Investigation Of A Gan Based Power Supply Topology Utilizing Solid State Transformer For Low Power Applications

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Investigation of a GaN-based Power Supply Topology Utilizing Solid State Transformer for Low Power Applications

Author : Akrem Mohamed Elrajoubi
Publisher :
ISBN 13 :
Total Pages : 340 pages
Book Rating : 4.:/5 (11 download)

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Book Synopsis Investigation of a GaN-based Power Supply Topology Utilizing Solid State Transformer for Low Power Applications by : Akrem Mohamed Elrajoubi

Download or read book Investigation of a GaN-based Power Supply Topology Utilizing Solid State Transformer for Low Power Applications written by Akrem Mohamed Elrajoubi and published by . This book was released on 2018 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride (GaN) power devices exhibit a much lower gate capacitance for a similar on-resistance than its silicon counterparts, making it highly desirable for high-frequency operation in switching converters, which leads to their significant benefits on power density, cost, and system volume. High-density switching converters are being realized with GaN power devices due to their high switching speeds that reduce the size of energy-storage circuit components. The purpose of this dissertation research is to investigate a new isolated GaN AC/DC switching converter based on solid-state transformer configuration with a totem-pole power factor corrector (PFC) front-end, a half-bridge series-resonant converter (SRC) for power conversion, and a current-doubler rectifier (CDR) at its output. A new equivalent circuit model for the converter is constructed consisting of a loss-free resistor model for the PFC rectifier with first harmonic approximation model for the SRC and the CDR. Then, state-space analysis is performed to derive the converter transfer function in order to design the controllers to yield sufficient phase margins. The converter offers the advantages of voltage regulation feature of the solid-state transformer, low harmonics and close-to-unity power factor of the PFC rectifier, soft-switching of the half-bridge SRC, reduced size of the high-frequency transformer, and smaller leakage inductance of the CDR which is used for low-voltage high-current applications as the CDR draws half of the load current in the transformer secondary side yielding less copper losses. A high-frequency nanocrystalline toroid transformer, based on a modified equation to determine its leakage inductance, is designed and fabricated to satisfy the performance specifications of the converter. A meticulously planned gate driving strategy together with a Kelvin-source return circuitry is used to mitigate Miller effects, minimize gate ringing, and minimize the parasitics of the pull-down and pull-up loops of the converter. A new programming method that combines MATLAB Simulink embedded coder with code composer studio for the TMS320F28335 digital signal processor (DSP) controller is developed and demonstrated. Finally, the GaN-based AC/DC converter is experimentally verified for a 120Vac to 48Vdc/60Vdc conversion operating at 100 kHz for various loadings.

Power GaN Devices

Author : Matteo Meneghini
Publisher : Springer
ISBN 13 : 3319431994
Total Pages : 383 pages
Book Rating : 4.3/5 (194 download)

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Book Synopsis Power GaN Devices by : Matteo Meneghini

Download or read book Power GaN Devices written by Matteo Meneghini and published by Springer. This book was released on 2016-09-08 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the first comprehensive overview of the properties and fabrication methods of GaN-based power transistors, with contributions from the most active research groups in the field. It describes how gallium nitride has emerged as an excellent material for the fabrication of power transistors; thanks to the high energy gap, high breakdown field, and saturation velocity of GaN, these devices can reach breakdown voltages beyond the kV range, and very high switching frequencies, thus being suitable for application in power conversion systems. Based on GaN, switching-mode power converters with efficiency in excess of 99 % have been already demonstrated, thus clearing the way for massive adoption of GaN transistors in the power conversion market. This is expected to have important advantages at both the environmental and economic level, since power conversion losses account for 10 % of global electricity consumption. The first part of the book describes the properties and advantages of gallium nitride compared to conventional semiconductor materials. The second part of the book describes the techniques used for device fabrication, and the methods for GaN-on-Silicon mass production. Specific attention is paid to the three most advanced device structures: lateral transistors, vertical power devices, and nanowire-based HEMTs. Other relevant topics covered by the book are the strategies for normally-off operation, and the problems related to device reliability. The last chapter reviews the switching characteristics of GaN HEMTs based on a systems level approach. This book is a unique reference for people working in the materials, device and power electronics fields; it provides interdisciplinary information on material growth, device fabrication, reliability issues and circuit-level switching investigation.

A Scalable and Plug-and-play Solid-State Transformer Based on Input-series-output-parallel Architecture

Author : Xin Zhao (Ph. D. in electrical and computer engineering)
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis A Scalable and Plug-and-play Solid-State Transformer Based on Input-series-output-parallel Architecture by : Xin Zhao (Ph. D. in electrical and computer engineering)

Download or read book A Scalable and Plug-and-play Solid-State Transformer Based on Input-series-output-parallel Architecture written by Xin Zhao (Ph. D. in electrical and computer engineering) and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As an eventual replacement of the century-old line frequency transformer (LFT), the Solid-State Transformer (SST) has been investigated intensively in the past decade due to its ability to offer higher power density and many smart functionalities, such as output voltage regulation, grid reactive power support and power flow control in the distribution grid. As more and more distributed energy resources (DERs) are connected to the grid to achieve the high penetration of renewable energies, the SST serves as an Energy Router, the intelligent interface between the DERs and the distribution grid. To make the deployment of the SST simple and efficient, SSTs should also provide power and communication plug-and-play (PnP) feature. The power PnP feature enables instant power exchange between the medium voltage distribution grid and the DERs and loads, and the communication PnP enables the instant management and many SSTs as a collective Energy Routers. So far, the investigation on the SST with the PnP feature is limited. This thesis’s main contribution is to investigate the capability of a proposed PnP SST, which can achieve immediate power flow once the connection between SST and the medium voltage grid is established. The proposed PnP SST has an input-series-output-parallel (ISOP) modular configuration using a number of SST cells. This greatly improves the scalability and reliability of the PnP SST for medium voltage application. To better adopt the PnP feature, a distributed controller solution is proposed to control the SST cell. To further improve the power density and control robustness, a single stage direct AC/AC power conversion topology is used for the PnP SST. The AC/AC converter employs the soft switching LLC resonant converter to improve the power efficiency. To enable the PnP start-up of the SST, a distributed Flyback auxiliary power supply is proposed to facilitate automatic control power generation. For the modular PnP SST, the input voltage balance is a major concern and is investigated in this thesis. A major contribution from this research is that the LLC based modular PnP SST solution can achieve input voltage balance even with an open loop control, eliminating complex centralized controller needed in traditional SST. The voltage balance performance is capable of tolerating component parameter variations within a reasonably large range. This paves the way for the PnP to achieve very high input voltage needed for medium voltage grid connection. The modular PnP SST also features very high input impedance hence very low in-rush current. Direct PnP to the medium voltage grid can be applied to simplify the installation and the need for a large in-rush current limiter is eliminated. The salient smart functions of the proposed PnP SST is also investigated. The investigation indicates that the proposed PnP SST has the capability of achieving fast dynamic voltage regulation, bi-directional power flow, and reactive power processing. A SiC based PnP SST prototype was developed as part of this thesis. Experiments verified that the SST cell achieves 97.88% peak efficiency. Each cell has a 11 kW power capability and a 550Vrms input voltage. The natural input voltage balance is verified by the PnP SST prototype with two SST cells

GaN Transistors for Efficient Power Conversion

Author : Alex Lidow
Publisher : John Wiley & Sons
ISBN 13 : 1118844769
Total Pages : 266 pages
Book Rating : 4.1/5 (188 download)

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Book Synopsis GaN Transistors for Efficient Power Conversion by : Alex Lidow

Download or read book GaN Transistors for Efficient Power Conversion written by Alex Lidow and published by John Wiley & Sons. This book was released on 2014-09-15 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride (GaN) is an emerging technology that promises to displace silicon MOSFETs in the next generation of power transistors. As silicon approaches its performance limits, GaN devices offer superior conductivity and switching characteristics, allowing designers to greatly reduce system power losses, size, weight, and cost. This timely second edition has been substantially expanded to keep students and practicing power conversion engineers ahead of the learning curve in GaN technology advancements. Acknowledging that GaN transistors are not one-to-one replacements for the current MOSFET technology, this book serves as a practical guide for understanding basic GaN transistor construction, characteristics, and applications. Included are discussions on the fundamental physics of these power semiconductors, layout and other circuit design considerations, as well as specific application examples demonstrating design techniques when employing GaN devices. With higher-frequency switching capabilities, GaN devices offer the chance to increase efficiency in existing applications such as DC–DC conversion, while opening possibilities for new applications including wireless power transfer and envelope tracking. This book is an essential learning tool and reference guide to enable power conversion engineers to design energy-efficient, smaller and more cost-effective products using GaN transistors. Key features: Written by leaders in the power semiconductor field and industry pioneers in GaN power transistor technology and applications. Contains useful discussions on device–circuit interactions, which are highly valuable since the new and high performance GaN power transistors require thoughtfully designed drive/control circuits in order to fully achieve their performance potential. Features practical guidance on formulating specific circuit designs when constructing power conversion systems using GaN transistors – see companion website for further details. A valuable learning resource for professional engineers and systems designers needing to fully understand new devices as well as electrical engineering students.

Chip-Scale Power Supplies for DC-Link and Grid Applications

Author : Christoph Rindfleisch
Publisher : Springer Nature
ISBN 13 : 3031608208
Total Pages : 256 pages
Book Rating : 4.0/5 (316 download)

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Book Synopsis Chip-Scale Power Supplies for DC-Link and Grid Applications by : Christoph Rindfleisch

Download or read book Chip-Scale Power Supplies for DC-Link and Grid Applications written by Christoph Rindfleisch and published by Springer Nature. This book was released on with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Design and Improved Switching Transient Modeling for A GaN-based Three Phase Inverter

Author : Yang Luo
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)

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Book Synopsis Design and Improved Switching Transient Modeling for A GaN-based Three Phase Inverter by : Yang Luo

Download or read book Design and Improved Switching Transient Modeling for A GaN-based Three Phase Inverter written by Yang Luo and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, wide-bandgap devices (WBG) such as silicon carbide (SiC) and gallium nitride (GaN) transistors have drawn significant research attention in power conversion applications where higher efficiency, higher power density and lower cost are required, for example, in electric vehicle (EV) applications. Owing to its better figures of merit on on-resistance, switching speed and junction temperature, enhancement-mode GaN high electron mobility transistors (HEMTs) are able to be operated with switching frequency up to the megahertz range, through which the size of passive components in the power converters can be significantly reduced. Consequently, the power converter's integration level and power density can be increased. In GaN-based power converters, the switching energy loss increases naturally along with the switching frequency, which is the dominant loss component. Consequently, it is always one of the top priority performances to be considered in research and development activities. For device manufacturers, with access to internal materials and dimensional parameters, physics-based device models are usually used. Although these models can reveal detailed characteristics of the devices, they are not accessible to the public and can be very time-consuming to develop. Analytical models, that can emulate the transistor's dynamic behaviour and predict the switching energy loss without consuming too much computing resources, are always an essential tool to help provide guidelines to engineers for circuit design and performance optimization purposes. This thesis develops a computationally inexpensive and straightforward switching transient model which proves to be more accurate than conventional model through simulation and experiments. Currently, in the commercial market, there are only a few mature designs of GaN three-phase inverter products, and most of them are costly. This unavoidable phenomenon is led by the fact that the gate driver and power loop design for GaN is demanding. Some companies such as EPC, Navitas and Power Integrations are committed to monolithic-integrated gate drivers, but they are complex and expensive. Thus, this thesis also aims to design a GaN-based three-phase inverter with low cost and low complexity in the gate drive circuit. In addition, to achieve high performance GaN-based inverter, parasitic components in the power loop have to be minimized. In this thesis study, parasitic parameters of the power loop are extracted through Ansys Q3D simulation and then validated through experimental test results. With accurate parasitic parameters, the layout of the PCBs is improved to achieve better inverter performance.

GaN Transistor Modeling for RF and Power Electronics

Author : Yogesh Singh Chauhan
Publisher : Elsevier
ISBN 13 : 0323999409
Total Pages : 262 pages
Book Rating : 4.3/5 (239 download)

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Book Synopsis GaN Transistor Modeling for RF and Power Electronics by : Yogesh Singh Chauhan

Download or read book GaN Transistor Modeling for RF and Power Electronics written by Yogesh Singh Chauhan and published by Elsevier. This book was released on 2024-05-31 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN Transistor Modeling for RF and Power Electronics: Using The ASM-GaN-HEMT Model covers all aspects of characterization and modeling of GaN transistors for both RF and Power electronics applications. Chapters cover an in-depth analysis of the industry standard compact model ASM-HEMT for GaN transistors. The book details the core surface-potential calculations and a variety of real device effects, including trapping, self-heating, field plate effects, and more to replicate realistic device behavior. The authors also include chapters on step-by-step parameter extraction procedures for the ASM-HEMT model and benchmark test results. GaN is the fastest emerging technology for RF circuits as well as power electronics. This technology is going to grow at an exponential rate over the next decade. This book is envisioned to serve as an excellent reference for the emerging GaN technology, especially for circuit designers, materials science specialists, device engineers and academic researchers and students. This book provides an overview of the operation and physics of GaN-based transistors All aspects of the ASM-HEMT model for GaN circuits, an industry standard model, are described in depth by the developers of the model Parameter extraction of GaN devices and measurement data requirements for GaN model extraction are detailed

Advanced Modeling of Solid State Transformer

Author : Mohammad Ebrahim Adabi Firouzjaee
Publisher :
ISBN 13 :
Total Pages : 158 pages
Book Rating : 4.:/5 (112 download)

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Book Synopsis Advanced Modeling of Solid State Transformer by : Mohammad Ebrahim Adabi Firouzjaee

Download or read book Advanced Modeling of Solid State Transformer written by Mohammad Ebrahim Adabi Firouzjaee and published by . This book was released on 2018 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The solid state transformer (SST) is seen as a proper replacement of the conventional iron-and-copper transformer in the future smart grid . The SST offers several benefits (e.g. enhanced power quality performance or reactive power control at both primary and secondary sides) that can be of paramount importance for the development of the smart grid . This research focuses on the development and implementation of an advanced model of a three stage bidirectional SST in Matlab/Simulink. The goal is to obtain an realistic SST model (i.e. as close to the real SST as possible) that could duplicate the performance of a real MV/LV SST. This considered design consists of three main stages: medium voltage (MV) stage, isolation stage, and low voltage (LV) stage. When the power flows from the MV side to the LV side, the input power-frequency ac voltage is converted into a MV dc voltage by the three-phase ac/dc converter, which in such case works as rectifier. The isolation stage, which includes a high-frequency transformer (HFT) and the two corresponding MV- and LV-side converters, first converts the MV-side dc voltage into a high-frequency square-wave voltage applied to the primary of the HFT; the secondary side square-wave signal is then converted to a LV dc waveform by the LV-side converter, which also works as rectifier. Finally, the output LV-side three-phase dc/ac converter, which works as inverter, provides the output power-frequency ac waveform from the LV-side dc link. Si-based semiconductor technologies can be used for MV applications using a multilelvel configuration. Recently, modular multilevel converter (03C) topologies have attracted attention for high or medium voltage applications. These converters can provide an effective topology for the MV side of the SST; their main advantages are modularity and scalability: the desired voltage level can be easily achieved by a series connection of 03C sub-modules (SMs). In addition,a 03C topology can provide high power quality and efficiency with reduced size of passive filters. These features made the 03C option an attractive topology for the MV stage of the SST. This thesis proposes a three-stage SST configuration based on 03C technology for MV converters. * The input stage of the SST is connected to the distribution system via RL filters and its three-phase configuration uses a 03C technology. A half-bridge configuration is proposed for each SM. * The isolation stage consists of three parts: a MV single-phase 03C, the high-frequency transformer (HFT), and a single-phase LV PWM converter. * The LV side of the SST uses a three-phase four-leg PWM converter, with an RL impedance for filtering currents and a capacitor bank for filtering voltages. The converters and their controller have been implemented adn tested considering models without and with semiconductor losses, while the SST model has been tested as a stand-alone device and a compnent of a distribution system. The model has been tested under severe dynamic and unbalanced conditions. The simulation results support the choices made for any SST stage and proves that the proposed design could be a feasible choice for the future SST.

Design and Development of GaN-based Vertical Transistors for Increased Power Density in Power Electronics Applications

Author : Dong Ji
Publisher :
ISBN 13 : 9780355764284
Total Pages : pages
Book Rating : 4.7/5 (642 download)

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Book Synopsis Design and Development of GaN-based Vertical Transistors for Increased Power Density in Power Electronics Applications by : Dong Ji

Download or read book Design and Development of GaN-based Vertical Transistors for Increased Power Density in Power Electronics Applications written by Dong Ji and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride (GaN)-based devices have entered the power electronics market and shown excellent progress in the medium power conversion applications. For power conversions applications > 10 kW, devices with vertical geometry are preferred over lateral geometry, since the former allows more current for a given chip area, thus provides a more economical solution for high-voltage and high-current applications. Moreover, the vertical geometry is attractive for its dispersion-free performance without passivation, a phenomenon that causes high dynamic on-state resistance (R[subscript on]) in lateral geometry high electron mobility transistors (HEMTs). In this study, GaN-based vertical transistors, which include trench current aperture vertical electron transistors (CAVETs) and in-situ oxide, GaN interlayer based trench field-effect transistors (OGFETs), have been studied both theoretically and experimentally. In order to model the devices for DC and switching performances, a device/circuit hybrid simulation platform was developed based on Silvaco ATLAS. The validation of the model was obtained by calibrating it against commercially available HEMT data. Using this hybrid model, one can start with a two-dimensional (2D) drift-diffusion model of the device and build all the way up to its circuit implementation to evaluate its switching performance. The hybrid model offers an inexpensive and accurate way to project and benchmark the performance and can be extended to any GaN-based power transistors.In the experimental portion of this study, a high voltage OGFET was designed and fabricated. An OGFET shows improved characteristics owing to a 10 nm unintentionally doped (UID) GaN interlayer as the channel. A normally-off (V[subscript th] = 4 V) vertical GaN OGFET with 10 nm UID-GaN channel interlayer and 50 nm in-situ Al2O3 was successfully demonstrated and scaled for higher current operation. By using a novel double-field-plated structure for mitigating peak electric field, a higher off-state breakdown voltage over 1.4 kV was achieved with a significantly low specific on-state resistance (R[subscript on,sp]) of 2.2 m[omega] cm2. The metal-organic chemical vapor deposition (MOCVD) regrown 10 nm GaN channel interlayer enabled a channel resistance lower than 10 [omega] mm with an average channel electron mobility of 185 cm2/Vs. The fabricated large area transistor with a total area of 0.4 mm × 0.5 mm offered a breakdown voltage of 900 V and an Ron of 4.1 [omega]. Results indicate the potential of vertical GaN OGFET for greater than 1 kV range of power electronics applications.In addition to the OGFET, the CAVET with a trench gate structure was studied in this work. By taking advantage of the two-dimensional electron gas (2DEG) in the AlGaN/GaN structure, the trench CAVET can secure an even higher channel electron mobility compared to the OGFET. The first functional trench CAVET with a metal-insulator-semiconductor (MIS) gate structure was fabricated in this work with a breakdown voltage of about 225 V. With the improvement in the fabrication process, an 880 V device with an R[subscript on,sp] of 2.7 m[omega] cm2 was demonstrated. One of the notable features of the fabricated trench CAVET is that it requires a standard MOCVD growth condition for HEMT epilayers. The simplification of the growth process is a significant achievement. Finally, a regrowth-free CAVET was demonstrated and patented. The transformative approach was realized using Si ion implantation based doping compensation in the aperture.

GaN-based Vertical Power Devices

Author : Yuhao Zhang (Ph. D.)
Publisher :
ISBN 13 :
Total Pages : 170 pages
Book Rating : 4.:/5 (1 download)

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Book Synopsis GaN-based Vertical Power Devices by : Yuhao Zhang (Ph. D.)

Download or read book GaN-based Vertical Power Devices written by Yuhao Zhang (Ph. D.) and published by . This book was released on 2017 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Power electronics based on Gallium Nitride (GaN) is expected to significantly reduce the losses in power conversion circuits and increase the power density. This makes GaN devices very exciting candidates for next-generation power electronics, for the applications in electric vehicles, data centers, high-power and high-frequency communications. Currently, both lateral and vertical structures are considered for GaN power devices. In particular, vertical GaN power devices have attracted significant attention recently, due to the potential for achieving high breakdown voltage and current levels without enlarging the chip size. In addition, these vertical devices show superior thermal performance than their lateral counterparts. This PhD thesis addresses several key obstacles in developing vertical GaN power devices. The commercialization of vertical GaN power devices has been hindered by the high cost of bulk GaN. The first project in this PhD thesis demonstrated the feasibility of making vertical devices on a low-cost silicon (Si) substrate for the first time. The demonstrated high performance shows the great potential of low-cost vertical GaN-on-Si devices for 600-V level high-current and high-power applications. This thesis has also studied the origin of the off-state leakage current in vertical GaN pn diodes on Si, sapphire and GaN substrates, by experiments, analytical calculations and TCAD simulations. Variable-range-hopping through threading dislocations was identified as the main off-state leakage mechanism in these devices. The design space of leakage current of vertical GaN devices has been subsequently derived. Thirdly, a novel GaN vertical Schottky rectifier with trench MIS structures and trench field rings was demonstrated. The new structure greatly enhanced the reverse blocking characteristics while maintaining a Schottky-like good forward conduction. This new device shows great potential for using advanced vertical Schottky rectifiers for high-power and high-frequency applications. Finally, we investigated a fundamental and significant challenge for GaN power devices: the lack of reliable and generally useable patterned pn junctions. Two approaches have been proposed to make lateral patterned pn junctions. Two devices, junction barrier Schottky devices and super-junction devices, have been designed and optimized. Preliminary experimental results were also demonstrated for the feasibility of making patterned pn junctions and fabricating novel power devices.

GaN-Based HEMTs for High Voltage Operation: Design, Technology and Characterization

Author : Eldad Bahat-Treidel
Publisher : Cuvillier Verlag
ISBN 13 : 3736940947
Total Pages : 220 pages
Book Rating : 4.7/5 (369 download)

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Book Synopsis GaN-Based HEMTs for High Voltage Operation: Design, Technology and Characterization by : Eldad Bahat-Treidel

Download or read book GaN-Based HEMTs for High Voltage Operation: Design, Technology and Characterization written by Eldad Bahat-Treidel and published by Cuvillier Verlag. This book was released on 2012-06-08 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride (GaN)-based High Electron Mobility Transistors (HEMTs) for high voltage, high power switching and regulating for space applications are studied in this work. Efficient power switching is associated with operation in high OFF-state blocking voltage while keeping the ON-state resistance, the dynamic dispersion and leakage currents as low as possible. The potential of such devices to operate at high voltages is limited by a chain of factors such as subthreshold leakages and the device geometry. Blocking voltage enhancement is a complicated problem that requires parallel methods for solution; epitaxial layers design, device structural and geometry design, and suitable semiconductor manufacturing technique. In this work physical-based device simulation as an engineering tool was developed. An overview on GaN-based HEMTs physical based device simulation using Silvaco-“ATLAS” is given. The simulation is utilized to analyze, give insight to the modes of operation of the device and for design and evaluation of innovative concepts. Physical-based models that describe the properties of the semiconductor material are introduced. A detailed description of the specific AlGaN/GaN HEMT structure definition and geometries are given along with the complex fine meshing requirements. Nitride-semiconductor specific material properties and their physical models are reviewed focusing on the energetic band structure, epitaxial strain tensor calculation in wurtzite materials and build-in polarization models. Special attention for thermal conductivity, carriers’ mobility and Schottky-gate-reverse-bias-tunneling is paid. Empirical parameters matching and adjustment of models parameters to match the experimental device measured results are discussed. An enhancement of breakdown voltage in AlxGa1-xN/GaN HEMT devices by increasing the electron confinement in the transistor channel using a low Al content AlyGa1-yN back-barrier layer structure is systematically studied. It is shown that the reduced sub-threshold drain-leakage current through the buffer layer postpones the punch-through and therefore shifts the breakdown of the device to higher voltages. It is also shown that the punch-through voltage (VPT) scales up with the device dimensions (gate to drain separation). An optimized electron confinement results both, in a scaling of breakdown voltage with device geometry and a significantly reduced sub-threshold drain and gate leakage currents. These beneficial properties are pronounced even further if gate recess technology is applied for device fabrication. For the systematic study a large variations of back-barrier epitaxial structures were grown on sapphire, n-type 4H-SiC and semi-insulating 4H-SiC substrates. The devices with 5 μm gate-drain separation grown on n-SiC owning Al0.05Ga0.95N and Al0.10Ga0.90N back-barrier exhibit 304 V and 0.43 m × cm2 and 342 V and 0.41 m × cm2 respectively. To investigate the impact of AlyGa1-yN back-barrier on the device properties the devices were characterized in DC along with microwave mode and robustness DC-step-stress test. Physical-based device simulations give insight in the respective electronic mechanisms and to the punch-through process that leads to device breakdown. Systematic study of GaN-based HEMT devices with insulating carbon-doped GaN back-barrier for high voltage operation is also presented. Suppression of the OFF-state sub-threshold drain leakage-currents enables breakdown voltage enhancement over 1000 V with low ON-state resistance. The devices with 5 μm gate-drain separation on SI-SiC and 7 μm gate-drain separation on n-SiC exhibit 938 V and 0.39 m × cm2 and 942 V and 0.39 m × cm2 respectively. Power device figure of merit of ~2.3 × 109 V2/-cm2 was calculated for these devices. The impacts of variations of carbon doping concentration, GaN channel thickness and substrates are evaluated. Trade-off considerations in ON-state resistance and of current collapse are addressed. A novel GaN-based HEMTs with innovative planar Multiple-Grating-Field-Plates (MGFPs) for high voltage operation are described. A synergy effect with additional electron channel confinement by using a heterojunction AlGaN back-barrier is demonstrated. Suppression of the OFF-state sub-threshold gate and drain leakage-currents enables breakdown voltage enhancement over 700 V and low ON-state resistance of 0.68 m × cm2. Such devices have a minor trade-off in ON-state resistance, lag factor, maximum oscillation frequency and cut-off frequency. Systematic study of the MGFP design and the effect of Al composition in the back-barrier are described. Physics-based device simulation results give insight into electric field distribution and charge carrier concentration depending on field-plate design. The GaN superior material breakdown strength properties are not always a guarantee for high voltage devices. In addition to superior epitaxial growth design and optimization for high voltage operation the device geometrical layout design and the device manufacturing process design and parameters optimization are important criteria for breakdown voltage enhancement. Smart layout prevent immature breakdown due to lateral proximity of highly biased interconnects. Optimization of inter device isolation designed for high voltage prevents substantial subthreshold leakage. An example for high voltage test device layout design and an example for critical inter-device insulation manufacturing process optimization are presented. While major efforts are being made to improve the forward blocking performance, devices with reverse blocking capability are also desired in a number of applications. A novel GaN-based HEMT with reverse blocking capability for Class-S switch-mode amplifiers is introduced. The high voltage protection is achieved by introducing an integrated recessed Schottky contact as a drain electrode. Results from our Schottky-drain HEMT demonstrate an excellent reverse blocking with minor trade-off in the ON-state resistance for the complete device. The excellent quality of the forward diode characteristics indicates high robustness of the recess process. The reverse blocking capability of the diode is better than –110 V. Physical-based device simulations give insight in the respective electronic mechanisms. Zusammenfassung In dieser Arbeit wurden Galliumnitrid (GaN)-basierte Hochspannungs-HEMTs (High Electron Mobility Transistor) für Hochleistungsschalt- und Regelanwendungen in der Raumfahrt untersucht. Effizientes Leistungsschalten erfordert einen Betrieb bei hohen Sperrspannungen gepaart mit niedrigem Einschaltwiderstand, geringer dynamischer Dispersion und minimalen Leckströmen. Dabei wird das aus dem Halbleitermaterial herrührende Potential für extrem spannungsfeste Transistoren aufgrund mehrerer Faktoren aus dem lateralen und dem vertikalen Bauelementedesign oft nicht erreicht. Physikalisch-basierte Simulationswerkzeuge für die Bauelemente wurden daher entwickelt. Die damit durchgeführte Analyse der unterschiedlichen Transistorbetriebszustände ermöglichte das Entwickeln innovativer Bauelementdesignkonzepte. Das Erhöhen der Bauelementsperrspannung erfordert parallele und ineinandergreifende Lösungsansätze für die Epitaxieschichten, das strukturelle und das geometrische Design und für die Prozessierungstechnologie. Neuartige Bauelementstrukturen mit einer rückseitigen Kanalbarriere (back-barrier) aus AlGaN oder Kohlenstoff-dotierem GaN in Kombination mit neuartigen geometrischen Strukturen wie den Mehrfachgitterfeldplatten (MGFP, Multiple-Grating-Field-Plate) wurden untersucht. Die elektrische Gleichspannungscharakterisierung zeigte dabei eine signifikante Verringerung der Leckströme im gesperrten Zustand. Dies resultierte bei nach wie vor sehr kleinem Einschaltwiderstand in einer Durchbruchspannungserhöhung um das etwa Zehnfache auf über 1000 V. Vorzeitige Spannungsüberschläge aufgrund von Feldstärkenspitzen an Verbindungsmetallisierungen werden durch ein geschickt gestaltetes Bauelementlayout verhindert. Eine Optimierung der Halbleiterisolierung zwischen den aktiven Strukturen führte auch im kV-Bereich zu vernachlässigbaren Leckströme. Während das Hauptaugenmerk der Arbeit auf der Erhöhung der Spannungsfestigkeit im Vorwärtsbetrieb des Transistors lag, ist für einige Anwendung auch ein rückwärtiges Sperren erwünscht. Für Schaltverstärker im S-Klassenbetrieb wurde ein neuartiger GaN-HEMT entwickelt, dessen rückwärtiges Sperrverhalten durch einen tiefgelegten Schottkykontakt als Drainelektrode hervorgerufen wird. Eine derartige Struktur ergab eine rückwärtige Spannungsfestigkeit von über 110 V.

Modeling and Control of a Solid-State Transformer with Small Passive Components for DC Grid Applications

Author : Sandro P. Martin
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis Modeling and Control of a Solid-State Transformer with Small Passive Components for DC Grid Applications by : Sandro P. Martin

Download or read book Modeling and Control of a Solid-State Transformer with Small Passive Components for DC Grid Applications written by Sandro P. Martin and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The modern electrical power grid increasingly features semiconductor-based power electronics converters in place of traditional transformers. Known as solid-state transformers (SST), these converters are distinguished for their controllability, their efficiency, and their reduced size and weight. Of the existing converter topologies, the modular multilevel converter (MMC) is popular for implementation as a solid-state transformer, including in direct current (DC) grid interfaces. In the existing engineering literature, the MMC is often studied operating under a low-frequency sinusoidal modulation, and is often implemented with large passive components. This tends to make the converter more stable, and relaxes the requirements placed on the control system. By changing the MMC so that it instead operates with a medium-frequency square waveform in a DC SST, the passive components can be significantly reduced, as well as the semiconductor device ratings. However, a greater emphasis and burden is then placed on the control system's speed and accuracy. This is problematic because an MMC with small passive components experiences tight coupling among its state variables, which significantly complicates efforts to design a traditional control system for it. This dissertation proposes and investigates methods for modeling and controlling an MMC that uses small passive components. Two major strategies are investigated: two approaches based on the traditional proportional-integral (PI) control, and one approach based on the increasingly popular model predictive control (MPC). By taking advantage of the square-wave operation, it is possible to design simplified model-based PI controllers that achieve power flow control. A more complete model that fully accounts for the MMC's internal dynamics is also proposed and studied in this dissertation. Although it is difficult to apply the full benefits of this model to PI controller design, an MPC-type controller can easily make full use of it and achieve good control of the MMC's power flow and internal dynamics. Unlike most other MPC controllers in the engineering literature, the MPC controller proposed in this dissertation has a very low computational burden and does not require iterative solutions. Simulation and experimental results are provided to validate the proposed models and the developed control systems.

Reliability and Failure Analysis of GaN-on-Si Power Devices

Author : Wen Yang
Publisher :
ISBN 13 :
Total Pages : 155 pages
Book Rating : 4.:/5 (129 download)

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Book Synopsis Reliability and Failure Analysis of GaN-on-Si Power Devices by : Wen Yang

Download or read book Reliability and Failure Analysis of GaN-on-Si Power Devices written by Wen Yang and published by . This book was released on 2021 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wide bandgap power semiconductor devices, especially Gallium Nitride (GaN) high electron mobility transistors (HEMTs), have gained a lot of attention for high power applications due to their low on-resistance and high switching speed compared to their silicon counterparts. However, the reliability and failure issues related to dynamic performance, gate reliability, and electrostatic discharge have limited the wide applications of GaN power devices. This dissertation presents a systematic study of reliability and failure analysis of GaN-on-Si power devices. Firstly, the correlation between the physical trap mechanisms and the dynamic on-resistance (R[subscript on]) degradation has been investigated using a multi-frequency C-V measurement during pulse-mode stress. The experimental results indicate that the deep-level traps originated from the buffer layer play a dominant role in the dynamic R[subscript on] degradation. Secondly, the Si substrate in GaN-on-Si lateral power devices can be used as an independent contact termination rather than a thermal cooling pad. Therefore, the substrate bias effect in dynamic R[subscript on] and Gate Charge (Q[subscript g]) is necessary to explore both conduction and switching loss in GaN-based converter. A reverse dual polarity (RDP) substrate pulse technique has been developed to mitigate the dynamic R[subscript on] degradation. Thirdly, the gate reliability issues, including Time-dependent dielectric breakdown (TDDB), and Bias Temperature Instability (BTI) have been explored to improve the current capability. The physical model of TDDB in GaN power devices has been established by applying the substrate biases. And three phases of threshold voltage degradation have been presented under Negative Bias Temperature Instability stress. Lastly, the ESD characteristics of GaN power devices are considered for the development of a monolithic GaN-on-Si platform. The breakdown mechanisms under ESD stress have been comprehensively studied using Transmission Line Pulse (TLP) and Very-fast Transmission Line Pulse (VFTLP) measurements.

Fault-tolerant Topology and Operation of Multi-port Interlink Modular Multilevel Converter Based Solid-state Transformer in Future Distribution Systems

Download Fault-tolerant Topology and Operation of Multi-port Interlink Modular Multilevel Converter Based Solid-state Transformer in Future Distribution Systems PDF Online Free

Author : Jiajie Zang
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Fault-tolerant Topology and Operation of Multi-port Interlink Modular Multilevel Converter Based Solid-state Transformer in Future Distribution Systems by : Jiajie Zang

Download or read book Fault-tolerant Topology and Operation of Multi-port Interlink Modular Multilevel Converter Based Solid-state Transformer in Future Distribution Systems written by Jiajie Zang and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conventional radial AC distribution systems cannot effectively accommodate the rapidly increasing renewable energy sources (RESs) and new loads such as fast charging stations of electric vehicles. To address the pressing challenges, active distribution grids and DC systems have attracted significant interests with their many potential benefits. Considering that AC and DC systems will coexist in future distribution grids wherever suitable, hybrid AC/DC distribution is regarded as a promising and practical solution for future distribution systems. The focus of this work, multiport interlink modular multilevel converter-based solid-state transformers (iMMC-SSTs), is expected to play a key enabling role in hybrid distribution systems to integrate different grid entities, including both AC and DC networks at both medium and low voltage levels. The iMMC-SST features capabilities such as bidirectional power transfer, fault isolation and restoration, system reconfiguration, and voltage regulation. However, power electronics-based SSTs are more vulnerable under abnormal conditions, which hinders their adoption in practical systems. The high number of circuit elements are potential fault sources in the iMMC-SST. The possible faults of the SST and the connected feeders can destroy balance of the system and even result in second faults. A comprehensive protection scheme for the iMMC-SST is indispensable to ensure the device's safety and improve the system's reliability and robustness. Based on the fault location, abnormal conditions are in general divided into external and internal types. In this work, grounding scheme for the SST is designed and investigated to address typical external fault conditions such as the single line-to-ground (SLG) short-circuit fault and single pole-to-ground (SPG) short-circuit fault. For internal abnormal conditions, power switch faults are of major concerns of the iMMC-SST since a switch failure will lead to arm voltage imbalance, circulating current increase, and second faults. The submodule (SM) switch open-circuit (OC) fault analysis is presented considering different operation modes of the iMMC-SST in Chapter 4. Unlike traditional MMC applications, the iMMC-SST has different fault characteristics, and the previous fault diagnosis and fault-tolerant schemes developed for other applications are not applicable here. Based on detailed analysis of the fault behaviors, a fault-tolerant scheme based on the global redundant module and unbalanced control is proposed in Chapter 5. Similarly, the dual active bridge (DAB) switch OC fault is studied in detail, and a DC current injection fault-tolerant method is proposed to address the overcurrent and transformer saturation issues in Chapter 6. The proposed solutions and their analysis are verified with MATLAB simulations and experiments with scaled-down laboratory prototypes.

Circuit Modeling and Performance Evaluation of GaN Power HEMT in DC-DC Converters

Author : Krushal S. Shah
Publisher :
ISBN 13 :
Total Pages : 72 pages
Book Rating : 4.:/5 (781 download)

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Book Synopsis Circuit Modeling and Performance Evaluation of GaN Power HEMT in DC-DC Converters by : Krushal S. Shah

Download or read book Circuit Modeling and Performance Evaluation of GaN Power HEMT in DC-DC Converters written by Krushal S. Shah and published by . This book was released on 2011 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The power generated by renewable sources such as solar photo-voltaic (PV) arrays and wind turbines is time varying and unpredictable. In order to minimize the wastage of power obtained from such sources, there is a great need of efficient power converters which are compact and can effectively manage power in Smart Grid applications. The design of such power converters would require the use of new semiconductor materials, novel device structures, improved switching and control circuits, and advanced packaging technologies. Wide bandgap materials are promising for RF/microwave and power switching electronics. Among these materials, III-V Nitrides - especially Gallium Nitride (GaN), and Silicon Carbide (SiC) are heavily investigated by industry because of their superior electrical and thermal properties, and improved radiation hardness compared to the standard semiconductor material -silicon. A smart DC microgrid suitable for high-penetration in commercial applications and that efficiently utilizes energy available from distributed, renewable generators is described. GaN HEMTs based converters should be incorporated in the DC microgrid. It iv is shown that the proposed DC power distribution system can produce savings in excess of 10-15% over the current approach that uses inverters. Performance evaluation between silicon MOSFET and GaN HEMT is presented for chip-scale and maximum peak power tracking DC-DC power converter applications. The current circuit model available for GaN HEMTs does not converge for converter topology. Thus circuit calculations are based on improved circuit model for the FET with accurate description of capacitances and thermal on-resistance. It is shown that GaN power HEMTs used in a synchronous buck converter topology (for a 19/1.2VDC, 7.2W) can potentially lead to nearly 77 % power conversion efficiency at 25°C when switched at 5 MHz. However, results show that the current formulation for loss calculation in the topology described is erroneous and so there is a need of new loss formulation and device selection criteria based on circuit dynamics and device parameters. Similarly simulations were carried out for a DC-DC boost converter topology (200/380VDC, 10kW) and it has been shown to have 93 % power conversion efficiency at 25°C when switched at 1 MHz. But using new semiconductors materials like GaN HEMT and SiC in this case causes high dv/dt stress on switch and diode during switching which may cause failure of device.

GaN Transistors for Efficient Power Conversion

Author : Alex Lidow
Publisher : John Wiley & Sons
ISBN 13 : 1119594421
Total Pages : 470 pages
Book Rating : 4.1/5 (195 download)

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Book Synopsis GaN Transistors for Efficient Power Conversion by : Alex Lidow

Download or read book GaN Transistors for Efficient Power Conversion written by Alex Lidow and published by John Wiley & Sons. This book was released on 2019-08-12 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: An up-to-date, practical guide on upgrading from silicon to GaN, and how to use GaN transistors in power conversion systems design This updated, third edition of a popular book on GaN transistors for efficient power conversion has been substantially expanded to keep students and practicing power conversion engineers ahead of the learning curve in GaN technology advancements. Acknowledging that GaN transistors are not one-to-one replacements for the current MOSFET technology, this book serves as a practical guide for understanding basic GaN transistor construction, characteristics, and applications. Included are discussions on the fundamental physics of these power semiconductors, layout, and other circuit design considerations, as well as specific application examples demonstrating design techniques when employing GaN devices. GaN Transistors for Efficient Power Conversion, 3rd Edition brings key updates to the chapters of Driving GaN Transistors; Modeling, Simulation, and Measurement of GaN Transistors; DC-DC Power Conversion; Envelope Tracking; and Highly Resonant Wireless Energy Transfer. It also offers new chapters on Thermal Management, Multilevel Converters, and Lidar, and revises many others throughout. Written by leaders in the power semiconductor field and industry pioneers in GaN power transistor technology and applications Updated with 35% new material, including three new chapters on Thermal Management, Multilevel Converters, Wireless Power, and Lidar Features practical guidance on formulating specific circuit designs when constructing power conversion systems using GaN transistors A valuable resource for professional engineers, systems designers, and electrical engineering students who need to fully understand the state-of-the-art GaN Transistors for Efficient Power Conversion, 3rd Edition is an essential learning tool and reference guide that enables power conversion engineers to design energy-efficient, smaller, and more cost-effective products using GaN transistors.

GaN-based Materials and Devices

Author : Michael Shur
Publisher : World Scientific
ISBN 13 : 9789812562364
Total Pages : 310 pages
Book Rating : 4.5/5 (623 download)

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Book Synopsis GaN-based Materials and Devices by : Michael Shur

Download or read book GaN-based Materials and Devices written by Michael Shur and published by World Scientific. This book was released on 2004 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique materials properties of GaN-based semiconductors havestimulated a great deal of interest in research and developmentregarding nitride materials growth and optoelectronic andnitride-based electronic devices. High electron mobility andsaturation velocity, high sheet carrier concentration atheterojunction interfaces, high breakdown field, and low thermalimpedance of GaN-based films grown over SiC or bulk AlN substratesmake nitride-based electronic devices very promising.