A critical evaluation of large scale DD wind turbine electrical machines manufacturing techniques considering sustainability aspects and recyclability issues (“CEDEMSARI”) 

Direct-drive electrical generators are large and low speed machines requiring robust and heavy supporting structures capable of withstanding a demanding set of loads. Several academic investigations have been conducted with the aim of optimizing these structures at an early design stage using different techniques. However, an outstanding knowledge gap remains in understanding the manufacturing process of large scale wind turbine electrical machines.  

Figure 1. Detailed view of the IEA 15MW Offshore Reference Wind Turbine electrical generator electromagnetic and structural design parameters (Courtesy of NREL)

In this project, the available manufacturing techniques will be characterized considering machine’s total cost, functionality and recyclability of materials. Taking as an example the IEA 15MW NREL direct-drive wind turbine and by looking at Scotland’s supply chain, its structure will be optimized under these parameters and compared with the actual structure. The optimization procedure will be monitored with a view to learn about its advantages and disadvantages. Typical structural materials, e.g. steel or cast iron, as well as other high-performance materials, such as fibre-reinforced polymer composites, will be also evaluated and taken into account so that benefits and limitations of its use can be fully understood. This will allow automating the task which in turn will help engineers to develop lightweight and cost-effective designs for future larger scale machines to be produced in mass.