Design Optimization and Performance Evaluation of Hybrid Excited Low Speed Aero-generator

This study presents an optimal design of a low-speed aero generator based on the approach of associating geometric parameterization with electromagnetic performance evaluation. The optimal topology of the hybrid excited flux switching (HEFS) generator is dedicated to low-wind speed ranges. The machine is analyzed by the 2-D finite element method (FEM) and the influence of different excitation currents on the saturation state of the magnetic circuit is investigated. Sensitivity analyses of the Form Factor (FF), as well as the Flux Excursion Factor (FE), are investigated using the Non-Sorting Genetic Algorithm (NSGA II) to assess the speed/power limitations of the proposed topology. The two-dimensional FEM of the HEFS generator is used to perform the sensitivity analyses and to establish a multi-objective optimization of the generator for a rated power of 3kW. The multi-objective design optimization leads to trade-off solutions between conflicting objectives (maximizing the generated power and minimizing the basic speed). Three study cases, based on FEA simulations and conventional sequential design strategies, are presented for performance comparison in order to minimize the size of the generator and maximize its performance. By evaluating the criterion of minimizing the generator’s weight, relevant machine candidates of the Pareto front solutions are compared to the initial machine as well as other existing prototypes for small wind turbine generators.