Current in-house developments
XEMC Darwind’s basic design principle is a variable speed, direct drive wind turbine, using a High Voltage Permanent Magnet generator and a four-quadrant power converter.
The advantages of our implemented innovations are quite well known:
- Variable speed: improved efficiency in the partial load range due to optimal aerodynamic matching of wind speed and rotor speed;
- Permanent magnet: no energy losses for excitation of the generator, no slip ring required for excitation;
- High voltage generator: lower cable losses and extended cable twist range;
- Four quadrant power converter: good conformity to grid codes due to grid support with reactive power and excellent Low Voltage Ride Through behaviour.
XEMC Darwind is currently working on the following innovations:
- Design of new types of segmented multi-MW generators using concentrated windings. This type of generator is easily transportable and can be easy assembled on-site.
- Island operation mode (patent). By making the operation of turbines independent from the availability of a grid, enormous amounts of diesel fuel needed for auxiliary power of an (off)shore wind farm can be saved when there are problems with the export cable. In case of a grid loss, a single turbine can provide power to the rest of the array to load the UPS systems of the other turbines. A single turbine can also be able to generate power to keep its own UPS systems up.
- Individual pitch control IPC. By pitching blades individually rather than collectively, mechanical loads on the structure are reduced, enabling larger rotor diameters, longer lifetime or lighter constructions.
- LiDAR based feed forward control. Investigation of benefits of using LiDAR based feed forward control algorithms for load reduction, power optimization and yaw alignment.
- Hybrid Towers. Concrete in combination with tubular steel segments for hub heights up to 140 meter.
In several of these projects we cooperate with universities, research institutes and industrial suppliers.