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.

Comments

Re:Efficiency

[PIBM]

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...

Re:Efficiency

[slashkitty]

95.4% efficient in the conversion per the Datasheet http://littleboxchallengecetpo...

Re:Efficiency

[Anonymous Coward]

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

GaN Transistors are the future

[stevel]

Gallium Nitride transistors have a lot of nice characteristics, but low yields and high costs have slowed their introduction. Two tiny laptop chargers, the FinSix Dart and Avogy Zolt, were said to use GaN transistors. The Dart still hasn't shipped, a year past its claimed release date. The Zolt has but is apparently using older Silicon Carbide-substrate transistors instead (Also see here.) (I received my Zolt recently and it is working well.)

It won't be a surprise to anyone following this technology that it can make inverters more efficient - that's what FinSix and Avogy have been claiming/demonstrating for two years at least.

Re:GaN Transistors are the future

[MattskEE]

RF GaN parts are certainly expensive - the GaN is grown on silicon carbide substrates which is incredibly expensive by itself, and high-speed RF stuff has much more demanding fabrication needs like very small T-shaped gates, better contact resistances, and so on.

GaN for power electronics is much cheaper, grown on 6 inch silicon substrates, and produced in much higher volumes. You can buy GaN parts from EPC on Digikey for a couple of dollars each, the other GaN power device manufacturers aren't selling publicly that I know of (just to partners, or nobody) but the cost per unit is not tremendous - a bit more than the same voltage and current rating silicon device but the GaN part can switch faster.

Re:Efficiency

[Ol Olsoc]

Ah, I didn't look that closely to see that. On the other hand, I still wouldn't consider them 'astoundingly efficient' as the headline claims. This article discusses a design for a 97.09% efficient inverter. (I admit at this point I'm beginning to be argumentative, but I still think the headline should have been astoundingly dense inverters, though my theory is that slashdot injects in intentional errors to drive comments and traffics from those who like to nitpick submissions).

I disagree that you're being argumentive. While efficiency can mean a lot of things, it's a dead lock given that in a story about electric inverters, that efficiency would mean conversion efficiency.

Because the "efficiency" they were actually referring to was efficiency in th enature of efficiency apartments.

I certainly don't want to disparage what they did, because it was very impressive. This was more an issue with the person who wrote the original article.

Re:Efficiency

[DeathToBill]

According to [1], the winner achieves 95.4% efficiency - not actually that impressive as inverter efficiencies go.

[1] http://littleboxchallengecetpo...