Generator / PM technology: High yields and multi-megawatt innovations

VENSYS wind turbines don't need expensive gearboxes that are highly susceptible to wear, and are based on the generator concept of a synchronous machine with permanent magnet excitation. The rotating speed of the rotor is transferred directly to the multipolar generator – without any intermediate gearboxes.

The permanent magnets are mounted to the outer shell of the rotor and are cooled by the outside air. When compared to DC excitation, the saved excitation power is fully available as an additional energy yield. This is especially advantageous when working at partial load and helps to reduce the heat in the generator. Slip rings are also no longer needed to transfer the excitation power, meaning another wear part is saved.

On the VENSYS 1.5 MW platform, the generator is cooled by the outside air. In doing this, the winding is only exposed to minimal amounts of outside air. The VENSYS frequency converter is also air-cooled. The variable-speed generator operation with downstream frequency converter significantly reduces stresses, and makes the VENSYS wind turbine resistant to torque peaks and wind gusts.

In the VENSYS 2.5 MW platform, the cooling system is a closed circuit which dissipates heat into the surrounding environment through a heat exchanger. The full enclosure protects the winding and the interior of the generator from external influences, such as salty and humid air. At the same time, no coolants or oils are needed. This is because the cooling system has one primary goal – to work correctly (whilst being simple in design and robust).

The fully enclosed, permanent magnet excited high-performance generator means that the technology implemented successfully on gearless turbines on land can be used offshore for the first time – with the VENSYS 2.5 MW platform. Thanks to its compact design, the tower head mass of 132 t is remarkably low for a multi-megawatt turbine.