As you and HF are doing with DC is the way to go for these goals.

Battery or not, it's rather simple, and DC motors are more forgiving on voltage fluctuations than single phase AC. If voltage drops too much with single phase AC, you run the risk of burning your motor up.

Like with solar, there is a lot to electric motors as well, quite a bit more.

Scooting around the web, I noticed Vertex is using a BLDC (Brushless DC) motor in their solar rig. Now, they have that one nailed down! As Scott mentioned, there is a bunch of engineering involved in the packaged systems.

A BLDC motor is actually made like an AC motor, and then there is a whole bunch of crazy stuff on how they are controlled. I have a couple of them up north in boxes, someplace, but they run off of AC, thru a controller.

The new kid on the block is a PMAC (Permanent Magnet AC) 3 phase motor, which is pretty much like a BLDC motor. Oh, they are sweet and becoming more available. Similar to an AC Servo motor without the extremely high price. Kinda confusing.

About a year and a half ago I had to spec out VFD's for a glass factory project. Choice was to go with ABB for this application. A bit less expensive than PowerFlex 753's and we were only running pumps, so didn't need to go super fancy.

While browsing around, downloading manuals and such, I saw this:


Kinda neat and downloaded the brochure, but got a YIKES feeling just based on the size of the array they showed. Never got into the specs.
ABB recently purchased PowerOne for like a Billion to add to their portfolio. They also bought Baldor Electric, which is a premium motor manufacturer.

Now we're getting into 3 phase motors from solar, which is more exciting!

Franklin Electric (well pumps) recently purchased Cerus, a VFD manufacturer. I've used their drives on a couple projects (boss said so), but they turned out to be really nice and very solid. Well, they have a solar rig out now, which is pretty decent.

Because I am more into control and communication with devices, I lean toward the more robust/reliable EtherNet/IP protocol. That's a whole other can of worms.

If you did notice on your solar control adventures, a few speak Modbus RTU and TCP/IP, which is also really solid.

Probably not where you want to go blowing bubbles in your pond, but there is a lot of neat stuff out there in the solar world.