There are abundant of wave energy converter technologies available to convert wave energy into useable energy. However, most of them are huge and suitable for large application. Thus, this paper aimed to propose portable pico generator designs for small scale application. Investigation on the performance of designs with varying halbach magnet shapes was mainly focused and discussed. Two designs of different magnet shape i.e. triangular and trapezoid were proposed. Open-circuit simulation and optimization results were obtained using Finite Element Method. From the results, it was found out that Trapezoid Magnet Design produced better performance and lower material cost compared to another proposed design, Triangular Magnet as well as conventional Rectangular Magnet shape.

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Abstract-This paper presents the study on direct drive linear generator designs with aluminium spacer and alternate slot winding for wave energy conversion system. The study involved the development of permanent magnet linear generator designs with the variation on aluminium spacer utilization as part of the magnet assembly and alternate slot winding usage instead of conventional winding arrangement. The proposed designs were simulated using Finite Element Method (FEM) software to attain the results on flux distribution, air-gap flux density, and open circuit results. The total weight and material cost of each design were also estimated. These results are significant in finding the acceptable design's alternatives to counter the need of huge and heavy linear generator in wave energy converter system. Comparative studies on simulation results and calculated data were conducted between the alternative and conventional design. It is found out that alternate slot winding design improves the performance of conventional design with no impact on design's weight and material cost while aluminium spacer design yields more significant negative results on the performance than the positive effects in term of design's weight and material cost.

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Linear generator utilization in a wave energy converter (WEC) is an attractive alternative to a rotary generator. This paper presents the design of a permanent magnet linear machine (PMLM) for WEC applications in low wave power areas. In this paper, the wave height and vertical speed of Malaysian water is used for the simulation and design. Two design variants are introduced which are tubular PMLM with no spacer (TPMLM-NS) and tubular PMLM with spacer (TPMLM-S). Finite element analysis (FEA) has been conducted to investigate the performance and to refine the main dimensions of the design in terms of split ratio, pitch ratio and tooth width. The FEA results are then validated using an analytical method which is established according to the design’s magnetic field distribution. Based on main dimension refinement, it can be deduced that both the split ratio and the pitch ratio have a significant influence on the airgap flux density and back EMF of the design. The obtained FEA results also reveal that the TPMLM-NS variant is capable of producing 240 V back EMF, 1 kW output power with satisfactory efficiency. Consequently, this indicates the capability of the design to convert wave energy with good performance. Additionally, good agreement between the analytical predictions and FEA results was obtained with a low percentage of error, thus providing concrete assurance of the accuracy of the design.