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Google Challenge Results In Astoundingly Efficient Inverters
AmiMoJo writes: A few summers ago, Google and IEEE announced a one million dollar prize to build the most efficient and compact DC to AC inverter. It was called the Little Box Challenge, with the goal of a 2kW inverter with a power density greater than 50 Watts per cubic inch. Typical solar inverters have a density of about 5 W/cubic inch. Now the results are in, with the winners hitting 143 W/cubic inch using GaN transistors, and two other teams meeting Google's goal.
If you had read the challenge when it was proposed (or went to read the rules), the efficiency was required to be > 95%
. Produce a DCAC conversion efficiency of > 95%
From https://www.littleboxchallenge...
From the website https://www.littleboxchallenge.com/:
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 O 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 60C 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
I think he forgot the /sarc at the end of his post.
You are assuming GP male. This kind of sexist assumption is exactly the type of thing that needs to be stamped out in the industry.
Now if you need me, I'll be in my safe space. /sarc
They can go hand in hand; they don't have to go hand in hand. Generally speaking, efficiency of power conversion is fairly high, 95% isn't all that uncommon for a design that tries hard. Some of the problems are that when you're doing conversion at the KW level, 5% is 50 watts, which tends to be RFI (both direct and indirect) and heat - that's efficient in one sense, and a serious problem in another. Going from 95% to 97.5% cuts that to 25 watts; and that's not space saved once per installation, that's money saved and more energy for other things and less crap in the air every moment the conversion is ongoing.
In the case of houses and cars, where KW is the order of the day, space is a minor problem; efficiency is the major problem. I'd take a 97.5% efficient box at 10x the volume over at 95% converter any time. But it isn't even 10x the volume, generally speaking.
That's why the first thing I looked for was competition for conversion efficiency, and why I was a little put off by it not even being there.
I've fallen off your lawn, and I can't get up.
Another nice improvement the winners made above the requirements was that Google asked for 230 or 240 VAC output, but the winning device provides 240 VAC split phase, which means it can also be used to provide two legs of 120 VAC. Not that it's terribly hard to add a 240 VAC -> 120 VAC transformer, but with this design there's no need.
Cubic inches?! So this isn't a project intended to be looking beyond the borders of one country?
-Matt