Design and analysis of a dual stator spoke type linear vernier machine for wave energy extraction

In general, the conventional permanent magnet (PM) linear machine can reduce the energy conversion steps by eliminating the rotary to linear conversion mechanism which in turn reduces the maintenance cost in the wave energy extraction, while it suffers from bulky size due to a large number of poles for low speed operation. Therefore, the permanent magnet linear vernier machine has been regarded as a suitable alternative, which can produce high thrust force at low speed by using the “magnetic gearing effect”. In this paper, a dual stator spoke type linear vernier machine (DSSLVM) for the wave energy extraction application is proposed, which produces a competitively high thrust force and force density at low operation speed. To predict the performance of the proposed machine in perspective, the transient 2D finite element method (FEM) is utilized and main performance is compared with a presented linear primary permanent magnet vernier machine (LPPMVM).