is an interesting paper about GaN FETs, some of you might already be familiar with it. They do have some notable difference from MOSFETs. They are more sensitive and not always as forgiving. They (those?) are not (cannot be?) avalanche-rated either and so not exceeding VDS is even more important.
We shouldn't let any charge control issues come in the way of the MPPT project
, there is time to find pathways.
Regarding specs and after looking into GaN FETs, I would be increasingly tempted to favour a design intended for say ~300W. There are lots of smaller installations that would have no use for a large unit and would incur unnecessary cost. Even just cost+complexity aspects could well warrant designing a more modest converter and installing two instead of one large one, splitting the solar
Of course, that also means 300W panel max, but realistically, on a boat...?
I can see that an interleaved buck converter of that capacity could be small and low cost compared to a large unit, it would look like two of the power stage of the small Genasun unit, off-the-shelf toroidal inductors hopefully and within the thermal capabilities of the GaN FETs without having to deal with significant heat removal
. GaN FETs are not as well set up for heatsinking compared to MOSFETs.