A New Method for Design and Optimization of DFIG for Wind Power Applications

Doubly fed induction generator (DFIG) is one of the important generators that is used in the wind turbines structure. In the previous years, DFIGs based wind turbine system that have installed in the onshore and offshore wind farms have more number than other generators. In this paper, a new method has been presented for design and optimization of a 500 kW DFIG. At first, equations of the optimal design are reviewed for this generator, and then a model is presented for the study of the generator operation. The detailed design of DFIG is done and finite element analysis (FEA) is used to verify the design. In the following, a link is created by a software between FEA tool and genetic algorithm (GA) that is used for optimization. In each iteration, input parameters are changed by GA and is sent to FEA tool for calculation of cost functions. In other words, GA presents a new rotor, and stator slot dimension in each iteration and effect of these parameters is checked on generator operation by FEA tool, e.g., Ansys Maxwell Software. Input parameters that are created the best cost functions are selected as optimized parameters. Rotor and stator slots dimension have been selected as input parameters and cost functions are efficiency, rotor copper loss, and electromagnetic torque. In the results section, a comparison is done between analytical design and FEA design and then output wave of designed DFIG is proposed. In the following, sensitivity analysis is presented that is a study about effect of changing slot dimension on DFIG parameters. Finally optimization results are proposed for each cost function. Results show effectiveness of the proposed method, i.e., we can improve output parameters of DFIG via changing slot dimension.