A Novel Consequent-Pole Magnetic Lead Screw and its 3-D Analytical Model With Experimental Verification for Wave Energy Conversion

The magnetic lead screw (MLS) applied to the point-absorbing wave energy converter (WEC) can convert the low-speed linear motion of the buoy into a high-speed rotational motion that can drive a rotating motor to generate electrical power. Aiming at the high permanent magnet (PM) consumption of the traditional MLS, a novel type of consequent-pole MLS is proposed in this paper, a consequent-pole type is adopted on the translator to save the PM consumption. At the same time, the traditional bipolar type is adopted on the rotor to increase the maximum thrust force. To analysis the performance of the proposed MLS, a three-dimensional (3-D) analytical method (AM) model is proposed. Two different materials that are non-ferromagnetic and ferromagnetic, for teeth between the helical PMs on the translator can be considered in the proposed model. To verify the model, a prototype of the proposed MLS and its test platform is developed. To ensure that the manufactured prototype is closer to the design one, a new helical PM installation method through the bolts is introduced in this paper. And a corresponding improved thrust force and torque equations are proposed for the prototypes which the installation method used. Finally, the comparative results of 3-D AM, 3-D finite element method (FEM) model and experiment are given.