Solar power system is a free sources of sustainable power unlike fossil fuels, and inexhaustible. Converters can shift the level of voltage from one to another through switches. Which is very important for solar power system. Transistor plays a vital role in any converter circuit because the overall efficiency of a circuit depends on the switching losses. Transistor works as switch in a converter circuit. In last few years it has been proven that Gallium Nitride (GaN) based switches have benefits over silicon switches. Using GaN technology reduces the cost of design and the construction of transistors. The GaN based transistor has the ability to operate at a high frequency with low switching power loss. This study is based on a boost converter circuit, where three different transistor model were used to compare their output and efficiency. The output was measured based on simulation conducted on LTSpice platform. Then comes to a decision as to which transistor can give better performance.
This book demonstrates to readers why Gallium Nitride (GaN) transistors have a superior performance as compared to the already mature Silicon technology. The new GaN-based transistors here described enable both high frequency and high efficiency power conversion, leading to smaller and more efficient power systems. Coverage includes i) GaN substrates and device physics; ii) innovative GaN -transistors structure (lateral and vertical); iii) reliability and robustness of GaN-power transistors; iv) impact of parasitic on GaN based power conversion, v) new power converter architectures and vi) GaN in switched mode power conversion. Provides single-source reference to Gallium Nitride (GaN)-based technologies, from the material level to circuit level, both for power conversions architectures and switched mode power amplifiers; Demonstrates how GaN is a superior technology for switching devices, enabling both high frequency, high efficiency and lower cost power conversion; Enables design of smaller, cheaper and more efficient power supplies.
The need for more efficient and compact DC-DC converter design has directed recent research to the use of Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs), capable of achieving higher switching speeds, in place of Silicon (Si) Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) which are nearing their theoretical maximum performance limit. The Single-ended Primary Inductor Converter (SEPIC) is one of the simplest designs of DC-DC converter with a relatively low component count, yet is capable of both buck and boost operation. A GaN-based current-regulated SEPIC, is therefore attractive for applications such as in solid state lighting; which is the prime focus of this research. This thesis reports work conducted to evaluate GaN HEMT's performance against a Si FET with matching specifications. This comparison was carried out over a range of frequencies and duty cycles. The results of this work show a marked improvement in performance efficiency of GaN in comparison to Si over MHz frequency range. Moreover, a GaN-based SEPIC using discrete components having current regulation was developed. The underlying idea for building this circuit is to develop a regulated simple and efficient power supply, capable of being integrated for solid state lighting applications in the future.
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.
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.
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.
The intent of this handbook is to aid in the adoption ofGaN power transistors by examining power solutions for data centers and telecommunicationssystems through hardware examples. This handbook examines the benefits of enhancementmodegallium nitride FETs (eGaN® FETs) in power conversion applications with an inputvoltage range centered around 48 VDC with load voltage as low as 1 VDC.
Gallium nitride (GaN) technology is being adopted in a variety of power electronic applications due to their high efficiencies even at high switching speeds. In comparison with the silicon (Si) transistors, the GaN-based devices exhibit lower on-state resistance and parasitic capacitances. The thermal performance of the GaN transistors are also better than the Si counterparts due to their higher junction temperature and lower temperature-coefficient of on-resistance. These unique properties make the gallium-nitride power transistors an appropriate selection for power electronic converters and radio-frequency power amplifiers, where size, efficiency, power density, and dynamic performance are major requirements. Foreseeing the immense capabilities of the GaN transistors in the near future for the fast-growing electronic industry, this thesis endeavors to make the following contributions: (a) analyze the important properties of GaN as a semiconductor material, (b) study the formation of the 2-dimensional electron gas layer required for current conduction, (c) determine the functionality of the GaN as a field-effect transistor, and (d) test its performance through simulations and experiments at high switching frequencies in power electronic converters, where the Si-based transistors cease to operate normally. The critical material properties include the intrinsic carrier concentration, the specific on-resistance, and the intrinsic carrier mobility. The dependence of these properties on the temperature is investigated. The comparison of these properties are made with the silicon and silicon-carbide (SiC) semiconductor materials to give a clear view about the superior performance of GaN over the other types. While the Si MOSFETs create a channel to conduct the electrons and holes between the source and drain terminals, the GaN field-effect transistors (FET) form a 2-dimensional electron gas (2-DEG) layer, whose thickness is controlled by the applied gate potential. Because of the high electron density in the 2-DEG layer, the GaN FETs are termed as high-electron mobility transistors (HEMT). The operation of both enhancement and depletion mode GaN FETs are discussed in detail and the model of the drain current through the 2-DEG layer is provided. The figure-of-merit (FOM) for the GaN transistors is explained and then compared with that of Si and SiC transistors. Two important implementations of GaN transistors are in the (a) pulse-width modulated synchronous-buck DC-DC power converters and (b) Class-D resonant inverters. These circuits are better representative examples since they comprise of one GaN FET (high-side switch) connected to a "hot" point and the other GaN FET (low-side switch) referenced to ground. While the low-side switch consumes minimum gate-drive power for turn ON/OFF transitions, the high-side switch demands a higher gate-drive power to operate the transistor as a switch. Also, these switches exhibit switching losses due to the charge/discharge process of the parasitic capacitances. The gate-drive power and switching losses increase as the switching frequency is increased. However, due to the superior performance and very low values of the device parasitic resistances and capacitances in the GaN transistors, higher switching frequencies can be achieved at very minimal switching losses. Simulations were performed to analyze the behavior of the two circuits at different switching frequencies and were compared with those using Si transistors. It is observed that the overall efficiency reduced to 48% at 5 MHz for the Si-based buck converter and down to 41% at 5 MHz for the Si-based Class-D inverter. However, using GaN transistors showed an improved performance, where the overall efficiency reduced to only 71% at 15 MHz for the buck converter and 60% at 10 MHz for the Class-D inverter. Further, experimental validations were performed on a prototype of the synchronous buck converter developed using the high-frequency, half-bridge switching network module EPC9037 manufactured by Efficient Power Conversion Corporation. The module comprises of the enhancement-mode GaN transistors and a high-speed, dual-side, high-performance gate-driver LM5113 by Texas Instruments. The experimental results showed the immense capability of the GaN transistors to achieve high efficiencies. The experimentally measured efficiency of the synchronous buck converter was 85% at a switching frequency of 5 MHz and reduced to 60% at 8MHz. The theoretical predictions were in good agreement with simulation and experiment results.
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.
