ABB supplies generators for all main wind turbine concepts with outputs ranging from 55 kW to 5 MW and more.
Generator concepts can be divided into three categories:

Fixed speed generators
The traditional stall concept with the generator coupled to the grid.

Doubly fed, semi-variable speed generators
Mainstream pitch concept with the rotor connected to the grid using a small converter.

Full variable speed generator
The full power converter between the generator and the grid enables the full speed range.