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IEEE Texas Power and Energy Conference (TPEC)

作者： Pujan Adhikari Mona Ghassemi Department of Electrical and Computer Engineering Zero Emission Realization of Optimized Energy Systems (ZEROES) Laboratory The University of Texas at Dallas Richardson TX USA

In the ever-growing landscape of electrical power demand, the future of power electronics module packaging lies in the realm of wide-bandgap (WBG) materials, including silicon carbide (SiC), gallium nitride (GaN), and cutting-edge ultra WBG (UWBG) materials like diamond, aluminum nitride (AlN), and hexagonal-boron nitride (h-BN). These materials offer superior properties to traditional silicon-based devices, promising higher power density, reduced weight, and increased operating temperature, voltage, and frequency. However, pushing the boundaries for power electronics modules presents challenges in insulation systems as the encapsulation material and the ceramic substrate may not withstand the functional parameters, potentially leading to unfavorable conditions like high field stress and partial discharge (PD), ultimately resulting in insulation failure. This paper presents a thorough analysis of the characteristics of the electrical insulation materials used in power electronics devices based on the research in WBG packaging conducted in recent years. The significance of maximum electric field stress at triple points (TPs) is examined. Furthermore, the paper reviews the strategies and techniques employed to mitigate the challenges related to maximum field stress and PDs in both encapsulation and substrate materials. It is concluded that the mitigation strategies are promising in improving insulation systems for packaging, but the studies lack their implementation under actual operating conditions of WBG power modules.

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A Test System Meeting Requirements Under Normal and Contingency Conditions at Multiple Loadings for Transmission Expansion Planning

A Test System Meeting Requirements Under Normal and Continge...

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Proceedings of the IEEE Dallas Circuits and systems Workshop (DCAS)

作者： Bhuban Dhamala Mona Ghassemi Department of Electrical and Computer Engineering Zero Emission Realization of Optimized Energy Systems (ZEROES) Laboratory The University of Texas at Dallas Richardson TX USA

ISBN: (数字)9798350349535

ISBN: (纸本)9798350349542

This paper introduces a high-voltage test system tailored specifically for transmission expansion planning (TEP). The network incorporates long transmission lines, and the line series impedance and shunt admittance for each line are computed utilizing the equivalent $\pi$ circuit model for long transmission lines to account for the distributed nature of line parameters. The proposed test system offers technically feasible load flow solutions under normal and all single contingency conditions for three distinct loading scenarios: peak, dominant, and light loading conditions. As the real power system is subject to various loading scenarios and should be effectively operable under all conditions, this test system accurately replicates the properties of real power systems. The test system introduced in this paper can be a valuable resource for TEP research.

关键词： Technical requirements Power transmission lines Loading Contingency management High-voltage techniques Planning Power system reliability

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Characterizing Nonlinear Field Dependent Conductivity Layers to Mitigate Electric Field Within (U)WBG Power Modules Under High Frequency, High Slew Rate Square Voltage Pulses

Characterizing Nonlinear Field Dependent Conductivity Layers...

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IEEE Texas Power and Energy Conference (TPEC)

A vast majority of research on (U)WBG power modules has been going on to implement nonlinear resistive field grading material on metal-brazed substrates in reducing the electric field that is maximum at triple points (TPs). However, nearly all investigations have been conducted under either DC or 50/60 $\mathbf{H}_{\mathbf{Z}}$ sinusoidal AC voltages, even though the actual operation of envisioned (U)WBG power modules involves high-frequency square voltages with high slew rates. It has been validated by several studies that fast rise times of square voltages rapidly degrade the breakdown strength of insulation materials, leading to premature failure. Therefore, this paper introduces a nonlinear resistive field grading material or field-dependent conductivity (FDC) layer around the TP and metal edges to evaluate the electric field mitigation under a high frequency and high slew rate square voltage. The modeling and simulation of both coated and uncoated (U)WBG substrates were performed in COMSOL Multiphysics to assess the electric field reduction with the nonlinear FDC layer. The improvement of reduction in electric field under 100 kHz high slew rate square voltage is compared with that of 60 Hz. The results reveal a significant decrease in field stress at the TP, even under square voltages with fast rise times and high frequencies, when applying a nonlinear FDC coating, as opposed to the uncoated substrate. The influence of switching field $(\mathbf{E}_{\mathbf{b}})$ and nonlinearity coefficient $(\alpha)$ of nonlinear FDC layer is studied under 100 kHz square voltage, and it is concluded that $\alpha$ and $\mathbf{E}_{\mathbf{b}}$ should be more than 10 and less than 8 kV/mm, respectively to achieve effective performance of resistive field grading material.

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Design of Distributed Nonlinear Observers Without Using Global Inputs

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IEEE Transactions on Automatic Control 2025年

作者： Cao, Ganghui Wang, Jinzhi Polycarpou, Marios M. Peking University State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering Science College of Engineering Beijing100871 China University of Cyprus KIOS Research and Innovation Center of Excellence and the Department of Electrical and Computer Engineering Nicosia1678 Cyprus

This paper investigates the design of distributed observers for a class of nonlinear systems. The designed distributed observers reside in a network of sensor nodes. The communication links in the network enable each sensor node to estimate all states of the nonlinear system, even though each one can only collect a small portion of the system's outputs. However, all inputs of the system are still needed at each node to carry out a correct state estimation. For this problem, the paper further proposes a distributed nonlinear observer without using global inputs, in which each sensor node only needs partial input information of the nonlinear system. © 1963-2012 IEEE.

关键词： Nonlinear simulations

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Effect of Forced Heat Convection on Heat Transfer for Bipolar MVDC Power Cables in Envisaged Wide-Body All-Electric Aircraft

Effect of Forced Heat Convection on Heat Transfer for Bipola...

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Proceedings of the IEEE Dallas Circuits and systems Workshop (DCAS)

作者： Md Asifur Rahman Anoy Saha Mona Ghassemi Department of Electrical and Computer Engineering Zero Emission Realization of Optimized Energy Systems (ZEROES) Laboratory The University of Texas at Dallas Richardson TX USA

ISBN: (数字)9798350349535

ISBN: (纸本)9798350349542

Since transportation is one of the primary sources of greenhouse gas (GHG) emissions, its electrification is essential for achieving the net-zero GHG emissions target. As a part of transportation electrification, all-electric aircraft (AEA) have emerged as a viable approach to achieve net-zero emissions in aviation. Electric power systems (EPS) with high power density and low system mass are required for future wide-body AEA. Power cables, as one of the key components of the aircraft EPS, must be constructed to maximize the overall power density of the EPS. Because of the limited heat transfer by convection at cruising altitudes of wide-body AEA, the design of power cables faces significant thermal challenges. These difficulties are worsened using bipolar MVDC EPSs, which are generally composed of two power cables, negative and positive poles, adjacent to one another. Heat transfers that occur through convection and radiation are influenced by the cable's surface area. To offset the decrease in convective heat transfer brought on by the low air pressure, one method is to apply forced heat convection. Increasing the velocity of forced air in a cable duct, either the surface temperature of the cable can be reduced, or the core diameter can be reduced along with the cable weight maintaining the same temperature obtained from natural heat convection. This paper examines the impact of forced heat convection on a conventional cylindrical bipolar cable system. The cable system is equipped with our novel designed ARC-SCT-MMEI insulation system delineated in the paper, and its performance is compared to that of natural heat convection.

关键词： Power system measurements Power cables Density measurement Net zero Ducts Power cable insulation Transportation

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Digital Twin for Solar Photovoltaic Power Estimations Based on an Ensemble of Recurrent Neural Networks

Digital Twin for Solar Photovoltaic Power Estimations Based ...

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IEEE Conference on Industrial Electronics and Applications (ICIEA)

作者： Michael Walters Ganesh K. Venayagamoorthy Holcombe Department of Electrical and Computer Engineering Real-Time Power and Intelligent Systems Laboratory Clemson University Clemson SC U.S.A

ISBN: (数字)9798350360868

ISBN: (纸本)9798350360875

Planning, managing, and maintaining solar photovoltaic (PV) plants is becoming increasingly challenging as a result of their increasing implementation world-wide. Solar PV power generation estimations provide a source of knowledge and certainty, assisting system operators in day-to-day responsibilities. Digital twins (DTs) replicate physical entities within a virtual setting, providing a real-time platform to perform solar PV power generation estimations, further enhancing situational awareness and operational efficiency. In this paper, a DT is developed and implemented for Clemson University's 1 MW solar PV plant located in South Carolina, USA to perform solar PV power generation estimations. An ensemble of Elman recurrent neural networks (ERNNs) is utilized in the DT for solar PV power generation estimations, replicating PV plant behaviors and characteristics. The ERNN ensemble utilizes data collected at the PV plant site, i.e. generated power, solar irradiance and ambient temperature. The DT's performance is evaluated based on different weather conditions and ERNN ensemble's output selection methods. Typical results are presented to show the effectiveness of the neural network ensemble based DT for solar PV power generation estimations.

关键词： Photovoltaic systems Recurrent neural networks Accuracy Heuristic algorithms Power system dynamics Estimation Artificial neural networks

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Robust Feature Selection With Weight Cost Maximin Optimization

Robust Feature Selection With Weight Cost Maximin Optimizati...

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IEEE Workshop on Machine Learning for Signal Processing

作者： Mohammad Amin Omidi Babak Seyfe Shahrokh Valaee Department of Electrical Engineering Information Theoretic Learning Systems Laboratory (ITLS) Shahed University Tehran Iran Department of Electrical and Computer Engineering University of Toronto Toronto Canada

Recently, applying data-independent random feature extraction methods has been promising for time-series classifications. However, a large portion of the features generated by these methods is redundant. To address this problem, we propose a robust feature selection method that applies a maximin optimization to a weight cost function that makes a trade-off between dimension reduction and preserving the classification accuracy. It can be shown that the weight cost is discrete midpoint convex with respect to the sparsity parameter, and at the same time is concave with respect to the regularization parameter. Based on these findings, we propose an efficient implementation for feature selection with maximin optimization. Our empirical results show that for large classification tasks with a small sample size per class, our feature selection method removes more redundancies than the state-of-the-art methods, while preserving the classification accuracy.

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Multi-View Radar Autoencoder for Self-Supervised Automotive Radar Representation Learning

Multi-View Radar Autoencoder for Self-Supervised Automotive ...

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IEEE Symposium on Intelligent Vehicle

作者： Haoran Zhu Haoze He Anna Choromanska Satish Ravindran Binbin Shi Lihui Chen Department of Electrical and Computer Engineering Learning Systems Laboratory New York University NY USA NXP Semiconductors San Jose CA USA

ISBN: (数字)9798350348811

ISBN: (纸本)9798350348828

Automotive radar has been extensively utilized in cars for many years as an essential sensor, primarily due to its robustness in extreme weather conditions, its capacity to measure Doppler information in the surrounding environment, and its cost-effectiveness. Recently, developments in radar technologies and the availability of open-source radar data sets have attracted more attention to radars and using them for perception tasks in deep learning based autonomous driving. However, annotating radar data for large-scale autonomous driving perception tasks is challenging, i.e., it is difficult for humans to label this data and often requires a semi-automatic approach that involves projecting labels from other sensors, such as cameras and LiDARs. The lack of high-quality labeled data has limited the performance of radar perception models. In this paper, we propose MVRAE, a Multi-View Radar AutoEncoder, which employs self-supervised learning to learn meaningful representations from multi-view radar data without any labels. Our approach is based on the intuition that a good representation for multi-view radar data, which includes range-angle, range-Doppler, and angle-Doppler views, should enable the reconstruction of one view solely from the representations of the other two views. Experimental results demonstrate that our proposed self-supervised method, that can be used as a pre-training step for autonomous driving task, allows the model to learn meaningful representations from unlabeled radar data and achieves enhanced label efficiency for downstream tasks, such as radar semantic segmentation. To the best of our knowledge, MVRAE is the first work that employs self-supervised learning and conducts systematic experiments with multi-view radar data.

关键词： Representation learning Systematics Semantic segmentation Radar Self-supervised learning Data models Doppler radar

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Evaluating Dibenzyltoluene as a Dielectric Liquid for Encapsulation in High Voltage, High Power Density U(WBG) Power Electronics Modules

Evaluating Dibenzyltoluene as a Dielectric Liquid for Encaps...

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IEEE Green Energy and systems Conference (IGESC)

作者： Pujan Adhikari Easir Arafat Mona Ghassemi Department of Electrical and Computer Engineering Zero Emission Realization of Optimized Energy Systems (ZEROES) Laboratory The University of Texas at Dallas Richardson TX USA

ISBN: (数字)9798350379617

ISBN: (纸本)9798350379624

The integration of (ultra) wide bandgap (UWBG) semiconductor technologies, such as silicon carbide and diamond, is crucial for the advancement of zero-emission vehicles (ZEVs), all-electric aircraft (AEA), and renewable energy systems. These technologies operate at higher temperatures, frequencies, and voltages, necessitating the development of novel materials that can endure these demanding conditions. Specifically, the polymeric encapsulation materials currently in use, such as silicone gel and epoxy resin, must be replaced with materials possessing superior properties in every aspect. This paper evaluates the suitability of dibenzyltoluene (DBT), a dielectric liquid, by assessing its thermal conductivity, viscosity, and dielectric breakdown strength under AC voltage. The effects of increased temperature on these properties are examined. Compared to room temperature, DBT exhibits minimal decline in both breakdown strength and thermal conductivity, which are crucial characteristics for insulating media in power modules. When these properties are compared to those of silicone gel, the superior performance of DBT becomes evident. This paper also briefly highlights the challenges to be considered when selecting a dielectric liquid, using the issues related to DBT as a reference.

关键词： Encapsulation Viscosity Temperature Photonic band gap Multichip modules High-voltage techniques Conductivity Thermal conductivity Power electronics Dielectric liquids

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A High Voltage Test System Meeting Requirements Under Normal and All Single Contingencies Conditions of Peak, Dominant, and Light Loadings for Transmission Expansion Planning Studies

A High Voltage Test System Meeting Requirements Under Normal...

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IEEE Texas Power and Energy Conference (TPEC)

This paper introduces a new 17-bus 500 kV test system that has been specially designed to support transmission expansion planning studies. Unlike other test systems that have been developed for power system analysis, this system is unique because it focuses exclusively on transmission expansion planning at high voltage levels. Existing test systems that are used for TEP studies, in combination with electricity market problems or for integrating new generation or loads, tend to consider the system operations only under normal conditions and one loading condition. However, in practical scenarios, the system must be able to operate under different loading conditions and single contingencies to ensure reliability. Therefore, a reliable test system should mimic the behavior of a real power system, operating under both normal and all single contingency conditions for different loading conditions. This paper addresses this need by introducing a 17-bus 500 kV test system that can operate successfully under three different loading conditions (peak load, dominant load - 60% of peak load, and light load - 40% of peak load), while also being able to handle the operation at normal and single contingency conditions in each case.

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