Wolfspeed A Cree Company

Lake Park, NC, United States

Wolfspeed A Cree Company

Lake Park, NC, United States
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Hayes J.,Wolfspeed A Cree Company | George K.,Wolfspeed A Cree Company | Killeen P.,Wolfspeed A Cree Company | McPherson B.,Wolfspeed A Cree Company | And 2 more authors.
WiPDA 2016 - 4th IEEE Workshop on Wide Bandgap Power Devices and Applications | Year: 2016

Circuit protection devices and power distribution units for future More Electric / All Electric Aircraft (MEA/AEA) power systems require an increased level of control and intelligence along with fast-acting protection mechanisms. The trend towards utilizing solid-state power electronics for system-level protection of MEA/AEA systems has increased due to the many advantages provided over electromechanical solutions. Furthermore, the emergence and rapid maturation of Silicon Carbide (SiC) power semiconductor device technology has led to their preferred use in applications conventionally dominated by legacy Silicon (Si) technology. The superior electrical and thermal performance of SiC enables the implementation of rugged, power dense solid-state circuit breakers (SSCBs) that meet the current and future power demands of MEA/AEA power systems. This paper presents a SiC-based SSCB for applications within MEA/AEA power systems. The design and development of a SSCB technology demonstrator based on an all-SiC power module is presented. Experimental results demonstrating the interruption and extinction of a 250 A fault in 10 μs, and a 450 A fault in 70 μs on a 270 Vdc bus is given. © 2016 IEEE.


Ogunniyi A.,U.S. Army | Schrock J.,Texas Tech University | Hinojosa M.,U.S. Army | O'Brien H.,U.S. Army | And 3 more authors.
Materials Science Forum | Year: 2017

The silicon carbide (SiC) “Super” gate turn-off thyristor (SGTO) is a viable device for high voltage and fast dI/dt switching applications. These devices are well suited for various pulsed power applications requiring high peak currents in the kilo-amp regime. The turn-on transition speed is determined by the spreading velocity, which depends on applied gate current, applied anode current density, minority carrier lifetime, and both the gate base-width and the drift region of the thyristor. The impact of device parameters on switching performance is discussed in this work. © 2017 Trans Tech Publications, Switzerland.


Casady J.B.,A Cree Company | Hull B.,A Cree Company | Zhang J.,A Cree Company | Gajewski D.,A Cree Company | And 4 more authors.
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2017

For the first time we report on detailed, quantitative reliability measurements and accelerated life data for > 1,300 of 900V, 10mOhm, 32mm2 SiC MOSFETs being developed for automotive and industrial applications. SiC MOSFETs were characterized and subjected to High-Temperature Reverse Bias (HTRB), High-Temperature Gate Bias (HTGB), Thermal Shock, and High-Humidity High-Temperature Reverse Bias (H3TRB) in both module and discrete (TO-247) form. The maximum junction temperature (TJ) qualified was 175°C for the bare die. SiC MOSFET performance was benchmarked relative to commercial Si technology in an 88kW EV inverter similar to the 90kW Ford C-Max hybrid drive-train. Replacing Si IGBTs with only 32% of the chip area using SiC MOSFETs, measurements indicate a 78% reduction in drive-train inverter losses. © 2017 IEEE.


Olejniczak K.,Wolfspeed A Cree Company | Flint T.,Wolfspeed A Cree Company | Simco D.,Wolfspeed A Cree Company | Storkov S.,Wolfspeed A Cree Company | And 6 more authors.
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2017

Wide bandgap materials are having a transformational impact on the electrical, thermal, and mechanical performance of military, industrial, and commercial power electronic systems where silicon (Si) power semiconductors are the present material technology of choice. This paper reports on the design, analysis, and experimental verification of a compact allsilicon carbide (SiC)-based inverter to meet the inhospitable environmental demands of hybrid, plug-in hybrid, extended-range electrified vehicles, and fuel cell vehicle architectures. The compact 4.8 L, 6.6 kg inverter achieves a volumetric and gravimetric power density of 23.1 kVA/L and 16.8 kVA/kg, respectively. Three 1200 V, 3.6 mΩ, half-bridge power modules, each containing seven 25 mΩ SiC MOSFETs and six 50 A Schottky barrier diodes (SBDs) per switch position, comprise the power stage. Significant improvement in conduction, switching, and reverse-recovery losses allowed this SiC MOSFET-based inverter to achieve 96.3% average efficiency and 98.9% average peak efficiency over all experiments. This is superior to Si IGBT-based inverters throughout the entire range of torques, speeds, and bus voltages - and especially at light load operating points typical of electric vehicles. Dynamometer experiments used a 20 kHz switching frequency, double-update space-vector modulation, thermal controls for ambient and coolant temperatures, custom data acquisition, and a commercial three-phase power meter to collect performance data over 500 to 6000 RPM, 5 to 180 N-m, four bus voltages, and six thermal cases. © 2017 IEEE.


Van Brunt E.,Wolfspeed A Cree Company | Wang G.,Wolfspeed A Cree Company | Liu J.,Wolfspeed A Cree Company | Pala V.,Wolfspeed A Cree Company | And 3 more authors.
Proceedings of the International Symposium on Power Semiconductor Devices and ICs | Year: 2016

This work describes the operation of commercial 4H-SiC Junction-Barrier Schottky (JBS) Diodes at extreme voltage slew rates (dV/dt) in an attempt to force failures. Slew rates in excess of 700 kVμs were required to damage parts, in combination with high values of the reverse bus voltage. Cryogenic temperatures reduced the maximum bus voltage required to induce failure. Large quantities of parts were subjected to repetitive dV/dt stress with a slew rate of 400 kVμs, then tested for avalanche ruggedness in unclamped inductive switching (UIS) conditions. No differences were detected between the stressed diode population and a control population, indicating that dV/dt stress induces neither immediate failures nor latent weakness. © 2016 IEEE.

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