statistical support for learners’ acceptance of the remote laboratory. Smart citations: https://scite.ai/reports/10.61467/2007.1558.2026.v17i1.1173Dimensions.Open Alex.