Carport Roof - Ridge Beam/Board vs Gussets
Gussets wouldn't replace a ridge beam (which is different from a ridge board). You'd need a truss design with collar or rafter ties. 

If you don't have a ridge beam (which actually carries the load from the upper half of the rafters), you need rafter ties, which run across from wall to wall. Gussets don't provide the sort of bracing that rafter ties would.