Comparative Analysis of High Input Voltage and High Voltage Conversion Ratio Step-down Converters Equipped with Silicon Carbide and Ultrafast Silicon Diodes PDF Download

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

View

Book Description
DC to DC step-down applications with high input voltage and high voltage conversion ratio operational requirements, such as photovoltaic battery chargers, are subject to high conduction losses, high switching losses and substantial reverse-recovery losses when minority carrier principle diodes are used. The recent introduction of silicon carbide diodes with high breakdown voltages has made possible the elimination of reverse-recovery losses at high voltage levels and as such has sparked interest in their use due to the potential efficiency improvements. This report presents the results of a comprehensive analysis on the use of silicon carbide diodes and their counterparts, ultrafast silicon diodes, in conventional buck converters and isolated current-fed buck converters in high input voltage and high voltage conversion ratio step-down applications. The analysis illustrates both theoretically, with the use of steady-state average models, and experimentally the substantial efficiency benefits of the use of reverse-recovery free silicon carbide diodes in the conventional buck converter and the small but significant improvement in the efficiency of the isolated current-fed buck converter. The improvements of the conventional buck converter paired with silicon carbide diodes are shown to be significant enough to grant the variant the most efficient position for power levels below 1 kW. In addition, the four variants are categorized based on their cost and performance; therefore, providing engineers with a convenient guide to aid their selection of the appropriate converter depending on the operational requirements.

Author: Kasunaidu Vechalapu
Publisher:
ISBN:
Category :
Languages : en
Pages : 193

View

Book Description

Author: Douglas Pappis
Publisher: BoD – Books on Demand
ISBN: 3737609772
Category : Technology & Engineering
Languages : en
Pages : 270

View

Book Description
In power electronics designs, the evaluation and prediction of potential fault conditions on semiconductors is essential for achieving safe operation and reliability, being short circuit (SC) one of the most probable and destructive failures. Recent improvements on Wide-Bandgap (WBG) semiconductors such as Silicon Carbide (SiC) and Gallium nitrite (GaN) enable power electronic designs with outstanding performance, reshaping the power electronics landscape. In comparison to Silicon (Si), SiC and GaN power semiconductors physically present smaller chip areas, higher maximum internal electric fields, and higher current densities. Such characteristics yield a much faster rise of the devices’ internal temperatures, worsening their SC performance. In this way, this dissertation consists of a comprehensive investigation about SC on SiC MOSFETs, GaN HEMT, and GaN E-HEMT transistors, as well as contextualizing their particularities on SC performance by comparison with that of Si IBGTs. Moreover, an investigation towards how to prevent SC occurrences besides a review of available SC protection methods is presented.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 148

View

Book Description
A design based on a self- aligned, gate-implanted, trenched source-gate junction FET was selected for its near term technological readiness and its long term manufacturability. This project concentrated on several key processes required for the realization of a viable VJFET fabrication technology, namely, 1) Development of silicon carbide dry (plasma) etches; 2) Development of appropriate edge termination technology; and 3) Development of implantation and annealing recipes core to the design. Semiconductor devices, principally the Schottky barrier diode and the PiN junction rectifier, were fabricated to test design assumptions and to evaluate new process steps. The principal accomplishments of the effort can be summarized as follows: 1) The completion of a design for a 600-V self-aligned, gate-implanted, trench VJFET, shown to deliver blocking voltages in excess of 800 V, an specific on resistance as low as 5 mohm-cm2; 2) The development of critical VJFET and rectifier device fabrication processes, and 3) The demonstration of a multi-wafer PiN diode lot of 1.5 kV PiN diodes.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 126

View

Book Description
Silicon carbide as a semiconductor material possesses several significant physical properties which make it superior for applications to high power devices. This report documents the efforts to develop, demonstrate, and optimize the design and fabrication methodologies for the realization of power vertical junction field effect transistors in the 4H-polytype of silicon carbide. Theoretical prediction and modeling simulation, incorporating all the significant SiC specific device physics, are utilized to develop a design methodology which is to ultimately be used for device fabrication. The results illustrate that good agreement between theoretical prediction and accurately modeled simulations can be achieved and enable the forecasting of device performance as a function of temperature, design modification, and variations in material transport characteristics.

Author: Samantha Joellyn Gunter
Publisher:
ISBN:
Category :
Languages : en
Pages : 360

View

Book Description
In this thesis, we introduce two large-step-down dc-dc converter architectures that are designed to provide zero-voltage switching of the power devices. While the techniques used in these converters can be used in a wide range of applications, the operating voltage and power levels used in this thesis are for data centers, where dc distribution power delivery is expected to see its first deployment. The nominal 380 V bus voltage will need to be converted to 12 V using a high-efficiency dc-dc converter that can deliver several hundred watts of power to each rack to power the servers. The converters are expected to operate efficiently across a wide input voltage range of 260 V to 410 V and down to powers in the tens of watts range. The first converter architecture is based on the concept of an Impedance Control Network (ICN) resonant converter. Using phase-shift control along with a specifically designed impedance network, this converter can maintain resistive loading of the inverters as the input voltage varies. To back down in power, the converter can be efficiently operated using burst (on/off) mode control. To deliver lower power, we introduce an additional control technique using Variable Frequency Multiplier (VFX) inverters and/or rectifiers. The second converter architecture combines the properties of an active bridge converter with multiple stacked inverters, a multi-winding single core transformer, and a reconfigurable rectifier. The stacked inverter topology improves the range of powers over which zero-voltage switching can be achieved. The multi-winding transformer and reconfigurable rectifier further extend the efficient operating range to very low powers by reducing core loss and increasing zero-voltage switching capability. Both proposed architectures are suitable for large-step-down, wide-input voltage, wide-output power applications such as dc-dc converters for dc distribution.

Author: Jing Xue (Electrical engineer)
Publisher:
ISBN:
Category : High voltages
Languages : en
Pages : 198

View

Book Description
Power management Integrated circuits (ICs) have been used for providing constant and reliable supply voltages for different electronic circuits from unregulated voltages. About 80% of today’s power management ICs are designed to handle a high-voltage (HV) input range above 6 V. The HV power ICs can reduce the bill-of-material (BOM) cost and improve system reliability without compromising the system performance. It is crucial to maximize the power density and power efficiency of HV power converters. Operating the converter at a higher switching frequency would result in smaller converter volume and lower BOM cost but the large switching loss in conventional hard-switching HV power converters would significantly decrease the power efficiency. This dissertation develops a non-isolated QSW-ZVS boost converter by minimizing the switching power loss to achieve high power efficiency under high-frequency and HV conditions. The proposed converter achieves 92.7% at 1 MHz while increasing the switching frequency by at least 15x in comparison with the state-of-the-art counterparts. An effective gate driver is important to provide fast propagation delays with low power dissipation in the MHz range and generate appropriate dead-time to assist the ZVS operation under different conditions. An on-chip synchronous gate driver with automatic dead-time controller for GaN-based HV three-level converters is proposed in this dissertation. The proposed gate driver achieves ≤ 15-ns delays with 50-V/ns noise immunity and enables a 100-V 35-W isolated three-level half-bridge converter to achieve the peak power efficiencies of 90.7% at 2 MHz. The three-level converter can also be used to reduce the value of passive components. To maximize the benefits of three-level converters, the voltage across the flying capacitor must be controlled to half of the input voltage under different conditions. This dissertation develops a 2-MHz 12-V – 100-V integrated ZVS three-level DC-DC regulator. The constant-frequency adaptive-on-time V2 control enables the flying-capacitor self-balancing at 2 MHz over a wide input range. The body-diode based floating ZVS detector enables full ZVS in high-frequency low-duty-ratio operation with ≤ 5-ns ZVS turn-on delay. The proposed regulator achieves 90% peak power efficiency with more than 66x reduction in inductance compared with the state-of-the-art wide-input-range voltage regulators.

Author: Venkat Sai Prasad Gouribhatla
Publisher:
ISBN:
Category :
Languages : en
Pages : 80

View

Book Description
"The main objective of this thesis is to compare and analyze two different high-gain dc-dc power electronic converters based on coupled inductors and capacitor-diode multiplier cells. The idea of these converters is to integrate the solar energy with a 400V DC microgrid. DC microgrids are more efficient, less expensive, and more reliable compared to AC microgrids. They also favor the integration of renewable energy sources. With the growing need for the utilization of more renewable sources of energy, photovoltaic panels have become one of the trending technologies which convert the energy from the sun to a useable electrical power. But these panels produce a low dc output voltage which cannot directly be connected to the high voltage dc distribution of the grid. They require high-gain dc-dc converters suitable for converting the output voltage of the solar panels to the dc distribution grid voltage. The topologies studied in this thesis provide a high dc voltage gain suitable for this application. The other significant advantage of these topologies is a continuous input current which increases the effective utilization of the source. These converters can also be used in applications involving high gain dc-dc conversion such as fuel cells, and energy storage applications like ultracapacitors. In this thesis, the different operating modes of the two high-gain dc-dc converters are explained in detail. Also, the voltage and current stresses seen by the components have been derived and power loss analysis is carried out for both the topologies. Recently, GaN switches have gained popularity for their higher efficiencies at higher switching frequencies, so this thesis also makes an attempt to compare Si to GaN devices in terms of efficiency improvements for the studied converters"--Abstract, page iii.

Author: Ramin Rahimi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

View

Book Description
"This research is focused on developing several advanced topologies of high step-up DC-DC converters to connect low-voltage renewable energy (RE) sources, such as photovoltaic (PV) panels and fuel cells (FCs), into a high-voltage DC bus in renewable energy applications. The proposed converters are based on the combinations of various voltage-boosting (VB) techniques, including interleaved and quadratic structures, switched-capacitor (SC)-based voltage multiplier (VM) cells, and magnetically coupled inductor (CI) and built-in-transformer (BIT). The proposed converters offer outstanding features, including high voltage gain with low or medium duty cycle, a small number of components, low current and voltage stresses on the components, continuous input current with low ripple, and high efficiency. This research includes five new advanced high step-up DC-DC converters with detailed analyses. First, an interleaved converter is presented, which is based on the integration of two three-winding CIs with SC-based VM cells. Second, a dual-switch converter is proposed, which is based on the integration of a single three-winding CI with SC-based VM cells. Third, the SC-based VM cells are utilized to present three new Z-source (ZS)-based converters. Fourth, two double-winding CIs and a three-winding BIT are combined with SC-based VM cells to develop another interleaved high step-up converter. Finally, two double-winding CIs and SC-based VM cells are adopted to devise an interleaved quadratic converter with high voltage gain. The operating and steady-state analyses, design considerations, and a comparison with similar converters in the literature are provided for each converter. In addition, hardware prototypes were fabricated to verify the performance of the proposed converters"--Abstract, page iv.

Author: B. Jayant Baliga
Publisher: World Scientific
ISBN: 9812774521
Category : Technology & Engineering
Languages : en
Pages : 526

View

Book Description
Power semiconductor devices are widely used for the control and management of electrical energy. The improving performance of power devices has enabled cost reductions and efficiency increases resulting in lower fossil fuel usage and less environmental pollution. This book provides the first cohesive treatment of the physics and design of silicon carbide power devices with an emphasis on unipolar structures. It uses the results of extensive numerical simulations to elucidate the operating principles of these important devices. Sample Chapter(s). Chapter 1: Introduction (72 KB). Contents: Material Properties and Technology; Breakdown Voltage; PiN Rectifiers; Schottky Rectifiers; Shielded Schottky Rectifiers; Metal-Semiconductor Field Effect Transistors; The Baliga-Pair Configuration; Planar Power MOSFETs; Shielded Planar MOSFETs; Trench-Gate Power MOSFETs; Shielded Trendch-Gate MOSFETs; Charge Coupled Structures; Integral Diodes; Lateral High Voltage FETs; Synopsis. Readership: For practising engineers working on power devices, and as a supplementary textbook for a graduate level course on power devices.