Reduction of cogging force in linear permanent-magnet generators

Although linear permanent-magnet generators (LPMGs) are widely used for converting wave energy into electrical energy, they suffer from large cogging force. The cogging force causes oscillatory output power, which shortens lifetime and increases the maintenance costs of the generators. To reduce this force in the generator, we have designed and simulated a three-phase LPMG for direct wave energy conversion and predicted its performance using the finite-element method. We studied the influence of different design parameters on the cogging force and minimized this force by varying the proposed parameters. The results obtained confirm a large reduction in the cogging force and an enhancement in the generator performance.