https://repositorio.ufu.br/handle/123456789/18974 2026-08-31T04:44:37Z 2026-08-31T04:44:37Z https://repositorio.ufu.br/handle/123456789/49921 2026-08-28T06:20:05Z 2026-07-30T00:00:00Z

Title: Avaliação experimental da modelagem de cargas residenciais utilizando a representação ZIP em estudos de fluxo de potência em sistemas de distribuição Abstract: This undergraduate thesis aims to propose a residential load modeling approach more closely aligned with real-world conditions, based on the ZIP representation implemented in Model 8 of the OpenDSS software. The ZIP model is composed of three components associated with constant impedance, constant power, and constant current behaviors, which define the relationship between active and reactive electrical power and the variation of the voltage applied to the load. In order to obtain a representative composition, the P×V and Q×V behaviors of equipment commonly found in Brazilian households are experimentally analyzed, allowing not only the verification of the adherence of such equipment to classical ZIP load models, but also the quantification of the degree of participation associated with each model component (constant impedance, constant current, and constant power) whenever such adherence is confirmed. Based on the experimental results obtained, an aggregated load model more representative of the actual characteristics of Brazilian residential consumption was proposed, explicitly incorporating the predominant contribution of each ZIP component observed in the different analyzed devices. This approach not only improves the electrical representation of loads in computational studies, but also enables a critical assessment of the impacts of the adopted modeling on the calculation results of technical losses in distribution systems. Finally, the proposed modeling approach is compared with the methodology currently adopted by ANEEL in the process of calculating technical losses in distribution systems [Module 7 of PRODIST], highlighting some limitations of the regulatory approach, such as the use of generic load compositions and the greater complexity associated with its implementation. The obtained results demonstrate that the proposed model provides a more representative characterization of actual load behavior while requiring lower computational effort, thus constituting a more suitable and efficient alternative for technical loss studies in distribution systems.

2026-07-30T00:00:00Z https://repositorio.ufu.br/handle/123456789/49910 2026-08-28T06:20:02Z 2026-06-12T00:00:00Z

Title: Desenvolvimento de um sistema de monitoramento de área de custo reduzido empregando o microcontrolador Espressif ESP32 e o módulo Global Positioning System NEO-M8N

2026-06-12T00:00:00Z https://repositorio.ufu.br/handle/123456789/49876 2026-08-27T06:21:48Z 2026-07-29T00:00:00Z

Title: Otimização computacional dos parâmetros do rotor em Máquinas Síncronas de Relutância Abstract: This work aims to simulate a synchronous reluctance machine using the finite element method and to optimize the parameters of four different rotor topologies using the differential evolution algorithm. To this end, the open-source finite element method (FEM) software FEMM (Finite Element Method Magnetics) is employed, together with the PyFemm library, which allows automation of simulation routines and facilitates machine modeling, and the Python language, used for processing and analyzing the obtained results. The adopted methodology is based on the stator of a 2 HP induction machine. In this context, the machine's original rotor is replaced by reluctance rotors with distinct geometries, aiming to optimize torque and torque ripple. Thus, the performance of each topology is expected to be evaluated, identifying the most efficient geometry for application in synchronous reluctance machines.

2026-07-29T00:00:00Z https://repositorio.ufu.br/handle/123456789/49551 2026-08-15T06:28:05Z 2026-08-27T00:00:00Z

Title: Desenvolvimento e análise experimental de um regulador de tensão para o gerador de indução trifásico conectado na forma bifásica Abstract: This work presents the design and implementation of a digital voltage regulator for a threephase induction generator that is self-excited and connected in a two-phase arrangement using the Fukami configuration. In this configuration, the three-phase induction machine is excited by two capacitors connected between two phases, creating a central point where another capacitor is connected to the remaining phase and to the load, thus forming a two-phase configuration. This allows the induction generator to be used in isolated and portable applications, which is mainly possible due to the fact that the induction machine is more robust and more affordable than the synchronous machine currently used for this purpose. However, the operation of this type of machine as a generator is not able to keep the terminal voltage stable under a load change, since it depends on the reactive power balance of the system. To overcome this problem, a regulator based on the ESP32 microcontroller was proposed, containing a PI (Proportional-Integral) controller developed digitally in the C language. The generator voltage is monitored by a voltage acquisition system at the load, which provides the ESP32 analog-to-digital converter with a DC voltage level proportionally close to the RMS value of the generated voltage. As the actuating element, a configuration with a bidirectional power switch was used, controlled by a PWM signal generated by the ESP32 control circuit. Thus, according to the load variation in the generator, the PI controller continuously adjusts the duty cycle in order to keep the terminal voltage at the desired value of 220 V at the load, acting as a voltage step-down stage.

2026-08-27T00:00:00Z