Query: Silicon carbide benefits and advantages for power electronics circuits and systems

Candidate papers:

abstract: Silicon offers multiple advantages to power circuit designers, but at the same time suffers from limitations that are inherent to silicon material properties, such as low bandgap energy, low thermal conductivity, and switching frequency limitations. Wide bandgap semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN) provide larger bandgaps, higher breakdown electric field, and higher thermal conductivity. Power semiconductor devices made with SiC and GaN are capable of higher blocking voltages, higher switching frequencies, and higher junction temperatures than silicon devices. SiC is by far the most advanced material and, hence, is the subject of attention from power electronics and systems designers. This paper looks at the benefits of using SiC in power electronics applications, reviews the current state of the art, and shows how SiC can be a strong and viable candidate for future power electronics and systems applications.
author_names: Ahmed Elasser

T Paul Chow
title: Silicon carbide benefits and advantages for power electronics circuits and systems
venue: Proc. IEEE
year: 2002

abstract: The move towards smaller and more efficient power electronics devices has led to the introduction of wide band gap devices within the power electronics field. The fast switching characteristics of these devices that produce the advantages, also have an adverse impact: the harmonic content of these edges exacerbate the effects of parasitic inductance and capacitance in printed circuit boards, increase EMI and amplify transmission line effects. This paper investigates the use of wide band gap devices through the design and implementation of a silicon carbide (SiC) converter system in an electrical engineering final year capstone project, in which the deleterious effects of wide band gap devices are used as a learning tool. This allows students to consolidate, as well as extend, their electrical engineering knowledge and research skills. A case study is presented from a capstone project carried out at the University of Newcastle, Australia which highlights the benefits of using these devices as a learning tool.
author_names: R L Sykes

Terrence J Summers

C Starkey
title: Silicon Carbide Converters as a Learning Tool for Final Year Engineering Students
venue: 2019 29th Australasian Universities Power Engineering Conference (AUPEC)
year: 2019

abstract: Power systems designed for use in NASA space missions are required to work reliably under harsh environment conditions. Radiation, thermal cycling, and extreme temperature exposures, which are typically encountered in almost all of the space exploration missions, are a major concern for the operation and reliability of on board electronics of the spacecraft power system. Besides reliability, efficiency constitutes another critical requirement in space applications where size and weight are of utmost importance. This, in turn, would require the use of high power, low loss devices and circuits capable of operation in space borne radiation and other environmental stresses. Today's electronics based on silicon technology would not be able to meet the stringent requirements of space systems without the use of the present day conventional radiation shielding structures and thermal control elements for proper operation. Semiconductor devices based on wide bandgap materials, especially silicon carbide (SiC) are becoming more readily available as the enabling technologies begin to mature. The wide bandgap structure of SiC based power devices offers great benefits when compared with those made of silicon (Si) Some of these advantages include high breakdown voltage, higher power and current densities, low on resistance, higher switching frequency, and high operating temperatures. Table I lists a comparison of properties of silicon and silicon carbide semiconductor materials [1] By being able to withstand large voltages with small leakage currents and fast switching speeds, SiC devices show great promise and become good candidates for use in future power electronic systems. The low on resistance of wide band gap materials allows the development of a new generation of transistor devices that switch faster and with greatly reduced losses. The combined higher switching speed and efficiency of these transistors, for example, allows the operation of DC/DC converters at very high frequencies, thereby reducing weight, saving board space, and conserving power. Information pertaining to performance of these new wide bandgap devices in the space environment is very scarce. Such data is very critical so that proper design is implemented in order to ensure mission success and to mitigate risks associated with exposure of on board systems to the space operational environment. In this work, samples of an N channel enhancement mode metal oxide semiconductor field effect transistor (MOSFET) based on SiC technology were exposed to radiation followed by long term thermal cycling over a wide temperature range to determine their susceptibility and to address their reliability for use in space applications. The results of this experimental work are presented and discussed. This report must be viewed in COLOR.
author_names: Richard L Patterson

Robert J Scheidegger

Jean-Marie Lauenstein

Megan C Casey

Leif Scheick

Ahmad Hammoud
title: Impact of Total Ionizing Dose Radiation Testing and Long Term Thermal Cycling on the Operation of CMF20120D Silicon Carbide Power MOSFET
year: 2013

abstract: With an ever industrializing world, electrical power is a valuable commodity that is increasing in worth. As electricity is passed from the source of generation to the end users, it changes magnitude and often frequency, to optimize the delivery process. Power electronics play a crucial role in this effort. Since its inception in the 1950's, power electronic have relied on switchings devices created from silicon (Si) During this time, manufacturing capabilities have perfected to the point that the atomic properties of Si are quickly becoming a bottleneck to further progress in this field. Engineers would like devices that can sustain higher voltages, realize better efficiency, switch at faster speeds, and operate at higher temperatures. For these reasons and others, researchers are evaluating power devices created from wide bandgap (WBG) semiconductors. Two of these materials, silicon carbide (SiC) and gallium nitride (GaN) are already being offered commercially. In terms of power device functionality, these components switch at higher speeds and with a lower on resistance. Demonstrations of devices with breakdown voltages higher than their Si counterparts have already begun to appear. Operating at higher temperature is also possible with these new devices, however progress is moving slower in this area due to issues with packaging and auxiliary hardware. With all of these strengths, these components are not without some limitations. ii Switched capacitor (SC) circuits have been utilized in low power applications due in part to their ability to realize higher power density. In higher power applications, these circuits do have issues with voltage regulation and electromagnetic interference (EMI) However, as the following dissertation demonstrates, SC circuits are ideally suited for WBG power devices. As part of this effort, a modular SC platform was built to evaluate 200 V GaN devices. Through utilizing soft switching techniques, high efficiency was obtained for a voltage doubler operating at 500 W utilizing a switching frequency of 383 kHz and 893 kHz. Next, several modules were cascaded together to create a stand alone voltage doubler that is capable of converting 30 VDC into 120 VAC The benefits of a SC inverter were studied at voltage and power levels consistent with motor drives and grid tied inverters. A potential replacement for the traditional power electronic systems in a hybrid electric vehicle (HEV) was evaluated. Preliminary test results are shown for tests at 400 V and 5 kW. SC circuits have the unique ability to create circuits with multiple ports. One contribution of this work is a pulse width modulation (PWM) strategy for SC inverters that produces two AC ports utilizing a single DC port. The control strategy for this is presented in the following work along with supporting analysis and experimental results. Finally, a future application for high voltage, high current devices inside of fusion energy power supply systems was explored. This study demonstrates that significant advantages can be accrued using existing devices in these power systems. The case study for this investigation was the vertical stability coil power supply system and the
author_names: Mark J Scott
title: Applications, Benefits, and Challenges of Wide Bandgap Based Power Inversion
year: 2015

abstract: Silicon carbide (SiC) based semiconductor electronic devices and circuits are presently being developed for use in high temperature, high power, and high radiation conditions under which conventional semiconductors cannot adequately perform. Silicon carbide's ability to function under such extreme conditions is expected to enable significant improvements to a far ranging variety of applications and systems. These range from greatly improved high voltage switching for energy savings in public electric power distribution and electric motor drives to more powerful microwave electronics for radar and communications to sensors and controls for cleaner burning more fuel efficient jet aircraft and automobile engines [1 7] In the particular area of power devices, theoretical appraisals have indicated that SiC power MOSFET's and diode rectifiers would operate over higher voltage and temperature ranges, have superior switching characteristics, and yet have die sizes nearly 20 times smaller than correspondingly rated silicon based devices [8] However, these tremendous theoretical advantages have yet to be widely realized in commercially available SiC devices, primarily owing to the fact that SiC's relatively immature crystal growth and device fabrication technologies are not yet sufficiently developed to the degree required for reliable incorporation into most electronic systems. This chapter briefly surveys the SiC semiconductor electronics technology. In particular, the differences (both good and bad) between SiC electronics technology and the well known silicon VLSI technology are highlighted. Projected performance benefits of SiC electronics are highlighted for several large scale applications. Key crystal growth and device fabrication issues that presently limit the performance and capability of high temperature and high power SiC electronics are identified.
author_names: Philip G Neudeck
title: Silicon Carbide Technology
year: 2006

abstract: Electricity generation currently accounts for 40% of primary energy consumption in the U.S. and over the next 25 years is projected to increase more than 50% worldwide. Electricity continues to be the fastest growing form of end use energy. Power electronics are responsible for controlling and converting electrical power to provide optimal conditions for transmission, distribution, and load side consumption. Estimates suggest that the fraction of electricity processed through power electronics could be as high as 80% in the US by 2030 (including generation and consumption) approximately a twofold increase over the current proportion. The U.S. Department of Energy's Advanced Research Project Agency for Energy (ARPA E) was established in 2009 to fund creative, out of the box, transformational energy technologies that are too early for private sector investment, at make or break points in their technology development cycle. ARPA E's investment portfolio aims to generate options to address specific energy challenges that could provide dramatic benefits for the nation. Development of advanced power electronics with unprecedented functionality, efficiency, reliability, and reduced form factor will provide the U.S. a critical technological advantage in an increasingly electrified world economy. Fast switching power semiconductor devices are the key to increasing the efficiency and reducing the size of power electronic systems. Recent advances in wide band gap semiconductor materials, such as silicon carbide (SiC) and gallium nitride (GaN) are enabling a new generation of power semiconductor devices that far exceed the performance of silicon based devices. Past ARPA E programs (ADEPT, Solar ADEPT, SWITCHES) have focused on challenges associated with fabricating WBG high performance switching devices. Program developments led to a new generation of devices that operate at much higher powers, voltages, frequencies, and temperatures than traditional silicon based semiconductor devices. Two most recent programs recently launched by ARPA E in the area of power electronics are CIRCUITS and PNDIODES. The projects that comprise ARPA E's CIRCUITS (Creating Innovative and Reliable Circuits Using Inventive Topologies and Semiconductors) program seek to accelerate the development and deployment of a new class of efficient, lightweight, and reliable power converters, based on wide bandgap (WBG) semiconductors. CIRCUITS projects build on the earlier ARPA E programs by designing circuit topologies and building blocks optimally suited for WBG attributes to maximize overall electrical system performance and reliability. In addition, a reduced form factor (size and weight) will drive adoption of higher performance and more efficient power converters relative to today's state of the art systems. Innovations stemming from CIRCUITS projects have the potential to affect high impact applications wherever electrical power is generated or used, including the electric grid, industrial motor controllers, automotive electrification, heating, ventilation, air conditioning, solar and wind power systems, datacenters, aerospace control surfaces, wireless power transfer, and consumer electronics. PNDIODES (Power Nitride Doping Innovation Offers Devices Enabling SWITCHES) funds transformational advances and mechanistic understanding in the process of selective area doping in the III Nitride wide band gap (WBG) semiconductor material system and the demonstration of arbitrarily placed, reliable, contactable, and generally useable p n junction regions that enable high performance and reliable vertical power electronic semiconductor devices. The microscopic mechanistic understanding and transformational technologies will address the major obstacle in the fabrication of vertical GaN power electronic devices.
author_names: Isik C Kizilyalli

Yanzhi Xu

Eric P Carlson

Joseph S Manser

Daniel W Cunningham
title: Keynotes: "Current and future directions in power electronic devices and circuits based on wide band gap semiconductors"
year: 2017

abstract: Silicon carbide (SiC) is a very promising semiconductor material for the development of electronics that will operate at high temperature; it has the additional advantage that for some applications it should be less sensitive to radiation than Si or GaAs. There will be advantages to eventually using SiC to build very radiation resistant, high temperature circuits, which could be located near or within severe radiation environments. System benefits would come from development of circuits with sensor amplifier/multiplexer and control signal demultiplexer/motor drive electronics functions. The goal of our research is ultimately to demonstrate that high temperature radiation hardened circuits can be built to meet the kinds of needs discussed above, In this paper we report on the operation of state of the art SiC JFETs over a wide temperature range and in severe radiation environments. These devices represent the current state of the art but do not represent the limits of operation of SiC semiconductor devices. This work was in fact carried out to increase our understanding of the device characteristics so as to allow the design of new SiC circuits which could meet the extremely stressful requirements of nuclear power systems.
author_names: James McGarrity

Charles J Scozzie

James C Blackburn

W M Delancy
title: High temperature silicon carbide FETs for radiation environments
venue: 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference Record
year: 1995

abstract: Inductive power transfer (IPT) is widely discussed as an alternative to contact charger for plug in hybrid and electric vehicles. This paper analyzes a contactless battery charger back end power factor correction (PFC) concept, reducing the primary side circuit complexity and physical size. For that purpose, the main volume and loss factors of a contactless battery charger are identified, discussing the partitioning of tasks to perform a unity power factor operation. An analysis of the most commonly used front end PFC and the proposed back end PFC configuration is performed, with the aim of highlighting benefits and limitations of each variant. Moreover, performance of silicon (Si) and gallium nitride (GaN) devices has also been evaluated, defining the main advantages and drawbacks of both semiconductor technologies in different IPT scenarios. The study is verified experimentally on a 3.2 kW contactless battery charger.
author_names: Ander Avila

Asier Garcia-Bediaga

Ugaitz Iruretagoyena

Irma Villar

Alejandro Rujas
title: Comparative Evaluation of Front and Back End PFC IPT Systems for a Contactless Battery Charger
venue: IEEE Transactions on Industry Applications
year: 2018

abstract: 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 are identified, discussing the partitioning of tasks to perform a unity power factor operation. An analysis of the most commonly used front end PFC and the proposed back end PFC configuration is performed, with the aim to highlight benefits and limitations of each variant. Moreover, Silicon (Si) and Gallium Nitride (GaN) devices performance has been also evaluated, defining the main advantages and drawbacks of different semiconductor technologies in this application. The considerations are verified experimentally on a 3.2 kW contactless battery charger.
author_names: Ander Avila

Asier Garcia-Bediaga

Ugaitz Iruretagoyen

Irma Villar

Alejandro Rujas
title: Comparative evaluation of front and back end PFC IPT systems for a contactless battery charger
venue: 2017 IEEE Energy Conversion Congress and Exposition (ECCE)
year: 2017

abstract: The superior properties of silicon carbide (SiC) power electronic devices compared with silicon (Si) are expected to have a significant impact on next generation vehicles, especially hybrid electric vehicles (HEVs) The system level benefits of using SiC devices in HEVs include a large reduction in the size, weight, and cost of the power conditioning and/or thermal systems. However, the expected performance characteristics of the various semiconductor devices and the impact that these devices could have in applications are not well understood. Simulation tools have been developed and are demonstrated for SiC devices in relevant transportation applications. These tools have been verified by experimental analysis of SiC diodes and MOSFETs and can be used to assess the impact of expected performance gains in SiC devices and determine areas of greatest impact in HEV systems. INTRODUCTION Presently, almost all of the power electronics converter systems in automotive applications use silicon(Si based power semiconductor switches. The performance of these systems is approaching the theoretical limits of the Si fundamental material properties. The emergence of silicon carbide(SiC based power semiconductor switches likely will result in substantial improvements in the performance of power electronics converter systems in transportation applications. SiC is a wide bandgap semiconductor, and SiC based power switches can be used in electric traction drives and other automotive electrical subsystems with many benefits compared with Si based switches. In this paper, experimental characteristics of Si and SiC are used to develop a simulation model for SiC power electronics devices. The main objective of developing these simulation tools is to show some of the systemlevel benefits of using SiC devices in HEVs such as the large reduction in the size, weight, and cost of the power conditioning and/or thermal management systems. Temperature dependent circuit models for SiC diodes and MOSFETs have been developed. Power losses and device temperatures have been computed for a traction drive in HEVs. Temperature and efficiency profiles have been created for the devices for powering a vehicle over an urban driving cycle. The system benefits in using SiC devices are highlighted through simulation and experimental results. At Oak Ridge National Laboratory (ORNL) a SiC power MOSFET is presently being designed. This power device will be used in power electronics converter systems for automotive applications to demonstrate the benefits of SiC based power devices. One of the selected automotive applications for this project is a traction drive. New gate drive layouts, circuit topologies, and filter requirements will also be developed to take advantage of the special properties of SiC devices. ADVANTAGES OF SiC COMPARED WITH Si As mentioned earlier, SiC is a wide bandgap semiconductor, and this property of SiC is expected to yield greatly superior power electronics devices once processing and fabrication issues with this material are solved. Some of the advantages of SiC compared with Si based power devices are as follows: 1. SiC based power devices have higher breakdown voltages (5 to 30 times higher than those of Si) because of their higher electric breakdown field. 2. SiC devices are thinner, and they have lower onresistances. The substantially higher breakdownvoltage for SiC allows higher concentrations of doping and consequently a lower series resistance. For lowbreakdown voltage devices ~50V) SiC unipolar device on resistances are around 100 times less; and at higher breakdown voltages ~5000V) they are up __________________________________________________ *Prepared by the Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, managed by UT Battelle for the U.S. Department of Energy under contract DE AC05 00OR22725. The submitted manuscript has been authored by a contractor of the U.S. Government under Contract No. DE AC0500OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty free license to publish from the contribution, or allow others to do so, for U.S. Government purposes. to 300 times less [1] With lower Ron, SiC unipolar power devices have lower conduction losses (Figure 1) and therefore higher overall efficiency. 3. SiC has a higher thermal conductivity and thus a lower junction to case thermal resistance, Rth jc. This means heat is more easily conducted away from the device junction, and thus the device temperature increase is slower. 4. SiC can operate at high temperatures because of its wider bandgap. SiC device operation at up to 600degC is mentioned in the literature [2] Most Si devices, on the other hand, can operate at a maximum junction temperature of only 150degC. 5. Forward and reverse characteristics of SiC power devices vary only slightly with temperature and time; therefore, SiC devices are more reliable. 6. SiC based devices have excellent reverse recovery characteristics [3] With less reverse recovery current, the switching losses and electromagnetic interference (EMI) are reduced and there is less or no need for snubbers. Typical turn off waveforms of commercial Si and SiC diodes are given in Figure 2. 7. SiC is extremely radiation hard; i.e. radiation does not degrade the electronic properties of SiC. MACHINE AND INVERTER MODELING System level simulation tools have been developed to calculate the conduction and switching losses of the power devices in an inverter used as a motor drive in an HEV. The efficiency of the inverter can then be determined from these losses. The simulation tool is also able to estimate the junction temperature of the power semiconductor devices and recommend an appropriate heatsink size. In this paper, an averaging technique [4] is used to model the power electronics switching losses in an HEV traction drive system. The models are compatible with the Department of Energy's ADvanced VehIcle SimulatOR (ADVISOR) models. The developed system models use torque and speed values from the ADVISOR simulation to determine the current profile of the system over the Federal Urban Driving Schedule (FUDS) Circuit level simulation is not practical for this work because the device variables are in microor nanoseconds and the system variables are in 1 second increments. Figure 3 shows the block diagram of the system modeling approach, and Figure 4 shows the three phase inverter and induction machine for the traction drive system. 300 320 340 360 380 400 420 440 460 480 500 0.01 1
author_names: Leon M Tolbert

Burak Ozpineci

Syed Kamrul Islam

Fang Zheng Peng
title: Impact of SiC Power Electronic Devices for Hybrid Electric Vehicles
year: 2002