Introducing the Little Box Challenge
An open competition to build a (much) smaller power inverter, with a $1,000,000 prize.
Design and build a kW-scale inverter with the highest power density (at least 50 Watts per cubic inch).
Know what that means? Have a healthy disregard for the perceived limits of engineering?
Then you’re exactly who we’re looking for.
Congratulations to the Red Electrical Devils, $1,000,000
grand prize winners of the Little Box Challenge
Power Density: 143 W/in3
The Red Electrical Devils from CE+T Power were honored at a ceremony at the 2016 ARPA-E Summit in Washington DC. Two other teams, Schneider Electric and the VirginiaTech Future Energy Electronics Center, whose inverters passed 100 hours of testing at NREL were also recognized. More details are available on the Google Research Blog. Thank you to all the teams that participated.
Finalist Technical Approach Documents
As a condition of entering the competition, all teams agreed to have their technical approach documents, describing how they built their inverters, made public. We post links to the technical approach documents of the 18 finalists selected for testing at NREL here in order to recognize their achievements and in hopes of furthering the state of the art in power electronics. The documents can be accessed by clicking on the team name.
Grand Prize Winner
(CE+T Power, Belgium)
Olivier Bomboir, Paul Bleus, Fabrice Frebel, Thierry Joannès, François Milstein, Pierre Stassain, Christophe Geuzaine, Carl Emmerechts, Philippe Laurent
Top 3 Finalists
Miao-xin Wang, Rajesh Ghosh, Srikanth Mudiyula, Radoslava Mitova, David Reilly, Milind Dighrasker, Sajeesh Sulaiman, Alain Dentella, Damir Klikic, Chandrashekar Devalapuraramegowda, Michael Hartmann, Vijaykumar Atadkar
Jih-Sheng Lai, Lanhua Zhang, Xiaonan Zhao, Rachael Born, Chung-Yi Lin, Ming-Chang Chou, Shu-Shuo Chang, Kye Yak See
Eckart Hoene, Johann W. Kolar, Dominik Bortis, Yanick Lobsiger, Dominik Neumayr, Oliver Knecht, Florian Krismer, Stefan Hoffmann, Adam Kuczmik, Oleg Zeiter, Franc Zajc
Geoff Harvey, Alan Walbridge, Steve Love
John Wood, Ed Shelton, Tim Regan, Ellen Wood, Kyle Rogers, Dr Kevin Rathbone, Sam Harrup
Evgeny Sboychakov, Ruslan Kotelnikov
Bernd Eckardt, Stefan Endres, Maximilian Hofmann, Stefan Matlok, Thomas Menrath, Martin März, Stefan Zeltner
Jack Zhu, Mari Ma
Martin Pietka, Andrej Teren, Marian Vranka, Lubos Drozd, Peter Sedlacko
Ionel Jitaru, Nicolae Daniel Bolohan, Antonio Marco Davila
Daniel Costinett, Leon Tolbert, Fred Wang, Chongwen Zhao, Bradford Trento, Ling Jiang, Rick Langley, John Jansen, Reid Kress, Anthony Brun
Mike Tommasi, Alain Bailly
Robert Pilawa, Shibin Qin, Christopher Barth, Yutian Lei, Wen-Chuen Liu, Andrew Stillwell, Intae Moon, Derek Chou, Thomas Foulkes
Herbert Venderbosch, Gerard Bruggink
Cooler-sized Isn’t Cool
Inverters are the essential boxes that take direct current from devices such as solar panels and batteries and turn it into alternating current for use in homes, businesses, and cars.
The problem is household inverters are too big—roughly the size of a picnic cooler. Making them smaller would enable more solar-powered homes, more efficient distributed electrical grids, and could help bring electricity to the most remote parts of the planet.
That’s where you come in: figure out how to shrink an inverter down to something smaller than a small laptop (a reduction of > 10× in volume) and smaller than everyone else, and you’ll win a million dollars (and help revolutionize electricity for the next century).
First, the competition dates:
- Applicants contemplating competing in the prize must register their team by the registration deadline: September 30, 2014.
- Eligible academics interested in pursuing grant funding must apply by the grant application deadline: September 30, 2014 by visiting the University Relations site.
- Registered teams must submit a technical approach and testing application by July 22, 2015.
- Up to 18 finalists will be notified of their selection for final testing at the testing facility. They are required to bring their inverters in person to a testing facility in United States by October 21, 2015.
February - March 2016
- The grand prize winner will be announced sometime in February or March, 2016.
What the inverter needs to do
The winning inverter will be the one that achieves the highest power density and meeting a list of other specifications, as determined by a panel of judges, while undergoing testing for 100 hours.
In brief, the other specifications are :
- Must be able to handle up to 2 kVA loads
- Must achieve a power density of equal to or greater than 50 W/in3
- Must be able to handle loads with power factors from 0.7–1, leading and lagging in an islanded mode
- Must be in a rectangular metal enclosure of no more than 40 in3
- Will be taking in 450 V DC power in series with a 10 Ω resistor
- Must output 240 V, 60 Hz AC single phase power
- Must have a total harmonic distortion + noise on both voltage and current of < 5%
- Must have an input ripple current of < 20%
- Must have an input ripple voltage of < 3%
- Must have a DC-AC efficiency of greater than 95%
- Must maintain a temperature of no more than 60°C during operation everywhere on the outside of the device that can be touched.
- Must conform to Electromagnetic Compliance standards as set out in FCC Part 15 B
- Can not use any external source of cooling (e.g. water) other than air
- Does not require galvanic isolation
Our testing philosophy is to not look inside the box. You provide us with a box that has 5 wires coming out of it: two DC inputs, two AC outputs and grounding connection and we only monitor what goes into and comes out of those wires, along with the temperature of the outside of your box, over the course of 100 hours of testing. The inverter will be operating in an islanded mode—that is, not tied or synced to an external grid. The loads will be dynamically changing throughout the course of the testing, similar to what you may expect to see in a residential setting.
A more detailed description of the technical specifications for the inverter, the testing procedure and the requirements for technical approach and testing application can be found in this document (updated 7/17/2015).
How to register
The registration process is a simple form to fill out. Information must be provided in each of the fields, but any serious entry (e.g. not containing offensive material or clearly gibberish) submitted in english, regardless of approach suggested or team background, will be successful in registering. You should receive a confirmation email within three business days of your registration with a unique confirmation code.
Once registered, all the team members listed will receive updates and reminders about the prize. You must register before the registration deadline (September 30, 2014) in order to submit a technical approach and testing application and be qualified to win the prize.
Testing Facility: National Renewable Energy Laboratory
Google and the IEEE Power Electronics Society have announced that the National Renewable Energy Laboratory (NREL) in Golden, Colorado, USA will be the testing facility for the competition. Up to 18 finalist teams will be invited to bring their inverters for extended testing (up to approximately 100 hours) at NREL’s Energy Systems Integration Facility (ESIF) using state of the art equipment and supervised by world-class technical staff. The results will help us ensure that the best entry wins. When they come to Colorado, the finalists will also be invited to attend an event hosted by Google, the IEEE Power Electronics Society and NREL, where they will get a chance to discuss and present on their designs as well as get a tour of the facility.
One promising set of new technologies which may allow for the achievement of higher power densities are wide bandgap (WBG) semiconductors, such as Gallium Nitride (GaN) and Silicon Carbide (SiC). Below are a list of WBG device manufacturers who have made pages describing their technology, how it might enable contestants to win the competition and opportunities for obtaining some of their devices.
Are you a wide bandgap device manufacturer that thinks it should be listed above? Click here for an application to be listed (must be submitted by 9/30/2014 to be considered).
Are you an academic interested in trying to win The Little Box Challenge? Research at Google is also making a limited number of awards of available to academics in concert with the prize. Visit their website here.
Got some questions? Here are some answers.
Why does Google care about inverters?
We believe that inverters will become increasingly important to our economy and environment as solar PV, batteries, and similar power sources continue their rapid growth. More broadly, similar forms of power electronics are everywhere: in laptops, phones, motors drives, electric vehicles, wind turbines, to give just a few examples. We expect that the innovations inspired by this prize will have wide applicability across these areas, increasing efficiency, driving down costs, and opening up new uses cases that we can’t imagine today. It also doesn’t hurt that many of these improvements could make our data centers run more safely and efficiently.
Who is IEEE?
IEEE, The Institute of Electrical and Electronics Engineers, is the world’s largest professional association dedicated to advancing technological innovation and excellence for the benefit of humanity. IEEE and its members inspire a global community through its highly cited publications, conferences, technology standards, and professional and educational activities. The IEEE Power Electronics Society (PELS), has facilitated and guided the development and innovation in power electronics technology for over 25 years. This technology encompasses the effective use of electronic components, the application of circuit theory and design techniques, and the development of analytical tools toward efficient conversion, control and condition of electric power. PELS will assist in judging and overseeing the competition.
Who can compete in this competition?
Anyone in the world can apply (with a few exceptions—see T&Cs). We’re expecting university teams and private companies, but we’d love anyone with a good idea to throw their hat in the ring.
What happens if I win?
First, you’ll have made a tremendous breakthrough in electrical engineering, so congrats. Second, you’ll get a million dollars from us. Third, your technical approach document will be published for all to benefit.
Does Google own the intellectual property created during the competition?
No. Google is not requiring any IP or licenses be granted except a non-exclusive license to be used only for the purpose of testing the inverter and publicizing the prize. We want entrants to benefit themselves through the advancements they make in order to help grow an advanced power electronics ecosystem.
However, in the spirit of advancing this power electronics community, Google may choose to make public some or all of the teams’ high-level technical approach documents. These documents outline the key innovations used to overcome the problems which currently limit high power density in inverters. They do not need to reveal any IP. We only want to show the world what techniques are possible in creating a new generation of power electronics. More details on the requirements for this document can be found in the full terms and conditions and detailed inverter specifications for the prize.
Can I change the members of my team during the competition?
Yes, except for the main point of contact. The point of contact for the team must remain the same between the registration and the submission of the technical approach and testing application. The other team members may change after the initial registration. The team list submitted with the technical approach and testing application will be considered final.
Can I be on multiple teams?
No. You can only be listed as part of one team. You are free to consult with any number of teams, but if more than one team promises to share their prize money with you, this will disqualify both you and the teams in question.
Will Google pay/arrange to get the inverters to the Testing Facility?
No. Unfortunately due to the variety of laws and procedures which are required to transport complicated electronic equipment from countries around the world to the USA, Google cannot take responsibility for getting the inverter from the applicants to the testing facility.
Successful finalists must be able to bring their inverters to a testing facility in the United States in person. They may also appoint an individual to bring it on their behalf, if they are unable to make it themselves. Google will not take responsibility for receiving packages from logistic providers. The testing facility will likely be announced in Q3 or Q4 2014 and emailed to those who have registered for the competition.
Who gets the prize money?
The prize money will be given to the point of contact from the winning team. The team members must work out between themselves any subsequent division of the funds.
How do I apply for a grant?
The applicant must be an academic, i.e., full time faculty at a degree granting, accredited University, located in a region eligible to participate in the prize. More details on the grant application process, who is eligible and the specific request for proposals is available on the Google University Relations Grant application website.
To make sure that no one had an unfair advantage in receiving extra information about the prize, questions were periodically consolidated and answered in a document posted here. No information about who asked the question was posted.