How thick is the concrete? What wind load?
I used to have a concrete roof on a structure that sloped from 9" to 6"- definitely thick enough to hold anchors for posts that carry solar panels, even under the high wind loads here. (Mountain top ocean facing = windy)
I have another platform, fairly large (4000sqft) but the concrete is only 1 to 2" thick.. I see no way to put panels there.
A 3rd location.. 6" slab (6" to 8" sloped) holds a rack presently. I have 1/4" thick flat metal pieces 8" x 12" bolted in the concrete and then 4" wide flange beams as posts welded on the flat metal.
For the bolting, I used 5/8" threaded rods with 2 component epoxy to glue them in a 3/4" hole. Make sure to blow out all dust after drilling the hole before setting the threaded rods.
Storms have been no problem, I am more thinking of earthquakes.