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• The U.S Department of Energy launched the PowerAmerica Institute under the initiative of “National Network of Manufacturing Institutes (NNMI)” to Accelerate Adoption Wide Band Gap (WBG) power devices • PowerAmerica started operations in 2015 with $140M funds over 5 years, and is managed by North Carolina State University in Raleigh, NC USA • PowerAmerica addresses gaps in technology to enable manufacturing...
Inductive power transfer (IPT) is widely discussed as an alternative to contact charger for plug-in hybrid and electric vehicles (PHEV/EV). This paper analyzes a contactless battery charger back end power factor correction (PFC) concept, which allows to reduce the primary side circuit complexity and physical size. For that purpose, the main volume and loss factors of a contactless battery charger...
For the excellent electrical performance, Gallium Nitride (GaN) new-type semiconductor devices are preferred in high voltage, high frequency and high power applications. However, GaN devices have low on-resistance and the loop layout requires low damping in high frequency loop. These both can lead to voltage and current oscillations under high frequency and even cause uncontrollable oscillations,...
Gallium Nitride (GaN) transistors are emerging as promising candidates for making high-frequency, low-loss and small-size power converters. To realize normally-off, p-GaN gate technique is widely adopted in commercially available GaN-based power devices. However, owing to the distinctions in device structure, the intrinsic capacitances with regard to gate region vary from those of Si MOSFET. Besides,...
Vertical GaN power semiconductors promise higher power with faster switching speeds but the development of this technology has been slowed. This is due to the expense and lack of familiarity with GaN substrates. This paper will detail the functionality of HRL's cutting-edge vertical GaN transistor which is mounted onto a specially made PCB and tested. The testing consists of a static characterization...
This paper presents the design process of a 13.56 MHz 10 kW and high efficiency inverter for wireless power transfer systems. The new 650V E-mode GaN is used in multiphase resonant topology to obtain high output power. The optimized efficiency design and the driver design are presented in detail. The circuit simulation results show that the inverter achieves 10 kW output power with the efficiency...
Gallium nitride (GaN) devices, as their better performance in high temperature, high efficiency and high power density converters, have been recognized as the most promising successor for Si MOSFET in the future. In order to take advantages of the superiority of depletion-mode GaN devices, a low voltage Si MOSFET is in series to drive the depletion-mode GaN device, which is well known as cascode structure...
GaN HEMT is generally characterized as fast switching and expected to achieve a power converter with high efficiency and high power density as a next-generation power semiconductor. However, the fast switching generates large switching noise, causing gate voltage fluctuation. Therefore, GaN HEMT can suffer from false triggering such as a false turn-on phenomenon due to its own low threshold voltage...
This paper presents a multilevel modular step-down DC-DC switched-capacitor converter that utilizes soft switching resonant operation. Previous versions of traditional multilevel modular switched-capacitor dc-dc converters (MMSCC) have a low switching device voltage rating. Moreover, capacitor voltage stress increases proportionally as the voltage conversion ratio increments. Significant advantage...
This paper proposes an Active Gate Current Control (AGCC) strategy for non-insulating gate WBG devices, for example, gallium nitride gate-injection-transistor (GaN-GIT) and silicon carbide super junction transistor (SiC-SJT). It provides a tool for power converter designers to further improve the converter efficiency and to extend the life time of those higher cost power transistors. By continuously...
With switching transients as fast as 100 V/ns and a low threshold voltage of 1–2 V, GaN FETs in bridge-leg topologies are potentially vulnerable to crosstalk and the resultant unwanted partial turn-on, noise interference, and increased losses. Constant-strength gate drivers for GaN FETs limit switching speed to suppress crosstalk. In this work, active gate driving is shown to permit faster switching,...
This paper presents a bootstrap driver that can operate a normally-on, a depletion-mode, GaN FET power device as a normally-off device. The bootstrap driver based on a diode-clamp circuit which is composed of a capacitor and a diode, shifting the input voltage by a negative amount (−10V) to turn off the power switch with a negative threshold (−8V). However, due to the clamp capacitor discharge by...
Bi-directional switches, also called four quadrant switches (FQS), are the basic building blocks in many power converter circuits, such as cyclo-converters, matrix converters etc. Conventional approaches to realize bi-directional switch involves combination of unidirectional controllable blocking device (IGBT or MOSFET) and diode. In this approach, current flows through multiple devices for any direction...
The on-state resistance Ron of GaN devices can be affected by charge trapping as well as temperature effects. For the reliable application of the devices it is useful to distinguish between these two effects and understand the cause of power losses. In this work, three state-of-the-art GaN power transistors are investigated. An obvious Ron increase by trapping occurs in the GaN normally-off devices,...
Gallium Nitride (GaN) high electron mobility transistor (HEMT) is one of the promising candidates to replace existing switches in high-frequency high power converter applications. Reliability of GaN HEMT is an important issue for its commercial deployment. Online prognosis of this transistor ensures robust reliability for mission critical applications. Online prognosis requires identification of fault...
The emerging 650 V large current rating, Enhancement-mode (E-mode) Gallium Nitride High-Electron-Mobility Transistor (GaN HEMT) is a promising device for low to medium power, high power density converters (e.g., motor drives, battery chargers), which require high robustness levels. Thus, a comprehensive study of the short circuit behavior of high power E-mode GaN HEMT is the subject of this paper...
A GaN-on-Si power device is a strong candidate to replace power components based on silicon in high-end market for low-voltage applications, thanks to its electrical characteristics. To maximize opportunities of the GaN device in field applications, a package technology plays an important role in a discrete GaN power device. A few specialized package technologies having very lower stray inductance...
This paper presents a comparative study on high-frequency active rectifier-based zero voltage soft-switching (ZVS) resonant dc-dc power converters with Gallium Nitride Heterojunction-Field-Effect-Transistor (GaN-HFET) for inductive power transfer (IPT) systems. The two types of active rectifiers, i.e. high-frequency bridgeless rectifier (BLREC) and totem-pole rectifier (TPREC) are adopted for the...
The use of gallium nitride (GaN) high-electron mobility transistors (HEMTs) is a promising solution for a highly efficient motor drive design due to their high-switching speed and low on-state resistance. However, the higher reverse voltage drop of GaN HEMTs than that of the conventional silicon (Si) devices generates significant reverse conduction loss during the freewheeling period. This phenomenon...
Industry is adopting GaN HEMTs in 3kW or higher power systems, which exhibit excellent figure of merit compared to conventional Silicon devices. Thermal considerations as well as circuit parasitics in high power and high density GaN-based systems play a significant role in achieving overall performance. A high density and high efficiency Insulated Metal Substrate (IMS) based GaN HEMT power module...
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