Research on Finite Element Equivalent Models and Analysis of Motion Characteristics of Magnetic Screw for Wave Energy Conversion

As a linear rotary actuator with high force density and high energy conversion efficiency, magnetic screw (MS) is being studied for application in the field of wave energy conversion (WEC). In order to further study, optimize and improve the energy conversion performance of the MS, and because the permanent magnet (PM) of the MS is helical, it is necessary to conduct three-dimensional (3D) simulation modeling to study its internal magnetic field distribution and force. However, the calculation and solution of the 3D simulation model not only requires high hardware conditions of the computer, but also has so much grid points and takes a long time to calculate. Therefore, it is necessary to simplify the 3D model and establish a finite element equivalent model (EM). On the basis of fully studying the basic structure and working principle of the MS, the thrust equivalent model and the torque equivalent model of the MS are proposed, including 3D EM and 2D EM, respectively. In addition, the motion equations of MS are also established according to the EM study on the motion characteristics of MS. Finally, finite element simulation results are used to verify the effectiveness of EM and its significance for future work.