So I found out that there is a way to get power armor to respawn. I was sniping a location and one raider wnt and grabbed the T51 armor off a nearby flatbed. I was upset because I wanted the frame. So when the area respawned the raider was still walking around in the power armor with all new T51 pieces to loot one I killed him.

I don't know why the PA ever respawns I already have 20 from different locations and did not even have to buy a frame.