TECHNOLOGY

The ChapDrive solution solves some of the key issues that are faced by the wind turbine industry when developing multi-megawatt wind turbines. These are related to unreliable mechanical gearboxes with unexpected break-downs, frequent failures of components in frequency converters and high cost and weight of directly driven generators with or without permanent magnets. An additional advantage of the ChapDrive hydraulic drive train is that it enables a synchronous generator with reactive power control, which replaces the commonly used induction generator.

The main benefits of the ChapDrive solution can be summarized as follows:

• Reduction of cost of energy by up to 20 %
• Simplified solution with fewer critical components
      - No mechanical gearbox
      - No frequency converters
      - No transformers
• Reliable high efficiency hydraulic drivetrain with high power density
• Synchronous generator without permanent magnets
• Significant reduction of top weight which is becoming increasingly important as turbine size increases

As can be seen in the technology section ChapDrive has the flexibility to apply the hydraulic transmission as a nacelle solution or a ground solution. ChapDrive has evaluated these two concepts since 2005.

The nacelle solution is the preferred solution for onshore and offshore fixed foundation with the lowest cost of energy.

For a future market with large floating wind turbines ChapDrive sees a potential for the ground solution. The ground solution is characterized by moving critical components down to the foundation, enabling additional reduction of the top weight and the cost of the floating structure. This also opens an opportunity to improve the access to critical components and thereby a potential to further reduce operation and maintenance cost and increase availability of the floating wind turbines.