Separated magnet yoke for permanent magnet linear generator for marine wave energy converters

•We model direct drive permanent magnet linear generators for wave energy converters.•We review the magnetic forces and the electrical output power.•We suggest new optimised design for direct drive linear generator.•The optimisation aims reduction of forces parallel and normal to axis of motion.•The optimisation aims increase of the electrical power output.

In this paper the performance of a longitudinal flux permanent magnet linear generator (PMLG) for wave energy converters (WEC) is investigated. The influence of the number of slots per pole, phase q and the number of stator's winding sections are analysed. The power output and the cogging forces in the PMLG are calculated and reviewed with respect to the above design parameters. In addition, an optimised PMLG model is designed and simulated. Three-dimensional Finite Element Method (FEM) is used for solving the combined field and circuit equations of the generator.