Description
The wind energy conversion market is experiencing a turnaround from previous years, due to the change in the conversion topology used, being increasingly Full Converter (FC) topology at low voltage (LV) instead of the classical Doubly Fed topology (DFIG). The main objective of the project is to develop a power conversion system scalable and modular based on conversion units of 4 - 4,5 MW for FC grid connections. Many challenges must be overcome: - Reduce the total volume between 18 -28% and weight 5-10% - Achieve a robust and reliable design that enables to increase system availability minimizing downtime and optimizing maintenance - Get a lower harmonic distortion 3% - Achieve an overall system efficiency >97% - Optimum ratio "cost / MW" The involvement of the Norwegian University of Science and Technology is necessary as one of the fundamental aspect and technological challenge is the research, definition and design of optimal topologies for combining converters 4-4.5 MW low voltage.
Summary of project results
The wind energy conversion market is experiencing a turnaround from previous years. The turnaround is mainly due to the change in the conversion topology used, being increasingly Full Converter (FC) topology at low voltage (LV) instead of the classical Doubly Fed topology (DFIG). In offshore wind power applications, the FC topology has fewer limitations to face up the grid disturbances, while with a DFIG topology the turbine suffers rough torque transients and the mechanical train must be dimensioned assuming an increase in the cost. This causes the turbine manufacturers opt for FC solutions for high wind generation, and especially, in case of marine power locations. The main objective of the project has been to develop a power conversion system scalable and modular based on conversion units of 4 - 4,5 MW for FC grid connections, minimizing the necessary investment cost for offshore wind power in LV up to 9MW, ensuring the quality of the energy injected to the grid.
Summary of bilateral results
The activity developed by NTNU and INGETEAM is the optimal combination of the power converter in the range of 8-9 MW in LV and FC grid connections. The selection of the optimum configuration is far from being straightforward, as the volume and cost of each possible solution needs considering. To do this, the many possible modulation techniques that can be used and their influence on the filter design needs have been studied in great detail. All this bearing in mind the desired objective of reducing the overall cost of the final solution, either by reducing the number of semiconductors, by reducing the size and cost of the filters, or by optimizing the overall dc-link capacitance. The study around a new topology of conversion to renewable energy applications has been the subject of publications in international technical forums of Electrical Energy Conversion, which will have continuity in 2016 with the presentation of new publications.