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

[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

[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.

Cubic inches?

[HammerToe]

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

-Matt