Waner Wodson Aparecido Goncalves Silva

This paper proposes a hierarchical control architecture for trajectory tracking of differential-drive nonholonomic mobile robots intended for the Very Small Size Soccer (VSSS) competition. The proposed framework integrates a high-level nonlinear trajectory-tracking controller, which computes the desired linear and angular velocity references based on the robot pose and prescribed trajectory, with a low-level Linear Quadratic Gaussian (LQG) controller responsible for the independent velocity regulation of the drive motors. The LQG controller combines optimal state feedback through a Linear Quadratic Regulator (LQR) with integral action and state estimation provided by a Kalman filter, enabling accurate velocity regulation in the presence of modeling uncertainties and measurement noise. The complete architecture is implemented on an embedded differential-drive robotic platform equipped with incremental encoders, vision-based localization, and an ESP32-based controller, and is validated exclusively through real-time experimental tests under practical operating conditions. The experimental evaluation includes wheel velocity step-response tests and circular and lemniscate trajectory tracking under both forward and reverse motion. The results demonstrate accurate wheel velocity regulation, effective attenuation of encoder measurement noise, consistent tracking of the prescribed trajectories, and experimentally measurable trade-offs between spatial tracking accuracy, wheel velocity regulation, and control effort under different trajectory geometries and motion directions. Overall, the proposed architecture provides a modular hierarchical framework that integrates nonlinear high-level trajectory tracking with optimal low-level velocity regulation for real-time autonomous mobile robot applications.

Maintaining a constant frequency is vital for grid stability and reliability, especially during dynamic changes in load and generation, which are caused by the increasing incorporation of renewable intermittent energy sources such as solar and wind power. These energy sources decrease the system’s inertia, which compromises the primary frequency regulation, a process historically sustained by the speed regulators of conventional synchronous generators. In this study, to mitigate this issue, we investigate a battery energy storage system (BESS) operating with virtual synchronous machine (VSM) control to provide ancillary services of primary frequency control. A multilevel cascade H-bridge static converter with eleven levels is controlled to emulate the dynamic behavior of a conventional synchronous machine, allowing primary frequency control support. The case studies are evaluated using Matlab/Simulink R2024a software and tested under contingency scenarios involving load rejection and step-load insertion within an isolated power grid comprising other synchronous machines, alongside an analysis of the BESS-controlled power dispatch. Our simulation results demonstrate that the energy storage system, operating under a virtual synchronous machine (VSM) strategy, effectively emulates the dynamic behavior of a conventional synchronous generator, enabling controlled active and reactive power dispatch. Furthermore, the proposed control strategy provides virtual inertia support, mitigating the Rate of Change of Frequency (RoCoF) following disturbances, improves the damping of frequency oscillations, and ensures a smoother frequency recovery after load variations. These findings indicate that the proposed BESS can provide effective primary frequency control support in power systems characterized by a high penetration of converter-interfaced renewable energy sources. Nonetheless, further investigations into the influence of VSM parameters on the system’s dynamic response are needed to further optimize the performance of the proposed solution.

This work introduces a non-isolated high step-up dc-dc interleaved boost converter combining magnetic coupling and voltage multiplier cells (VMCs). The proposed topology features a transformer with two primary windings of equal turns, interconnected to each other, enabling improved current sharing, and multiple secondary windings that contribute to extending the voltage gain. A three-winding coupled inductor is integrated into the design, while VMCs not only boost the output voltage but also significantly reduce the voltage stresses on the switches, eliminating the need for extreme duty ratios. The converter exhibits inherent modularity, allowing for voltage gain adjustments either through the turns ratio of the coupled inductor or by incorporating additional VMCs. An in-depth analysis of the topology is derived, and an experimental prototype rated at 48 V/400 V, 25 kHz, and 1 kW is implemented to verify and validate the theoretical claims, achieving an efficiency of 95.12% at full-load conditions.

This article presents a systematic literature review aimed at identifying and consolidating the main trends, challenges, and opportunities shaping the growth of renewable energy in Brazil from a global perspective. Based on the PRISMA guidelines and a qualitative and quantitative analysis of publications from 2010 to 2025, seven core studies were selected from the Scopus database, complemented by other relevant academic sources. The results highlight advances in energy storage technologies, such as pumped hydro storage (PHS), the rise of green hydrogen, the decentralization of electricity generation, and Brazil’s international leadership in the renewable sector. However, significant challenges remain, including regulatory bureaucracy, transmission infrastructure deficiencies, and socio-environmental conflicts. The study concludes that Brazil's energy transition requires greater coordination between science, public policy, and social inclusion to ensure a sustainable, fair, and competitive energy future.

This article presents a systematic literature review aimed at identifying and consolidating the main trends, challenges, and opportunities shaping the growth of renewable energy in Brazil from a global perspective. Based on the PRISMA guidelines and a qualitative and quantitative analysis of publications from 2010 to 2025, seven core studies were selected from the Scopus database, complemented by other relevant academic sources. The results highlight advances in energy storage technologies, such as pumped hydro storage (PHS), the rise of green hydrogen, the decentralization of electricity generation, and Brazil’s international leadership in the renewable sector. However, significant challenges remain, including regulatory bureaucracy, transmission infrastructure deficiencies, and socio-environmental conflicts. The study concludes that Brazil's energy transition requires greater coordination between science, public policy, and social inclusion to ensure a sustainable, fair, and competitive energy future.

The main objective of this work is to address problems related to the speed control of mobile robots with non-holonomic constraints and differential traction—specifically, robots for football games in the VSS (Very Small Size) category. To achieve this objective, an implementation and comparison is carried out between two control strategies: an adaptive control strategy by gain scheduling and a fuzzy multimodel intelligent control strategy. The mathematical models of the wheel motors for each operating range are approximated by a first-order system since data acquisition is performed using the step response. Tuning of the proportional and integral gains of the local controllers is carried out using the root locus technique in discrete time. For each mathematical model obtained for an operating range, a local controller is tuned. Finally, with the local controllers in hand, the implementation of and comparison between the gain scheduling adaptive control strategy and the fuzzy multimodel intelligent control strategy are carried out, in which the control strategies are programmed into the low-level code of a non-holonomic robot with a differential drive to verify the performance of the speed tracking dynamics imposed on the wheel motors to improve robot navigation during a robot football match.

This paper aims to present the computational implementation of a photovoltaic generating unit integrated with an energy storage system using Lithium-ion batteries connected on grid. The system under analysis aims to control the power factor at the PCC (Point of Common Coupling), as well as regulate the load demand curve. For this, the control of the inverter and the dc/dc converters of the photovoltaic plant and the battery bank in a decoupled manner was implemented, thus enabling the individual performance of each device. For charging and discharging the battery bank, a hysteresis control system based on the constant current/voltage method and the constant current method, respectively, was used. The entire implementation was carried out in Matlab/Simulink software. The obtained results demonstrate the technical viability of the system in order to control the power factor in the PCC and regulate its load curve.