To use a 50 amp service with your 30 amp plug, you will not need a converter, but you will need a 30 to 50 amp adapter. Some CG's have both 50 amp and 30 amp outlets on the power pedestal, but it is still a good idea to have the adapter. You will also need a 15 to 30 amp adapter to use the 15 amp service. Be aware, the 15 amp service will most likely not power more than 1 or 2 of your ac devices at once, and may not power your air conditioner at all depending on the size of your air conditioner. Both adapters can be found at a decent RV store and Walmart carries some of the adapters.
__________________
TV, 2000 Dodge RAM 2500 Quad cab short bed, Cummins 5.9, Edge Comp, Gauges.
5ver, 2011 Palamino Sabre 31 RETS.