Jorge Lara

Este trabajo presenta el desarrollo de un analizador de suelo basado en lógica difusa para determinar el estado de salud de una planta de chile. El analizador se basa en el sensor de suelo JXBS-3001-TR capaz de monitorear siete parámetros, i.e., pH, temperatura, humedad y conductividad eléctrica (PH-T-H-CE), así como los niveles de nutrientes de nitrógeno, fósforo y potasio (NPK). La información generada se guarda en un archivo con formato .CSV, el cual a su vez se almacena en una memoria SD colocada dentro de una placa de expansión de registro de datos conectada a una tarjeta Arduino Mega2560. Así, se crea la base de datos que eventualmente se transmitirá de manera inalámbrica a través de un transceptor LoRa Reyax RYLR998 con protocolo MODBUS RTU RS485 a una computadora para su análisis mediante lógica difusa. Para facilitar el proceso de carga de la información en formato CSV, se desarrolló una interfaz gráfica intuitiva y útil, mientras que, para su análisis se desarrolló un código en Python conteniendo la fuzzificación, las reglas difusas, las funciones de membresía y la defuzzificación. Dentro de este programa también se compararon las lecturas experimentales contra parámetros predefinidos considerados como los saludables de la planta de chile, para así determinar su grado de pertenencia al estado enfermo, sano u óptimo. El presente estudio provee la base que permitirá en un trabajo futuro tomar acciones de control orientadas a convertir una siembra enferma en una sana, y así reducir pérdidas económicas en la cosecha de un cultivo.

Este trabajo presenta un filtro activo paralelo basado en un convertidor de celda en U empaquetada (CUE) para mejorar la calidad de la energía eléctrica en una red monofásica de baja tensión. Esta topología tiene la gran ventaja de generar 5 niveles de voltaje y constar de tan solo seis interruptores de potencia, por lo cual es muy atractiva para la industria. Sin embargo, este convertidor requiere de la implementación de una técnica para la regulación del voltaje de sus dos capacitores. Para este fin, aquí se propone una estrategia directa, la cual selecciona en cada instante de conmutación una ruta de carga o descarga, tanto en el segundo nivel como en el cuarto. Por otro lado, para la compensación de los armónicos se propone un controlador proporcional-resonante (PR) capaz de seguir la señal senoidal de la red eléctrica, gracias su ganancia infinita en la frecuencia de resonancia de 60Hz. Los resultados de la simulación del filtro activo se han validado en la plataforma de MATLAB-Simulink/Simscape. Diversas pruebas bajo diferentes condiciones de carga línea y no lineal se han llevado a cabo. Es remarcable la correcta regulación del voltaje de los capacitores durante las variaciones de carga, así como el buen desempeño del controlador PR, permitiendo reducir en estado estable la distorsión armónica total (DAT) de la señal de corriente de la red a 3%, cumpliendo así con el estándar IEEE 519 y demostrando en general la viabilidad de utilizar el convertidor CEU en aplicaciones de filtrado activo.

This paper presents the electromagnetic design optimization of a permanent magnet synchronous generator (PMSG) based on machine learning. Firstly, the optimization methodology is presented; then, a correlation and a sensitivity analysis are carried out to determine the set of design variables. The optimization goal is maximizing efficiency, which is equivalent to minimizing electrical PMSG losses. It also considers the core and copper materials by minimizing their weight. A deep neural network (DNN) architecture is developed and trained using PMSG 2D-FE data. The DNN is based on the nonlinear Rectified Linear Unit (ReLU). The resulting DNN was later used to construct the PMSG objective function, which was then solved using non-sorting genetic algorithms. Numerical results and comparisons between two genetic algorithms are given to demonstrate the validity of the proposed approach.

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This paper presents a multi-objective design optimization of a power transformer to find the optimal geometry of its core and the low- and high-voltage windings, representing the minimum power losses and the minimum core and copper weights. The optimal design is important because it allows manufacturers to build more efficient and economical transformers. The approach employs a manufacturer’s design methodology, which is based on the usage of the laws of physics and leads to an analytical transformer model with the advantage of requiring a low amount of computing time. Afterward, the multi-objective design optimization is defined along with its constraints, and they are solved using the Non-Sorting Genetic Algorithm III (NSGA-III), which finds a set of optimal solutions. Once an optimal solution is selected from the Pareto front, it is necessary to fine-tune it with the 3D Finite Element Analysis (FEA). To avoid the large computing times needed to carry out the 3D Finite Element (FE) model simulations used in multi-objective design optimization, Response Surface Methodology (RSM) polynomial models are developed using 3D FE model transformer simulations. Finally, a second multi-objective design optimization is carried out using the developed RSM empirical models that represent the cost functions and is solved using the NSGA-III. The numerical results of the optimal core and windings geometries demonstrate the validity of the proposed design methodology based on the NSGA-III. The used global optimizer has the feature of solving optimization problems with many cost functions, but it has not been applied to the design of transformers. The results obtained in this paper demonstrate better performance and accuracy with respect to the commonly used NSGA-II.

This paper presents the performance evaluation of a proposed single-phase bidirectional active neutral-point-clamped (ANPC) five-level converter (5LC) for active filtering in grid-to-vehicle (G2V), vehicle-to-grid (V2G) and vehicle-to-home (V2H) applications. In the system, the 5LC is series-connected with an electric vehicle battery charger based on a dual active half-bridge DC-DC converter (DAHBC). A cascaded strategy with a proportional-resonant compensator controls the 5LC whereas the DAHBC is controlled by a single phase-shift technique. A performance comparison is carried out for the proposed topology versus three NPC/ANPC 5L converters found in literature with similar topologies. The simulation results obtained in MATLAB-SimPowerSystems along with the experimental results obtained from a laboratory prototype validate the following: a) the first two literature topologies have the highest efficiencies, but they are incapable of balancing the voltage of the split-capacitors what increases the total harmonic distortion of both the grid current in the G2V/V2G modes and the 5LC output voltage in the V2H mode while producing a sluggish transient response, b) the 3rd literature topology like the proposed one properly balance the capacitors voltage and achieve a faster dynamics, but at the expense of an efficiency reduction, and c) unlike the former topology that continuously applies a natural but wasting unfedback voltage balancing strategy, the proposed one that includes a closed-loop control allows achieving an ANPC 5LC with a superior performance featured by a higher efficiency, a reduced switches stress, a flatter power losses distribution and a better power quality improving under the three modes of operation.

This article presents the optimal design of a permanent magnet synchronous generator (PMSG). A finite element (FE) model is used to construct a metamodel, which afterward is utilized to define the objective function that models the PMSG. Kriging modeling is employed along with the design of experiments based on Latin hypercube sampling. The utilization of a surrogate model allows to speed up the optimization process while keeping the accuracy since they are developed from the FE analysis. On the other hand, it has been reported that the non-sorting genetic algorithm (NSGA) III is better than NSGA-II because it can solve multi- and many-objective optimization problems. This article demonstrates by numerical experiments that NSGA-III can be successfully used in the optimal design of PMSG with three objectives.

This paper presents a bidirectional electric vehicle (EV) charger with ancillary power quality (PQ) capabilities in grid-to-vehicle (G2V), vehicle-to-grid (V2G) and vehicle-to-home (V2H) applications. The proposed configuration consists of a five-level (5L) neutral point clamped (NPC) converter in cascaded with a dual-active half bridge (DAHB) DC-DC converter. The proposed cascaded control strategy used for regulating the common DC bus voltage as well as for compensating the grid current harmonics and the reactive power through the 5L-converter is based on a performant proportional-resonant (PR) compensator. By applying the single-phase-shift (SPS) technique to the DAHB converter, the battery power flow is accurately regulated. A detailed study with exhaustive tests and simulation results obtained in MATLAB-SimPowerSystems for a full-scale power system based on a Nissan Leaf´s battery validate the fairly good performance of the proposed configuration and control strategies. The main achievements of this work are: 1) the system’s stability is maintained even during fairly abrupt changing conditions, 2) in steady state of the G2V/V2G operation modes, the total harmonic distortion (THD) of the grid current remains below 3% while the power factor (PF) is kept at unity, 3) the reactive power demanded from the grid is zero in spite of feeding a highly nonlinear load, and 4) when a power outage occurs, the transition to the V2H mode is seamless and the home load is uninterruptedly supplied with a very low-distortion output voltage from the 5L-converter.

This paper presents a novel single-phase (SP) active-neutral point clamped (ANPC) five-level bidirectional converter (FLBC) for enhancing the power quality (PQ) during the grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operation of an electric vehicle (EV) charger connected in series. This EV charger is based on a dual-active half-bridge DC-DC converter (DAHBC) with a high frequency isolation transformer. Unlike the comparable ANPC topologies found in literature, the proposed one has two more switches, i.e., ten instead of eight. However, with the addition of these components, the proposed multilevel converter not only becomes capable of properly balancing the voltage of the DC-link split capacitors under various step-changing conditions but it achieves a better efficiency, a lower stress of the switching devices and a more even distribution of the power losses. The resulting grid-tied ANPC-SPFLBC and DAHBC are accurately controlled with a cascaded control strategy and a single-phase shift (SPS) control technique, respectively. The simulation results obtained with MATLAB-SimPowerSystems as well as the experimental results obtained in laboratory validate the proposed ANPC-SPFLBC for a set of exhaustive tests in both V2G and G2V modes. A detailed power quality analysis carried out with a Fluke 43B alike demonstrates the good performance of the proposed topology.

This paper presents a novel single-phase grid-tied neutral-point-clamped (NPC) five-level converter (SPFLC). Unlike the literature on five-level NPC topologies, the proposed one is capable of inherently balancing the voltage of the DC-link split capacitors. For this purpose, a simple Multicarrier Phase Disposition (MPD) Pulse Width Modulation (PWM) technique is used, thus avoiding both complex modifications to the Space Vector Modulation (SVM) and offset voltage injections into the carrier based (CB) PWM, as commonly done in most conventional balancing algorithms. Bearing in mind that the proposed balancing strategy only requires measuring the capacitors’ voltages and the sign of the converter output current, it has a very low complexity. The developed strategy is not only straightforwardly implemented but is also very effective for obtaining symmetrical and undistorted voltage levels from the proposed multilevel converter, as well as for significantly improving the power quality of the SPFLC output voltage and, in turn, of the grid current. The simulation results obtained with MATLAB-SimPowerSystems as well as the experimental results obtained with the prototype built in the laboratory validate the topology of the proposed NPC five-level converter and the voltage balancing strategy, by showing a good performance under step-changes and exhaustive operating test conditions.