DStatCom regulation by a fuzzy segmented PI controller

This paper presents a segmented PI controller for the 84-pulses DStatCom connected to the electric power system (EPS) and subjected to several common disturbances in voltage and load levels. The 84-pulses signal is obtained by combining one twelve-pulses voltage source converter (VSC) with an asymmetric single-phase seven-level converter, adding an injection transformer. This structure allows a reduced VSC output's total harmonic distortion. The synchronizing strategy ties the DStatCom to the EPS in an automatic way, preventing phase and frequency problems. PI controllers exhibit good performance around nominal conditions but they do not tolerate severe disturbances. Thus, a segmented PI strategy based on the error and error's variation is utilized and selected according to fuzzy rules. Simulations demonstrate the appropriateness of the proposal.