Cogging force alleviation in linear permanent magnet generators

In this paper a three-phase linear permanent magnet generator is designed for direct waves energy conversion. Its performance is then simulated using analytical and finite element method. Cogging force in this generator causes the oscillatory output power, shortens life time and increases the maintenance cost of the generator. Effects of design parameters including permanent magnet (PM) length, skewed stator teeth, radial PMs and use of stator semi-closed and open-slot on cogging force are investigated and results of simulations presented. The attempt is made to minimize this force by varying the above-mentioned design parameters. The reduction of cogging force includes: 80% by PM length reduction, 90% by a proper skewing angle and 34% by using semi-closed slots are shown.