A prototype of the turbine has been operating off Jeju Island to the south of the Korean peninsula since March.
DEWI has carried out tests since then to analyse the turbine's design, construction and safety before awarding the certificate.
Aerodyn designed the turbine from within its established Aeromaster range. It is geared and has a high-speed drivetrain with a medium-voltage generator. The 68-metre blades make for a rotor diameter of 139 metres. The nacelle sits on a 100-metre tower.
Hyosung already offers 750kW and 2MW models and has been involved in the wind industry through component manufacture since the mid-1990s.
Aerodyn said that an unnamed Chinese manufacturer will also install its own version of the German-designed 5MW turbine before the end of 2014.