40kw true sine wave inverter (single phase) for solar power

[MPaulHolmes]

My wife and I are moving to Arizona, and evidently it gets hot down there. And it's sunny! And solar panels have dropped to around $1.10/watt! A high powered true sine wave inverter is pretty expensive. It just so happens that I had a (still in development) DIY 3 phase AC controller laying around, so I figured that I should see if I could get a clean single phase AC signal out of it. Well, after changing a few lines of code, and adding an inductor/capacitor filter, it worked! I have an inductor that will do 200amp continuous, with a resistance of only 0.001 Ohms. Now I just need a bank of high ripple current caps. I only need around 4 or 5uF of capacitance, so it should be pretty cheap. Here's the first test!

http://www.youtube.com/watch?v=-v1sESqwuok

[dremd]

This is awesome!
Power your house with your car on grid power outage.
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I'm sure this is listed elsewhere, but what's the approximate cost of your controller.

[MPaulHolmes]

Hey! And you could probably use one or 2 of the phases of the motor as the inductor! Then all you'd need to do is include a filter cap in the circuit, which could be done just by adding a relay. Bam! Instant power to the house. I don't have a clue what a 40kW pure sine wave inverter would cost.

The parts for the controller are around $400-$450, but in bulk it could be cheaper. The igbts and capacitors in bulk would be a HUGE cost savings.

[MPaulHolmes]

I had some 4" x 6" one sided copper pcb (5 ounce!), so I'm using that, and 8 of these:
AC Filter Caps. 8 of these buggers!

8 of them are rated for 80 amps RMS, which is good enough for my purposes.



Now I just need a basic charge controller. Basically, I think I can just set a homemade buck charger to 100% duty until the battery bank reaches some max level, and then I start to reduce the duty to keep the voltage constant, until it gets dark. At that point, you live on the battery power, and in the morning, you do it all over again! haha.

The nice thing about the film caps is, they are rated for 60,000 hours at very high temperatures, so it's probably more like double that since they won't get too hot. I won't be close to their rated RMS amps.