3 ms·

I think the power density they quote (50 W/in^3) isn't for dissipation, it's inverted power. I'm not an expert in electrical engineering, but I can't think of a

by ISL 12y ago

I think the power density they quote (50 W/in^3) isn't for dissipation, it's inverted power. I'm not an expert in electrical engineering, but I can't think of a fundamental physics limitation that's a blocker here. If there is one, I'd guess that it'll involve the electromagnetic radiated power of the device. From the specification document [1], they're asking for 95+% efficiency. [1] https://www.littleboxchallenge.com/pdf/LBC-InverterRequirements.pdf https://www.littleboxchallenge.com/pdf/LBC-InverterRequireme... Edit - computed the radiation resistance; not a blocker at 60 Hz. Does anyone know a thermodynamic limit?

ChuckMcM 12y ago
Thanks for the link, you're correct they want to pull 2KVa out of a box no bigger than 40 cubic inches. These guys (http://www.apparent.com/products/ http://www.apparent.com/products/) have what I consider a very workable technology, basically 2W/cubic inch but one inverter per panel. Since you have to have panels anyway, having the panel produce power directly in the form you want eliminates the need for size as the panel is compelled to be a certain size anyway. But instead of changing the question (and age old trick of engineers to arrive at a feasible solution :-) The push here seems to be about efficiency. 95% efficient would be a huge improvement.
- keenerd 12y ago
  Whatever they go with, the tech is going to make a really killer subwoofer amp. Looking at the requirements (mostly the high DC input) it seems that an IGBT class-D would be the logical starting point, but those are hampered by a 150kHz-ish max switching rate. I think Don Lancaster's Magic Sinewaves (http://www.tinaja.com/magsn01.shtml http://www.tinaja.com/magsn01.shtml) meet the distortion requirements while offering the slowest switching requirements. Would be fun to be on one of the teams for this.
marcosdumay 12y ago
The bottleneck is in materials. We don't know how to recude the size of inductors or capacitors at will. That said, at 50W/in^3 heat dissipation may also become an issue.

by ISL 12y ago

ChuckMcM 12y ago

Thanks for the link, you're correct they want to pull 2KVa out of a box no bigger than 40 cubic inches. These guys (http://www.apparent.com/products/ http://www.apparent.com/products/) have what I consider a very workable technology, basically 2W/cubic inch but one inverter per panel. Since you have to have panels anyway, having the panel produce power directly in the form you want eliminates the need for size as the panel is compelled to be a certain size anyway. But instead of changing the question (and age old trick of engineers to arrive at a feasible solution :-) The push here seems to be about efficiency. 95% efficient would be a huge improvement.

keenerd 12y ago
Whatever they go with, the tech is going to make a really killer subwoofer amp. Looking at the requirements (mostly the high DC input) it seems that an IGBT class-D would be the logical starting point, but those are hampered by a 150kHz-ish max switching rate. I think Don Lancaster's Magic Sinewaves (http://www.tinaja.com/magsn01.shtml http://www.tinaja.com/magsn01.shtml) meet the distortion requirements while offering the slowest switching requirements. Would be fun to be on one of the teams for this.

marcosdumay 12y ago

The bottleneck is in materials. We don't know how to recude the size of inductors or capacitors at will. That said, at 50W/in^3 heat dissipation may also become an issue.