of Italy, Brazil, Quebec, Cuba, Iran, Syria, North Korea, or Sudan? (
3) not a person or entity under U.S. export controls or sanctions?..."And not to far from Google in mountain view and EPRI in palo alto. Must be an educational institution to get 30K development grant. So, probably Ber keley or Stanford.
Aside from the obvious US targets, probably stupid laws that pols would claim protect their benighted populations, like this one:
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
That's just unbelievable, it looks like someone's surplus stock from the 70s-
and "radar-range" ??? please give me a break.
The "radiation theme":
For those interested in novel ideas how to electricity to a house, search for "Possibilities of the Low Voltage DC-Distribution Systems" . It compares traditional 230/300 V 50 Hz, 1 kV 50 Hz and 1.5 kVdc for rural areas.
The 1 kVac system has been used for several years by some companies in the lake district of Finland, A 1 kV to 0.4 kV transformer is close to a group of few houses.
The 1.5 kV DC distributi>>
The current output for the 12 or 24 V sockets should be limited to say about 10 A, which would be more than enough for driving most small appliances. A laptop power supply would use 3 A from 24 V. Assuming 1 A drawn from 24 V for driving LEDs at 100 lm/W would produce 2400 lm, the equivalence of six 40 W incandescent lamp, enough to illuminate a whole room.
Since a higher voltage (AC or DC) network needs to be built anyway, why not generate the 12 or 24 V in each room independently and feed it to 12/24 V sockets or even integrate the converter into each mains socket. In the latter case, it would even make sense to have a +5 V output (USB).
IMHO the current problem is the huge number of wall warts.If a worldwide voltage and connector standard could be created, it would greatly help interoperability.
It is quite understandable that all small device manufacturers prefer wall warts, since you only need to certify the wall wart for national standards and mains connectors, instead of having to certify in each country the whole device (e.g. tablet) for each country separately.
You may not like it, but the normal DC input voltage to PV inverters is
350 to 500V DC from panels in series. :) The gear is designed to handle that. Of course, in the UK you'll be lucky to see 350V (present spell of weather excepted of course!).
nt of Italy, Brazil, Quebec, Cuba, Iran, Syria, North Korea, or Sudan? (3) not a person or entity under U.S. export controls or sanctions?.. ."
be an educational institution to get 30K development grant. So, probably B erkeley or Stanford.
That seems like a lot for a 40 in^3 prototype. How pricey are those wide ba ndgap FETS anyway?
Here's the sanctions stuff, some mainstream corp.s are included:
It's Amana ca. 1980- still works great, though not as even-heating as a modern microwave and it has kind of a soft start-up (high power, but you have to add a few seconds compared to modern microwaves of the same power).
LOL. I've tested the door with a leak detector and it's still okay, actually a bit better than a modern one.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Well, in that list of fancy logos:
EPC doesn't make any high enough in voltage, so scratch them off the list.
One actually has datasheets, but no product ("register to learn more!").
Another takes the "we provide, to you, the remarkable opportunity to register, just to maybe view some speculative datasheets!" angle. Yeah, how much you want to bet they don't have squat.
The rest are 'conventional' SiC from known manufacturers (Cree, NXP, etc.), who are shipping real product available at Digikey.
Problem: I searched for MOSFETs in the 600V (or somewhat higher) range, sub 50 miliohms Rds(on) (required to even begin to achieve the necessary conduction losses). SiC dropped out of the list. They don't even make any that beefy. Just plain old boring silicon Super Junction types (so to speak).
So I could go back and find a lower current SiC device and use two in parallel. And waste all the space I hoped to save. Yeah right. It's not like they're available in any fancier packages, TO-247 is TO-247.
If they had said it was 800VDC input, SiC would have better competition. But then, GaN wouldn't even be on the table, not that any products exist anyway.
Now, I am thinking SiC schottky diodes will be important. Ain't no silicon MOSFET that has anywhere near a realistic body diode in that product range.
Tim
-- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com wrote in message news:9d1c0010-5e95-4232-bfef-43bb05013119@googlegroups.com... On Saturday, July 26, 2014 12:30:27 PM UTC-4, edward....@gmail.com wrote: > > > https://www.littleboxchallenge.com/ > > > > > "To be eligible to enter the Contest, you must be: ... (2) not a > > resident of Italy, Brazil, Quebec, Cuba, Iran, Syria, North Korea, or > > Sudan? (3) not a person or entity under U.S. export controls or > > sanctions?..." > > > > And not to far from Google in mountain view and EPRI in palo alto. Must > be an educational institution to get 30K development grant. So, > probably Berkeley or Stanford. That seems like a lot for a 40 in^3 prototype. How pricey are those wide bandgap FETS anyway?
Huh? This is a contest, not an ITAR munitions deal. All that Google and others want is to not have to deal with nosy governments that want to pull the strings on any contest money that lands inside their borders. Unless contest winnings are now classified as munitions, I don't see the connection with ITAR.
Also, note that the ITAR proscribed countries list is much larger than the one used by Google and other contest sponsors:
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
You should be able to mount several of those devices on each of the four walls of the box, one wall for each switch in the full bridge configuration.
I wish there were a SiC FET that was affordable. This Cree C2M0025120D which is 1200 V 25 mOhms and TO-247 cost at least $75 to $100 in onsie's and (Digikey) $32 for 500 or them. And when 4 of them are needed without paralleling for a product, just ain't gonna happen for a consumer product.
Just not quite there yet I guess.
boB
I looked at some HVDC VSC (Voltage Source Converter) topologies.
Some use ordinary PWM with a lot of high power post filtering (such as ABB HVDC Light), while other use multilevel conversion, with nearly perfect sine wave and not much need for filtering (but with a capacitor in each switching module), such as Siemens HVDC Plus or Ahlstom).
Of course, an equal step multilevel converter would be practically useless at such low DC-link voltages as 450 Vdc.
Some unequal weight (such as 4-2-1) might produce quite good sine wave with a few switches.
Or use slow big dumb switches to inject +/-50 % output voltage at fundamental frequency (low switching losses), thus looking like "modified sine wave" and then use PWM to fix the waveform. Most of the filtering could be done at the switcher lower power levels and higher impedance levels, thus, reducing LC filter component sizes. The above sounds like feed forward in QUAD 405 current dumping amplifier :-)
Check the ripple specs too. In addition to the semiconductors being $$$, some pricey capacitors will be needed too. A brute force approach of big caps across the input won't work within the space requirements. A smaller bank of capacitors will need to be driven with high ripple voltages behind a secondary power supply.
It depends. If you qualify (as in University staff, or something), there is upto $30,000 development grant to make proof of concept prototype and $1,000,000 to make it real. Namely, you need to sub-contract or build your own device.
Old joke--Aggie goes to Harvard, asks a passing student:
Aggie: "Howdy pardnah, could you kindly tell me where the library's at?"
Student (aghast): "Ahhh I beg your paaadon suh. Here at Haaaavid, we don't end ouwah sentences with prepositions."
Aggie: "Yes of course, excuse me. Let me rephrase my question--could you kindly tell me where the library's at, asshole? "
Cheers, James Arthur
----------------------------^^^ Minutes.
Cheers, James Arthur
Oops and thanks. 9.3 minutes operating time is far to small to make this thing practical. If my calcs are correct, this inverter is not going to work at 95% efficiency to the required 100 hrs.
Gone sulking...
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
over
Oh my. VFD to 20 megawatt seems to be available.
Yikes! MV VFD to 160 megawatt can be ordered. Missed pretty badly here.
Schneider
and
instantaneous
instantaneous
1.0 powersine
the
inverter
You
No! It is not. It is a nasty rectifier with a bare capacitor filter. Nearly worst case for harmonic generation.
Well most of agree to that.
?-)
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