Data imbalance in training data often leads to biased predictions from trained models, which in turn causes ethical and social issues. A straightforward solution is to carefully curate training data, but given the eno...
The present proposal refers to a wing type micro unmanned aerial vehicle that provides low operation risk to people and instalations (Micro-Brosh). The UAV is intended for aerospace use, having dimensions less than 30...
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In recent years, distributed energy resources (DERs) have been increasingly integrated into power systems that affect grid management and operations. Since the operating conditions of DERs vary greatly and are more in...
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ISBN:
(数字)9798331505493
ISBN:
(纸本)9798331505509
In recent years, distributed energy resources (DERs) have been increasingly integrated into power systems that affect grid management and operations. Since the operating conditions of DERs vary greatly and are more intermittent than those of conventional energy systems, power systems are experiencing greater stability problems. Modular controllable transformers (MCTs) have been proposed as an optimum solution to address these issues. MCTs are specialized transformers that utilize fractionally rated power converters and perform several grid support functions in addition to isolation and voltage conversion. Protection requirements for MCT have not yet been defined in the standards. This paper aims to improve the performance and protection of MCTs by proposing and validating their protection schemes. These protection schemes include differential protection, overcurrent relay, and under and overvoltage relay. These protection schemes have been implemented, and simulation results that validate their effectiveness are presented in this paper.
As time progresses, the power capacity of the photovoltaic (PV) module grad.ally diminishes. Therefore, it is crucial to assess the PV module performance to ensure it aligns with the manufacturer specifications. One e...
As time progresses, the power capacity of the photovoltaic (PV) module grad.ally diminishes. Therefore, it is crucial to assess the PV module performance to ensure it aligns with the manufacturer specifications. One effective method to monitor the PV module performance is by examining its current-voltage (I- V) curve. Presently, numerous techniques are available to translate the I- V curve for specific irradiance and temperature conditions. However, many of these methods require a substantial number of parameters or are limited to a specific PV module technologies. These models have challenges to be implemented in commercial PV modules, requiring treatment of the PV module data, and adaptations in the original proposed methodologies. In this work, the four procedures techniques presented by the IEC 60891 standard are reviewed. The results show a fair agreement, with most of the relative errors up to 4%.
The importance of silicon cannot be undermined - in photovoltaics (PV) as well as in semiconductor industries. However, silicon is very brittle. Silicon cells/wafers crack easily during manufacturing assembly and/or d...
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ISBN:
(数字)9798331504779
ISBN:
(纸本)9798331504786
The importance of silicon cannot be undermined - in photovoltaics (PV) as well as in semiconductor industries. However, silicon is very brittle. Silicon cells/wafers crack easily during manufacturing assembly and/or during device operations. Crack Catcher AI uses novel smart fracture mechanics approach with Artificial Intelligence (AI) methodologies to predict and control crack/damage evolution in thin silicon cells/wafers. This is critical as semiconductor 3D integration technology calls for wafer-to-wafer bonding with utmost alignment accuracy and yield/reliability.
The delta connected cascade H-Bridge converter (Delta-HUB) has emerged as an interesting topology for STATCOM applications. A drawback of this topology is the low-frequency ripple in the sub module voltage that leads ...
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Especially in the mining industry, Pulse Width Modulated Voltage Source Converters (PWM-VSC) driving induction motors at long distances from the inverter is common. Due to the long cable used for the converter-to-moto...
Especially in the mining industry, Pulse Width Modulated Voltage Source Converters (PWM-VSC) driving induction motors at long distances from the inverter is common. Due to the long cable used for the converter-to-motor connection, several unwanted high-frequency phenomena occur. A new configuration for these motor drive systems was previously proposed to address this situation. The new configuration involves keeping the rectifier in its original location, while the inverter bridge is installed close to the motor terminals, and long cables are used as a DC transmission line. The environment in which the inverter will now be located is more hostile and can compromise the inverter’s lifetime. This situation creates new concerns about the system’s reliability, despite the various advantages of this new configuration. This paper presents a study on the reliability of the DC-Link capacitors for Three Level Neutral Point Clamped (3L-NPC) and Three Level Active Neutral Point Clamped (3L-ANPC) inverter topologies when operating in aggressive environments. For this purpose, methodologies based on Physics of Failure (PoF) and Design for Reliability (DfR) were used. In this sense, an investigation was conducted to find the configurations best suited to improve the solution regarding reliability, cost, energy, and volume.
We apply the chaos supremacy of laser chaos system to the high stabilization of THz waves. Stability was demonstrated by down converting the optical beats between laser longitudinal modes in the THz domain to the radi...
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Throughout the industry, pulse width modulation voltage source inverters (PWM-VSI) are commonly utilized with adjustable speed drives (ASD) to control, most commonly, induction motors. Especially in the mining and pet...
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ISBN:
(数字)9798350353402
ISBN:
(纸本)9798350353419
Throughout the industry, pulse width modulation voltage source inverters (PWM-VSI) are commonly utilized with adjustable speed drives (ASD) to control, most commonly, induction motors. Especially in the mining and petroleum industries, long cables connecting motors and inverters are often present, which can cause several problems. As an innovative solution, an alternative system configuration has been previously proposed, in which the rectifier is kept in its typical location, and the inverter bridge and DC bus capacitors are installed near the driven motor. Long cables are used as a DC transmission line, mitigating the high-frequency problems resulting from the inverter-cable-motor interaction. On the other hand, new concerns regarding the reliability of the power devices arise once the inverter is installed in harsh ambient conditions. In this context, this work proposes a reliability analysis of such drive configuration, applying the physics of failure (PoF) approach combined with the design for reliability (DfR) methodology to carry out the design adjustments to achieve the reliability required for the application, focusing on the inverter IGBT modules. Moreover, this paper will evaluate widely accepted multilevel inverter topologies and modulation strategies, verifying those capable of minimizing implementation costs and ensuring adequate reliability indexes for the system—aiming to enable the commercial use of this promising configuration. The results show that a three-level active neutral point clamped inverter (3L-ANPC) topology applying two pulse width modulation (PWM) strategies and 400 A – 6.5 kV IGBTs would be the most appropriate from this study's reliability and feasibility analyses.
Lightweight coresets are compact representations of data sets such that clustering methods present competitive results in relation to the complete data set. They are constructed by sampling important points from the c...
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ISBN:
(数字)9781728174457
ISBN:
(纸本)9781728174570
Lightweight coresets are compact representations of data sets such that clustering methods present competitive results in relation to the complete data set. They are constructed by sampling important points from the complete set. We propose a fast method to approximate the sampling of lightweight coresets from very large data sets which are distributed among multiple machines. We show that the proposed method is much faster and scalable, reaching results 48 times faster than the original lightweight coresets, while holding similar properties.
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