can we make that thing modular ? Like that you can add power as you go.
You'd basically have one 'controller' and one or more 'powerstages'.
It would make it a lot more reliable as well, each powerstage would operate independently of the others (apart from phase).
I've been thinking a bit about the 120/240 situation:
If you start out with a 120 V version you then have to stack multiple ones to get to 240, and your european variety would involve a good bit of redesign (or two inverters just to get started).
If on the other hand you simply ONLY make 240 V stages then there is no stacking requirement to get to 240 (just a center tap in the output transformer (assuming there is one) would be enough) and a European version would just require a frequency change.
Some more radical stuff:
You started off with a question about the microsine, and that is acutally quite a nice way to illustrate a drastic departure from the way things are done: Why not 'Bus' everything on the 240 side, charge controller, solar, wind and so on. Each of those - and the battery - would have an intertie component, the 240 connects it all and demand determines which way power flows (into the inverter or back out of it). The grid intertie facility then becomes the whole framework for the inverter.
Each unit can 'sample' the grid while it produces power to maintain phase lock and limit current. In exceptional situations (overcurrent, synch loss) that take longer than some pre-set maximum (to help start an inductive load for instance) the unit would go 'offline' until things normalise to avoid damage. That's pretty much how the microsine series operates.
All you'd need is for the devices to synch up in case of power loss, maybe some kind of signal superimposed on the powerlines could carry the synch information.
To avoid overload during restarts (all your freezers will come on at once, and if you have a leaky tap somewhere so will your pump !) there would have to be some synchronized attempt at putting the power back on. All this then gets fed into your regular housepanel as though it were one giant inverter, instead of a bunch of smaller ones chatting to each other.
These are pretty wild thoughts, I didn't spend any time on working out the implications but I think there may be some merit - and certainly some nice advantages - to doing it this way. It means that most of your switching will be done in the AC domain, which is a lot more friendly than DC, you have the ability to step up / down as needed and so on.
