Design of a double-sided tubular permanent-magnet linear synchronous generator for wave-energy conversion
Purpose - The purpose of this paper is to present a double-sided tubular linear machine layout direct-drive applications, with particular focus on wave-energy conversion. The paper documents both the computational and mathematical analysis of this novel machine layout. Design/methodology/approach - The selection and finite-element optimisation of the permanent-magnet array is presented. The machine is then modelled using magnetic circuit theory. By simultaneously solving the system of equations, a demonstrative design is developed and simulated so as to validate the mathematical model and compare the performance of the new layout with a traditional layout. Findings - A surface-mounted magnetic array, with unshaped-poles, is most suitable for the proposed layout. The mathematical model exhibits a suitable level of accuracy for design and analysis purposes. The calculated resultant force differs from the FEA calculation by 1.85 per cent. A higher force-density is exhibited by the proposed layout, when compared with flat layouts, with a reduction of 36.5 per cent in the spatial footprint and magnetic material of the machine. Research limitations/implications - Although the research is focused on the application of wave-energy conversion, the techniques are application-independent. However, certain design decisions should be reviewed for other applications. Practical implications - The practical implementation of such a machine poses many mechanical obstacles. These have been solved in theory, and are being implemented at the time of writing. Originality/value - The combination of a double-sided and a tubular layout has not previously been researched. This research fills that void and provides designers with the technical background and a mathematical model for development of such devices.
electric machines electromagnetism waves