Application of Particle Swarm Optimization in the Design of Halbach Permanent Magnet Synchronous Generators for Megawatt Level Wind Turbines

In this paper particle swarm optimization (PSO) is used to optimize a permanent magnet synchronous generator (PMSG) for use in megawatt level wind turbines. The PMSG unitizes Halbach Array as the arrangement of choice for its surface mounted rare earth magnetic pole pieces. Halbach array is expected to produce the same amount of flux density with less magnet mass than conventional array. The PMSG will be directly driven; therefore, it is expected to be large, heavy, and expensive. The aim of this research is to utilize Halbach array and PSO as means to reduce the cost and size of wind turbine direct-driven PMSGs. Machine dimensions and characteristics are outlined as well as the optimization process. The optimization process is run with three different optimization goals to produce three different Halbach PMSGs. First, the objective function is designed to reduce cost alone. PSO is to work with machine dimensional parameters to produce as low cost as possible a machine with as small a size without compromising basic design and electromagnetic requirements expected from such machines. Second, the objective function will then be adjusted to offer optimization with emphasis on efficiency as well as cost, and new results would be produced. finally, the optimization goal is readjusted again to optimize for efficiency alone regardless of the initial cost. Therefore, three differently optimized Halbach PMSGs are outlined, discussed, and compared in this paper, which highlights the capabilities of the optimization method.