Designing a Halbach Rotor Magnetic Gear for a Marine Hydrokinetic Generator
Hossein Baninajar, Sina Modaresahmadi, Ho Yin Wong, Jonathan Z. Bird, Wesley Williams, Bertrand Dechant
Abstract
This article presents the electromagnetic and mechanical design as well as experimental testing results for a 9.5:1 gear ratio, series connected, coaxial magnetic gear (MG) for use in a marine hydrokinetic generator. A two- and three-dimensional magnetostatic finite-element analysis (FEA) sizing analysis was also conducted and a torque density comparison between using a nested or series MG typology is presented. To achieve a high torque density, a four-segment per pole-pair Halbach rotor assembly with a unique slotted Halbach magnet arrangement was used that enables the Halbach rotor magnets to be more easily assembled, even with dimensional tolerance inaccuracies. A deflection and thermal FEA analysis along with experimental validation test results are presented. The experimentally measured torque and torque density for the MG design are 188.4 N·m and 236.5 N·m/L, respectively.