The current state of wide bandgap device technology is reviewed and its impact on power electronic system miniaturization for a wide variety of voltage levels is described. A synopsis of recent complementary technological developments in passives, integrated driver, and protection circuitry and electronic packaging are described, followed by an outline of the applications that stand to be impacted. A glimpse into the future based on the current technological trends is offered.

Wide Bandgap Technologies and Their Implications on Miniaturizing Power Electronic Systems

An improved model of medium voltage (1200 V) silicon carbide (SiC) MOSFET based on PSpice is proposed in this paper, which is suitable for wide temperature range applications especially at low temperature. The static characteristics of SiC MOSFET are described by introducing temperature-dependent voltage source and current source. The effect of negative turn-off gate drive voltage is also taken into account in the modeling. In order to reflect the low-temperature characteristics of SiC MOSFET accurately, low temperature (-25 °C) measurements are carried out, which provide the modeling basis. The determinations of key parameters in the model are analyzed in detail, including the on-state resistor, internal gate resistor, temperature dependent sources, and some capacitors. The proposed model is verified by the experimental tests on a buck converter prototype at different input voltages, input currents, and temperatures. Simulation results on the proposed model coincide well with the experimental test results, in terms of switching waveforms and power losses even at low temperature (-25 °C). These results demonstrate that the proposed model exhibits high accuracy within wide temperature range.

Improved Modeling of Medium Voltage SiC MOSFET Within Wide Temperature Range

The digital implementations of Sinusoidal Pulse Width Modulation (SPWM) generators have dominated over their counterparts based on analog circuits. In this paper, an FPGA-based SPWM generator is presented, which is capable to operate at switching frequencies up to 1 MHz (requiring FPGA operation at 100-160 MHz), thus it is capable to support the high switching frequency requirements of modern single-phase dc/ac power converters. The proposed design occupies a small fraction of a medium-sized FPGA and, thus, can be incorporated in larger designs. Additionally, it has a flexible architecture that can be tuned to a variety of single-phase dc/ac inverter applications. The post-layout simulation and experimental results confirm that compared to the past-proposed SPWM generation designs, the SPWM generator presented in this paper exhibits much faster switching frequency, lower power consumption, and higher accuracy of generating the desired SPWM waveform.

Development of an FPGA-Based SPWM Generator for High Switching Frequency DC/AC Inverters

SiC MOSFETs are a leading option for increasing the power density of power electronics; however, for these devices to supersede the Si insulated-gate bipolar transistor, their characteristics have to be further understood. Two SiC vertically oriented planar gate D-MOSFETs rated for 1200 V/150 A were repetitively subjected to pulsed overcurrent conditions to evaluate their failure mode due to this common source of electrical stress. This research supplements recent work that demonstrated the long term reliability of these same devices [1] . Using an RLC pulse-ring-down test bed, these devices hard-switched 600 A peak current pulses, corresponding to a current density of 1500 A/cm2. Throughout testing, static characteristics of the devices such as $B_{{\rm VDSS}}$ , $R_{{\rm DS}({\rm on})}$ , and $V_{{\rm GS}({\rm th})}$ were measured with a high power device analyzer. The experimental results indicated that a conductive path was formed through the gate oxide; TCAD simulations revealed localized heating at the SiC/SiO2 interface as a result of the extreme high current density present in the device's JFET region. However, the high peak currents and repetition rates required to produce the conductive path through the gate oxide demonstrate the robustness of SiC MOSFETs under the pulsed overcurrent conditions common in power electronic applications.

Failure Analysis of 1200-V/150-A SiC MOSFET Under Repetitive Pulsed Overcurrent Conditions

This paper presents a board-level integrated silicon carbide (SiC) mosfet power module for high temperature and high power density application. Specifically, a silicon-on-insulator (SOI)-based gate driver capable of operating at 200 °C ambient temperature is designed and fabricated. The sourcing and sinking current capability of the gate driver are tested under various ambient temperatures. Also, a 1200 V/100 A SiC mosfet phase-leg power module is developed utilizing high temperature packaging technologies. The static characteristics, switching performance, and short-circuit behavior of the fabricated power module are fully evaluated at different temperatures. Moreover, a buck converter prototype composed of the SOI gate driver and SiC power module is built for high temperature continuous operation. The converter is operated at different switching frequencies up to 100 kHz, with its junction temperature monitored by a thermosensitive electrical parameter and compared with thermal simulation results. The experimental results from the continuous operation demonstrate the high temperature capability of the power module at a junction temperature greater than 225 °C.

A High Temperature Silicon Carbide mosfet Power Module With Integrated Silicon-On-Insulator-Based Gate Drive

Silicon Carbide (SiC) power semiconductors have shown the capability of greatly outperforming Si-based power devices. Faster switching and smaller on-state losses coupled with higher voltage blocking and temperature capabilities make SiC an attractive semiconductor for high-performance, high-power-density power modules. However, the temperature capabilities and increased power density are fully realized only when the gate driver needed to control the SiC devices is placed next to them. This requires the gate driver to successfully operate under extreme conditions with reduced or no heat sinking requirements. In addition, since SiC devices are usually connected in a half- or full-bridge configuration, the gate driver should provide electrical isolation between the high- and low-voltage sections of the driver itself. This paper presents a 225°C operable, silicon-on-insulator (SOI) high-voltage isolated gate driver IC for SiC devices. The IC was designed and fabricated in a 1 μm, partially depleted, CMOS process. The presented gate driver consists of a primary and a secondary side which are electrically isolated by the use of a transformer. The gate driver IC has been tested at a switching frequency of 200 kHz at 225°C while exhibiting a dv/dt noise immunity of at least 45 kV/μs.

High-Temperature Silicon-on-Insulator Gate Driver for SiC-FET Power Modules

A half bridge gate driving circuit for providing gate driving circuits in a bi-hecto celcius (200 degrees celcius) operating environment having multiple functions including combinations of multiple level logic inputs, noise immunity, fault protection, overlap protection, pulse modulation, high-frequency modulation with transformer based isolation, high-frequency demodulation back to pulse width modulation, deadtime generator, level shifter for high side transistor, overcurrent protection, and undervoltage lockout.

High temperature half bridge gate driver

High Temperature Silicon-on-Insulator Gate Driver for SiC-FET Power Modules

Halve-brug poortaansturingskring voor het bieden van poortaansturingkringen in een bi-hecto Celsius (200 graden Celsius) werkomgeving met verschillende functies omvattende combinaties van logische ingangen op meerdere niveaus, ruisimmuniteit, foutbeveilging, overlappingsbeveiliging, pulsduurmodulatie, hoogfrequente modulatie met op transformator gebaseerde isolatie, hoogfrequente demodulatie terug naar pulsduurmodulatie, dode tijd generator, niveauverschuiving voor de hoge zijde transistor, overspanningsbeveiliging en onderspanningslock-out.

Caleb Paul Gutshall

Papers

High-Temperature Silicon-on-Insulator Gate Driver for SiC-FET Power Modules

High temperature half bridge gate driver

High Temperature Silicon-on-Insulator Gate Driver for SiC-FET Power Modules

Hoge-temperatuur halve-brug poortaansturing