WBG Revolution in Power ElectronicsAnant Agarwal, EERE/DOE

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What are Wide Band Gap (WBG) Semiconductors?Si SiC GaN

In‐direct band gap In‐direct direct =>  LED

Max. Temp. = 125° C 200° C 250° C

Breakdown Field = 0.3 MV/cm 2.2 MV/cm 2.6 MV/cm

6.5 kV IGBT 15 kV MOSFET 20 kV JFET

400 Hz 4 kHz 6 kHz

1.1 eV 3.25 eV 3.4 eV

Electrons& holes =>Slow Switching

ElectronsOnly =>Fast Switching

ElectronsOnly =>Fast Switching

Higher TemperatureHigher Voltage

Higher Frequency

More EfficientSmaller, CheaperPower Electronics 22

3Reference: ‘Selection of IGBT Modules and Safety Measures in Inverter Applications’, www.infineon.com.

Cosmic Ray Failures are not present in WBG

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SiC vs. GaN: Both technologies are critical to Power Electronics ‐ in different voltage ranges

• GaN based Power Electronics:– Suitable from 200 to 900 V– Ideal applications:  

– 0.1 to 10 kW Power Supplies– Laptop power adapters– Micro and string solar inverters up to 10 kW– Automotive electronics excluding the inverter

• SiC based Power Electronics:– Suitable from 900 to 15,000 V– Ideal applications:  

– String solar inverters >10 kW– Central Solar and Fuel Cell Inverters up to several MW– Automotive Inverters and Quick Chargers– Traction– Medium Voltage Motor Control for Oil and NG high rpm direct drive– Distribution Grid Based Power Flow Controllers4

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SiC PHEV Charger Prototype by APEI – 1200 V SIC MOSFETS

Toyota Now Prototype

Volume 387.5 in3 42 in3

Mass 6.6 kg 0.99 kgPower 1 kW 5 kW*Efficiency <90% >96%*

Present Toyota Si PHEV Charger

(1 kW) APEI Demo

SiC PHEV Charger (5 kW)

Weight and Volume Reduction and Higher η through 

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• AC Power Adapters:laptops, cell phones, tablets, printers, appliances…

Product Features:• Power Input: 100-240V ~ 50-60 Hz 1.5A • Power Output: 19.5V == 4.62A• Peak Efficiency: 75-80%

High Impact- Computer Power Supplies using GaN

6 W/cm3

Peak Efficiency: 93%

100 W

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DOE Relevant Applications for WBG Semiconductors

Device Rating Applications200 ‐ 600 V Switch Mode Power Supplies

600 ‐ 2000 V Solar, Wind, HVAC, Light Duty VehiclesDC Quick Charging, UPS

2 ‐ 10 kV Motor Speed Control (up to 10 MW), Trains, Heavy Duty Vehicles, Mining

10 ‐ 15 kV Motor Speed Control (10‐50 MW), Process Heating, Distribution Grid Tied Renewables, Grid Storage and Server Farms

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Next Generation Power Electronics (WBG) Initiative Strategy

Capture U.S. opportunity for manufacturing leadership in:– Wide Bandgap Power Devices – Power Electronics 

Commercial Foundry 

Power ElectronicsAdvanced Modules

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By providing access to WBG devices toResearchers, Students & Companies

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Dedicated WBG Foundry Requires $100 M+ Investment

• 20-30% loaded => High Cost of Chips

• Technology is in very few hands => Slow progress

• Researchers in Univs and Labs are excluded

• High chip cost & low systems cost arguments are

difficult

• Technology Risk high => VC investment not happening

Other countries may take a lead

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Foundry Services – Spurs Design and Applications Innovation through Fabless Model

Loaded US based 6” Si Foundries

Small and Large Industry

DoD

Universities National Labs

6” GaN 6” SiC

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Reduce cost using Commercial Foundry

0

10

20

30

40

50

60

1 2 3 4

¢/A for 1200 V, 20 A SiC MOSFET

100 mm dedicated FoundryLow Volume

100 mm Commercial150 mm Commercial

150 mm CommercialHigh Volume, Fabless

Silicon IGBTSilicon IGBT

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Benefits of Commercial Foundry:

• Use 10-20% capacity of an existing commercial foundry. 90% of the processes are the same.

• Reduced substrate and manufacturing costs by aggregating demand for 150 mm SiC wafers

• Robust and Reproducible Manufacturing- process recipes on proven equipment.

• Existing sales-force and distribution network. Existing customer base.

• Innovation by researchers, small companies and students through design and access to fabless model. Will encourage investments by VC firms as technology risks are reduced.

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Large Power Electric Motors (1‐50 MW) in COG IndustryApprox. 14% of the total electricity flows through Large Motors 

• Applications in Chemical, Oil and Gas Industry (COG)– Hydrogen Gas Compressors (Hydro‐cracking in Oil Refineries)– Booster Stations in NG Pipelines, High density polypropylene extruders– Ethylene Gas Compressors, Sea water injection and lift, etc.

• Steam, Gas Turbines and Diesel Engines for off‐shore applications are being replaced by large electric motors:– 20‐25% efficiency of off‐shore installations resulting in huge CO2 

emission (230,000 tons of CO2/year in a typical off‐shore pre‐compression project)

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Multi‐MW Pumps are used to handle water

DesalinationSource Water and Water TransmissionWaste Water TreatmentFlood Control, Dry Docks & DrainageWater PurificationIrrigation

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Over 900 Interstate Pipeline Compression Stations ‐Must electrify to reduce emissions over next 15 years

http://www.gaselectricpartnership.com/GFuture%20Compression%20Station%20Final.pdf

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Example – 13.4 MW Gas turbine Coupled Centrifugal Compressor

Starter Motor

Gas Turbine UnitOutput 8000 to 10000 RPM Compressor

Exhaust Gas Flow: 86.8 lb/sEmissions: NOx = 15 ppmv, CO = 10 ppmvEfficiency : 36% Maximum

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Example ‐ 20,000 hp Centrifugal Compressor for NG

Courtesy TECO Westinghouse, Austin

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Traditional Approach Wastes 20‐40% Energy

13.8 kV3 phase60 Hz

1-50 MWMotor

CompressorFixed Speed

60 Hz

Traditional

20-40% energy is wastedwith throttles andother mechanical devices

4.16 kV3 phase60 Hz

Big60 Hz

Transformer

GearBox

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Only 10-20% adoption of Si Based systems due to a big foot-print and capital cost

f = 20-60 Hz

4.16 kV3 phase60 Hz

Si BasedVariable SpeedDrive (VSD)

1-50 MWMotor

CompressorVariable Speed

Current Practice

40% energy can be saved/system but only 10-20% adoption

13.8 kV3 phase60 Hz

Big60 Hz

Transformer

Big FootprintExpensive

GearBox

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Integrated Motor System without Gear box for direct drive, high RPM Compressors

f = 200 – 600 Hz

13.8 kV3 phase60 Hz

VSDSiC Based3x Smaller Cheaper

1-50 MWMotor5x smaller

CompressorVariable Speed

Delivered asone box

New Approach

Big 60 Hz Transformer replaced by small high frequency TransformerVSD system is reduced in size & weight and cheaper due to WBG devices(High Voltage and high switching frequency)Gear Box eliminatedMotor size reduced by 5x – cheaper, less magnetsIncreased Adoption40% energy can be saved/system 20

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Size Reduction by going to higher RPM Direct Drive Motors

Size Reduction

http://www.gaselectricpartnership.com/GFuture%20Compression%20Station%20Final.pdf

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500 kW Si‐IGBT based Variable Speed Drive (VSD)

4 Interleaved Inverter each switching at 400 Hz, 96, 6.5 kV Si IGBTs

Courtesy: Dr. Subhashish Bhattacharya, NCSTATE University 22

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500 kW SiC Mosfet based drive can reduce system size

Much Cheaper than Si Solution15 kV SiCMOSFET/Diode

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The U.S. would gain a competitive advantage over foreign competitors by designing and manufacturing a “Made‐in‐the‐USA” integrated MV‐class electric motor system. 

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WBG Power Semiconductor Roadmap

• Device Progression– Each generation is smaller and more capable

• Cost Reduction– WBG is following a “Moore’s Law” of power semiconductors– Cost per Amp is reduced by 50% every 2 years

• What You Can Expect– WBG power devices have reached a tipping point in terms of cost‐performance 

that is leading to widespread adoption– Production on 6‐inch will enable WBG devices to replace Si in mainstream 

applications at 600V to 1700V in the next 5 years– 10‐15 kV devices will enable new applications in MV motor control and Grid 

Power Flow Control– The Overall market for WBG devices will double every 2 years from the current 

$100 M to $3 B in 10 years and Systems enabled by WBG will create $20 B new markets in US and Worldwide.

Courtesy: Cree, Inc.