Structural designs and forces in direct drive linear generators for marine wave power generation

In recent years a growing demand for renewable energy has emerged. In this paper the most common structural designs for direct drive linear generators are reviewed. Moreover, in the paper an investigation of magnetic core structural design and number of phases in the machine is carried out. Furthermore, in the paper explanation and ways of calculation of the cogging forces occurring in direct drive linear machines are presented. In addition, a review on the most common cogging forces reduction techniques is presented.