A hybrid fuzzy with feedback integral phase locked loop-based control strategy for unified power quality conditioner

This paper proposes a hybrid fuzzy control strategy comprising both Takagi-Sugeno fuzzy and Mamdani fuzzy along with novel feedback integral phase-locked loop based modified synchronous reference frame for unified power quality conditioner for power quality enhancement in power distribution network. The hybrid fuzzy controller can vary the gain nonlinearly for controlling dc-bus capacitor voltage of unified power quality conditioner, which limits the dc-bus voltage deviations during the load and supply voltage turbulences. Moreover, the proposed novel feedback integral phase-locked loop system is employed to improve the grid synchronization performance of unified power quality conditioner by considering the feedback integral loop and nonlinear adaptive-filter type phase detector approach. As a consequence, the proposed feedback integral phase-locked loop system can extract the positive sequence signal perfectly during power system disturbances. Additionally, the novelty of modified synchronous reference frame control technique relies upon nonintervention with low pass filter as well as high pass filter. Hence, the proposed control technique quickly and accurately extracts the reference signal from the distorted power system. The efficacy of the proposed control technique is justified through a real-time Opal-RT Hardware underneath different states of power system and compared with both conventional modified phase locked loop system and Takagi-Sugeno fuzzy with synchronous reference frame-based control system.