Modular and Stackable Power Generators for Efficient Renewable Power Generation

Stackable power generators enable very compact electric machines with high power density. How to identify an effective way of stacking is necessary and requires new knowledge for future guidance. In this paper, both possibilities of stacking modules concentrically and axially are explored and compared. An axial flux generator based on our existing double claw pole design is used as a case study. The claw pole generator, which is modular and stackable, significantly benefits on-site installation due to its flexible small modules that can be easily transported. This is particularly important to the installation of offshore wind turbines. Superconducting field windings are applied instead of copper in such power generators, which greatly increases their power density. In order to further increase their power density and reduce mass, we improved the modularity of 5 MW generators and stacked them in both ways. Results show that the power density versus mass as well as volume can be improved through stacking the modules both concentrically and axially, while the former approach is much more effective. Stacking two modules of 5 MW concentrically results in a 12.1 MW power generator with a more compact structure and higher power density than the original 10 MW generator.