The effect of the magnet placement for an internal permanent magnet wave energy converter generator

In this paper the effect of the magnet placement on the torque generaton of an internal permanent magnet (IPM) machine used as a WEC generator is investigated. Firstly, a v-shaped IPM machine is used as an initial WEC generator and the generator operation is established for a selected wave climate, through simulations. In order to evaluate the effect of the magnet placement and configuration, four sweep cases which have several stages are analysed. The generator behavior is obtained using finite element analysis (FEA) calculations. The v-shaped magnet sweeps indicate that placing the permanent magnets closer to the airgap result in torque improvement, therefore the inset magnet configuration is also evaluated. The inset design provide a torque improvement of up till 15% compared with the initial WEC generator. When the inset generator used as the WEC generator, the current value to reach the maximum operation point decreases approximately 14%, which in turn improves the total WEC electrical system losses by 23% for the maximum operating point.