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

Efficiency

[fyngyrz]

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.

Re:Efficiency

[guruevi]

Don't they go hand-in-hand though? You can only dissipate so much (waste) energy in a particular cubic volume. Decreasing the amount of waste energy increases the amount you can pack together. It wouldn't be a challenge if you're just looking for miniaturization.

Re:Efficiency

[Stewie241]

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).

Re:Efficiency

[fyngyrz]

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.

Re:Efficiency

[JimSadler]

Wouldn't it be wonderful to do that energy conversion outside the home with a tiny box. Keep in mind that the more equipment inside a home the more power the home will consume. In hot weather a big box inside the home would add to the cooling energy load on the home. If installed outside the home a duct could, in cold weather, direct that excess heat from the converter to keep pipes warm or pumps from freezing up. Most people fail to realize that once power is sent down the power line to the home or industry that that power will be converted to heat again. Whether it is an air conditioner, a TV set, a computer or an electric motor or water heater all of that electricity is converted to heat. To really fight global warming we must control heat generation at both ends of the power line. One way is to reuse the heat emitted from every device to be used by other devices. For example, heat radiated by your hot water heater could be used to heat your home a bit. Heat generated from an air conditioner is already used to heat some hot water tanks. I wonder how many people have even considered this sort of thing.

Re:Efficiency

[torkus]

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.

Watts per cubic inch?

[Anonymous Coward]

Are guys fucking serious?!?

If you really want to use your old units, why not horse power per cubic inch?

Re:AC is by its very nature inefficient

[DeathToBill]

If you don't understand why this isn't going to happen, you need to be kept away from grid design.

Replacing the AC network with a DC network would mean either replacing or substantially modifying the entire fleet of existing generation plant, all distribution and conversion equipment, all industrial equipment powered by electricity and most appliances. You might well be right that you can achieve better efficiency in a new network with DC than with AC; when you have to replace the entire electricity system, from spinning turbine to phone charger, it just ain't gunna happen.

Cubic inches?

[HammerToe]

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

-Matt

Re:Who participated?

[suutar]

I think that's the point - to remove some of the challenges not everyone else has so they have the opportunities everyone else does.

Whether any given program actually achieves that is of course debatable.

How $1 million cost, for an inverter company?

[raymorris]

If you started with nothing and had to buy all of the tooling and equipment, recruit people, etc., I could see this easily costing $1 million, but the winner is an inverter company. They already have all of the tooling, equipment, expertise, etc.

They "just" needed to optimize one of their existing designs for size. Also, they only needed a working prototype, not a full production model. How do you figure that costs a million dollars?

Google suckered everyone

[ArchieBunker]

Sounds like Google had very specific design requirements and didn't want to spend the money in house doing development. So they dream up a contest and offer a cash prize. Meanwhile Google saves way more than the $1 million they paid out.