The 25-year-old forward made 26 appearances for the German club last season, helping them finish second in the league. He will link up with his Wolves team mates after the international break.
"Hwang's a player we've watched for a few years now," Wolves technical director Scott Sellars said in a statement. "He's got a lot of talent and is very versatile - he can play across all the front positions, a striker, second striker or wide.
"He's got a good pedigree, having played Champions League football and at a World Cup. He's got a lot of pace, power and strength - he's probably a little bit different to what we've got, and we think he's a strong acquisition for the squad."
Hwang is Wolves sixth signing of the transfer window, following the arrivals of defenders Rayan Ait Nouri, Yerson Mosquera, Bendeguz Bolla, goalkeeper Jose Sa and winger Francisco Trincao, who joined on loan from Barcelona.