Fuzzy Controller-Based Intelligent Operation of Grid-Connected DFIG During Recurring Symmetrical Faults

Abstract

The grid-connected doubly fed induction generator (DFIG) can get adapted to modern grid rules to maintain synchronism and stability during disturbances if controlled by good control strategy. Every country framed certain grid rules such that in general the DFIG has to be in synchronism for approved time period during low voltages is called low voltage ride through (LVRT). Hence, for better power transfer capability and guarantee transient and dynamic stability margin improvement, enhanced FOC (EFOC) is proposed in the RSC of DFIG converter. The inner fast control loops are controlled using fuzzy controller with an aim to better voltage compensation, electromagnetic oscillations damping, and surge currents limit. This further leads to continued operation of DFIG under voltage sags. The proposed EFOC method helps in superior reactive power control with enhanced stability of current and voltage waveforms from rotor and stator to grid disturbance. The system behavior with recurring symmetrical low-voltage fault with decrease in voltage by 30 and 60% of the rated voltage happening at the point of common coupling (PCC) between 1–1.5 s and 2.5–3 s is analyzed using simulation studies.