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Google Challenge Results In Astoundingly Efficient Inverters

Posted by timothy on from the now-multiply-by-a-few-million dept.

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.

16 of 245 comments (clear)

  1. Efficiency by fyngyrz · · Score: 4, Insightful

    Astoundingly Efficient Inverters

    This doesn't seem to be about efficiency at all, but rather about power density (how much power can be converted in a particular cubic volume.)

    Not that small isn't a worthy goal, but efficiency is important in any application where available power isn't both free and copiously oversupplied.

    --
    I've fallen off your lawn, and I can't get up.
    1. Re:Efficiency by PIBM · · Score: 5, Informative

      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...

    2. Re:Efficiency by slashkitty · · Score: 4, Informative

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

      --
      -- these are only opinions and they might not be mine.
    3. Re:Efficiency by Anonymous Coward · · Score: 5, Informative

      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

    4. Re:Efficiency by Stewie241 · · Score: 4, Insightful

      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).

    5. Re:Efficiency by fyngyrz · · Score: 5, Insightful

      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.
    6. Re:Efficiency by Ol+Olsoc · · Score: 4, Informative

      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.

      --
      The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
    7. Re:Efficiency by AmiMoJo · · Score: 4, Interesting

      Batteries. Current inverters are rather large compared the batteries that can provide their maximum output power.

      Electric vehicle charging would benefit from this. You want to be pushing 120kW+ DC into the battery. You can also go back the other way and run your house from the car battery to save money when your solar panels are not producing anything.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
    8. Re:Efficiency by torkus · · Score: 4, Insightful

      Electrical Efficiency is loosely coupled to volumetric efficiency. We're talking about an inverter roughly the size of a fist that's outputting 2kW. Without very high efficiency your cooling solution would be larger than your inverter. A moderate size CPU cooler (sinking ~65w) is the size of this whole inverter.

      The rules require efficiency >95% which is typical for high efficiency inverter systems. At that, the primary benefit to higher efficiency is lowered cooling requirements (i.e. size) which is the primary goal of the competition.

      So the rules basically *do* set teams out to maximize efficiency. Having small, highly efficient inverters is useful is many applications (solar, vehicular, UPS, etc.)

      As for Google's exact benefit? I could see them running these in datacenters: deliver 450VDC rails to all your racks and power them off a hockey puck inverter or two. Simple to scale - add more battery, more racks with inverters as needed. Everything becomes modular.

      Beyond that, solar and larger UPS systems typically run at 450VDC - so this means you can also scale your UPS and solar installation in conjunction with your datacenter. Basically combine all the technologies together without requiring large monolithic components. Ok, TLDR my own post.

      --
      You can get rich if you own a politician, but you have to be rich to buy one in the first place.
  2. Re:AC is by its very nature inefficient by dlleigh · · Score: 4, Funny

    Is that you Thomas Edison?

    Stop electrocuting elephants!

  3. GaN Transistors are the future by stevel · · Score: 4, Informative

    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.

  4. Re:Who participated? by cc1984_ · · Score: 5, Funny

    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

  5. Astoundlingly dense by Anonymous Coward · · Score: 4, Funny

    There's probably a joke to be made at your expense, here.

  6. Split phase by shawn2772 · · Score: 5, Interesting

    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.

  7. Cubic inches? by HammerToe · · Score: 5, Insightful

    Cubic inches?! So this isn't a project intended to be looking beyond the borders of one country?

    -Matt

    1. Re:Cubic inches? by fibonacci8 · · Score: 4, Funny

      And in English no less, the third most commonly spoken first language in the world. Could we please get these summaries in Mandarin and Spanish? If we're going to base things in the US on what more people are doing elsewhere, why stop at measurements?

      --
      Inheritance is the sincerest form of nepotism.