ABSTRACT. Low-power devices rely on batteries, making energy efficiency crucial. Measuring and understanding their actual consumption is vital to optimize performance. This project designs and builds a device that measures small amounts of energy, accounting for variations with high-precision components such as a 24-bit ADC to measure current, ensuring reliable measurements. The device takes thousands of samples per second, synchronized by an algorithm, and can be measured continuously for an entire day. The results are comparable to commercial devices, facilitating the estimation of the device's operational time or battery depletion.

ABSTRACT. This work discusses development an innovative ex- perimental alternative of a wireless device for the acquisition of mechanical frequencies up to 40 Hz. The system used Arduino Pro-Mini boards, the ADXL335 accelerometer and NRF24L01 Radio Frequency for wireless and wired data communication. To acquire the vibration signal on a mechanical part, an 8090 Aluminum cantilever beam was subjected to an impact to excite it. The time domain signal is processed with the FFT to obtain the frequency spectrum and analyze the vibrations and the Butter- worth filter attenuates the signal. The fundamental frequency in the cantilever with the wireless sensor system is compared with a wired sensor system and a mechanical simulation in Ansys, shows average of 10.63 Hz for wireless, 10.16 Hz wired, and 10.96 Hz in mechanical simulation, respectively. Test results show that the system is efficient up to 40 Hz with a relative error of 3 percentage.

ABSTRACT. Given the growing demand for alternative energies, multilevel inverters, known for their efficiency in medium/high voltage systems and their application in these alternative sources, have faced a significant incidence of failures. Among these, the open-circuit failure (OCF) in their switches stands out. This failure, which may go unnoticed, affects performance and the quality of the energy injected into the grid. The methodology shown in this paper, focuses on the controlled introduction of OCFs into a five-level H-bridge multilevel inverter to analyze their impact compared to normal operation. To do this, an artificial neural network (ANN) to monitor these behaviors is implemented.

ABSTRACT. This paper presents the simulation, the design, and the implementation of a three-level neutral point clamped (NPC) inverter. This inverter is designed for low voltage applications. As the modulation technique, in this paper it is used a simplified version of the space vector pulse width modulation (PWM) strategy. This PWM strategy is based on the average value of the instantaneous maximum and minimum values of the index modulation signals, given in the stationary three-phase reference frame. This simplified PWM technique reduces the computational burden in obtaining the PWM gate signals. A simulation of the NPC inverter with a RL load is carried out in MATLAB Simulink. To support the simulation results, a NPC inverter prototype is design and it is used. The experimental and simulation results show the same behavior during the test. The results show the excellent performance of the inverter prototype and an efficiency of 95.58 %.

ABSTRACT. With the global energy landscape moving towards renewable sources, the dependability and long-term viability of solar power systems have gained greater importance. This paper examines the crucial factors related to the deterioration of solar panels, with a specific emphasis on crystalline silicon panels, which are the predominant type utilised in the solar industry. The research highlights the significance of comprehending ageing effects in order to optimise the design, maintenance, and financial planning of solar power installations. This is achieved by studying specific degradation mechanisms like Potential Induced Degradation and Light Induced Degradation, and using Monte Carlo simulations to predict performance over a ten-year period.

ABSTRACT. The efficiency of photovoltaic modules can be affected by different factors, such as environmental variables, place and form of installation, as well as the accumulation of dirt on their surface that interferes with the reception of irradiance of the module. Such dirt can come from environmental elements such as dust, tree leaves and pollution that are carried by the wind, in addition to bird esses. This significantly reduces the efficiency of the module, which has led to the development of different cleaning methods such as maintenance for the modules. PV module cleaning techniques can be divided into two main categories: wet cleaning, which uses water or waterbased substances to remove dirt, and dry cleaning, which employs physical methods that do not require water, such as brushing or vibration. In this study, the efficiency and electrical parameters of the photovoltaic modules were compared when using a wet cleaning prototype and a dry cleaning prototype, also evaluating the effectiveness of the system in removing dirt from the modules, simulating a year of cleaning. This analysis showed that wet cleaning is 10.63% more efficient than dry cleaning, affecting the electrical parameters of the module in a lesser way, and with a system that consumes 85.52% less energy than the dry cleaning system, however, cleaning the photovoltaic modules with water takes more time

ABSTRACT. This document proposes and tests a simplified control scheme versus a traditional control scheme for controlling the power flow through a bidirectional DC-DC converter. The starting point is the analysis of the converter, where elements that absorb or yield energy are two direct voltage buses. The analytic development is shown in order to obtain the switched, averaged, static and linear models. Then, the controllers are tuned according to the desired characteristics of the system’s frequency response. The control schemes are tested through simulation and the control effectiveness of the simplified proposed scheme is verified, thus controlling the dynamical variables and bringing them at the desired operating points.

ABSTRACT. This paper presents an automated methodology for comprehensive power system static and dynamic security assessment integrated with DigSILENT PowerFactory using Python scripting. Industry criteria are implemented to analyze voltage, frequency, transient stability, and inverter-based resource fault-ride-through (FRT) across various scenarios and contingencies. Results on a Colombian power system model demonstrate the tool's effectiveness in statistics analysis for static and dynamic power system security. The study revealed that voltage violations were most prevalent at 66kV and 110kV levels, while frequency and overvoltage FRT violations were dominant in dynamic assessments, particularly during maximum demand scenarios. These findings highlight critical areas for improving grid security.

ABSTRACT. The region of Rio Mearim, located in the state of Maranhão, Brazil, has ideal geographical and climatic conditions for renewable energy projects, with an extensive coastline, consistent winds and large tidal ranges. In this context, the methodology of this study aimed to reduce the costs of tidal data collection and predict hotspots for oceanic and riverine generation. It demonstrated that hydrodynamic modeling and image processing are viable and cost-effective alternatives. These techniques significantly reduce data acquisition time and provide comprehensive information for characterizing the area of interest, thereby facilitating its analysis.

ABSTRACT. Low-frequency switching in multilevel inverters significantly minimizes switching losses and electromagnetic interference, and have applications in off-line power supplies, uninterruptible power supplies and motor drives. However, its widespread use is restricted by the inherent high harmonic distortion. Increasing the number of voltage levels and using selective harmonic elimination techniques can reduce total harmonic distortion and filtering requirements. This paper evaluates the effectiveness of four passive filters in mitigating harmonic content in low-frequency switching, grid-tied, symmetrical cascaded H-bridge inverters through numerical simulations. Output transfer functions are analyzed and guidelines for selecting filter components are proposed. The results can help to identify the most suitable filter configuration with low-frequency switching operation.

ABSTRACT. The power converters have rapidly evolved to meet industry requirements. Nowadays, renewable energies and the storage of energy applications require an interaction between different levels of DC voltages. In some cases, these levels are very far between them, hence an efficient conversion system with a high conversion ratio is required. In this paper, a DC-DC high-gain step-up transformerless converter is proposed. This converter can increase the output voltage up to ten times regarding input voltage with a duty cycle near 0.5. The proposed topology comprises a switching inductor cell, a switching capacitor cell, as well as a conventional boost converter. For the proposal, a steady-state analysis of the converter is performed to obtain voltage and current ripples to size the storage energy elements. Besides, an efficiency analysis considering the parasitic elements of the converter is performed. Finally, the proposed topology is assessed through numerical simulation on the 1 kW system.

ABSTRACT. In this paper, an active balancing circuit is analyzed and a controller is proposed that is designed to balance the voltage between two series-connected capacitors that are in turn connected to a single DC voltage source. Such series-connected capacitors are found, for example, in the split DC-link commonly used in multilevel inverters such as NPC, ANPC or T-type inverters. The circuit is simple, requiring only two power switches and one inductor. The active balancing circuit is modeled and a controller is proposed that achieves regulation and stability to ensure a constant voltage difference across the two series capacitors, even with different characteristics or capacitances and regardless of the application. The proposal can also achieve asymmetric voltage balancing. Advantages of the proposal are the modular design and the implementation with a single H-bridge leg. It can be easily added or removed from inverter topologies without modifying the inverter. The circuit and its control are evaluated through simulations on a three-phase, three-level, NPC inverter with an unbalanced AC load. The results demonstrate good performance and effective voltage balance regulation.

ABSTRACT. This paper presents the comparison between two balancing methods: Active balancing using a Buck-Boost Converter and Passive Balancing by resistance switching. The active balancer was realized using a DC-DC Converter, which is operated by a Peak Current Control (PCC). This allows the inductor current to be tracked to reduce or increase the voltage to be spread over a pair of cells. The Passive balancer works with a switching resistor which allows to transform the voltage excess of each battery, in form of heat, being the resistance controlled by a microcontroller while carrying out the balancing of two cells. Both methods balance the voltage of the cells and are intended to properly work with a couple of LiPo cells and a nominal voltage of 3.7 V and 16,000 mAh connected in series. The two battery balancers were constructed and experimentally verified by measuring the rolling time of the cells, comparing cost and manufacturing times. The results are validated and compared with the measurements of a data logger, in order to scale the prototype to a 5.6 kWh energy rating for an 83 kW electric motorbike vehicle.

ABSTRACT. Currently, the integration and coordination of a high quantity of distributed generators (DG) into traditional electrical distribution networks has introduced technical challenges to maintain electrical parameters, such as voltage and frequency, within acceptable levels. Distributed control schemes offer a promising solution to handle the computational demands of coordinating numerous DG units, enabling direct data sharing among DGs and simpler communication structures. This paper proposes a distributed control approach based on a leaderfollower consensus algorithm to ensure voltage stability across all grid buses. By regulating the active power injected by the DGs, the method aims to achieve consensus among the units and adjust power generation to maintain uniform operation. Simulations on the IEEE 34-bus network demonstrate the effectiveness of the proposed method under various load conditions, and in all cases where the proposed method was applied, the voltage was maintained within the allowed limits across all phases.

ABSTRACT. Integrating distributed energy resources into electric distribution systems causes issues in control, operation, and even protection strategies. This paper presents an analysis of the effect of selecting an inadequate load model for relay coordination on the performance of the overcurrent protection commonly used in power distribution systems. As a result of the research performed considering four different load models (constant impedance, constant current, constant power, and exponential recovery), it is noticed how some of them, such as the constant current and exponential recovery, have excessive time delays, which could affect the relay coordination. These effects are especially noticeable for the tests considering non-bolted faults at 40 and 80

ABSTRACT. The penetration of alternative energy sources has changed the composition of electrical power systems, reducing the importance of conventional sources. However, alternative sources are intermittent, posing challenges for the planning and operation of these systems as they require power electronics for grid connection. Power electronics affect the quality of electric energy by generating a set of undesirable phenomena. Therefore, engineers have resorted to various analysis techniques and the combination of some to address issues related to detecting disturbances that affect energy quality. This paper presents a hybrid method using the combination of discrete wavelet transform and Hilbert-Huang transforms (HHDWT) to detect, identify, and classify power quality events.

ABSTRACT. This paper presents a study on the integrated operational planning of Medium Voltage (MV) and Low Voltage (LV) networks considering the insertion of Distributed Generation (DG). The proposed model considers the planning of MV and LV networks to reduce energy losses, voltage drops, and investment in reinforcements, utilizing Genetic Algorithm (GA) and multi-agent systems. The planning of MV distribution networks involves cable replacement, sizing and positioning of capacitors and DG, and phase load balancing. In turn, the planning of LV networks involves cable replacement, transformer exchange, and phase load balancing for consumers. The objective function to be minimized includes the operational costs of the proposed changes, energy losses, and voltage constraints. A power flow for radial distribution networks, based on a backward/forward sweep using current summation, was developed to validate the solutions.

ABSTRACT. Speech recognition as part of automatic decision-making systems has advanced in recent years, becoming a consistent reality in several engineering sectors. Especially in power systems, speech-to-text recognition allows a significant increase in the quality of process operation involving audio communication. In this way, it becomes possible to transcribe the audios involving the communication and also future audits. A growing number of tools have been proposed lately in order to automate speech recognition, but these still have analysis limitations, not allowing redundancy in the transcription process, for example. This work proposes a methodology for analyzing audio in separate channels based on recordings of calls between electrical system operators, aiming increasing the degree of robustness in the application of speech-to-text recognition processes.

ABSTRACT. With the growth of the industrial sector, the manipulation of the profiles that constitute the motion dynamics of the machines has taken great importance, this because by means of the proposal of new profiles it can improve the stability, precision and efficiency of the machine. In this work a position profile based on the hyperbolic tangent function is proposed to reduce the jerk effect by means of Matlab simulations.

ABSTRACT. This paper presents the implementations of a commutation sequence for a five and seven-level cascaded H-bridge multilevel inverter (CHBMLI) using a Field Programmable Gate Array (FPGA). The versatility and efficiency of the CHBMLI inverters are highlighted due to their modular configuration, which allows for generating high fidelity output voltages and minimizing harmonics in the output signal. The fundamental frequency switching modulation technique generates the required output voltages. The implementation of this modulation in the FPGA by using VHDL language enables precise execution of the commutation sequence. The capability of FPGAs to handle the generation of control sequences for each voltage level is demonstrated with a laboratory prototype. The evaluation of the inverters output waveforms validates the effectiveness of the design and its implementation, achieving a low total harmonic distortion (THD).

ABSTRACT. The comfort in human life, as well as support for environmental care, is one of the main tasks today. That's why this project proposes reducing the activities carried out by the user while simultaneously decreasing the carbon footprint they produce. This article focuses on explaining the development of an intelligent module for a light bulb that helps users eliminate daily routine tasks while maintaining control over energy savings. The module is centered around the use of IoT tools and electronic components for automation and device control.