Voith Turbo Wind: Because of the growing shortage of fossil fuels and the ongoing CO2 discussion, wind energy is growing in importance.

The situation
Because of the growing shortage of fossil fuels and the ongoing CO2 discussion, wind energy is growing in importance. The technological challenge when it comes to generating power in the multimegawatt classes is to find reliable, efficient wind turbines that satisfy all requirements regarding power fed into the grid in compliance with power plant standards. Current concepts employ frequency converter technology, usually coupled with mechanical gear drives, and cannot satisfy all aspects of these requirements.

The innovation
As a highly dynamic mechatronic system, WinDrive is an innovation that makes it possible, for the first time, to employ in wind turbines the technologies that have proven themselves over time in power plants. As a result, wind farms can generate electricity that matches the quality from conventional power plants. Using the innovative WinDrive unit, frequency converter technologies with their MTBF (mean time between failures) of less than two years, are no longer needed. Component-specific downtime is reduced considerably. In this regard, the power electronics unit is responsible for approx. 50% of all failures. The result: greater availability of wind turbines as well as a reduction of operating and maintenance costs in the high 2-figure range. Moreover, the increase in size of the WinDrive is less than proportional to output power, so that for multi-megawatt systems there are considerable weight savings in the nacelles and thus the sizes of the associated towers and foundations. The highly dynamic mechatronic WinDrive system is protected by patents worldwide: PCT WO 2004/088132.

The uniqueness

A growing market for renewable energy sources
Increasing prices for raw materials and a major shift towards renewable energy sources will result in a greater demand for this type of technology in the coming 20 years. The uniqueness of the innovative WinDrive concept and the associated benefits clearly distinguish it from all of its competitors.

Above-average benefits for the target group
The WinDive is the first and only technology that employs the time-proven system components used in conventional fossil fuel power plants and thus represents a significant contribution to the primary challenge associated with future developments the stability of the power grid.

Advantages over alternatives in the target market
Continued development of a highly dynamic mechatronic system that does not require use of frequency converter technology in wind turbines. This translates into a considerable reduction in the amount of downtime and, therefore, increased reliability.

Supports a local content strategy for wind turbines
Based on use of the WinDrive, the local content strategy for wind turbines can be expanded. While this strategy encompasses only towers and foundations, generators and other hardware for integrating wind farms into the grid can be incorporated in the future.

Worldwide shipping and handling logistics are no problem
The highly dynamic mechatronic system is a single component with a size of approximately 2 m long x 1.5 m in diameter. It features simple, easily understood interfaces to the drivetrain and to the generator. Shipping and transportation pose no major challenges and installation can be carried out by local personnel.

Patented and a single-source product
Voith Turbo Wind GmbH & Co. KG has the unique know-how that resulted in this single-source, innovative, and highly dynamic mechatronic system. A basic patent and four subpatent applications have been filed worldwide. All patents have been granted.

The benefits

High quality power fed into the grid
By using time-tested synchronous generators, various requirements such as reactive power (VAr) compensation or grid stabilization in the event of a short circuit can be met without difficulty.

Outstanding reliability
By eliminating the frequency converter and step-up transformers, the complexity of the wind turbines is reduced significantly. As a result, the probability of failure and downtime decreases, and the reliability increases by more than 30%.

Exceptional efficiency
Because the WinDrive is designed for variable-speed operation, the wind rotor can be operated at different speeds (i.e. the aerodynamic optimum for the rotor and even at different wind speeds). Synchronous generators permit operation at the medium voltage level without the need for additional components. As a result, the overall efficiency of a wind farm improves by more than 1%.

Reduced maintenance requirement
By eliminating the need for frequency converter technology and incorporating synchronous generators without slip rings, the complexity of the wind turbines and variety of parts involved on the electrical side is reduced to one-quarter of its previous level.The WinDrive has response times in the millisecond range, which means a considerably lower load in the drivetrain under dynamic load conditions. The result of this lower load is a longer service life for the electricityconducting assemblies.

Moderate initial investment
By incorporating the WinDrive technology, the maximum operating loads in the drivetrain are reduced. In large systems, this translates into material savings of up to 20% for the tower and foundation (steel and cement). Per wind turbine, this means hundreds of tons in weight that can be saved.

Wide field of application
The WinDrive technology can be installed and operated at a variety of locations. Wind turbines have already demonstrated that their components are suitable for both on- and off-shore operation. Operation on an island is also possible. Use at various altitudes (including up to more than 4,000 meters above sea level) and connection to weak energy grids pose no problems for the WinDrive. In addition, the WinDrive can be employed to increase efficiency in hydroelectric power sta-tions where water-powered turbines operate at variable speeds. A pilot project will be completed in Germany in 2008.