In my mind- not to dirt/earth.
But definitely needs to be grounded to itself and- depending on the AIO- N-G bond established in the main circuit breaker panel.
Different jurisdictions may apply interpretations of NEC rules and require a ground rod. And there are reasons why this could be ‘beneficial’ including “lightning” although some jurisdictions do not require a ground rod for an off-grid system. Some jurisdictions may also require permits and inspections, others do not.
Where is the solar array located? The frames should be dirt/earth grounded independently anyway.
If there is no other path to the “source of power” with what is essentially a mobile vehicle then having a reference to earth/dirt doesn’t have a benefit. What is important is that the AC power system has a “ground” to itself for safety and fault protection. Equally important in my mind is that each circuit has GFCI protection.
Folks like
@timselectric and others who are EE’s or master electricians will likely have input as to the NEC and practical considerations where my opinion has holes. I am neither EE nor electrician.