The Influence of Different Slot Permanent Magnet Magnetization Directions on the Power Density Enhancement of Transverse Flux Linear Generator

In the past decades, various linear generators have been applied in direct drive wave energy converter (DDWEC). However, linear generators have the demerit of low power density in low-speed applications. The transverse flux linear generator (TFLG) can achieve higher power density due to the decoupling of electromagnetic loads and the use of laminated silicon steel sheets in primary to reduce iron loss. Also, the magnetic field-modulated machine is a suitable solution in low-speed large thrust application scenario. In this article, a TFLG used in DDWEC is proposed. In addition to the magnetic field modulation effect, another highlight of this topology is the use of permanent magnets (PMs) in the slots, which further enhances power density. The simulation results prove that the proposed TFLG reaches large power density and has relatively low thrust ripple. Tangential magnetization type can achieve higher power density than its radial counterpart, but it is difficult to fix the slot PM in tangential magnetization type. The power density per PM volume of the TFLG prototype is 975.1 kW/m3, and the thrust ripple is 2.62%.