For solos, it looks like around 40 times on the show through the first four seasons:
Around another half a dozen times in Season 5
(I didn't count real carefully, and sometimes it gets a little complex; but those numbers are close for the show).
You can search through this page and this page for more wins outside the show; although I'm sure it won't contain everything that Maddie has won (esp. like from when she was tiny, well before Dance Moms started.)