A fuzzy self-tuning PI controller for HVDC links

This paper introduces a fuzzy logic-based tuning of the controller parameters for the rectifier side current regulator and inverter side gamma controller in a high voltage direct current (HVDC) power system. A typical point-to-point system has been taken with the detailed representation of converters, transmission links transformers and filters. The current error (and its derivative) and the gamma error (and its derivative) are used as the principal signals to adjust the proportional and integral gains of the rectifier pole controller and the inverter gamma controller, respectively, for optimum HVDC power system performance under various normal and abnormal conditions. Finally, a comparative study has been performed with and without tuning, to prove the superiority of the proposed control scheme