Google and the Institute of Electrical and Electronic Engineers’ Power Electronics Society (IEEE PELS) have launched the Little Box Challenge, an open competition with a $1m prize to create a much smaller but higher-power-density inverter.
Inverters take direct current from devices such as solar panels and batteries and convert it into alternating current for use in homes, businesses and cars. The problem is that household inverters are too big. 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.
The challenge is to figure out how to shrink an inverter to something smaller than a small laptop (a reduction of >10x in volume). The winning inverter will be the one that achieves the highest power density and meets a list of other specifications, as determined by a panel of judges, while undergoing testing for 100 hours.
The other specifications are:
must be able to handle up to 2kVA loads; must achieve a power density equal to or greater than 50W/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 40in3; will be taking in 450V DC power in series with a 10Ω resistor; must output 240V, 60Hz AC single-phase power; must have a total harmonic distortion + noise on both voltage and current of <5%; 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; cannot use any external source of cooling (e.g. water) other than air; and does not require galvanic isolation.
“By participating in this challenge, members of industry and academia can play a pivotal role in a technological innovation that could have a major impact on the world,” comments IEEE PELS president Don Tan.
Google and IEEE comment that a promising set of technologies that may allow the achievement of higher power densities are wide-bandgap (WBG) semiconductors such as gallium nitride (GaN) and silicon carbide (SiC). WBG device manufacturers including Cree, EPC, GaN Systems, Monolith Semiconductor Inc, NXP, Rohm Semiconductor, Transphorm, and United Silicon Carbide Inc (USCi) have created web pages describing their technology, how it might enable contestants to win the competition, and opportunities for obtaining some of their devices.
The application deadline is 30 September. Eligible academics may also register and apply for grants to assist in the development of their devices. Registered teams must then submit a technical approach and testing application by 22 July 2015. Up to 18 finalists will be notified of their selection for final testing. They are required to bring their inverters in person to a testing facility in the USA by 21 October 2015. The grand prize winner will be announced in January 2016.
