The Canadian put up 18 aces to beat Berdych in the final at the Impact Arena in 1 hour, 17 minutes.
It was Raonic's fifth tour victory, adding to the three in San Jose from 2011-13 and Chennai in 2012. He also improved his unbeaten record over Berdych to 2-0 after also beating the Czech player in the Cincinnati Masters last year.
Berdych had his chances in the match with a set point at 6-5 in the first but Raonic used his big serve to force a weak return before sending a forehand winner to escape. He then relied on powerful serves to force the tie-break, which he sealed with another booming serve.
Raonic managed an early break in the second game to take a 2-0 lead in the second after Berdych netted two successive shots. At 5-3, Raonic produced another ace to set up a championship point before blasting a forehand winner to take the match.