
Google offering $1M prize for a much smaller power inverter - staunch
http://www.littleboxchallenge.com/
======
keenerd
Alright, something that is almost my day job. I can make you one as small as
you want. How many microamps do you need?

~~~
eigenvector
Given the relative simplicity of scaling down existing designs for lower
current ratings, one would assume that Google is looking to achieve reduced
heat dissipation (<=> increased conversion efficiency) from existing designs
at a given current rating, resulting in a higher kVA/m^3 value.

There are few immediately obvious ways to attempt this, but all of them
involve trade-offs in either cost, THD or operating flexibility. It'll be
interesting to see what the full requirements are.

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beambot
There was a HN article about "Dart" (and their Kickstarter) about a month ago.
They're building vastly-smaller switching power converters in the VHF
frequencies (upwards of 300MHz). I'm not sure about the validity of their
claims, though I believe the tech originated at MIT. This could be one
compelling route?

[1]
[https://news.ycombinator.com/item?id=7593909](https://news.ycombinator.com/item?id=7593909)

~~~
ChuckMcM
I believe you have it backwards, Dart is a switched mode power supply (SMPS)
which is sometimes called a _con_ verter, and things which take DC and return
90-240VAC are called _in_ verters. (not to be confused with logic inverters)

A typical inverter uses MOSFET or IGBT transistors to switch a DC voltage
which is then fed through a capacitor as a form of isolation. Typical
inverters are use on Solar panel systems to convert PV cells energy into AC,
battery backup to AC (Uniinterruptible power supplies), or single phase to
multiphase AC to drive AC motors efficiently.

One of the reasons they are "big" is because typically they operate at 60 or
50 hz, and at those frequencies if you are using magnetic fields for isolation
(like you would if you drove one side of a transformer) the transformers are
annoyingly large and hard to make efficient. [1] Many modern inverter start
with 280 - 480v DC and use a series of transistors to create an approximation
of a sine wave (this is how the cheesy plug into your car lighter inverters
usually work). Once you get above a 100W it starts to get a bit more difficult
to do cheaply and with reasonable efficiency.

Efficiency drains are also present in the upscaling the voltage (whether your
using a boost switching circuit or a simple diode/capacitor pump). So getting
these things to be efficient is hard, and they are of course generally fairly
large per watt.

I suspect Google is looking for something to invert PV solar arrays, but high
density power conversion is always valuable.

[1] That said, a lot of people made high voltage supplies out of using a 555
to switch a transistor on and off which fed the 'low' side of a power supply
transformer. I had a Xenon Strobe circuit that did that, made a nice little
600V supply.

~~~
beambot
I'm not saying that Dart's technique is directly applicable. What I _am_
saying: Fundamentally rethinking assumptions (like operating frequency) is
probably critical to a breakthrough in inverter design.

BTW.... Dart and others (like the iPad recharger [1]) typically convert AC->HV
DC (rectifier)->Flyback (at 10's of kHz)->low voltage DC. The intermediate
conversion to DC followed by "chopping" at a higher frequency on the flyback
transformer allows designers to use smaller magnetics than what would be
required of "classic" 50-60Hz wallwarts. I'm sure you're already well aware of
all of this given your comment. But so am I (despite the comments suggesting
I'm misunderstanding _converters_ -vs- _inverters_ ). ;-)

If the Google call is for energy generation, then there's also the added
difficulty of maximum power-point tracking as well...

[1] [http://www.righto.com/2014/05/a-look-inside-ipad-chargers-
pr...](http://www.righto.com/2014/05/a-look-inside-ipad-chargers-pricey.html)

~~~
ChuckMcM
_... Fundamentally rethinking assumptions (like operating frequency) is
probably critical to a breakthrough in inverter design._

Works fine except for the output which by spec has to be 50 or 60hz. I believe
even existing designs use a boost switcher to convert x DC to ~ 200V DC before
shaping it into something that looks nominally like a 110V sine wave.

So if you break the problem in two (input to source DC) and (source DC to 110V
AC sine wave) then I completely agree that advances in SMPS design components
and techniques can really help the first part, but I think we're still
searching for a low loss power amplifier for the second part.

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Tycho
Why don't companies do this more often? Write down a list of stuff they
need/would-like for their projects but aren't yet actively devoting resources
to, and then offer prizes to anyone who comes up with the goods. I know that
crowd-source design contests have been common (and controversial) but R&D I
don't hear about so much.

~~~
TwoBit
Because usually what the companies are willing to pay is much too low for the
actual effort involved.

~~~
Tycho
That would explain a lack of participation, but this seems more like a lack of
offers. It doesn't cost the company anything to put up a reward.

~~~
mentat
It would cost them the legal due diligence and setup which could be
significant for complicated requests and/or large companies.

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dylandrop
I feel like making a much smaller power inverter would be worth a hell of a
lot more than $1M.

~~~
eurleif
Well, it's not clear whether Google is buying the rights to the product with
their $1MM, or if they're just offering the prize to spur innovation.

------
sehugg
This was mentioned in the White House's FACT SHEET [1] on solar initiatives,
fwiw.

Certainly the inverter is an expensive hunk of metal, but soft costs like
installation and permiting dominate the average residential PV installation.
And if it were easy to make a more efficient inverter, wouldn't Xantrex have
made one by now?

Kinda confused. Oh well. Guess we'll find out more later.

EDIT: Maybe they're talking about microinverters. I'd still like to see the
spreadsheet describing the economics though.

[http://en.wikipedia.org/wiki/Solar_micro-
inverter](http://en.wikipedia.org/wiki/Solar_micro-inverter)

[https://completesolar.com/micro-inverters-vs-string-
inverter...](https://completesolar.com/micro-inverters-vs-string-inverters)

[1] [http://www.whitehouse.gov/the-press-
office/2014/05/09/fact-s...](http://www.whitehouse.gov/the-press-
office/2014/05/09/fact-sheet-president-obama-announces-commitments-and-
executive-actions-a)

~~~
rrmm
Ahh, thanks, that makes so much more sense! It seems that 5kW inverters have
efficiencies around 97% which is pretty good. I wonder if they could print the
micro-inverters as part of the panel manufacture and then just add the caps
and inductors they need during packaging.

This might also be a good opportunity to add features like distributed power
generation, so that for remote locations, a power grid could be setup with
residential panels, but no central power station.

~~~
crdoconnor
Inverters tend to die a lot quicker than panels, so it probably would not make
sense to make them part of the panel itself.

A dead inverter would mean a dead panel that was otherwise just fine.

------
krushin
I know this would be worth quite alot...

but given google is sponsoring this. What kind of application could this have,
or better yet if we get one that is super small/meets the qualification. What
kind of potential does it have?

~~~
drakaal
Power has to be stored as DC.

If google wants to "own the grid" and we know they do. Then power will need to
be efficiently converted from DC to AC.

If you do this at the outlet, then LED's and other DC favoring electronics
could be powered by wires that are DC, and AC would only be used when
necessary.

Think of all the devices you have with a power brick to take AC to DC. All of
those are losing electrons along the way... (most power supplies are less than
75% efficient).

~~~
dannypgh
Power does not need to be stored as DC. Flywheels store rotational energy, and
starting with a spinning flywheel it's pretty simple to get AC out of it.

~~~
eigenvector
True, but your electrical output would be variable-frequency AC at the drive
terminal. This isn't particularly useful unless you use a back-to-back
converter (i.e. DC link) to get constant-frequency AC.

~~~
derekp7
Would it have to be variable? If it goes through a CVT, then you can keep the
output whatever speed you want.

~~~
eigenvector
I'm no mechanical engineer but at first glance the conversion efficiency of
using a CVT with a synchronous AC drive (vs. direct coupling the motor rotor
and the flywheel rotor and using a variable-frequency induction motor + back-
to-back converter) would seem to be lower.

Modern VFDs have very high part-load efficiency and we can easily maintain a
constant power characteristic through the full speed range by operating in the
field weakening mode. One way or another you're losing energy in frequency
conversion, it's just a question of whether you do that mechanically (with
CVT) or electrically (with back-to-back converters).

Also keep in mind that for grid storage devices, we're usually talking about
500+ kW on each flywheel which, at low speed, is A LOT of torque.

------
nanidin
It's slightly pathetic that when viewing the website with Google's own
browser, the font in the "SOMETIMES THE BIGGEST..." block is rendered
incorrectly with stray pixels on top of the S's, O's, and G's.

I'm assuming it's not intentional since zooming in causes the artifacts to
disappear, but they come back when zoomed back out to 100%.

~~~
User9821
Chrome doesn't render Google web fonts well, it's been that way for as long as
I remember. It's a known issue, and it's been reported countless times.

You would expect this to be high priority, since reading text in the most
important aspect of the internet. For whatever reason, Google doesn't seem to
care, and they have no problem using these poorly rendered fonts all over the
place.

~~~
smaddock
This is slightly incorrect as the problem only affects Google Chrome on
Windows. Also, the Chrome team is actively working on this problem as seen in
in its issue report [1]. The progress can be seen by launching Chrome Canary
with the --enable-direct-write flag. chromestatus.com indicates that its
scheduled to be released in M36.

[1]
[https://code.google.com/p/chromium/issues/detail?id=25541](https://code.google.com/p/chromium/issues/detail?id=25541)

~~~
User9821
Chrome for Windows is one of the most common setups for browsing the internet,
so this isn't an edge case situation. That post originated in 2009, over 4.5
years ago.

It's good to hear it might be finally addressed, but I wouldn't say they've
been actively working on it, when all the other popular browsers had this
sorted years ago.

------
drakaal
And if it is worth $1m to Google think how much it is worth to you.

This is the opposite of a good deal. Build something that is probably worth
$250M and get $1m for it.

~~~
femto
The problem with building the world's best power inverter in your garage is:
Who do you sell it to? It's only worth $250M if you can connect with the buyer
who is prepared to spend that much. The real value with something like a $1M
prize is that it will lead to interest from people who are prepared to pay
$250M. $1M for non-exclusive rights may be cheap for Google, but it is
probably still good value for the inventor if it leads to bigger things.

~~~
jussij
> Who do you sell it to?

I would assume if you actually did build it in the garage and it worked, the
next step would be to get a patent and after that go talk to a venture
capitalist.

Strangely enough, probably not much different to the way Google itself came to
being.

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naterator
Isn't this the type of thing a place like Bell Labs would, or Google X should,
be on top of? And not fruitlessly rehashing the space elevator idea?

~~~
melling
It's probably a lot cheaper to crowd source the solution. You'll get a lot
more effort for the money. Crowd sourcing a problem for a prize is a well
proven method that's centuries old. Here are some famous examples:

[http://en.wikipedia.org/wiki/Longitude_prize](http://en.wikipedia.org/wiki/Longitude_prize)

[http://en.wikipedia.org/wiki/Spirit_of_St._Louis](http://en.wikipedia.org/wiki/Spirit_of_St._Louis)

And of course, the modern X-Prizes: [http://x-prize.com](http://x-prize.com)

The one improvement would be to crowd-source the challenges and the money.
Think KickStarter but participants vote for the projects and donate the prize
money.

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restlessdesign
If Google is willing to pay $1M for this, I suspect that such a design is
worth significantly more.

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mfkp
"WATCH THIS SPACE FOR MORE DETAILS SOON."

No, I'm not going to keep refreshing this page every day to check for updates.

~~~
jeena
I wish they would have added a RSS/Atom feed.

~~~
kalleboo
It's Google, they would have made a Google+ page.

