Comparative Analysis of Tubular Permanent Magnet Linear Generator With Equidirectional Toroidal Windings and Conventional Toroidal Windings

Tubular permanent magnet linear generators (TPMLGs) are widely used in direct drive wave energy conversion system due to their simple structure, friendly maintenance, and high efficiency. Unfortunately, the power density of this type of generator is relatively small due to their low operation speed. To improve the power density, a TPMLG with equidirectional toroidal windings (ED-TWs; ED-TPMLG) is proposed in this article. First, the structure of the ED-TPMLG is introduced, and its windings configuration and windings coefficient are analyzed and compared with those of TPMLG with conventional toroidal windings (C-TPMLG). Furthermore, to investigate the performances and the unique advantages of the ED-TPMLG, comparative analysis of the ED-TPMLG and C-TPMLG is conducted based on the similar dimensions. The results indicate that the proposed ED-TPMLG has superiority in detent force and power density than the C-TPMLG. Then, the unstable ac electricity generated by the generators is rectified, which can be transformed to the stable dc electricity for supplying the equipment. Finally, a planar linear generator prototype with the same ED-TWs is manufactured to validate the reasonable of the proposed winding configuration (ED-TWs) and the credible of the above finite element analysis method.