The pattern almost looks like they might have appliqued some standard 1/2 square fan blocks onto a white center which is the background fabric to make the circular effect. Like fitting them in as they went. Some have the extensions (green print with some small dots/flowers on it) sewn on to make them into square blocks & some don't, they just have the background fabric. They probably left the outside edges of all the fan blocks oversized until all the center was joined together, then the outside edge was trimmed off evenly.
The only reason I am guessing this, is I have owned The Electric Quilt products for several years. At the Quilt Festival in Houston this year, 2013, I bought the "Pieced Drawing" by Patti Anderson book. Just yesterday, I was learning how to draw circle blocks. These are two parts of what would be a 4 part circle. Probably any fan/wheel pattern could be adapted to make this pretty pattern. The fans have to be a little offset to allow for the circular curves.
Let's see if others who have been doing this a lot longer than me have any better ideas.
I used YAHOO and searched for Round Fan Quilts. I got a lot of hits, but none exactly like you are looking for.
These websites offer free or for sale, fan patterns that could be adapted for your project.
http://www.ebay.com/itm/QUILT-PATTER...item3f2bf4a204
http://www.ebay.com/itm/Grand-Fans-Q...item3a8757f9bc
http://www.quiltviews.com/free-grand...basement-quilt
http://tlc.howstuffworks.com/home/tr...uilt-block.htm
http://fabricsandflowers.blogspot.co...rn-part-1.html