Google Offers a Million Bucks For a Better Inverter 260
An anonymous reader writes: With the Little Box Challenge, Google (and IEEE, and a few other sponsors like Cree and Rohm) is offering a $1 million prize to the team which can "design and build a kW-scale power inverter with the highest power density (at least 50 Watts per cubic inch)." Going from cooler-sized to tablet sized, they say, would make a whole lot of things better, and the prize is reserved for the best performing entrant. "Our testing philosophy is to not look inside the box. You provide us with a box that has 5 wires coming out of it: two DC inputs, two AC outputs and grounding connection and we only monitor what goes into and comes out of those wires, along with the temperature of the outside of your box, over the course of 100 hours of testing. The inverter will be operating in an islanded more—that is, not tied or synced to an external grid. The loads will be dynamically changing throughout the course of the testing, similar to what you may expect to see in a residential setting." The application must be filled out in English, but any serious applicants can sign up "regardless of approach suggested or team background." Registration runs through September.
"to not look inside the box" (Score:2, Interesting)
An awesome way to smuggle a wifi sniffer - or something naughtier - into the googleplex!
Re:"to not look inside the box" (Score:4, Insightful)
An awesome way to smuggle a wifi sniffer - or something naughtier - into the googleplex!
...more like an awesome way for Google to grab a profitable patent in exchange for the prize money.
Seriously - if you can pop those kind of specifications, you can make a hell of a lot more than a million bucks from the patent alone.
Re:"to not look inside the box" (Score:4, Informative)
Except they are not claiming any of the IP, just a 100 hr license to use it for the test. Also, why they claim they will not open the box up.
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" Also, why they claim they will not open the box up."
And I would ask that I be allowed to personally observe my box during the entire time, if need be, to ensure that. That is all under the assumption I had such a device. I've seen it from AC-DC for LED drivers, but not that kind of efficiency in reverse.
Re:"to not look inside the box" (Score:4, Informative)
If you've got a patent for it, you just let everyone use it for 15 years then sue them all for billions in damages.
Isn't that how patents work?
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a very small bomb.
at 50W/in2 a 2kW inverter is only 40in3. Thats a cube Less than 3.5in. About the volume of 2 cans of coke.
I've heard this one... (Score:5, Interesting)
Word is, there was no spec for lifecycle so the devices met the contract as stated, and the government couldn't return the devices.
So I'd recommend to Google: At some point, look in the box.
Re: I've heard this one... (Score:2)
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Just reverse the wires.
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....120 times per second.
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K. gimme an oscillator, variac, and an inductor.
Deuces.
Re: Hamsters? (Score:2)
Re:I've heard this one... (Score:5, Insightful)
Based on a weak urban myth?
Besides, if you get a battery that can do this work and meet these conditions, you would have invented a new type of battery. One that would make you billions.
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At 50 W per cubic inch, you'd make more money by just selling those batteries if they last longer than a few hours...
Re: I've heard this one... (Score:3, Insightful)
Now you know why government contracts have to be so complicated.
To fight dickery.
Re:I've heard this one... (Score:5, Informative)
It needs to last for 100 hours of testing.
It must be smaller than 50W/in3
That's 305000W.h per litre. 1100MJ/Litre.
If you've got a battery with that kind of power density, $1M is chump change. You've solved the electric car problem, since you've got well over 1000x the power density of current lithium batteries.
Re:I've heard this one... (Score:4, Informative)
since you've got well over 1000x the power density of current lithium batteries.
Energy density. And nearly 100x that of gasoline, too.
Re:I've heard this one... (Score:4, Interesting)
If you've got a battery with that kind of power density, it's actually a formidable explosion hazard. With thirty times the energy density of rocket fuel, even a minor internal short would cause a chain reaction that would make a battery pack the size of a laptop battery explode with the power of over one hundred kilograms of TNT.
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Given that this would be upwards of 2000x higher density than a lithium battery, does that mean a 60Wh laptop battery has the explosive capacity of half a stick of TNT?
60Wh = 216kJ
0.19kg stick of TNT = 532kJ
The 65L of petrol in my car stores 2340MJ and is equivalent to nearly a ton of TNT.
TL;DR: Comparing batteries to explosives is a bad idea. They're completely different. A battery isn't going to explode, it's going to burn.
The difference between burning petrol and exploding petrol is your car running perf
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There appears to be a significant flaw in the specification. Technically whilst the inverter is limited in size, they have not limited what the inverter is contained in, so a liquid nitrogen bath comes to mind. Doing so makes the inverter quite easy to achieve and the temperature would remain very low even excluding the affect of the liquid nitrogen beyond it's super conductivity enhancing ability. So they should require the inverter function in a room temperature environment.
This is really all about mat
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They said it must be air cooled.
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That's 305000W.h per litre.
This isn't an energy storage device. It' an energy conversion device and as such stores nothing*. Think of it as a piece of wire. Power in, power out. With some minor loss which produce heat. An inverter is just 'magic wire' where DC goes in and AC comes out.
*Technically not exactly true, as an inverter has some smoothing filters. But they store energy for a time period on the order of half an AC cycle, not hours.
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If you can provide 2kva for 100 hours from 40in^3 you'll have a lot now than $1m coming your way! Heck the Nobel committee alone will give you $2m, $1m each in physics and chemistry.
Why? (Score:4, Interesting)
If you're running devices that need a kW you're already at a reasonable size for your device, and you can build a lot of cheap, larger inverters for what it would cost to build this small one.
You could also probably build the powered devices to run off 12V for less than what this inverter would cost.
Is what is keeping AC power from the hinterlands this is intended to serve really the size of the inverter, or is it more likely the cost?
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You could also probably build the powered devices to run off 12V for less than what this inverter would cost.
Lower voltage, higher amperage required for same power, rapidly increasing power loss with increasing wire length, even at residential scale. There's a reason that your power supply for your 12V lights goes close to the lights and you don't run 12V through your house.
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It could work if you're only going from bottom of rack UPS to rack equipment. It's already done in some datacenters, though usually at 24 or 48V rather than 12V.
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It could work if you're only going from bottom of rack UPS to rack equipment. It's already done in some datacenters, though usually at 24 or 48V rather than 12V.
Oh, absolutely yes in data centers. But not in houses.
Re:Why? (Score:5, Interesting)
and this is the reason it is 48V.
Copper is expensive. You don't want your 42U rack, which pulls 8kW powering it's 42 1U servers, drawing upwards of 700A.
For a 1% power loss over 1 metre at 700A, you need 0000AWG cable. It's about 1kg of copper (that's a single conductor, you'd need one for the return path, another kg and another 1% power loss)
But 0000AWG can't actually handle that amount of current without active cooling. for 90C rating, it's only 260A.
700A for 1M distance has cost you 160W of power and 2kg of copper and you need some fancy cable cooling technology.
If you upped the voltage to 48V, you only need 175A.
You'll be fine with 2AWG cable if you can keep it cool and only lose 30W. You could use 0AWG, which would cost you 1kg of copper and only have 19W of wasted power.
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For a 1% power loss over 1 metre at 700A, you need 0000AWG cable. It's about 1kg of copper (that's a single conductor, you'd need one for the return path, another kg and another 1% power loss)
Bah, just use the chassis as return; the frames might only be steel, but there's a good amount of it. That and I suggest 600V for truly limiting the amount of power lost through cables. ;)
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600? 480VDC would be fine. 5A roughly? Easy-peasy.
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The wiki page they link to has a photo of a converter that converts solar DC to electric grid AC. I'm not sure if they're looking to do residential solar with the inverter on the back side of the panel group or use this in a datacenter...
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> One question: why?
We believe that inverters will become increasingly important to our economy and environment as solar PV, batteries, and similar power sources continue their rapid growth. More broadly, similar forms of power electronics are everywhere: in laptops, phones, motors drives, electric vehicles, wind turbines, to give just a few examples. We expect that the innovations inspired by this prize will have wide applicability across these areas, increasing ef
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Having read the actual Spec Document, the input voltage is 450V DC, with an equivalent series resistance of 10Ohm. Definitely not 12V DC.
so... (Score:4, Insightful)
what is the state of the art w.r.t. the 12VDC->110VAC/60Hz 1kW inverters?
Solar power? (Score:2)
An inverter converts DC power to AC power. The most obvious use is for solar power. For rooftop solar arrays, you want efficiency, but you don't care much about density. In many cases, you have a small inverter under each panel, and size isn't an issue. But if you could get a few percent more AC out for a given DC in, that would matter.
On the other hand, if you want a solar-powered Chromebook, the inverter could be a deal-breaker on the weight. I'm guessing it's applications like that that have inspire
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Low-power inverters used to be common in laptops to drive the backlight. You still see them sometimes, but most new laptops use LED backlights now. No need for inverters on those. That's a good part of the appeal.
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Yup, you're completely right. I'm not sure what I was thinking. Probably too much air conditioning froze my brain.
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"if you want a solar-powered Chromebook"
I'm a little confused... why would you convert dc to ac, only to convert it back to dc for the computer to use? If it's a dedicated power source for one device, wouldn't it make more sense to keep it dc?
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But I don't get it - why convert DC to AC, when all you're likely to do in the end is convert that AC back to DC somewhere else to actually power something?
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"On the other hand, if you want a solar-powered Chromebook, the inverter could be a deal-breaker on the weight."
You wouldn't need an inverter, really. In many cases, low-power laptops run on ~10VDC, so a direct solar panel connection with resistor would be roughly fine to hit the battery through its charge controller. For those needing ~20V, you just use a cheap-ass boost converter and resistor before you feed to the charging/power circuitry.
Been there, done that, made solar-powered headless laptop servers.
$1M? (Score:2)
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Developing a working prototype and developing a commercially-feasible product are two different things. You could conceivably meet the requirements of this, but by using components or techniques that are not commercially feasible due to cost, safety, or other issues. However, it would be a big step in the direction towards doing such a thing. Google is paying for you to help make that step... not necessarily to develop a device that's worth commercializing.
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Here is a silly question of sorts.
what is in the process of making this, you used some patented off the shelf part and perhaps created something else as a part inside it that seems to be covered by a patent.
I'm assuming that as long as you don't sell it, the off the shelf part is covered (maybe even if you did sell it) but the other patent, would it require royalties or whatever just for this proof of concept device because it won a prize? Of course I could be wrong on it all, I don't really know the answer
I know this is /. but RTFA (Score:5, Informative)
Stupid objection the first: "This is worth a lot more than a million dollars."
Response:
Stupid objection the second: (something stupid about 12 volts)
Response:
I know that slashdotters don't RTFA, but seriously, all of you jaw-jacking about 12 volts or about how a million is chump change are a bunch of Useless McToolbags. STFU already.
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Go ahead and do lots of work with almost no chance of payment.
If you aren't already working on this, or don't already have a pretty good idea with at least a fair chance of succeeding, then you're probably not too smart if you decide to take this challenge on. So what? There are those who are working on solving this problem already. If they have the means to produce a product, they're already doing that. If not, then this will give them some money for production of prototypes for larger systems, and probably attract some investment dollars from Google.
I don't understand the problem here. (Score:2)
The base price for an off-the-shelf 2000 Watt Complete Grid-Tied DIY AC Solar Kit [anapode.com] is $4600.
The kit includes eight 8 x 8 x 5 inch Enphase inverters weighing 6 lbs each. Retailing for about $150 each. All offers for Enphase M215 Micro-Inverter [amazon.com]
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Which gives a power density of 0.78 watts per cubic inch. The Google challenge calls for a minimum power density of 50 watts per cubic inch.
I have a truly (Score:2)
Everything but the 40 in^3 (Score:2, Interesting)
About 4x beyond current production. (Score:2)
As an actual product available right now, there's this 250 watt inverter. [enphase.com] from Enphase, intended to work with one solar panel. That's 54 cubic inches, or 12W/cubic inch. Google wants 50W/cubic inch, so Google is asking for 4x the power density. This one happens to be configured for 48VDC input, but that's not hard to change. It exceeds the efficiency limit set by Google.
Enphase sells those little inverters for a one-inverter-per-solar-panel system, where power is combined on the AC side. The inverter, a
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I looked at http://www.amsc.com/pdf/PM3000... [amsc.com]
The spec sheet claims "power density of up to 130 W/in. (7.9 W/cm)"
But I also see:
Dimensions 38.2in*19.8in*18.7in = 14100 in^3
AC Power 690V * 750A = 520000 VA
Density: 37 VA/in^3 (also an upper bound on W/in^3)
What is the justification for the 130 W/in^3 claim?
Cubic Inches? (Score:3)
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American engineering tends to use US-customary units. Scientific research mostly uses metric, but engineering uses mostly US-customary, somewhat varying by field (e.g. medical devices tend to use metric).
Interestingly it's so ingrained into a lot of aspects of North American production that even Canada, which has switched to using metric for engineering, has a lot of parts specified in a way that obviously refers to customary units, with things strangely coming in multiples of 25.4mm, 0.454kg, and the like.
Re:110 or 240v (Score:5, Informative)
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 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
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The US does run 220(ish)V 60Hz for heavy loads. Really big appliances and light industrial.
Re:110 or 240v (Score:4, Insightful)
Re:110 or 240v (Score:5, Informative)
Except it requires more wires. 220/240V split phase requires 3 wires.
3-phase generally requires 4.
And unless you really need 3-phase, split phase is easier to deal with - with 3-phase you need to monitor all three phases to ensure they are working (failure of one phase is a common failure mode that requires immediate shutdown of the other two phases lest any dangerous currents develop).
Though, one thing I don't get about this challenge - they're using they want 2kVA output, but then demanding 50W/in^3 with a max size of 40in^3, meaning you have to provide 2000W.
And 2000W can mean providing way more than 2000VA. (The reason we use VA for inverters instead of watts is VA captures virtual power. 2000VA requires just as much power handling components (transformers, transistors, etc) as supplying 2000W at a 1.0PF (i.e., all resistive). Even if you have a really bad power factor and your real power draw is only 1000W - the hardware has to be able to instanteously supply the current and voltage for 2000W at periods in the cycle. The virtual power is virtual, because it's "given back" during another part of the cycle, but that means all the equipment has to handle it.
A lot of electric companies will have a power factor surcharge because of it - if your power factor can't be corrected to within limits, they charge more because they have to install bigger equipment.
The only real saving grace is that the input voltage is 450VDC, so you're really just doing a buck converter.
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3 Phase doesn't require the return neutral, unless your load is very unbalanced. So they both require 3 wires to transmit.
And yes, it does appear to be a simple buck converter. Though you could probably use a Z-Source inverter too.
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3 phase requires the return by code. Technically however, you are correct. That's just for safety and I often question if it makes any sense myself.
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3 phase requires the return by code. Technically however, you are correct. That's just for safety and I often question if it makes any sense myself.
In an industrial settings I deal with a lot of loads that are three phase L1, L2, L3 + safety ground only (shield on cable, chassis on machine). No Neutral. Even 4160V loads. Unbalanced loads are brought back through L1, L2, L3.
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It's pretty pointless to hook a neutral up to a delta-wired motor, code or no :D
3-phase 4-wire feeds are used all the time for commercial power here in Canada. Either 208V or 600V depending on what is required. Single phases are circuited off for 208V/120V or 347V single-phase feeds, respectively. A neutral conductor is definitely required for this application, yes. 208V single-phase circuits don't use a neutral, since they use two of three phases as if they were single phase. Their "split neutral" would be
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Though, one thing I don't get about this challenge - they're using they want 2kVA output, but then demanding 50W/in^3 with a max size of 40in^3, meaning you have to provide 2000W.
What is it you don't get?
Requirements are >=50W/in^3 and <= 40in^3.
I would expect some of the entrants will exceed those requirements - doing more W/in^3 and/or less space.
Re:110 or 240v (Score:4, Interesting)
Don't worry, I cut it up when I was done.
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Yes, because the US cheats and uses 220 split-phase to provide 110 power. Most everywhere else that needs high power uses 3-phase, as it's smoother, easier to produce and rectify, and just as safe to transmit.
3 phase makes electric motors more efficient, and that's it. Technically, you could have as many phases as you could imagine having... each making the motor a tad more efficient. But they are not "smoother" and don't improve transmission.
'Phase' is often considered by some to be some magic property of electricity that somehow makes it better... it's not at all. It's a purely mechanical feature that's revolves around generators and motors. 2 phase means there are 2 electro magnets on the motor. 1 to the nort
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Yes, because the US cheats and uses 220 split-phase to provide 110 power. Most everywhere else that needs high power uses 3-phase, as it's smoother, easier to produce and rectify, and just as safe to transmit.
3 phase makes electric motors more efficient, and that's it. Technically, you could have as many phases as you could imagine having... each making the motor a tad more efficient. But they are not "smoother" and don't improve transmission.
3-Phase AC produces a smoother (considerably less ripple) DC current pattern when rectified than single or split-phase AC.
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Yes, because the US cheats and uses 220 split-phase to provide 110 power. Most everywhere else that needs high power uses 3-phase, as it's smoother, easier to produce and rectify, and just as safe to transmit.
3 phase makes electric motors more efficient, and that's it. Technically, you could have as many phases as you could imagine having... each making the motor a tad more efficient. But they are not "smoother" and don't improve transmission.
3-Phase AC produces a smoother (considerably less ripple) DC current pattern when rectified than single or split-phase AC.
I've seen 3 phase 700V+ DC drives at over 1000kW that are very harmonic rich. Over 100% THD. Not smooth AT ALL.
Re: 110 or 240v (Score:2)
A DC drive is generally variable voltage/current and switched through a scr. At full power, they would be smoother. At low power, the switching frequency will cause severe ripple. 3 phase is better for simple rectifiers and is indeed smoother.
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Actually, we generate 3 phase just like everyone else. We just don't run all three to each house. Industrial and commercial users do commonly get 3 phase.
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it's 240V in USA/Canada (Score:5, Informative)
In the USA/Canada typical residential setups use two conductors at 120V to ground, but the conductors are out-of-phase so there is 240V between them.
There really isn't any such thing as 110V or 230V in the USA/Canada, both of which you'll sometimes see referenced. 208V does exist, it's the difference between two legs of a 3-phase setup where each leg is at 120V to ground.
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I just finished building and wiring up a full hydroponics building. You get ~277V, split-phase, and in reality, it's higher than that, because it's 120VRMS and upwards of 170V peak, so you're looking at a potential spread of 340V or more.
"There really isn't any such thing as 110V or 230V in the USA/Canada,"
From a technical standpoint, yes. From a practical standpoint, not really. RMS is good enough. Trust me, if the electronics we have were not that robust, they'd have been fried long ago. Hooray for tolera
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You get ish-voltages anyway. The grid doesn't always run exactly on spec, so you need equipment that can handle a considerable variation in input voltage.
240V is fairly common (Score:3)
240V would be used for kitchen stove/range, clothes drier, electrical heat (air and water). Some commercial cappucino machines use 240V.
A home shop could very well use 240V for a welder and any number of power tools...lathe, jointer, planer, tablesaw, mortiser, wide belt sander, dust collector, shaper, etc.
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No-one uses 240V.
The UK used to use 240V. We dropped down to 230 when the EU standardized voltage across member states.
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220v is mostly in single or duplex residential settings. Otherwise, it's often 208v (convieniantly available by connecting to two phases of 3 phase power).
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Just about anything apartment-wise after the 80s uses split phase 240RMS/277 typical peak.
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Whoah, google spent $7,300,000,000 on data centers last year [datacenterknowledge.com] and doesn't even know what voltage they run on? Time to sell my stock!
Google built its business by developing its own infrastructure, starting with custom servers in pizza boxes and lego. What crazy company runs out and develops its own filesystem for its own internal use? Google did [wikipedia.org].
Re:110 or 240v (Score:4, Informative)
The 240V 60Hz is so that it can handle both North American and UK voltage levels. If you look at the technical specifications document, you'll see that there are 2 different grounding configurations that the contestants may specify. In both configurations the inverter output is fed into an isolation transformer. One specification has the input of the isolation transformer center tapped and grounded which makes the AC outputs from the inverter swing +/- 120V from ground like you would expect in the USA. The other configuration doesn't have a center tapped transformer, but one leg of the input is grounded making one of the AC outputs swing +/- 240 V in referenced to ground and the other output is tied to ground. I suspect the 60Hz specification is due to the way transformers work. A transformer designed to operate at 50Hz using minimal materials will operate fine at 60Hz. However a transformer designed to operate at 60Hz using minimal materials will saturate magnetically at 50Hz causing it to overheat and eventually fail.
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In both configurations the inverter output is fed into an isolation transformer.
Which is going to be bigger and heavier than the inverter module. And have higher losses as well.
So what was the point of this contest?
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Just about any component after the transformer will work fine, frequency independent, minus things like oscillators, radio crystals, etc. resistors DGAF, caps DGAF as long as you match or are lower than its rated voltage, diodes are voltage drops and DGAF about frequency...
Do you even basic electronics?
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It seems contradictory that they're worried about power factor, and also want to force contestants to output nice clean sine waves. Best way to get a PF of 1
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So you'd rather lose power in wires instead?
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I know nothing about electricity
So you figured you'd post your suggestion on /. instead of attempting even the most cursory self-directed research. Gotcha. Laziness for the win.
Is it just that we're so used to designing electronics etc. to use AC, or are there other benefits?
Its easier to transmit long distances, at high voltages.
Its trivial to step up and down to different voltage levels via transformers. The equivalent in DC is not simple.
Mechanical AC generators are simpler and cheaper to build and maint
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But, seriously....thanks!
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AC isn't about transmission easy, it is all about transformers and mechanical systems.
I guess it would be more correct to say that AC is easier to transmit *because* of the relative simplicity of transformers at the end points.
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Can I use kittens in my design?
Yes, as long as they fit in the box (so you're likely limited to 1 kitten), and as long as they're not water cooled kittens.
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Also, Google gets to keep the boxes for over 100 hours, and you'll only be guaranteed to have power for 100 of those hours, and they make no guarantee of the storage conditions when it's not being tested, so if you want to have a living kitten at the end of it, you may need to do a lot of work.
College kids created Google, Microsoft, Facebook (Score:2)
A few friends who are electrical engineering majors certainly might achieve this. After all, it was a small group of college kids who created Google, Microsoft, and Facebook. On the other hand, 10 Google employees sitting in meetings to discuss the requirements document costs over $2,000 / hour once you factor in taxes and such. A million dollars is enough to motivate some ramen-eating college kids, and small enough that it's not much more than the cost of paperwork and approvals for many projects at larg
Re:Weird restrictions (Score:4, Insightful)
Quebec is a ridiculous backwater corrupt banana republic with a monstrous, bloated bureaucracy that not even Google can deal with.