Wide-bandgap devices,such as silicon-carbide metal-oxide-semiconductor field-effect transistors(MOSFETs)and gallium-nitride high electron mobility transistors(HEMTs),exhibit an excellent figure of merits compared to c...Wide-bandgap devices,such as silicon-carbide metal-oxide-semiconductor field-effect transistors(MOSFETs)and gallium-nitride high electron mobility transistors(HEMTs),exhibit an excellent figure of merits compared to conventional silicon devices.Challenges of applying such fast switches include accurate extraction and optimization of parasitics especially when 6high-efficiency operation,all of which require the comprehensive understanding of such switch especially its interaction with peripheral circuits.Particularly for the enhancement-mode GaN HEMTs without the intrinsic body diode,when reverse conducting,its high voltage drop causes a high dead-time loss,which has rarely a concern in silicon devices.This paper focuses on 650V/30~60A enhancement-mode GaN HEMTs provided by GaN Systems,analytically models its switching behaviors,summarizes the impact of parasitics and dead time,and applies it in two DC/DC converters.Systematic design rules are generated not only for soft switching but also for hard switching applications.展开更多
Wide-bandgap(WBG)devices such as Gallium-Nitride(GaN)High Electron Mobility Transistors(HEMTs)have become popular in the power electronics industry as they offer a lower switching loss,higher thermal capability and hi...Wide-bandgap(WBG)devices such as Gallium-Nitride(GaN)High Electron Mobility Transistors(HEMTs)have become popular in the power electronics industry as they offer a lower switching loss,higher thermal capability and higher power density than conventional silicon devices.As an attempt of applying WBG devices to the wireless charging technology,this paper adopts two different types of normally-off GaN HEMTs.One adopts the cascode structure provided by Transphorm Inc,operated under 800kHz to charge a battery pack on an electric scooter at 48 V/500W,with the air gap between the transceiver and receiver of~10cm.The other is enhancement-mode GaN HEMTs provided by GaN Systems Inc,operated at~6MHz to use one transceiver to charge multiple cell phones@~20W.Both of these chargers have no magnetic cores to reduce the cost and weight.Experimental results show both types of GaN HEMTs significantly increased the charging efficiency over conventional Si devices.Challenges of applying such fast-transition devices are discussed,e.g.,common-source inductance and the gate-drive-loop parasitic.展开更多
文摘Wide-bandgap devices,such as silicon-carbide metal-oxide-semiconductor field-effect transistors(MOSFETs)and gallium-nitride high electron mobility transistors(HEMTs),exhibit an excellent figure of merits compared to conventional silicon devices.Challenges of applying such fast switches include accurate extraction and optimization of parasitics especially when 6high-efficiency operation,all of which require the comprehensive understanding of such switch especially its interaction with peripheral circuits.Particularly for the enhancement-mode GaN HEMTs without the intrinsic body diode,when reverse conducting,its high voltage drop causes a high dead-time loss,which has rarely a concern in silicon devices.This paper focuses on 650V/30~60A enhancement-mode GaN HEMTs provided by GaN Systems,analytically models its switching behaviors,summarizes the impact of parasitics and dead time,and applies it in two DC/DC converters.Systematic design rules are generated not only for soft switching but also for hard switching applications.
文摘Wide-bandgap(WBG)devices such as Gallium-Nitride(GaN)High Electron Mobility Transistors(HEMTs)have become popular in the power electronics industry as they offer a lower switching loss,higher thermal capability and higher power density than conventional silicon devices.As an attempt of applying WBG devices to the wireless charging technology,this paper adopts two different types of normally-off GaN HEMTs.One adopts the cascode structure provided by Transphorm Inc,operated under 800kHz to charge a battery pack on an electric scooter at 48 V/500W,with the air gap between the transceiver and receiver of~10cm.The other is enhancement-mode GaN HEMTs provided by GaN Systems Inc,operated at~6MHz to use one transceiver to charge multiple cell phones@~20W.Both of these chargers have no magnetic cores to reduce the cost and weight.Experimental results show both types of GaN HEMTs significantly increased the charging efficiency over conventional Si devices.Challenges of applying such fast-transition devices are discussed,e.g.,common-source inductance and the gate-drive-loop parasitic.
