German new-look drive-train project

German researchers have kicked off a €1.55m ($2.1m) project to design a new lightweight direct-drive wind turbine based around an integrated hub generator.

The 3MW concept, being hatched by a team from Fraunhofer IWES and Saarland Technical College, will use a modular drive-train architecture in which the rotor blades are connected directly to a permanent magnet generator rather than to the nacelle hub.

The design is calculated to create a featherlight construction with standardised parts that will streamline the "very complex and cost-intensive" logistics of transport and installation of heavy turbine components, especially on hostile offshore environments.

"Future wind turbines are to be more efficient, more cost-effective and less maintenance intensive," says Fraunhofer project leader Patrick Tober. "As gearless or direct drive [concepts] are equipped with fewer components and are therefore less susceptible to damage, this is regarded as the future for wind turbine technology."

"Material and cost savings are to be achieved through a modular and compact construction as also increased turbine robustness and less damage susceptibility."

The project will also explore further cost reduction and performance enhancement through the use of fully enclosed or open generator design, minimal component numbers and alternative cooling systems.

"On top of all this, research is being done into how reductions in the mass of the tower head and an integrated lightweight design can be achieved," adds Tober.

The hub generator concept is being designed for up-scaling to ultra-large class turbine designs.

The project is funded through to the end of 2015.