Straight Facts about Linear MOSFETs and their Applications BY José Padilla, Director Product Marketing; Aalok Bhatt, Product Marketing Engineer; Vladimir Tsukanov, Senior Principal R&D, Littelfuse-BODO POWER SYSTEM

Straight Facts about Linear MOSFETs and their Applications Linear-mode applications such as class-A audio amplifiers, active DC-link discharge, battery charge-discharge, inrush current limiter, low-voltage DC motor control or electronic loads demand the power MOSFETs to be operated within the current saturation region. Standard MOSFETs are prone to ETI when used in linear-mode applications leading to possible device destruction. Linear MOSFETs are the most appropriate choice for linear-mode applications to ensure reliable operation. José Padilla, Director Product Marketing; Aalok Bhatt, Product Marketing Engineer; Vladimir Tsukanov, Senior Principal R&D, Littelfuse

Introduction – What is linear-mode operation and why is it required Power MOSFET’s output characteristic can be divided in to three distinct regions namely ohmic region, non-linear region, and saturation or active region as displayed in Figure 1. In the ohmic region, the drain current ID is directly proportional to the drain-source voltage VDS for a given gate-source voltage VGS. The MOSFET acts as a resistor in this operation mode with a value equal to its on-state resistance RDS(ON). In the non-linear region, the MOSFET’s resistance behaves non-linearly and the rate of increase of ID with VDS slows down. In the active region, the MOSFET’s channel is saturated with majority charge carriers. In this region, ID is independent of VDS. ID is governed only by VGS and it remains constant for any given VDS. In other words, the MOSFET exhibits the behavior of a constant current sink. This operating mode is commonly known as linear operation mode of power MOSFETs. In this operating mode, the MOSFETs typically dissipate higher power levels than they would in the more common switched-mode applications due to simultaneous occurrence of high voltage and current[1].

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Recherches d’optimums d’énergies pour charge/décharge d'une batterie à technologie avancée dédiée à des applications photovoltaïques T H E S E préparée au Laboratoire d’Analyse et d’Architecture des Systèmes du CNRS en vue de l’obtention du DOCTORAT DE L’UNIVERSITE DE par Jean-François REYNAUD

 Recherches d’optimums d’énergies pour charge/décharge d'une batterie à technologie avancée dédiée à des applications photovoltaïques 

T H E S E préparée au Laboratoire d’Analyse et d’Architecture des Systèmes du CNRS en vue de l’obtention du DOCTORAT DE L’UNIVERSITE DE TOULOUSE

Délivré par l’Université Toulouse III – Paul Sabatier 

Discipline : Génie Electrique présentée et soutenue par Jean-François REYNAUD 

LINK: http://thesesups.ups-tlse.fr/1482/1/2011TOU30136.pdf

Système d’alimentation photovoltaïque avec stockage hybride pour l’habitat énergétiquement autonome -Akassewa Tchapo Singo- Thèse présentée pour l’obtention du titre de Docteur de l’Université Henri Poincaré, Nancy-I en Génie Electrique

 Thèse présentée pour l’obtention du titre de Docteur de l’Université Henri Poincaré, Nancy-I en Génie Electrique par Akassewa Tchapo SINGO Ingénieur ENSEM Système d’alimentation photovoltaïque avec stockage hybride pour l’habitat énergétiquement autonome .

Soutenue publiquement le 3 février 2010

 INTRODUCTION GENERALE 

Avec l’arrivée du nouveau millénaire, les débats sur l’avenir énergétique de la planète se sont intensifiés compte tenus des besoins sans cesse croissants dans le domaine et les conséquences que cela peut engendrer à moyen terme. En effet, l’évolution démographique et le développement de certaines zones géographiques, l’Asie aujourd’hui, l’Amérique Latine et la Russie demain, laissent présager une augmentation considérable de la consommation en énergie. A ce rythme, les réserves en énergies fossiles ne pourront assurer les besoins que pour quelques décennies encore, entrainant des situations de pénurie dont les prémices se sont faites ressentir à travers la crise du pétrole de ces deux dernières années. Les gisements de ressources énergétiques d’origines fissiles, même si elles offrent une alternative à court/moyen terme, posent quant à elles de réels problèmes environnementaux liés au traitement des déchets radioactifs et au démantèlement des centrales nucléaires obsolètes. Une première piste à cette crise annoncée étant la diminution de la consommation énergétique, c’est ainsi que sont apparus sur le marché, ces dernières années, des appareils de faible consommation de classe A ou A+ (réfrigérateurs, laves linge, ampoules basse consommation, …). En parallèle, il faut développer de nouvelles sources d’énergie propres et renouvelables. A ce sujet, le soleil, le vent, la biomasse, la mer, … apparaissent comme des énergies inépuisables et facilement exploitables. Ainsi, d’après l’Agence Internationale de l’Energie (AIE), si l’on prend l’exemple du soleil, une surface de 145000km² (4% de la surface des déserts arides) de panneaux photovoltaïques (PV) suffirait à couvrir la totalité des besoins énergétiques mondiaux. Au-delà de toutes considérations hypothétiques, il apparait que le photovoltaïque se présente comme une solution d’avenir car il offre une multitude d’avantages : · la production de cette électricité renouvelable n'émet pas de gaz à effet de serre, il faut cependant réduire l’impact environnemental de la fabrication du système, · la lumière du soleil étant disponible partout et quasi-inépuisable, l'énergie photovoltaïque est exploitable aussi bien en montagne, dans un village isolé que dans le centre d'une grande ville, et aussi bien au Sud que dans le Nord, · l'électricité photovoltaïque peut être produite au plus près de son lieu de consommation, de manière décentralisée, directement chez l'utilisateur, ce qui la rend accessible à une grande partie de la population mondiale.

LINK: https://hal.univ-lorraine.fr/tel-01748214/document

Optimal sizing and control of energy storage systems for the electricity markets participation of intelligent photovoltaic power plants Andoni Saez de Ibarra Martinez de Contrasta UNIVERSITE GRENOBLE ALPES

 Optimal sizing and control of energy storage systems for the electricity markets participation of intelligent photovoltaic power plants Andoni Saez de Ibarra Martinez de Contrasta 

 THÈSE Pour obtenir le grade de DOCTEUR DE LA COMMUNAUTE UNIVERSITE GRENOBLE ALPES

 Spécialité : Génie Electrique 

 Dimensionnement et contrôlecommande optimisé des systèmes de stockage énergétique pour la participation au marché de l'électricité des parcs photovoltaïques intelligents 

Thèse soutenue publiquement le 7 octobre 2016, devant le jury composé de : M. Cristian NICHITA Professeur à l’Université Le Havre, Président M. Bruno BURGER Fraunhofer ISE, Rapporteur M. Luis MARTINEZ SALAMERO Professeur à l’Universitat Rovira i Virgili, Rapporteur M. Ionel VECHIU Professeur à l’ESTIA, Rapporteur M. Seddik BACHA Professeur à l’Université Grenoble Alpes, Directeur de thèse M. Vincent DEBUSSCHERE Maître de Conférences Grenoble INP, Co-encadrant de thèse M. Aitor MILO IK4-IKERLAN Technology Research Centre, Co-encadrant de thèse Mme. Haizea GAZTAÑAGA IK4-IKERLAN Technology Research Centre, Examinatrice M. Tuan TRAN QUOC CEA-INES, Invité

Abstract 

The present PhD deals with the integration of intelligent photovoltaic (IPV) power plants in the electricity markets in an environment subject to free competition. The IPV power plants are those that include energy storage systems to reduce the variability and to provide the entire group a controllability increase. These technical objectives are obtained thanks to the bidirectional exchanging and storing capability that the storage system contributes to, in this case, battery energy storage system (BESS). In order to obtain the maximum profitability of the BESS, the sizing must be optimized together with the control strategy that the BESS will be operated with. In the present PhD, once the most performing battery energy storage technology has been selected, the lithium-ion technology, an innovative IPV power plant electricity market participation process is proposed which optimizes both the sizing and the energy management strategy in the same optimization step. This optimization process together with the electricity market participation has been applied in a real case study, confirming that this procedure permits to maximize the economic profitability of this type of generation. Keywords: photovoltaic power plant, energy storage system, grid, optimization, electricity markets, sizing, energy management strategy.

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Design and Implementation of a Radiation Hardened GaN Based Isolated DC-DC Converter for Space Applications Victor Turriate- Virginia Polytechnic Institute and State University - Master of Science In Electrical Engineering

 

Design and Implementation of a Radiation Hardened GaN Based Isolated DC-DC Converter for Space Applications Victor Turriate-Gastulo Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Master of Science In Electrical Engineering

ABSTRACT 

Power converters used in high reliability radiation hardened space applications trail their commercial counterparts in terms of power density and efficiency. This is due to the additional challenges that arise in the design of space rated power converters from the harsh environment they need to operate in, to the limited availability of space qualified components and field demonstrated power converter topologies. Recently released radiation hardened Gallium Nitride (GaN) Field Effect Transistors (FETs) with their inherent radiation tolerance and superior performance over Silicon Power Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), however, offer a promising alternative to improve power density and performance of space power converters. This thesis presents a practical implementation of the Phase Shifted Full Bridge DC-DC Isolated converter with synchronous rectification for space applications using newly released radiation hardened GaN FETs. A survey outlining the benefits of new radiation hardened GaN FETs for space power applications compared to existing radiation hardened power MOSFETs is included. In addition, this work summarizes the main design considerations to implement the selected converter topology for space applications. Furthermore, the overall design process followed to design the DC-DC converter power stage, as well as a comprehensive power loss analysis are included. This work also includes details to implement a conventional hard-switched Full Bridge DC-DC converter using radiation hardened GaN FETs for this application. An efficiency and component stress comparison was performed between the hard-switched Full Bridge design and the Phase Shifted Full Bridge DC-DC converter design. This comparison highlights the benefits of phase shift modulation (PSM) and zero voltage switching (ZVS) for GaN FET applications. Furthermore, different magnetic designs were characterized and compared for efficiency in both converters. The DC-DC converters implemented in this work regulate their outputs to a nominal 20 V, delivering 500 W from a nominal 100 V DC Bus input. Failure mode and effects analysis (FMEA) and protection circuitry required for complete radiation qualification of the Phase Shifted Full Bridge DC-DC converter topology are not addressed by this work.

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https://vtechworks.lib.vt.edu/bitstream/handle/10919/98232/Turriate_VO_T_2018.pdf?sequence=1&isAllowed=y

Multiphase Design and Control Techniques Applied to a Forward Micro-Inverter TESIS DOCTORAL Autor: David Meneses Herrera Ingeniero Industrial por la Universidad Politécnica de Madrid DEPARTAMENTO DE AUTOMÁTICA, INGENIERÍA ELECTRÓNICA E INFORMATICA INDUSTRIAL

 

Multiphase Design and Control Techniques Applied to a Forward Micro-Inverter 

 TESIS DOCTORAL Autor: David Meneses Herrera Ingeniero Industrial por la Universidad Politécnica de Madrid 

 DEPARTAMENTO DE AUTOMÁTICA, INGENIERÍA ELECTRÓNICA E INFORMATICA INDUSTRIAL Universidad Politécnica de Madrid

 Abstract 

 In the last decade the photovoltaic (PV) installed power increased with an average growth of 49% per year and it is expected to cover the 16% of the global electricity consumption by 2050. Most of the installed PV power corresponds to grid-connected systems, with a significant percentage of residential installations. In these PV systems, the inverter is essential since it is the responsible of transferring into the grid the extracted power from the PV modules. Several architectures have been proposed for grid-connected residential PV systems, including the AC-module technology. An AC-module consists of an inverter, also known as micro-inverter, which is attached to a PV module. The AC-module technology offers modularity, redundancy and individual MPPT of each module. In addition, the expansion of this technology will enable the possibility of economies of scale of mass market and “plug and play” for the user, thus reducing the overall cost of the installation. However, the micro-inverter must be able to provide the required voltage boost to interface a low voltage PV module to the grid while keeping an acceptable efficiency in a wide power range. Furthermore, the quality standards must be satisfied and size and lifetime of the solutions must be always considered. In this thesis a single-stage forward micro-inverter with boundary mode operation is proposed to address the micro-inverter requirements. The transformer in the proposed topology remains as in the classic forward converter and bidirectional switches in the secondary side allows direct connection to the grid. In addition the selected control strategy allows high power factor current with a simple implementation. The operation of the topology is presented and the main design issues are introduced. With the intention to propose a simple and low-cost solution, an analog controller for a PFC operated in boundary mode is utilized. The main necessary modifications are discussed, with the focus on the zero current detection (ZCD) and the compatibility of the controller with a MPPT algorithm. The experimental results show the limitations of the selected analog controller implementation and the transformer is identified as a main losses contributor. The main objective of this thesis is to contribute in the application of control and design multiphase techniques to the PV micro-inverters. Two different multiphase configurations have been applied to the forward micro-inverter proposed in this thesis. The first one consists of a parallel-series connected variation which enables the use of low turns ratio, i.e. well coupled, transformers to achieve a proper voltage boost with an improved performance. This multiphase configuration implements BCM control at maximum load however. With this control method the switching frequency increases significantly for light load operation, thus jeopardizing the efficiency. Therefore, in order to keep acceptable weighted efficiency levels, DCM operation is selected for low power conditions. The second multiphase variation considered in this thesis is the interleaved configuration with two different phase shedding techniques: depending on the DC power extracted from the PV panel, and depending on the demanded instantaneous power. The application of interleaving techniques is interesting in PV grid-connected inverters for the possibility of flat efficiency behavior in a wide power range. The interleaved variations of the proposed forward micro- inverter are operated in DCM to avoid the current loop, which is important when the number of phases is large. The adequate transformer cores for all the multiphase configurations are selected according to the area product parameter and a detailed design of each required transformer is developed. With this information and simulation results, the impact in size and efficiency of the number of transformer used can be assessed. The considered multiphase topologies are compared in this thesis according to the results of the introduced analysis.

 LINK VIEW FULL TEXT:https://oa.upm.es/39988/1/DAVID_MENESES_HERRERA.pdf

Predictive Maintenance of VRLA Batteries in UPS towards Reliable Data Centers July 2020 Conference: IFAC World Congress 2020At: Berlin, Germany Project: Artificial Intelligence for Cyber Physical Systems Authors: Jing-Xian Tang Tsinghua University Jin-Hong Du Carnegie Mellon University Lin Yiting Sun Yat-Sen University Qing-Shan Jia Tsinghua University

Predictive Maintenance of VRLA Batteries in UPS towards Reliable Data Centers July 2020 Conference: IFAC World Congress 2020At: Berlin, Germany Project: Artificial Intelligence for Cyber Physical Systems Authors: Jing-Xian Tang Tsinghua University Jin-Hong Du Carnegie Mellon University Lin Yiting Sun Yat-Sen University Qing-Shan Jia Tsinghua University Abstract: The reliability of data centers can be severely aected when battery failure occurs in the Uninterruptible Power Supply (UPS). Thus it has become a central issue for the industry to discover failure-impending batteries in UPS. In this paper, we consider this important problem and present a data-driven method for predictive battery maintenance. The major contributions are as follows.First, we develop a changepoint detection technique for ecient data labeling. Second, new features are designed to fully utilize the dataset. Third, we build a predictive classication model which can discriminate between healthy and failure-impending batteries. Our method has been built and evaluated on 209,912,615 records from Tencent data center involving nearly 300 batteries monitored over 2 years. The experiment on test set shows that our method is able to predict battery replacement with 98% accuracy and averagely 15 days in advance, which outperforms the previous maintenance policy by more than 8%.

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https://www.researchgate.net/publication/339677454_Predictive_Maintenance_of_VRLA_Batteries_in_UPS_towards_Reliable_Data_Centers

Comparing Quasi-Resonant and Active Clamp Flyback Topologies for 65W Wall Charger Applications Using GaN Technology-By Harshit Soni and Rajesh Ghosh, Tagore Technology Inc.-MAGAZINE BODO´S POWER SYSTEM AUGUST 2021

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LINK PAPER WEB: https://ieeexplore.ieee.org/document/9487353