Performance Enhancement of UPQC Using Takagi–Sugeno Fuzzy Logic Controller

This paper proposes Takagi–Sugeno (TS) fuzzy logic controller for three-phase four-wire unified power quality conditioner (UPQC). Here, TS fuzzy controller uses numerical consequent rule, which can be either a linear expression or a constant. In this premise, the efficiency of the proposed controller with linear consequent rules is analyzed for DC-link voltage regulation and hysteresis band calculation of both shunt and series voltage source inverters. Mamdani-type fuzzy logic controller has limitation in providing a broad range of variation in gaining control over UPQC to solve various power quality problems during load transients and source voltage fluctuations. The proposed controller provides a wide range of variation in gaining control, which results in improved tracking performances of UPQC during the transient, unbalanced load and distortions which are observed in the power system. Synchronous reference frame theory is implemented with two steps, viz., Generation of current reference signal and Generation of reference voltage signal. TS controller reduces the complexity using brief computation, whereas Mamdani system involves several fuzzy rules that makes it complicated. To control hysteresis band for shunt and series inverters, the fuzzy logic controller is modeled with the implementation of linear rules. The proposed controller is validated using MATLAB/SIMULINK. Adequate results of comparison with proposed Takagi–Sugeno-type fuzzy controller and Mamdani-type fuzzy controller are reported.