A direct drive generator is one which attaches directly to the shaft of the driving machinery without going through a gearbox. With wind generators this means a very slow turning generator, hense the large number of poles specified. However, the 80 poles specified (assuming 50Hz operation) would mean a synchronous speed of 75rpm which differs significantly from the 9-19prm range also specified so there needs to be some clarification there.
Once you have established the generator you intend to use you then need to design the speed/excitation control equipment which will ensure that the output connection to the grid will always be at grid frequency as the rotational speed of the generator will vary as the wind strength varies.
Smithy