Brushless doubly fed induction generator control using complex fuzzy logic controllers

Among the various alternatives to traditional generators, the brushless doubly fed induction machine (BDFIM) is particularly well suited for variable-speed applications. However, advanced control strategies are required to fully exploit its capabilities. This study therefore proposes a novel cascaded field-oriented control (FOC) strategy incorporating complex fuzzy logic controllers (CFLCs). The primary objective of this approach is to introduce complex-valued control while reducing the overall dimensionality of the control scheme by exploiting both the magnitude and phase components of the complex control parameters. To assess the effectiveness of the proposed CFLC structure, simulations were carried out in the MATLAB/SIMULINK environment on a BDFIM system combined with a Maximum Power Point Tracking (MPPT) algorithm for wind energy generation. The results demonstrate clear and significant advantages over a standard Complex Proportional Integral (CPI) controller. The CFLC achieves a more efficient trajectory in the complex plane, reflecting smoother and more direct transitions. Additionally, it exhibits reduced power coupling and overshoot, an accelerated phase response, and enhanced voltage regulation, which may mitigate equipment stress. These findings underscore the effectiveness of the CFLC and highlight promising alternatives, thereby providing a strong impetus for continued research in the emerging domain of complex fuzzy control.