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.

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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

A Novel Analog Circuit Design for Maximum Power Point Tracking of Photovoltaic Panels Nesrine Mhiri, Abdulrahman Alahdal, Hamza Ghulman, and Anis Ammous Power Electronics Group (PEG), National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia 2DEE, Umm Al Qura University, Makkah, Saudi Arabia

 

A Novel Analog Circuit Design for Maximum Power Point Tracking of Photovoltaic Panels Nesrine Mhiri,1 Abdulrahman Alahdal,2 Hamza Ghulman,2 and Anis Ammous1,2 Power Electronics Group (PEG), National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia DEE, Umm Al Qura University, Makkah, Saudi Arabia Correspondence should be addressed to Anis Ammous; aaammous@uqu.edu.sa Received 7 April 2017; Revised 20 June 2017; Accepted 26 July 2017; Published 25 September 2017 Academic Editor: Mohamed Orabi Copyright © 2017 Nesrine Mhiri et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A new analog technique is proposed in order to track the maximum power point (MPP) of PV panels. The proposed technique uses the well-known simple functions of electronic circuits. The proposed technique is validated by applying it to boost based off grid PV system. The simulation of the PV system was done on the circuit oriented simulator Proteus-ISIS. A good efficiency of the analog technique (more than 98%) was registered. The variation of irradiation was introduced in order to study the robustness of the proposed analog MPPT technique.

LINK: https://downloads.hindawi.com/archive/2017/9409801.pdf